Metered snuff back for material dispense

Abstract

A dispenser is configured to emit a material on a substrate. The dispenser includes a dispense valve that controls material flow to a material outlet through which the material is emitted. A snuff back assembly is disposed downstream of the dispense valve and upstream of the material outlet. The snuff back assembly pulls material from downstream of the snuff back valve back upstream to prevent undesirable emission of the material after a dispense is complete.

Description

[0001]

[0002] METERED SNUFF BACK FOR MATERIAL DISPENSE CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No.

[0003] 63 / 753,017 filed February 3, 2025 and entitled “METERED SNUFF BACK FOR MATERIAL DISPENSE,” and claims priority to U.S. Provisional Application No.

[0004] 63 / 796,764 filed April 29, 2025 and entitled “METERED SNUFF BACK FOR MATERIAL DISPENSE,” the disclosures of which are hereby incorporated by reference in their entireties.

[0005] BACKGROUND

[0006] The present disclosure concerns fluid dispense. More specifically, the present disclosure concerns valving for fluid dispense.

[0007] Material dispensers are configured to emit a material for application on a substrate. The material can be a single component material or a plural component material, formed by mixing multiple constituent components together. Material dispensers include an orifice through which the material is dispensed for application on the substrate. A dispense valve can control flow of the material to the orifice for dispensing. Emission of the material is stopped by shutting the dispense valve. After shutting the dispense valve, the material near the orifice can drip or ooze from the orifice, leading to undesirable material waste and mess.

[0008] SUMMARY

[0009] According to an aspect of the present disclosure, a material dispenser includes a first dispense valve actuatable between a first dispense open state and a first dispense closed state; a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; and a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state.

[0010] According to an additional or alternative aspect of the present disclosure, a material dispenser configured to apply a plural component material on a substrate includesa first dispense valve actuatable between a first dispense open state and a first dispense closed state; a second dispense valve actuatable between a second dispense open state and a second dispense closed state; a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; a second material flowpath extending between the second dispense valve and a second material orifice through which a second material is output from the second material flowpath; a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state; a second snuff back assembly fluidly connected to the second material flowpath at a location downstream of the second dispense valve and upstream of the dispense orifice, the second snuff back assembly actuatable between a second snuff back open state and a second snuff back closed state, wherein the second snuff back assembly is configured to draw the second material upstream and away from the second material orifice as the second snuff back assembly is actuated from the second snuff back closed state to the second snuff back open state; and a mix assembly configured to receive the first material from the first material flowpath and configured to receive the second material from the second material flowpath, the mix assembly including a dispense orifice through which the plural component material formed by mixing of the first material and the second material is emitted.

[0011] According to another additional or alternative aspect of the disclosure, a dispense system includes a material dispenser; a support on which the material dispenser is mounted, the support configured to move the material dispenser to position the material dispenser relative to a substrate; and a position controller configured to control movement of the support to position the material dispenser. The material dispenser includes a first dispense valve actuatable between a first dispense open state and a first dispense closed state; a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; and a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closedstate, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state. The first snuff back assembly is actuated between the first snuff back open state and the first snuff back closed state based on position information from the position controller.

[0012] According to yet another additional or alternative aspect of the disclosure, a material dispenser configured to apply a plural component material on a substrate includes a first dispense valve actuatable between a first dispense open state and a first dispense closed state; a second dispense valve actuatable between a second dispense open state and a second dispense closed state; a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; a second material flowpath extending between the second dispense valve and a second material orifice through which a second material is output from the second material flowpath; a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state; a second snuff back assembly fluidly connected to the second material flowpath at a location downstream of the second dispense valve and upstream of the dispense orifice, the second snuff back assembly actuatable between a second snuff back open state and a second snuff back closed state, wherein the second snuff back assembly is configured to draw the second material upstream and away from the second material orifice as the second snuff back assembly is actuated from the second snuff back closed state to the second snuff back open state; a mix assembly configured to receive the first material from the first material flowpath and configured to receive the second material from the second material flowpath, the mix assembly including a dispense orifice through which the plural component material formed by mixing of the first material and the second material is emitted and the mix assembly including a mixer disposed within a mix housing; a motor connected to the mixer and configured to drive rotation of the mixer; and a controller operatively connected to the first snuff back assembly, the second snuff back assembly, the first dispense valve, the second dispense valve, and the motor. The controller is configured to, during a dispense event, stop the motor to stop rotation of the mixer; cause the first dispense valve to actuateto the first dispense closed state after the motor is stopped; cause the second dispense valve to actuate to the second dispense closed state after the motor is stopped: and cause the first snuff back assembly to actuate to the first snuff back open state and the second snuff back assembly to actuate to the second snuff back open state after the first dispense valve is in the first dispense closed state and the second dispense valve is in the second dispense closed state.

[0013] According to yet another additional or alternative aspect of the disclosure, a method of dispensing a plural component material includes opening a first dispense valve to allow a flow of a first constituent material downstream to a mix assembly including a mixer within a mix housing and opening a second dispense valve to allow a flow of a second constituent material downstream to the mix assembly: activating a motor to cause rotation of the mixer within the mix housing; outputting the first constituent material from a first snuff back assembly and into the flow of the first constituent material and outputting the second constituent material from a second snuff back assembly and into the flow of the second constituent material; stopping rotation of the motor to stop rotation of the mixer with the first dispense valve and the second dispense valve open; closing the first dispense valve and the second dispense valve based on a first delay after the motor stops; and drawing the first constituent material upstream from the mix assembly by the first snuff back assembly and drawing the second constituent material upstream from the mix assembly by the second snuff back assembly after the first dispense valve and the second dispense valve are closed.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a dispense system.

[0015] FIG. 2 is a block diagram of a dispense system mounted on a support. FIG. 3 is a cross-sectional view of a material dispenser.

[0016] FIG. 4 is an isometric view of a dispense system.

[0017] FIG. 5 is a schematic diagram of a dispense control scheme.

[0018] DETAILED DESCRIPTION

[0019] The present disclosure relates generally to material dispensers. The material dispenser is configured to output material from a dispense orifice. The material can be provided to the material dispenser under pressure, which pressure is configured to drive the material to and through the dispense orifice. The material dispenser includes a dispense valve that is actuatable between a dispense open state and a dispense closed state. The material can flow downstream past the dispense valve and to the dispense orifice foremission from the material dispenser with the dispense valve in the dispense open state. The material is prevented from flowing downstream past the dispense valve with the dispense valve in the dispense closed state. The material dispenser further includes a snuff back assembly fluidly connected to a material flowpath of the material dispenser at a location downstream of the dispense valve. The snuff back assembly is actuatable between a snuff back open state and a snuff back closed state.

[0020] The snuff back assembly of the material dispenser is configured to draw the material upstream and away from the dispense orifice as the snuff back valve transitions from the snuff back closed state to the snuff back open state. The snuff back assembly pulling the material upstream and away from the dispense orifice prevents undesirable material emission when the dispense valve is in the dispense closed state. The snuff back assembly can thereby prevent undesirable oozing or dripping of the material from the dispense orifice after a dispense is completed and with the dispense valve in the dispense closed state.

[0021] According to various aspects of the disclosure, the snuff back assembly can be adjustable to control a volume of material drawn upstream. The material volume drawn by the snuff back assembly can, in various examples, be set based on a target dispense rate for the material dispenser.

[0022] In additional or alternative examples, the displacement rate of the snuff back assembly can be actively controlled. The snuff back assembly can be controlled to dispense material back into the material flowpath at a location upstream of the dispense orifice during a subsequent dispense. In various examples, the snuff back assembly can be controlled to dispense the material into the material flowpath based on a target dispense rate of the material from the material dispenser. In additional or alternative examples, the snuff back assembly can be controlled to dispense the material into the material flowpath based on a target mix ratio between constituent materials forming a plural component material. In some additional or alternative examples, the snuff back assembly can be configured to displace at different rates between opening of the snuff back assembly and closing of the snuff back assembly.

[0023] According to additional or alternative aspects of the disclosure, the material dispenser can include a controller configured to control actuation of the dispense valve and / or the snuff back valve. The controller can be configured to control actuation of the dispense valve between respective open and closed states separately from controlling actuation of the snuff back assembly between respective open and closed states. In variousexamples, the controller can be configured to control actuation of the snuff back assembly to the snuff back open state based on the state of the dispense valve. For example, the controller can cause the snuff back assembly to actuate to the snuff back open state based on the dispense valve having closed.

