Spray machine alignment system and method

Abstract

A system and method for aligning a spray gun in a spraying system, comprising a pair of adjustment mechanisms. The laser alignment system employs a target device.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 533,614, filed August 19, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates to industrial spraying, and more specifically, to a spray gun alignment system and method for coating the interior of metal cans. Background Technology

[0003] Beverage cans are typically formed from a single, thinned, stretched can body with an open end to which the can "end" is sewn after filling. Beverage cans, and some food cans, often undergo an internal protective coating, commonly referred to as "paint," during a spraying process. This coating provides a barrier between the can's metal material and the contents after the can has been filled with beverage or food contents.

[0004] A two-piece can has a cylindrical body with thin sidewalls and a typically arched bottom that is integral with the sidewalls. The can body is formed by stamping a circular disc or blank from a sheet of metal, drawing the blank into a cup shape, thinning and stretching the cup's sidewalls by forcing it through a series of dies with decreasing diameters, forming an arch at the bottom of the cup, and then forming a flange at the open end of the upper part of the can. Cans produced through this process are called "thin-stretch cans" or DWI cans.

[0005] A three-piece can consists of a sidewall and a pair of ends at the top and bottom of the closed sidewall. The sidewall is typically formed by rolling a sheet of metal into a cylinder and welding the edges of the sheets together. One end is then sewn to an end cap. After filling, the other end is sewn to the open end of the can to seal the can. Three-piece cans can be painted before or after the bottom end is sewn to the sidewall. As used herein, the term "can body" refers to the DWI can body of a two-piece can (with a closed bottom integral with the sidewall), the three-piece can body with one sewn end cap, and the sidewall of a separate three-piece can (i.e., before being joined to the end cap at either end).

[0006] Two-piece beverage cans are commonly used to hold beverages, with diameters ranging from 52mm to 84mm and heights from 88mm to 204mm. Three-piece cans are primarily used for food packaging, with diameters ranging from 52mm to 153mm and heights from 38mm to 178mm. Most beverage can bodies are made of aluminum, with the ends made of a higher grade of aluminum alloy. Most food cans are made of tinplate, a type of tinplate.

[0007] Referring to Figure 1, a conventional paint sprayer 110 includes an indexing turntable 120, a rotating assembly 130, a paint spraying system 140, and an unloading turntable 150. The turntable 120 includes a star wheel 121. Unpainted cans 99 are fed from a feed track 112 into recesses 124 of the star wheel 121. Recesses 124 are spaced around the periphery of the indexing turntable 120, causing the cans 99 to rotate about a center 122 of the turntable 120. The cans 99 are held in place in their respective recesses 124 by a vacuum chuck 126 (also called a rotating pad), which can hold the can's sidewalls and / or hold the can's base (if present, e.g., in a two-piece can) against the vacuum chuck 126 by suction or vacuum pressure. If the cans being sprayed are steel, they can be magnetically held in place, for example, on a rotating pad. Vacuum chuck 126 and rotary assembly 130 are shown together in Figure 1 because they are conventional and aligned in the embodiment shown in the figure. As those skilled in can manufacturing and / or can spray coating will understand, turntable 120 can be a conventional turntable for handling can bodies. Reference numeral 120 is used to refer to the complete turntable assembly, while only a portion of the turntable is shown in the figure.

[0008] The turntable 120 is indexed (i.e., rapidly moved to a predetermined rotational position) to position two canisters 99 relative to two fixed spray guns 142 for applying a coating during a dwell period (i.e., the period during which the turntable is stationary in a turntable indexing cycle). An indexing box (not shown in the figures, but well known to those skilled in the art of spray coating) controls the start and stop of the indexing turntable 120 via an internal cam, as is well known in the art. During the dwell period, the drive belt 134 of the rotating assembly 130 engages each vacuum chuck 126 of the canister to rotate the canister as it is positioned in front of the spray gun. The drive belt 134 is driven by a motor 132 that engages with chuck pulleys 136 and idler pulleys 138.