[0024] According to additional or alternative aspects of the disclosure, the valving of the material dispenser can be controlled based on a position of a carrier that supports the material dispenser. For example, the material dispenser can be mounted on a robotic carrier (e.g., a robotic arm such as a multi-axis robotic arm) that positions the dispense orifice relative to the substrate for material dispensing. A controller can be configured to control operation of the carrier to control positioning of the dispense orifice. The same or a different controller can be configured to control operation of the snuff back assembly such that the snuff back assembly is operated, at least in part, based on the position of the dispense orifice.

[0025] According to some aspects of the disclosure, the material dispenser can be configured to emit a plural component material, which plural component material can be formed from mixing two or more constituent materials that chemically interact to form the plural component material. The material dispenser can include a dispense valve associated with the flow of each constituent material and can include a snuff back valve associated with the flow of each constituent material. The snuff back assemblies associated with each constituent material can be controlled independently of the snuff back assemblies associated others of the constituent materials

[0026] Components can be considered to radially overlap when those components are disposed at common axial locations along an axis. A radial line extending from the axis will extend through each of the radially overlapping components. Components can be considered to axially overlap when those components are disposed at common radial and circumferential locations relative to an axis such that an axial line parallel to the axis extends through the axially overlapping components. Components can be considered to circumferentially overlap when aligned about the axis, such that a circle centered on the axis passes through the circumferentially overlapping components.

[0027] FIG. l is a block diagram showing dispense system 10. Dispense system 10 includes material dispenser 12, material supply 14, feed pump 16, and controller 18. Material dispenser 12 includes dispenser body 20, dispense valve 22, snuff back assembly 24, dispense orifice 26, and material pathway 28. Snuff back assembly 24 includes holdingchamber 30, plunger 32, displacer 34, and stroke adjustor 36. Control circuitry 40. memory 42, and user interface 44 of controller 18 are shown.

[0028] Dispense system 10 is configured to output a material for application on a substrate. Material supply 14 is configured to store a supply of the material for application on the substrate. While a single material supply is shown, it is understood that not all examples are so limited. For example, dispense system 10 can be configured as a plural component system in which a plural component material formed by mixing two or more constituent materials together is emitted for application on the substrate. In such an example, the dispense system 10 can include a material supply 14 associated with each constituent material. The constituent materials are separately stored and pumped to material dispenser 12 and are mixed downstream of the valving in material dispenser 12 to form the plural component material.

[0029] Feed pump 16 is configured to drive material downstream from material supply 14 to material dispenser 12 under pressure. Feed pump 16 can be of any configuration suitable for displacing material under pressure, such as a piston pump, diaphragm pump, gear pump, progressive cavity pump, among other options. It is understood that in various examples the dispense system 10 can include one or more additional pumps disposed downstream of feed pump 16 and upstream of material dispenser 12 that can increase the pressure of the material output by feed pump 16, decrease the pressure of the material output by feed pump 16, and / or meter the flow output by feed pump 16 and provided to material dispenser 12.

[0030] Material dispenser 12 is configured to emit the material onto a substrate. Material dispenser 12 includes dispenser body 20 that can be connected to, supports, and / or contains various other components of material dispenser 12. It is understood that dispenser body 20 can be formed from one or multiple component parts that are fixed together.

[0031] Material dispenser 12 includes dispense orifice 26 through which material is emitted from material dispenser 12 for application on the substrate. The dispense orifice 26 can, in various examples, be configured to emit a jet of material, a stream of material, a spray of material, beads of material, among other options.

[0032] Material pathway 28 is disposed in dispenser body 20. Material pathway 28 extends downstream from dispense valve 22. Material pathway 28 extends from dispense valve 22 to a material orifice 38 through which the material is output from material pathway 28. In some examples, the material orifice 38 is the same orifice as the dispense orifice 26 from which material is output from material dispenser 12. In some examples, such as inplural component systems, the material orifice 38 can be disposed upstream of the dispense orifice 26 through which the plural component material is emitted.

[0033] Dispense valve 22 is disposed upstream of material orifice 38. Dispense valve 22 is configured to control flow of material to the dispense orifice 26 for emission from the dispense orifice 26. Dispense valve 22 is actuatable between a dispense open state and a dispense closed state. With dispense valve 22 in the dispense open state, the material can flow through dispense valve 22 and the material pathway 28 to dispense orifice 26 for emission from material dispenser 12. With dispense valve 22 in the dispense closed state, the material is prevented from flowing through dispense valve 22 to the material pathway 28. Dispense valve 22 can be of any desired configuration suitable for controlling flow of the material to material orifice 38. Dispense valve 22 can be an actively controlled valve that is actively caused to actuate between the dispense open and dispense closed states. Dispense valve 22 can be controlled pneumatically, hydraulically, or electrically.

[0034] Snuff back assembly 24 is fluidly connected to portion of the material pathway 28 disposed downstream of dispense valve 22 and upstream of material orifice 38. Snuff back assembly 24 is fluidly connected to material pathway 28 at a location upstream of dispense orifice 26. Snuff back assembly 24 can be referred to as a snuff back valve. Snuff back assembly 24 can be configured as a syringe among other options. Snuff back assembly 24 is actuatable between a snuff back open state and a snuff back closed state. Snuff back assembly 24 is configured to draw material upstream from dispense orifice 26 as snuff back assembly 24 actuates from the snuff back closed state to the snuff back open state. Snuff back assembly 24 can store a reserve volume of the material with the snuff back assembly 24 in the snuff back open state. Snuff back assembly 24 can be configured to output the reserve volume of the material to the material pathway 28 as the snuff back assembly 24 is actuated from the snuff back open state to the snuff back closed state.

[0035] Snuff back assembly 24 includes holding chamber 30 that material is drawn into as snuff back assembly 24 transitions to the snuff back open state. The holding chamber 30 can store the reserve volume of the material. The snuff back assembly 24 can be configured to output the reserve volume into the material pathway 28 during a subsequent dispense event such that that material is output through dispense orifice 26.

[0036] In the example shown, snuff back assembly 24 includes plunger 32 that is movable to transition snuff back assembly 24 between the snuff back open and snuff back closed states. Displacer 34 is connected to plunger 32 and configured to displace plunger 32. Displacer 34 can be of any type suitable for causing displacement of plunger 32. Forexample, displacer 34 can be pressure actuated, mechanically actuated, and / or electrically actuated. In some examples, displacer 34 is configured as a piston head configured to be displaced by pressure, such as compressed gas or non-compressible hydraulic oil. In some examples, displacer 34 is configured as a solenoid or other electronic actuator.

[0037] In various examples, the snuff back assembly 24 is configured such that the volume of the holding chamber 30 is adjustable. The volume of the holding chamber 30 with the snuff back assembly 24 fully open can be adjusted to change the reserve volume that is drawn by the snuff back assembly 24. Such a configuration allows for the reserve volume to be set depending on the particular needs of the dispense event.

[0038] In the example shown, snuff back assembly 24 includes stroke adjustor 36. Stroke adjustor 36 is configured to set the distance that plunger 32 can move between the snuff back closed state and the snuff back open state. Stroke adjustor 36 can thereby set the volume of material that snuff back assembly 24 pulls upstream and away from material orifice 38. In various examples, the stroke adjustor 36 can be configured to physically inhibit movement of the plunger 32 to thereby set the opening distance of the snuff back assembly 24.

[0039] In some examples, the stroke adjustor 36 can provide information to controller 18 that informs the controller 18 of the desired opening distance for snuff back assembly 24. The controller 18 can be configured to cause displacer 34 to displace the plunger 32 the desired opening distance, such as by setting an amount of electric cunent provided to a solenoid forming displacer 34, among other options.

[0040] Stroke adjustor 36 can be accessible from an exterior of snuff back assembly 24. In such an example, the user can access stroke adjustor 36 and manipulate stroke adjustor 36 to set the desired opening distance of the snuff back assembly 24.

[0041] Controller 18 is configured to store software, implement functionality, and / or process instructions. Controller 18 is configured to perform any of the functions discussed herein, including receiving an output from any sensor referenced herein, detecting any condition or event referenced herein, and controlling operation of any components referenced herein. Controller 18 can be of any suitable configuration for controlling operation of the pumps within system 10, controlling operation of dispense valve 22 and / or snuff back assembly 24, gathering data, processing data, etc. Controller 18 can include hardware, firmware, and / or stored software, and controller 18 can be entirely or partially mounted on one or more circuit boards. Controller 18 can be of any type suitable for operating in accordance with the techniques described herein. While controller18 is illustrated as a single unit, it is understood that controller 18 can be disposed across one or more discrete control units. In some examples, controller 18 can be implemented as a plurality of discrete circuitry subassemblies.

[0042] Controller 18 is operatively connected to dispense valve 22 and can control actuation of dispense valve 22 between the dispense open and dispense closed states. Controller 18 is operatively connected to snuff back assembly 24 and can control actuation of snuff back assembly 24 between the snuff back open and snuff back closed states. Controller 18 can be operatively connected to the dispense valve 22 and / or the snuff back assembly 24 to control actuation of the dispense valve 22 and / or snuff back assembly 24. It is understood that controller 18 can be considered to be operatively connected to the dispense valve 22 and / or snuff back assembly 24 by controlling operation of components that actuate dispense valve 22 and / or snuff back assembly 24, such as valving configured to control pressurized flow (e.g., compressed gas, non-compressible hydraulic oil, etc.) for actuating dispense valve 22 and / or snuff back assembly 24, a solenoid configured to electrically actuate the dispense valve 22 and / or snuff back assembly 24, etc.

[0043] Memory 42 is configured to store software that, when executed by control circuitry 40, controls dispense valve 22 and / or snuff back assembly 24. For example, control circuitry 40 can include one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other equivalent discrete or integrated logic circuitry.

[0044] Memory 42, in some examples, is described as computer-readable storage media. In some examples, a computer-readable storage medium can include a non-transitory medium. The term “non-transitory” can indicate that the storage medium is not embodied in a carrier wave or a propagated signal. In certain examples, a non-transitory storage medium can store data that can, over time, change (e.g., in RAM or cache). In some examples, memory 42 is a temporary memory, meaning that a primary purpose of memory 42 is not long-term storage. Memory 42, in some examples, is described as volatile memory, meaning that memory 42 does not maintain stored contents when power to controller 18 is turned off. Examples of volatile memories can include random access memories (RAM), dynamic random access memories (DRAM), static random access memories (SRAM), and other forms of volatile memories. Memory 42, in one example, is used by software or applications running on control circuitry 40 to temporarily store information during program execution. Memory 42, in some examples, also includes one or more computer-readable storage media. Memory 42 can further be configured for long-term storage of information. Memory 42 can be configured to store larger amounts of information than volatile memory. In some examples, memory 42 includes non-volatile storage elements. Examples of such non-volatile storage elements can include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories.

[0045] User interface 44 can be any graphical and / or mechanical interface that enables user interaction with controller 18. For example, user interface 44 can implement a graphical user interface displayed at a display device of user interface 44 for presenting information to and / or receiving input from a user. User interface 44 can include graphical navigation and control elements, such as graphical buttons or other graphical control elements presented at the display device. User interface 44, in some examples, includes physical navigation and control elements, such as physically actuated buttons or other physical navigation and control elements. In general, user interface 44 can include any input and / or output devices and control elements that can enable user interaction with controller 18.

[0046] During operation, dispense valve 22 is actuated to the dispense open state to initiate a dispense event during which the material is actively emitted through dispense orifice 26 and the dispense valve 22 is actuated to the dispense closed state to stop the dispense event. The snuff back assembly 24 is operated to prevent undesired dispense of material through dispense orifice 26 between dispense events. Snuff back assembly 24 is configured to draw material upstream from dispense orifice 26 to prevent such an undesired dispense, which undesired dispense can be in the form of the material oozing or dripping from dispense orifice 26.

[0047] Snuff back assembly 24 is configured to increase a volume of a holding chamber 30 of the snuff back assembly 24 as the snuff back assembly 24 is actuated from the snuff back closed state to the snuff back open state. The snuff back assembly 24 is configured to decrease the volume of the holding chamber 30 as the snuff back assembly 24 is actuated from the snuff back open state to the snuff back closed state. Snuff back assembly 24 is configured to generate pressure equalization or negative pressure in the material pathway 28 upstream of dispense orifice 26 that draws material away from dispense orifice 26 and prevents post-dispense dripping or oozing.

[0048] Controller 18 can control operation of dispense valve 22 and / or snuff back assembly 24. During a dispense event, the dispense valve 22 is actuated from the dispenseclosed state to the dispense open state. The snuff back assembly 24 is maintained in the state that the snuff back assembly 24 is in at the initiation of the dispense event, typically the snuff back closed state. With dispense valve 22 in the dispense open state, the material provided to material dispenser 12 can flow past dispense valve 22, flow downstream through material pathway 28, and be emitted through dispense orifice 26. At the end of a dispense event, the dispense valve 22 is actuated back to the dispense closed state to stop flow of the material downstream past dispense valve 22.

[0049] The snuff back assembly 24 is actuated to the snuff back open state at the end of a dispense event. The snuff back assembly 24 being actuated to the snuff back open state increases the volume of the holding chamber 30 in the snuff back assembly 24, drawing the material upstream and away from dispense orifice 26. In this way, the snuff back assembly 24 pulls the material away from dispense orifice 26 and prevents undesired emission of excess material. For example, displacer 34 can move the plunger 32 to increase the volume of the holding chamber 30, thereby creating the pressure differential that draws material upstream and away from dispense orifice 26.

[0050] Controller 18 can be configured to sequence actuation of the dispense valve 22 and snuff back assembly 24 at the end of a dispense event. For example, the controller 18 can be configured to cause the snuff back assembly 24 to begin actuating to the snuff back open state after the dispense valve 22 is actuated to the dispense closed state. With the dispense valve 22 in the dispense closed state, the material upstream of dispense valve 22 is fluidly isolated from the material pathway 28. Actuating the snuff back assembly 24 to the snuff back open state after actuating the dispense valve 22 to the dispense closed state prevents the snuff back assembly 24 from drawing in material from upstream of dispense valve 22. Instead, the snuff back assembly 24 will draw material away from dispense orifice 26.

[0051] Snuff back assembly 24 is configured to hold the material between dispense events. In various examples, the snuff back assembly 24 can hold the material until a subsequent dispense event occurs. In some examples, the material is actually drawn into and held within holding chamber 30. In some examples, the material is held in a pathway between the holding chamber 30 and material pathway 28. At the initiation of a subsequent dispense event, the dispense valve 22 is actuated from the dispense closed state to the dispense open state. The dispense valve 22 actuating to the dispense open state allows material to flow past the dispense valve 22, downstream through material pathway 28, and out through dispense orifice 26.Snuff back assembly 24 can be actuated from the snuff back open state to the snuff back closed state during the dispense event. The plunger 32 can be moved to decrease the volume of the holding chamber 30 and push the material held by snuff back assembly 24 back into the material pathway 28. Such an actuation evacuates the material from within the holding chamber 30 back into the material pathway 28 to be emitted through dispense orifice 26. Snuff back assembly 24 can meter flow of the material back into the material pathway 28 during the subsequent dispense event.

[0052] The controller 18 can be configured to control the actuation rate of snuff back assembly 24. Material dispenser 12 is configured to output the material through dispense orifice 26 based on a target dispense rate, which can be a volumetric flow rate among other options. The controller 18 can be configured to control the actuation rate of the snuff back assembly 24 from the snuff back open state to the snuff back closed state based on the target dispense rate of the material through dispense orifice 26. In some examples, the controller 18 can cause the snuff back assembly 24 to output the material at an output flow rate set based on the target dispense rate. In some examples, the output flow rate can be set equal to the target dispense rate. In some examples, the output flow rate can be set to be less than the target dispense rate. The output flow rate being set equal to or less than the target dispense rate provides for even, consistent emission from the dispense orifice 26 during the dispense event. The output flow rate being set equal to or less than the target flow rate can prevent emission of a large glob of the material at the initiation and during of the dispense event.

[0053] In additional or alternative examples, the controller 18 can be configured to control actuation of the snuff back assembly 24 from the snuff back open state to the snuff back closed state based on the target dispense volume for the dispense event. For example, the controller 18 can be configured to vary the output flow rate based on the target dispense volume. In various examples, the controller 18 can control the output flow rate such that the snuff back assembly 24 actuates fully to the snuff back closed state prior to the end of the dispense event. Such a configuration can provide for full evacuation of material from the snuff back assembly 24, preventing the material from residing in snuff back assembly 24 which can potentially degrade the quality of the material.

[0054] Snuff back assembly 24 provides significant advantages. Snuff back assembly 24 is configured to draw material away from dispense orifice 26 after a dispense event is completed. Drawing the material away from dispense orifice 26 prevents undesirable oozing or dripping of the material from dispense orifice 26, which drippingand / or oozing can apply the material at undesirable locations on the target substrate and cause undesirable mess and material waste.