[0009] In conventional spraying operations, the can 99 typically rotates at 2000-2750 rpm. This rotation (of the can about its longitudinal axis) improves the uniformity of the coating on the can's internal surfaces. For a typical can rotating at 2400 rpm, three rotations are generally considered sufficient to evenly coat the appropriate amount of paint. The spraying time is approximately 100 ms. In many commercial embodiments, the dwell time is longer than the spraying time because several milliseconds are required to open and close the spray gun. After the dwell time, the indexing box rapidly rotates the turntable to advance the sprayed can beyond its position relative to the spray gun and move the next unsprayed can to the spraying position (described more fully below). The turntable 120 then transfers the sprayed can 99 to the unloading turntable 150, which in turn transfers the can 99 to the unloading track 114 for conveying to further manufacturing stages of the production line, such as necking and flanging operations.

[0010] The two spray guns 142 of the spraying system 140 are typically oriented such that one points (i.e., aims or aligns) towards the side wall of the tank and the other towards the base of the tank. The spray guns are held in place by spray gun mounts or spray gun supports 144.

[0011] The second of the two spray guns is typically located downstream of the first spray gun (i.e., relative to the movement of the can on the turntable 120). For each can 99, the turntable 120 is indexed to position one of the cans to receive coating from the first (i.e., upstream) spray gun. After a dwell period, the turntable is indexed to advance the can (at this point only partially coated) to a position to receive coating from the second spray gun, and to advance the uncoated can to a position to receive coating from the first spray gun. In this configuration, the system applies coating to both cans (via the two spray guns) during any dwell period of each sprayer. For three-piece cans without a sewn base, it may be necessary to use only one spray gun for coating the sidewalls. Prior art sprayers are disclosed in WO2014 / 147163, provided by a sister company of the applicant.

[0012] Regulations and / or standards of beverage or food companies specify minimum weights or thicknesses for coatings on virtually all internal metal surfaces. The coating must be able to withstand the can manufacturing process and subsequent use of the can throughout its shelf life. For beverage and food cans, the coating must be non-toxic and non-polluting.

[0013] Existing spray gun alignment methods typically employ templates or clamps to position each spray gun in the appropriate spatial and directional or angular orientation. When can size changes from one specification to another, for example, from a 25cl beverage can to a 50cl beverage can, or from a standard height can to a taller can, each pair of spray guns must be adjusted to ensure sufficient paint coverage on the inner wall. Existing techniques require manually setting two parameters: the X and Y distances (in millimeters) between the spray gun nozzle and the center of the dome, and the angular position of the nozzle relative to the center of the dome (in degrees). The existing swivel mount is loosened from its fixed operating state, and the angular position of the spray gun is manually adjusted while simultaneously adjusting the X and Y distances. This is performed by the first operator, and the second operator must (re)secure (return) the mount to its operating state. A number of cans are then passed through the paint sprayer, and the operator visually checks the coverage, iteratively repeating the spray gun adjustment process as needed. Failure to do this can result in insufficient paint coverage and ultimately, customer complaints.

[0014] Spray painting machines are typically supplied in units of six to ten. The same spray gun setup process must then be performed on each machine in the unit until all machines are finally tuned and ready for the new can type. This process is not only extremely time-consuming and delays production restarts, but it can also lead to inconsistent paint coverage between machines. Each operator may have their own specific spray gun setup technique, making the process unrepeatable.

[0015] Furthermore, as the industry shifts from solvent-based paints to water-based paints, the inventors have discovered that water-based paints require higher alignment precision and accuracy compared to solvent-based paints in order to meet industry specifications without using excessive amounts of paint.

[0016] Furthermore, once the paint is sprayed into the can, its properties become unpredictable, leading to greater coverage variability, especially when moving from one sprayer to another. Cans from the sprayer furthest from the main conveyor in the sprayer unit experience longer transport times than those from closer sprayers, resulting in more diffusion. Therefore, stronger process control is required. Summary of the Invention

[0017] A system for aligning a spray gun includes an alignment mechanism adapted to position the spray gun tip at a predetermined reference point. A corresponding method for repeatedly aligning a spray gun of a paint spraying machine in a can manufacturing production line includes the steps of: determining a reference point and an angular orientation of the spray gun such that a desired alignment of the spray gun is achieved; and recording at least the alignment coordinates of the reference point. Subsequent alignment of the spray gun is achieved by resetting the spray gun to the alignment coordinates associated with the reference point.