[0055] Snuff back assembly 24 is controllable independent from the dispense valve 22, providing for precise control and providing high quality material output from material dispenser 12. The snuff back assembly 24 can be actuated between the snuff back open state and the snuff back closed state based on the state of dispense valve 22. Snuff back assembly 24 can be actuated from the snuff back closed state to the snuff back open state after dispense valve 22 is closed, ensuring that material is drawn away from dispense orifice 26 and not from upstream of dispense valve 22.

[0056] The actuation rate of snuff back assembly 24 can be controlled to provide for efficient and effective pulling of material away from dispense orifice 26 and emission of material from snuff back assembly 24 back into material pathway 28. The controller 18 can cause the snuff back assembly 24 to actuate from the snuff back closed state to the snuff back open state at a relatively quick rate, fast enough to draw the material upstream away from dispense orifice 26 without causing cavitation. Such a configuration provides for quick withdraw of the material away from the dispense orifice 26 to prevent oozing and / or dripping. Controller 18 can cause the snuff back assembly 24 to actuate from the snuff back open state to the snuff back closed state based on the target dispense rate and / or target volumetric output for the material. Such a configuration provides for quality, consistent output from dispense orifice 26.

[0057] FIG. 2 is a block diagram of dispense system 10 further showing material dispenser 12 mounted on support 46. In the example shown, the support 46 is configured as a robotic support that is configured to move and position material dispenser 12 for emitting the material. For example, support 46 can be configured as a multi-axis robotic arm, among other options. Support 46 can also be referred to as a carrier.

[0058] Position controller 48 is operatively connected to support 46 and is configured to control operation of support 46 to position the dispense orifice 26 relative to the substrate. Position controller 48 is substantively similar to controller 18 and can include control circuitry, memory, and a user interface as discussed above with regard to controller 18. While position controller 48 is shown as separate from controller 18, it is understood that the functionality attributed to position controller 48 and / or to controller 18 can be implemented by one or a plurality of control devices.

[0059] Controller 18 can be configured to control actuation of dispense valve 22 and snuff back assembly 24 based on the position of support 46. Controller 18 can beconfigured to control actuation of dispense valve 22 and snuff back assembly 24 based on the position of dispense orifice 26, such as the position of dispense orifice 26 relative to the substrate. Controller 18 can be configured to control actuation of one or both of dispense valve 22 and snuff back assembly 24 based on position information from position controller 48. For example, the controller 18 can cause the snuff back assembly 24 to be maintained in the snuff back open state until the dispense orifice 26 is positioned over the target substrate at a location at which the material is meant to be dispensed. In some examples, the controller 18 can cause the snuff back assembly 24 to actuate from the snuff back closed state to the snuff back open state prior to the support 46 moving the dispense orifice 26 away from a portion of the substrate on which the material is meant to be dispensed.

[0060] FIG. 3 is a cross-sectional view of a material dispenser 12. Dispense valves 22a, 22b (collectively herein “dispense valve 22” or “dispense valves 22”), snuff back assemblies 24a, 24b (collectively herein “snuff back assembly 24” or “snuff back assemblies 24”), material pathways 28a, 28b (collectively herein “material pathway 28” or “material pathways 28”), dispense orifice 26, mix assembly 50, and drive 52 of material dispenser 12 are shown. Dispense valves 22 each include valve seat 54, valve seal 56, and dispense actuator 58. Snuff back assemblies 24 each include holding chamber 30, plunger 32, displacer 34, and stroke adjustor 36. Mix assembly 50 includes mixer 60 and mix housing 62. Drive 52 includes motor 64 and drive shaft 66.

[0061] Material dispenser 12 is configured for use in a plural component dispensing system 10 in the example shown in FIG. 3. It is understood, however, that the discussion with regard to FIG. 3 applies equally to a single component dispensing system in which the material provided through a dispense valve 22 is not mixed with another component prior to dispensing. Such a single component dispense system 10 can include dispense valve 22a and snuff back assembly 24a for controlling flow and dispense of the single component material.

[0062] In a plural component dispense system, a first constituent material and a second constituent material are provided to mix assembly 50 and mixed within mix assembly 50 to form a plural component material that is output through dispense orifice 26. The plural component material can be configured to be applied in any desired manner, such as by spraying, by bead application, as a stream, etc. The constituent materials are pumped according to target parameters, such as ratio, temperature, flow rate and / or pressure. The first and second constituent materials are mixed in mix assembly 50 to form the plural component material that is applied to the substrate by material dispenser 12. The resultantplural component material can form an adhesive, a sealant, a foam (e.g., to form gaskets or other components), among other options.

[0063] The constituent materials are individually pumped to material dispenser 12 and are not combined upstream of mixer 60. The constituent materials are configured to react (e.g., chemically react) to form the plural component material. The resultant plural component material can be configured as an expansive material that expands after mixing, such as in the case of foam, among other plural component material options. The plural component material is formed in mix assembly 50 upstream of dispense orifice 26 and such expansion can cause the material to drip or ooze through dispense orifice 26 after dispense valves 22a, 22b are closed. Snuff back assemblies 24a, 24b are configured to draw the material away from dispense orifice 26 to prevent such undesired emission of the material through dispense orifice 26.

[0064] The first and second constituent materials are provided to material dispenser 12. Material dispenser 12 can be configured to provide the constituent materials to mix assembly 50 at any desired ratio required to form the plural component material. Some plural component materials are formed by 1:1 mix ratios while others require unbalanced mix ratios such as 2:1, 3:1, 5:1, 10:1, among others. Snuff back assemblies 24a, 24b are initially in respective snuff back closed states such that the plungers 32 are displaced in direction AD2 along the respective displacement axes DA.

[0065] Dispense valve 22a and dispense valve 22b each include a valve seal 56 that is movable relative to a valve seat 54 to actuate the dispense valve 22 between dispense open and dispense closed states. Valve seal 56 can sealingly engage with valve seat 54 to place dispense valve 22 in the dispense closed state. Valve seal 56 is shifted relative to valve seat 54 to disengage from valve seat 54 to place dispense valve 22 in the dispense open state.

[0066] For each dispense valve 22a, 22b, the dispense actuator 58 is connected to the valve seal 56 and configured to displace the valve seal 56 relative to the valve seat 54. In the example shown, the dispense actuator 58 is formed as a piston head that is configured to be pressure actuated to cause displacement of the dispense actuator 58 and thus of valve seal 56. For example, dispense actuator 58 can be acted on pneumatically or hydraulically. The controller 18 (FIGS. 1 and 2) can be configured to control provision of a working fluid (e.g., compressed gas, non-compressible hydraulic oil, etc.) to cause displacement of dispense actuator 58 and thus of valve seal 56. In various other examples, dispense actuator 58 can be configured as an electronic actuator that displaces the valve seal 56 in responseto an electric signal. For example, dispense actuator 58 can be configured as a solenoid, among other options. The controller 18 can be configured to control provision of the electronic actuation signal to the dispense actuator 58 to cause displacement of valve seal 56.

[0067] Material pathway 28a extends downstream from the interface between the valve seal 56 and valve seat 54 of dispense valve 22a. Material pathway 28a is configured to convey the first constituent material downstream from dispense valve 22a to mix assembly 50. Material pathway 28a outputs the first constituent material through material orifice 38a. Material pathway 28b extends downstream from the interface between the valve seal 56 and valve seat 54 of dispense valve 22b. Material pathway 28b is configured to convey the second constituent material downstream from dispense valve 22a to mix assembly 50. Material pathway 28b outputs the second constituent material through material orifice 38b. In the example shown, material orifices 38a, 38b are disposed upstream of the dispense orifice 26 through which the plural component material is output. In the example shown, the material pathways 28a, 28b do not combine or cross-over at locations upstream of mix assembly 50. As such, the first and second constituent materials remain fluidly separated at locations upstream of the mix assembly 50. The first and second constituent materials do not mix at locations upstream of material orifices 38a, 38b.

[0068] Mix assembly 50 is connected to the dispenser body 20. Mix assembly 50 is configured to receive the first and second constituent materials and mix the constituent materials together to form the plural component material. In the example shown, mix housing 62 is mounted to dispenser body 20. Mixer 60 is disposed within mix housing 62. Mixer 60 can include projections, such as fins among other options, that cause blending and mixing of the constituent materials. Mixer 60 can include one or more projections that extend helically, among other options.

[0069] In the example shown, drive 52 is connected to mixer 60 and is configured to cause rotation of mixer 60 within mix housing 62. Drive 52 includes motor 64 that generates a rotational output and drive shaft 66 that extends to and is connected to mixer 60. Rotation of the drive shaft 66 causes rotation of the mixer 60.

[0070] While material dispenser 12 is described as having mixer 60 that is rotated relative to mix housing 62 by drive 52, it is understood that not all examples are so limited. In various examples, the material dispenser 12 does not include a drive 52 and the mixer 60 is not rotated relative to mix housing 62. In such an example, the mixer 60 can remainstationary relative to the mix housing 62. In such a configuration, the material dispenser 12 can be considered to include a static mixer 60.

[0071] Snuff back assembly 24a is fluidly connected to material pathway 28a at a location downstream of dispense valve 22a and upstream of mix assembly 50. Snuff back assembly 24a is fluidly connected to material pathway 28a at a location upstream of material orifice 38a. Material line 68a extends between the assembly body 70a of snuff back assembly 24a and the dispenser body 20 in the example shown. It is understood that in various other examples the snuff back assembly 24a can be directly mounted to or integrated within the dispenser body 20. Snuff back assembly 24b is fluidly connected to material pathway 28b at a location downstream of dispense valve 22b and upstream of mix assembly 50. Snuff back assembly 24b is fluidly connected to material pathway 28b at a location upstream of material orifice 38b. Material line 68b extends between the assembly body 70b of snuff back assembly 24b and the dispenser body 20 in the example shown. It is understood that in various other examples the snuff back assembly 24b can be directly mounted to or integrated within the dispenser body 20. It is understood that the material line 68a can be considered to form at least a portion of the holding chamber 30 of snuff back assembly 24a and the material line 68b can be considered to form at least a portion of the holding chamber 30 of snuff back assembly 24b.

[0072] Each snuff back assembly 24a, 24b includes a plunger 32 that is configured to move within and relative to a cylinder 72 to increase or decrease the volume of the holding chamber 30 of that snuff back assembly 24. In the example shown, the plunger 32 is configured to move along a displacement axis DA to change the size of the holding chamber 30. The plunger 32 moving in axial direction ADI along displacement axis DA increases the volume of the holding chamber 30, drawing material out of material pathway 28a, 28b and away from dispense orifice 26, and the plunger 32 moving in axial direction AD2 along the displacement axis DA decreases the volume of the holding chamber 30, driving material out and back into the material pathway 28a, 28b.

[0073] Snuff back assembly 24a, 24b includes a displacer 34 that is connected to plunger 32 and is configured to displace plunger 32 along the displacement axis DA of its snuff back assembly 24. In the example shown, the displacer 34 is formed as a piston head that is configured to be pressure actuated to cause displacement of the plunger 32. For example, displacer 34 can be acted on pneumatically or hydraulically. The controller 18 (FIGS. 1 and 2) can be configured to control provision of a working fluid (e.g., compressed gas, non-compressible hydraulic oil, etc.) to cause displacement of displacer 34 and thus ofplunger 32. In various other examples, displacer 34 can be configured as an electronic actuator that displaces the plunger 32 in response to an electric signal. For example, displacer 34 can be configured as a solenoid, among other options. The controller 18 can be configured to control provision of the electronic actuation signal to the displacer 34 to cause displacement of plunger 32.

[0074] Stroke adjustor 36 provides for variable volumetric material ingestion by snuff back assembly 24. Stroke adjustor 36 can be actuated to vary a possible displacement distance of the plunger 32. In various examples, the stroke adjustor 36 is configured to physically limit displacement of the plunger 32 in axial direction ADI along the displacement axis DA, thereby limiting the maximum volume of the holding chamber 30 with the snuff back assembly 24 fully open. In the example shown, stroke adjustor 36 includes a limiter rod 74 that is configured to move towards or away from displacer 34 to change the possible opening distance of the snuff back assembly 24. The limiter rod 74 can be accessible from outside of snuff back assembly 24 such that a user can adjust the position of the limiter rod 74 to adjust the possible opening distance of the snuff back assembly 24.

[0075] The reserve volume of snuff back assembly 24a can be set independent of the reserve volume of snuff back assembly 24b. Such a configuration can be particularly advantageous in examples in which the constituent materials are mixed at ratios other than 1:1. The reserve volumes of the snuff back assembly 24a, 24b can be set based on the target ratio of the constituent materials.

[0076] By way of example, a ratio of 2:1 between the first constituent material, flowing through material pathway 28a, and the second constituent material, flowing through material pathway 28b is assumed. In such an example, the reserve volume of the snuff back assembly 24a can be set to be twice the reserve volume of the snuff back assembly 24b. Setting the reserve volumes of the holding chambers 30 of the multiple snuff back assemblies 24a, 24b based on the target mix ratio can maintain the desired mix ratio as the snuff back assemblies 24a, 24b actuate back to the snuff back closed states during a subsequent dispense event.

[0077] Controller 18 (FIGS. 1 and 2) can be configured to individually control actuation of snuff back assemblies 24a, 24b. In some examples, the snuff back assemblies 24a, 24b can be individually controlled for intake and emission of the constituent materials. Controller 18 can, in some examples, individually control actuation of the snuff back assemblies 24a, 24b such that snuff back assemblies 24a, 24b both return to the snuff backclosed state at proximately the same time (e.g., within 0.5 seconds, 0.25 seconds, etc.). In some examples, the controller 18 can be configured to cause the snuff back assemblies 24a, 24b to return to their respective snuff back closed states simultaneously.

[0078] In some examples, controller 18 can be configured to control actuation of the snuff back assemblies 24a, 24b based on the target mix ratio. For example, controller 18 can cause one snuff back assembly 24a, 24b to actuate quicker than the other snuff back assembly 24a, 24b based on an unbalanced mix ratio.

[0079] In some examples, controller 18 can cause one snuff back assembly 24a, 24b to open quicker than the other snuff back assembly 24a, 24b based on an unbalanced mix ratio. In such an example, the controller 18 can cause the snuff back assembly 24a, 24b associated with the higher volume component to actuate from the snuff back closed state to the snuff back open state quicker than the snuff back assembly 24a, 24b associated with the lower volume component. For example, if the mix ratio is 3:1 between the first constituent material (flowed through material pathway 28a) and the second constituent material (flowed through material pathway 28b), then the controller 18 can cause snuff back assembly 24a to actuate open quicker than snuff back assembly 24b. In such an example, the controller 18 can cause snuff back assembly 24a to actuate open three times quicker than snuff back assembly 24b. As such, the controller 18 can be configured to control the fill rates of the snuff back assemblies 24a, 24b proportionally to the target mix ratio.

[0080] In some examples, controller 18 can cause one snuff back assembly 24a, 24b to evacuate quicker than the other snuff back assembly 24a, 24b based on an unbalanced mix ratio. In such an example, the controller 18 can cause the snuff back assembly 24a, 24b associated with the higher volume component to actuate from the snuff back open state to the snuff back closed state quicker than the snuff back assembly 24a, 24b associated with the lower volume component. For example, if the mix ratio is 3:1 between the first constituent material (flowed through material pathway 28a) and the second constituent material (flowed through material pathway 28b), then the controller 18 can cause snuff back assembly 24a to actuate closed quicker than snuff back assembly 24b. In such an example, the controller 18 can cause snuff back assembly 24a to actuate closed three times quicker than snuff back assembly 24b. As such, the controller 18 can be configured to control the evacuation or closing rate of the snuff back assemblies 24a, 24b proportionally to the target mix ratio.During operation, dispense valves 22a, 22b are opened to initiate a dispense event. The first constituent material flows through material pathway 28a and to mix assembly 50 and the second constituent material flows through material pathway 28b and to mix assembly 50. The two constituent materials enter into mix housing 62 and are mixed by mixer 60. In the example shown, the drive 52 causes rotation of mixer 60 to mix the constituent materials and form the plural component material. As discussed above, however, it is understood that mixer 60 can be a static mixer in various other examples. The plural component material is output through dispense orifice 26 and applied to the substrate.

[0081] At the end of the dispense event dispense valves 22a, 22b are actuated to respective dispense closed states. The snuff back assemblies 24a, 24b are actuated to their respective snuff back open states. In the example shown, the plunger 32 of each snuff back assembly 24a, 24b is displaced in axial direction AD 1 to increase the volume of the holding chamber 30 of the snuff back assembly 24a, 24b. The plunger 32 of snuff back assembly 24a shifts in axial direction ADI to actuate the snuff back assembly 24a from the snuff back closed state to the snuff back open state. Such displacement of the plunger 32 can provide a negative or equal pressure to the pressure in mix assembly 50. The first constituent material can be pulled from material pathway 28a into snuff back assembly 24a. The plunger 32 of snuff back assembly 24b shifts in axial direction ADI to actuate snuff back assembly 24b from the snuff back closed state to the snuff back open state. Such displacement of the plunger 32 can provide a negative or equal pressure to that in mix assembly 50. The second constituent material can be pulled from material pathway 28b into snuff back assembly 24b. The two constituent materials being pulled upstream away from material orifices 38a, 38b and dispense orifice 26 pulls the plural component material away from dispense orifice 26, preventing undesired dripping or oozing of material from dispense orifice 26.