[0018] The method may include determining a reference point by the following steps: (a) recording the coordinates of the spray gun, (b) operating the spray gun to spray paint onto the interior of the can, (c) evaluating the characteristics of the paint coating on the interior of the can, (d) adjusting the position of the spray gun to improve the characteristics of the paint coating, and (e) repeating steps (a) through (d) until the desired alignment is achieved. The method may also include determining the angular direction of the spray gun by the following step: (f) adjusting the angular direction of the spray gun. Furthermore, the method may include fixing the spray gun to a support at the desired angular direction and / or adjusting the position of the spray gun using alignment screws to determine the reference point of the spray gun.

[0019] A system for reproducibly aligning a spray gun of a paint spraying machine in a can manufacturing production line includes: a support structure fixed relative to a base of the paint spraying machine, the support structure including a track and a spray gun mount; a spray gun fixed to the spray gun mount; at least two linear drive components adapted to move the spray gun mount relative to a reference point associated with a desired alignment of the spray gun; and an angle drive component adapted to move the spray gun mount relative to a desired angular direction of the spray gun. After alignment at the reference point is achieved through iterative operations of the linear drive components and the angle drive components, the coordinates of the reference zero point can be recorded for subsequent alignment of the spray gun by positioning the spray gun mount based on the coordinates. The track can be any structural support. The linear drive can be of any type, such as a screw (e.g., an Acme screw), rack and pinion, belt, or other actuator, which can be manually actuated (i.e., by hand, such as a knob rotated by a user's hand) or actuated by any type of motor.

[0020] The linear drive assembly may include at least two linear actuators: a first linear actuator is oriented to translate the spray gun mount along a first direction (i.e., linear or linear movement, as opposed to rotational movement), and a second linear actuator is oriented to translate the spray gun mount along a second direction orthogonal to the first direction. The track may be angled relative to a vertical line, enabling the first and second linear actuators to position the spray gun mount in XYZ coordinates.

[0021] The system may also include a third linear drive assembly, such that the first and second directions define a horizontal XY plane, and the third linear drive is adapted to translate the spray gun mount along the vertical Z direction. The linear drive may be a manual (i.e., hand-operated, for example physically operated by a user's hand) linear drive having a display indicating the position of the linear drive, such that the position recorded by the display at a reference point allows for subsequent alignment of the spray gun mount by resetting the linear drive to the recorded position.

[0022] Each of the linear drives may include an actuator for moving the linear drive, such that after a reference point is determined, the control system is adapted to send a signal to the actuator to position the linear drive at the reference point for subsequent alignment of the spray gun.

[0023] The angle drive component may be or include a display, such as an analog reader (e.g., a scale or marking on a micrometer), indicating the angular position of the angle drive, such that the position recorded by the display enables subsequent alignment of the spray gun mount by resetting the angle drive to the recorded position.

[0024] According to another aspect of this disclosure, a system for supporting a spray gun of a paint spraying machine in a paint spraying machine assembly line may include: a support structure fixed relative to a base of the paint spraying machine; a laser device coupled to the support structure and capable of generating at least one laser line; and a target device mounted at a predetermined position on the paint spraying machine. The target device is preferably positioned such that at least one laser line illuminates it. Thus, the positioning of the laser line indicates the relative alignment of the target device with respect to the target machine. The laser line is preferably a linear horizontal and / or vertical line. Other embodiments are also contemplated, for example, the laser line may be circular or other arc-shaped lines.

[0025] The support structure may include a track to which the laser device is coupled via a bracket. The target device may include an outwardly projecting domed surface adapted to receive illumination from horizontal and / or vertical laser lines.

[0026] In practice, for one embodiment of this system, linear deviation of the horizontal laser line illuminating the dome surface indicates angular misalignment of the laser device relative to the target device, and / or linear deviation of the vertical laser line illuminating the dome surface indicates angular misalignment of the laser device relative to the target device. Linear deviation of the horizontal laser line indicates angular misalignment of the laser device about the horizontal axis, and linear deviation of the vertical laser line indicates angular misalignment of the laser device. The deviation of the intersection of the horizontal and vertical laser lines relative to the center of the dome indicates misalignment of the laser device relative to the dome in a plane perpendicular to the central axis (i.e., the axis of the tank and / or the target device).

[0027] According to another embodiment, the target device is a stepped device including a base surface, a neck, and a front surface; the neck extends forward relative to the base surface such that the front surface is formed at the distal end of the neck. The front surface is flat, and the base surface is flat and parallel to the front surface, such that collinearity deviation of a horizontal laser line irradiated on the base surface relative to a horizontal laser line irradiated on the front surface indicates misalignment of the laser device relative to the target device, and / or collinearity deviation of a vertical laser line irradiated on the base surface relative to a vertical laser line irradiated on the front surface indicates misalignment of the laser device relative to the target device.