[0082] During a subsequent dispense event, the snuff back assemblies 24a, 24b are actuated from respective snuff back open states to respective snuff back closed states. The plungers 32 are displaced in axial direction AD2 and drive the constituent materials out of the snuff back assemblies 24a, 24b and back into material pathways 28a, 28b such that the constituent materials can flow to mix assembly 50 for mixing and formation of the plural component material.

[0083] Material dispenser 12 provides significant advantages. Snuff back assemblies 24a, 24b draw material away from dispense orifice 26 after a dispense event toprevent undesirable emission of the material. Drawing the material upstream and away from dispense orifice 26 minimizes mess and prevents application of the material at locations at which the material is not intended to be dispensed. Preventing undesirable emission also provides material savings by stopping oozing and dripping of the material, preventing material waste.

[0084] Snuff back assemblies 24a, 24b are fluidly connected to the material pathways 28a, 28b at locations upstream of mix assembly 50. Each snuff back assembly 24a, 24b pulls a single constituent material, which in combination draw the plural component material away from the dispense orifice 26. The snuff back assemblies 24a, 24b being associated with the single constituent materials prevents ingestion of the plural component material, which cures, into the snuff back assemblies 24a, 24b. Such a configuration prevents binding and curing in the snuff back assemblies 24a, 24b, providing for consistent operation and reducing maintenance requirements.

[0085] Snuff back assembly 24a can be operated independently from snuff back assembly 24b. Controller 18 can control actuation of snuff back assemblies 24a, 24b based on the target mix ratio for the plural component materials. The controller 18 can cause the snuff back assembly 24a, 24b associated with the higher volume material to actuate to the snuff back open state quicker than the snuff back assembly 24a, 24b associated with the lower volume material, maintaining the ratio during opening of snuff back assemblies 24a, 24b. In additional or alternative examples, controller 18 can cause the snuff back assembly 24a, 24b associated with the higher volume material to actuate to the snuff back closed state quicker than the snuff back assembly 24a, 24b associated with the lower volume material, maintaining the ratio during closing of snuff back assemblies 24a, 24b during a dispense event.

[0086] The reserve volume of the snuff back assemblies 24a, 24b can be set independent from each other. Such a configuration can be particularly advantageous for plural component materials formed at ratios other than 1:1. The reserve volumes of the snuff back assemblies 24a, 24b can be set based on the target mix ratio. The snuff back assembly 24a, 24b associated with the higher volume constituent material can be set to have a greater reserve volume than the snuff back assembly 24a, 24b associated with the lower volume constituent material. Such a configuration can provide for maintaining the desired target mix ratio during a subsequent dispense event as the snuff back assemblies 24a, 24b are actuated back to the respective snuff back closed states, providing for formation of high quality plural component material.FIG. 4 is an isometric view of material dispenser 12. Dispense valves 22a, 22b snuff back assemblies 24a, 24b dispense orifice 26, mix assembly 50, and drive 52 of material dispenser 12 are shown.

[0087] FIG. 5 is a schematic illustration of a control scheme for operation of material dispenser. Line LI illustrates triggering of a dispense event. Line LI shows provision and removal of dispense signal between points Pl, at the initiation of the dispense, and point P2 at the end of the dispense. It is understood that the material dispenser 12 can continue to dispense plural component material after point P2, so long as the dispense valves 22a, 22b are open. In the example shown, the dispense signal can be considered to be provided at point PL A cessation signal is provided at point P2. It is understood that the cessation signal can be formed as a signal separate from the dispense signal or by cessation of delivery of the dispense signal. For example, a trigger can be actuated at point Pl to start a dispense event and the trigger can be released at point P2 to stop the dispense event.

[0088] Line L2 illustrates actuation of dispense valves 22a, 22b open and closed. Dispense valves 22a, 22b are in respective closed states prior to point PL The dispense valves 22a, 22b are configured to shift to respective open states, allowing flow of the individual constituent components downstream to mix assembly 50, at point P3. In the example shown, delay DI is between point Pl at which the dispense signal is provided and point P3 at which the dispense valves 22a, 22b are opened. Delay DI is a temporal delay between the initiation of the dispense event at point Pl and the opening of the dispense valves 22a, 22b at point P3. It is understood that, in various examples, the delay DI is zero such that the dispense valves 22a, 22b are opened at point PL In various other examples, the delay DI is greater than zero.

[0089] Dispense valves 22a, 22b are actuated to respective closed states, blocking further flow of the individual constituent materials through the dispense valves 22a, 22b, to stop dispensing of the plural component material. In the example shown, the dispense valves 22a, 22b are actuated to their respective closed states at point P4. In the example shown, delay D2 is between point P2 at which the dispense signal is removed (or cessation signal actively provided) and point P4 at which the dispense valves 22a, 22b are actuated to respective closed states. Delay D2 is a temporal delay between the end point of the active dispense at point P2 and the closing of the dispense valves 22a, 22b at point P4. Delay D2 is greater than zero such that the dispense valves 22a, 22b remain in respective open states after point P2. With the dispense valves 22a, 22b still in their respective openstates between points P2 and P4, the constituent materials can continue to flow through dispense valves 22a, 22b and mix assembly 50 and the plural component material continues to be dispensed through the dispense orifice 26.

[0090] Line L3 illustrates operation of motor 64 that drives rotation of mixer 60 of mix assembly 50. While activated, the motor 64 can output rotational motion that drives rotation of the mixer 60 within mix housing 62. The rotating mixer 60 blends the individual constituent materials together to form the plural component material. It is understood that the mixer 60 can still blend the individual constituent materials to form the plural component material.

[0091] Motor 64 is deactivated while material dispenser 12 is not dispensing the material. In the example shown, motor 64 is activated at point P5. Point P5 can be the same as point P3 such that motor 64 is activated at the time that the dispense valves 22a, 22b are actuated to their respective open states. In some examples, motor 64 is activated based on opening of dispense valves 22a, 22b. For example, a signal provided by controller 18 to cause dispense valves 22a, 22b to actuate to respective open states can also cause the motor 64 to activate.

[0092] Motor 64 remains activated and drives rotation of the mixer 60 after point P5 and up to point P6. At point P6, the motor 64 is deactivated. At point P6, the motor 64 can brake such that the motor 64 stops rotating, thereby stopping rotation of the mixer 60. In the example shown, point P6 is the same as point P2 when the cessation signal is provided. Between points P6 and P4, the motor 64 is deactivated while the dispense valves 22a, 22b remain in respective open states. With motor 64 deactivated, the mixer 60 is stationary such that mixer 60 operates as a static mixer rather than a dynamic mixer.

[0093] Line L4 illustrates operation of snuff back assemblies 24a, 24b. Snuff back assemblies 24a, 24b are in respective snuff back open states, in which the snuff back assemblies 24a, 24b hold a volume of the individual constituent materials, prior to point PL The snuff back assemblies 24a, 24b are configured to shift from the respective snuff back open states to respective snuff back closed states at point P7. The snuff back assemblies 24a, 24b output the individual constituent materials as the snuff back assemblies 24a, 24b shift to their respective closed states. In the example shown, delay D3 is between point Pl at which the dispense signal is provided and point P7 at which the snuff back assemblies 24a, 24b begin moving towards respective snuff back closed states. Delay D3 is a temporal delay between the initiation of the dispense event at point Pl and the actuation of the snuff back assemblies 24a, 24b at point P7. It is understood that, in various examples, the delayD3 is zero such that the snuff back assemblies 24a, 24b begin emitting material at point Pl . In various other examples, the delay D3 is greater than zero.

[0094] Delay D4 is between point P3 at which the dispense valves 22a, 22b are opened and point P7 at which snuff back assemblies 24a, 24b are actuated towards their respective snuff back closed states. Delay D4 is a temporal delay between the opening of dispense valves 22a, 22b at point P3 and the emission of material from snuff back assemblies 24a, 24b beginning at point P7. Delay D4 can be zero or greater than zero.

[0095] Snuff back assemblies 24a, 24b can reach their fully closed states prior to the end of the dispensing of the material. In such an example, the snuff back assemblies 24a, 24b are maintained in the respective snuff back closed states while the dispensing finishes.

[0096] The snuff back assemblies 24a, 24b are actuated to their respective snuff back open states at point P8. Actuating the snuff back assemblies 24a, 24b to the snuff back open states pulls material into the snuff back assemblies 24a, 24b and upstream away from dispense orifice 26. In the example shown, delay D5 is between point P2 at which the dispense signal is removed (or cessation signal actively provided) and point P8 at which the snuff back assemblies 24a, 24b are actuated to respective snuff back open states. Delay D5 is between point P6 at which motor 64 is deactivated and point P8 at which snuff back assemblies 24a, 24b are actuated to draw material upstream away from dispense orifice 26. Delay D5 is a temporal delay between the end point of the active dispense at point P2 and the pulling back of material by snuff back assemblies 24a, 24b at point P8. Delay D5 is greater than delay D2 such that snuff back assemblies 24a, 24b are actuated to their respective snuff back open states after closing of the dispense valves 22a, 22b.

[0097] During a dispense event, the individual constituent materials flow downstream to mix assembly 50 while dispense valves 22a, 22b are open. The motor 64 driving rotation of the mixer 60 provides for efficient blending of the constituent materials to form the plural component material. The snuff back assemblies 24a, 24b pulling material away from dispense orifice 26 prevents dripping or oozing of material. It is desirable that the snuff back assemblies 24a, 24b do not pull the blended plural component material upstream into passages configured to convey the individual materials, as the plural component material can cure and block such flowpaths.

[0098] The motor 64 is disabled prior to closing of the dispense valves 22a, 22b. Stopping the motor 64 stops rotation of the mixer 60. The dispense valves 22a, 22b being open when the motor 64 is stopped allows additional individual constituent material to flowdownstream through dispense valves 22a, 22b and to mix assembly 50. With mixer 60 held stationary, the mixer 60 can act as a static mixer. The constituent materials have already blended within the mix assembly 50 when the motor 64 is stopped. Implementing the delay between stopping of the motor 64 and closing the dispense valves 22a, 22b allows the streams of the individual constituent materials to flow downstream and into the mix assembly 50. The individual constituent materials flowing through the dispense valves 22a, 22b drive the plural component material blended by the rotating mixer 60 further downstream within mix assembly 50 while the mixer 60 is held static.

[0099] Snuff back assemblies 24a, 24b are actuated to the respective snuff back open states after stopping the motor 64, delaying, and then closing the dispense valves 22a, 22b. Actuating the snuff back assemblies 24a, 24b to their respective snuff back open states after the delay between stopping of motor 64 and then closing the dispense valves 22a, 22b causes the snuff back assemblies 24a, 24b to draw the respective individual constituent materials upstream. The already blended plural component material is further down within mix assembly 50. The individual constituent materials are pulled upstream which avoids curing of plural component materials within flowpaths, such as those upstream of material orifices 38a, 38b.

[0100] Mix assembly 50 is actuated between dynamic, active mixing and static, passive mixing of the constituent materials during the dispensing of the plural component material. The plural component material is output by material dispenser 12 while dispense valves 22a, 22b are open. The motor 64 is operated during a portion of the material dispense and is stopped during another portion of the material dispense. The motor 64 is stopped during a terminal portion of the material dispense. Such a configuration cause snuff back assemblies 24a, 24b to pull back the individual constituent materials from mix assembly 50, preventing ingestion of the plural component material and keeping flowpaths upstream of the mix assembly 50 clear. Such a configuration provides for efficient mixing and dispensing of the plural component material while preventing fouling of the pathways upstream of the mix assembly 50.

[0101] While the invention(s) has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention(s) without departing from the essential scope thereof. Therefore, it is intended that the invention(s) not be limited tothe particular embodiment(s) disclosed, but that the invention(s) may include all embodiments falling within the scope of the appended claims. Any single feature, or any combination of features from one embodiment show herein, may be utilized in a different embodiment independent from the other features shown in the embodiment herein. Accordingly, the scope of the invention(s) and any claims thereto are not limited to the particular to the embodiments and / or combinations of the features shown herein, but rather can include any combination of one, two, or more features shown herein.

Claims

CLAIMS:

1. A material dispenser comprising :a first dispense valve actuatable between a first dispense open state and a first dispense closed state;a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; anda first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state.

2. The material dispenser of claim 1, wherein the first snuff back assembly is configured to output the material into the first material flowpath as the first snuff back assembly is actuated from the first snuff back open state to the first snuff back closed state.

3. The material dispenser of any one of claims 1 and 2, wherein the first snuff back assembly includes a first plunger connected to a first displacer, the first displacer configured to move the first plunger to actuate the first snuff back assembly between the first snuff back closed state and the first snuff back assembly open state.

4. The material dispenser of claim 3, wherein the first displacer is a piston head.

5. The material dispenser of claim 3, wherein the first displacer is a solenoid.

6. The material dispenser of any one of claims 1 -5 , wherein the first snuff back assembly includes a first stroke adjustor, the first stroke adjustor actuatable to set a reserve volume of the first snuff back assembly.

7. The material dispenser of claim 6, wherein the first stroke adjustor includes a limiter rod configured to physically set the reserve volume.

8. The material dispenser of any one of claims 1-7, further comprising:a controller operatively connected to the first dispense valve and the first snuff back assembly, the controller configured to:cause the first snuff back assembly to actuate from the first snuff back closed state to the first snuff back open state based on the dispense valve having been actuated from the first dispense open state to the first dispense closed state.

9. The material dispenser of claim 8, wherein the controller is further configured to control actuation of the first dispense valve between the first dispense open state and the first dispense closed state.

10. The material dispenser of any one of claims 8 and 9, wherein the controller is further configured to cause the first snuff back assembly to actuate from the first snuff back closed state to the first snuff back open state at a first displacement rate and the controller is configured to cause the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state at a second displacement rate different from the first displacement rate.

11. The material dispenser of claim 10, wherein the second displacement rate is less than the first displacement rate.

12. 1'he material dispenser of any one of claims 10 and 11, wherein the second displacement rate is set based on a flow rate of the material downstream through the first dispense valve with the first dispense valve in the first dispense open state.

13. The material dispenser of any one of claims 8-12, wherein the controller is further configured to cause the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state after the first dispense valve is actuated from the first dispense closed state to the first dispense open state.

14. The material dispenser of any one of claims 1-13, wherein the first material orifice is a dispense orifice through which the first material is emitted from the dispense assembly.

15. The material dispenser of any one of claims 1-13, further comprising:a second dispense valve actuatable between a second dispense open state and a second dispense closed state;a second material flowpath extending between the second dispense valve and a second material orifice through which a second material is output from the second material flowpath; and a second snuff back assembly fluidly connected to the second material flowpath at a location downstream of the second dispense valve and upstream of the dispense orifice.

16. The material dispenser of claim 15. further comprising:a mix assembly configured to receive the first material from the first material flowpath and configured to receive the second material from the second material flowpath, the mix assembly including a dispense orifice through which a plural component material formed by mixing of the first material and the second material is emitted.

17. The material dispenser of claim 16, wherein the mix assembly includes a mix housing and a mixer disposed within the mix housing, wherein the mixer is configured to rotate within the mix housing to mix the first material and the second material.

18. The material dispenser of claim 16, wherein the mix assembly includes a mix housing and a mixer disposed within the mix housing, wherein the mixer is a static mixer configured to remain stationary relative to the mix housing to mix the first material and the second material.

19. The material dispenser of any one of claims 16-18, wherein the first snuff back assembly being actuated to the first snuff back open state and the second snuff back assembly being actuated to the second snuff back open state draws the plural component material upstream within the mix assembly and away from the dispense orifice.

20. A dispense system comprising:a support on which the material dispenser of any one of claims 1-19 is mounted, the support configured to move the material dispenser to position the material dispenser relative to a substrate;a position controller configured to control movement of the support to position the material dispenser;wherein the first snuff back assembly is actuated between the first snuff back open state and the first snuff back closed state based on position information from the position controller.