[0028] The deviation of the intersection of the horizontal and vertical laser lines from the center of the front indicates that the laser device is misaligned relative to the target device in a plane perpendicular to the central axis (i.e., the axis of the tank and / or the target device).

[0029] A method for a spray gun support structure for a paint spraying machine in a can manufacturing production line, comprising the steps of: irradiating a target device (as defined in any of the appended claims) with at least one laser line from a laser device, the target device being positioned to receive irradiation from the at least one laser line; and adjusting the position of the support structure holding the laser device based on the linearity of the at least one laser line and / or based on the deviation of the center of the laser line (e.g., the intersection of a horizontal and a vertical laser line).

[0030] According to another embodiment, a system for aligning a spray gun of a paint spraying machine in a can manufacturing production line includes: a support structure fixed relative to a base of the paint spraying machine, the support structure including a track and a spray gun mount; a reference fixing device coupled to the spray gun mount; a laser device fixed to the reference structure; and a target device mounted at a predetermined position on the paint spraying machine, the target device being positioned such that at least one laser line from the laser device irradiates the target device. The reference fixing device and the target device are configured to be replaceable with the spray gun fixing device, and wherein, after the laser device is aligned with the target device, the reference device is replaced with the spray gun fixing device and the spray gun to position the spray gun at the desired predetermined position. Attached Figure Description

[0031] Figure 1 is a schematic view of the various parts of a conventional paint spraying machine;

[0032] Figure 2 This is a top perspective view showing the position of the spraying assembly on the inner surface of the spray can;

[0033] Figure 3 yes Figure 2 Bottom perspective view of the spraying assembly;

[0034] Figure 4 yes Figure 2 The main view of the spray painting component;

[0035] Figure 5 yes Figure 2 A top view of the spraying components;

[0036] Figure 6 yes Figure 2 A bottom view of the spray painting components;

[0037] Figure 7 This is a top view of the spraying assembly when aligned with the initial point, showing the spray gun oriented parallel to the longitudinal axis of the beverage can;

[0038] Figure 8 It is the spraying component in Figure 7 The top view during alignment, following the view shown, shows the spray gun oriented at an angle relative to the longitudinal axis of the beverage can.

[0039] Figure 9 It is the spraying component in Figure 8 The top view during alignment following the view shown shows the spray gun oriented at an angle relative to the longitudinal axis of the beverage can and the spray gun nozzle adjacent to the lip of the beverage can.

[0040] Figure 10 yes Figure 9 A magnified view of a portion;

[0041] Figure 11 It is the spraying component in Figure 9 The top view during alignment, following the view shown, shows the spray gun oriented at an angle relative to the longitudinal axis of the beverage can.

[0042] Figure 12 It is the spraying component in Figure 11 The top view following the view shown shows the spray gun oriented at an angle relative to the longitudinal axis of the beverage can and the spray gun nozzle in a ready-to-spray position, thus defining the reference position.

[0043] Figure 13 This is a perspective view of the system for the support arm used to align the spray gun assembly.

[0044] Figure 14 yes Figure 13 An enlarged view of a portion of the image shows the laser crosshairs and the target dome around the X′ axis;

[0045] Figure 15 This is an enlarged, partially transparent perspective view of the target device in the first embodiment;

[0046] Figure 15A It is a side-by-side, partially transparent perspective view of three embodiments of the target device;

[0047] Figure 15B This is a front view of three embodiments of the target device, showing misalignment relative to the laser device;

[0048] Figure 16 This is a front view of the target device in the first embodiment at the alignment position relative to the laser device;

[0049] Figure 17 This is a front view of the target device of the first embodiment, showing a degree of misalignment relative to the laser device;

[0050] Figure 18 This is a front view of the target device of the first embodiment, showing two degrees of misalignment relative to the laser device;

[0051] Figure 19 This is a front view of the target device of the first embodiment, showing a five-degree misalignment relative to the laser device;

[0052] Figure 20 This is a front view of the target device of the first embodiment, showing a 10-degree misalignment relative to the laser device;

[0053] Figure 21 This is an enlarged, partially transparent perspective view of the target device in the second embodiment;