21. The dispense system of claim 20, wherein the support is configured as a multi-axis robotic arm.

22. A material dispenser configured to apply a plural component material on a substrate, the material dispenser comprising:a first dispense valve actuatable between a first dispense open state and a first dispense closed state;a second dispense valve actuatable between a second dispense open state and a second dispense closed state;a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath;a second material flowpath extending between the second dispense valve and a second material orifice through which a second material is output from the second material flowpath;a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state;a second snuff back assembly fluidly connected to the second material flowpath at a location downstream of the second dispense valve and upstream of the dispense orifice, the second snuff back assembly actuat able between a second snuff back open state and a second snuff back closed state, wherein the second snuff back assembly is configured to draw the second material upstream and away from the second material orifice as the second snuff back assembly is actuated from the second snuff back closed state to the second snuff back open state; anda mix assembly configured to receive the first material from the first material flowpath and configured to receive the second material from the second material flowpath, the mix assembly including a dispense orifice through which the plural component material formed by mixing of the first material and the second material is emitted.

23. The material dispenser of claim 22, wherein the mix assembly includes a mix housing and a mixer disposed within the mix housing, wherein the mixer is configured to rotate within the mix housing to mix the first material and the second material.

24. The material dispenser of claim 22, wherein the mix assembly includes a mix housing and a mixer disposed within the mix housing, wherein the mixer is a staticmixer configured to remain stationary relative to the mix housing to mix the first material and the second material.

25. The material dispenser of any one of claims 22-24, further comprising:a controller operatively connected to the first snuff back assembly and the second snuff back assembly, the controller configured to control actuation of the first snuff back assembly and the second snuff back assembly.

26. The material dispenser of claim 25, wherein the controller is configured to:control, based on a target mix ratio between the first material and the second material, a first actuation rate of the first snuff back assembly from the first snuff back open state to the first snuff back closed state and control a second actuation rate of the second snuff back assembly from the second snuff back open state to the second snuff back closed state.

27. The material dispenser of claim 26, wherein:the target mix ratio is an unbalanced mix ratio of X:Y, in which X is associated with the first material, Y is associated with the second material, and X is greater than Y; andthe first actuation rate is greater than the second actuation rate.

28. The material dispenser of claim 26, wherein the target mix ratio is 1 : 1 and the first actuation rate matches the second actuation rate.

29. The material dispenser of claim 26, wherein the controller is configured to:control, based on the target mix ratio, a first actuation rate of the first snuff back assembly from the first snuff back closed state to the first snuff back open state and control a second actuation rate of the second snuff back assembly from the second snuff back closed state to the second snuff back open state.

30. The material dispenser of claim 29, wherein:the target mix ratio is an unbalanced mix ratio of X:Y, in which X is associated with the first material, Y is associated with the second material, and X is greater than Y; andthe first actuation rate of the first snuff back assembly from the first snuff back closed state to the first snuff back open state is greater than thesecond actuation rate of the second snuff back assembly from the second snuff back closed state to the second snuff back open state.

31. The material dispenser of claim 29, wherein the target mix ratio is 1:1 and the first actuation rate of the first snuff back assembly from the first snuff back closed state to the first snuff back open state matches the second actuation rate of the second snuff back assembly from the second snuff back closed state to the second snuff back open state.

32. The material dispenser of any one of claims 25-31, wherein the controller is further configured to control actuation of the first dispense valve between the first dispense open state and the first dispense closed state.

33. The material dispenser of any one of claims 25-32, wherein the controller is configured to cause the first snuff back assembly to actuate from the first snuff back closed state to the first snuff back open state at a first displacement rate and the controller is configured to cause the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state at a second displacement rate different from the first displacement rate.

34. The material dispenser of claim 33, wherein the second displacement rate is less than the first displacement rate.

35. The material dispenser of any one of claims 33 and 34, wherein the second displacement rate is set based on a flow rate of the material downstream through the first dispense valve with the first dispense valve in the first dispense open state.

36. The material dispenser of any one of claims 25-35, wherein the controller is further configured to cause the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state after the first dispense valve is actuated from the first dispense closed state to the first dispense open state.

37. The material dispenser of claim 22, further comprising:a motor connected to a mixer of the mix assembly, the motor configured to drive rotation of the mixer;a controller operatively connected to the first snuff back assembly, the second snuff back assembly, the first dispense valve, the second dispense valve, and the motor, the controller configured to: cause the first dispense valve and the second dispense valve to open in response to a dispense signal;cause the motor to activate to drive rotation of the mixer based on the dispense signal;cause the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state based on the dispense signal;cause the second snuff back assembly to actuate from the second snuff back open state to the second snuff back closed state based on the dispense signal;deactivate the motor to stop rotation of the mixer based on a cessation signal;cause the first dispense valve and the second dispense valve to close after the motor is deactivated;cause the first snuff back assembly to actuate from the first snuff back closed state to the first snuff back open state after the first dispense valve and the second dispense valve are closed; andcause the second snuff back assembly to actuate from the second snuff back closed state to the second snuff back open state after the first dispense valve and the second dispense valve are closed.

38. A dispense system comprising:a material dispenser comprising:a first dispense valve actuatable between a first dispense open state and a first dispense closed state;a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath; anda first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state;a support on which the material dispenser is mounted, the support configured to move the material dispenser to position the material dispenser relative to a substrate;a position controller configured to control movement of the support to position the material dispenser;wherein the first snuff back assembly is actuated between the first snuff back open state and the first snuff back closed state based on position information from the position controller.

39. A material dispenser configured to apply a plural component material on a substrate, the material dispenser comprising:a first dispense valve actuatable between a first dispense open state and a first dispense closed state;a second dispense valve actuatable between a second dispense open state and a second dispense closed state;a first material flowpath extending between the first dispense valve and a material orifice through which a first material is emitted from the first material flowpath;a second material flowpath extending between the second dispense valve and a second material orifice through which a second material is output from the second material flowpath;a first snuff back assembly fluidly connected to the first material flowpath at a location downstream of the first dispense valve and upstream of the material orifice, the first snuff back assembly actuatable between a first snuff back open state and a first snuff back closed state, wherein the first snuff back assembly is configured to draw the first material upstream and away from the first material orifice as the first snuff back assembly is actuated from the first snuff back closed state to the first snuff back open state;a second snuff back assembly fluidly connected to the second material flowpath at a location downstream of the second dispense valve and upstream of the dispense orifice, the second snuff back assembly actuatable between a second snuff back open state and a second snuff back closed state, wherein the second snuff back assembly is configured to draw the second material upstream and away from thesecond material orifice as the second snuff back assembly is actuated from the second snuff back closed state to the second snuff back open state;a mix assembly configured to receive the first material from the first material flowpath and configured to receive the second material from the second material flowpath, the mix assembly including a dispense orifice through which the plural component material formed by mixing of the first material and the second material is emitted and the mix assembly including a mixer disposed within a mix housing;a motor connected to the mixer and configured to drive rotation of the mixer;anda controller operatively connected to the first snuff back assembly, the second snuff back assembly, the first dispense valve, the second dispense valve, and the motor, the controller configured to, during a dispense event:stop the motor to stop rotation of the mixer;cause the first dispense valve to actuate to the first dispense closed state after the motor is stopped;cause the second dispense valve to actuate to the second dispense closed state after the motor is stopped; andcause the first snuff back assembly to actuate to the first snuff back open state and the second snuff back assembly to actuate to the second snuff back open state after the first dispense valve is in the first dispense closed state and the second dispense valve is in the second dispense closed state.

40. The material dispenser of claim 39, wherein the controller is configured to cause the motor to drive rotation of the mixer prior to causing the first snuff back assembly to actuate from the first snuff back open state to the first snuff back closed state.

41. A method of dispensing a plural component material, the method comprising:opening a first dispense valve to allow a flow of a first constituent material downstream to a mix assembly including a mixer within a mixhousing and opening a second dispense valve to allow a flow of a second constituent material downstream to the mix assembly; activating a motor to cause rotation of the mixer within the mix housing; outputting the first constituent material from a first snuff back assembly and into the flow of the first constituent material and outputting the second constituent material from a second snuff back assembly and into the flow of the second constituent material;stopping rotation of the motor to stop rotation of the mixer with the first dispense valve and the second dispense valve open;closing the first dispense valve and the second dispense valve based on a first delay after the motor stops; anddrawing the first constituent material upstream from the mix assembly by the first snuff back assembly and drawing the second constituent material upstream from the mix assembly by the second snuff back assembly after the first dispense valve and the second dispense valve are closed.

42. The method of claim 41, further comprising:activating the motor concurrently with the first dispense valve opening.

43. The method of any one of claims 41 and 42, further comprising:implementing a second delay between the opening of the first dispense valve and the second dispense valve and the outputting of the first constituent material from the first snuff back assembly and the outputting of the second constituent material from the second snuff back assembly.

44. The method of any one of claims 41-43, further comprising:implementing an opening delay between receipt of a dispense signal and the opening of the first dispense valve and the second dispense valve.

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