[0054] Figure 22 This is a front view of the target device in the second embodiment at the alignment position relative to the laser device;

[0055] Figure 23 This is a front view of the target device of the second embodiment, showing a degree of misalignment relative to the laser device;

[0056] Figure 24 This is a front view of the target device of the second embodiment, showing a 10-degree misalignment relative to the laser device;

[0057] Figure 25 This is a front view of the target device in the third embodiment at the alignment position relative to the laser device;

[0058] Figure 26 This is a front view of the target device of the third embodiment, showing a degree of misalignment relative to the laser device; Figure 27 This is a top view of the reference fixing device, showing another system and method for aligning the spray gun assembly; and

[0059] Figure 28 yes Figure 27 The view of the spray gun assembly after the reference fixture has been replaced by the spray gun bracket. Detailed Implementation

[0060] Figure 2 An embodiment of a spraying system 10 is shown, comprising a pair of spray gun assemblies 20a and 20b, a pair of alignment assemblies 40a and 40b, and a support structure 30. The embodiment of the spraying system 10 is shown in position for coating the inner surfaces of a pair of cans 99a and 99b. The first can 99a is positioned relative to the first spray gun assembly 20a, and the second can 99b is positioned relative to the second spray gun assembly 20b.

[0061] Cans 99a and 99b are held in corresponding recesses on the indexing turntable 120. It should be understood that, for clarity, Figures 2 to 12Some parts of the can handling and indexing system are omitted from the drawings. For example, the inlet track, unloading turntable, outlet track, can rotation mechanism, indexing mechanism, and the continuous line of the can are omitted from the drawings to allow for a clear view of the spraying system components. These and other parts omitted from the drawings may be conventional, such as (but not limited to) those described with respect to Figure 1 and / or those described in WO2016 / 193663 entitled "Spray Coating of Cans" from the same applicant as this application.

[0062] As those skilled in can manufacturing technology will understand, each spray gun assembly 20a and 20b can be a conventional spray gun commonly used in beverage can or similar manufacturing plants to apply coatings (e.g., paint). Spray gun assembly 20a includes a tip or nozzle 22a. Spray gun assembly 20b has a tip or nozzle 22b. For clarity, coating supply equipment is omitted. Each spray gun assembly 20a and 20b is oriented in a direction corresponding to its desired spraying direction.

[0063] The support structure 30 includes a base 32 and an arm or track 34. The base 32 may be fixed to a paint sprayer base, or the base 32 may have a separate support. The track 34 extends upward from the base 32, and in the embodiment shown in the figures, the track 34 provides a platform for supporting alignment systems 40a and 40b. The coordinate axes are... Figure 2 and Figure 4 The figures are shown to aid in description. The Z-axis is parallel to the major axis of track 34. The X and Y axes are perpendicular to the Z-axis. In the embodiment shown in the figures, the Y-axis is parallel to the plane defined by the star-shaped wheel surface of the indexing turntable 120, and the X-axis is perpendicular to the indexing turntable surface. Track 34 does not need to have an orientation with respect to the aforementioned axes. For any orientation of the Y and Z axes, movement along the X-axis can generally be considered as movement toward or away from the can to be coated.

[0064] The support structure 30 includes a pair of brackets 36a and 36b fixed to one side of the track 34. In the embodiment shown in the figures, the brackets 36a and 36b are rigidly fixed to the track 34, and the brackets 36a and 36b (best shown in…) Figure 4 It can also be adapted to slide up and down along the Y direction, for example, for rough manual adjustments.

[0065] The upper or first alignment component 40a includes a first Y-direction linear alignment mechanism 50a, a first X-direction linear alignment mechanism 60a, and a first angle alignment mechanism 70a.

[0066] The first Y-direction linear alignment mechanism 50a includes a sliding mechanism 52a, a bracket 54a, and an adjustment mechanism 56a. The first Y-direction linear alignment mechanism 50a is oriented such that the movement of the bracket 54a is along the Y-axis. The adjustment mechanism 56a may include a knob with a digital readout 58a to enable the first Y-direction linear alignment mechanism 50a to be set to its desired position, as described below.

[0067] The first X-direction linear alignment mechanism 60a includes a sliding mechanism 62a, a bracket 64a, and an adjustment mechanism 66a. The first X-direction linear alignment mechanism 60a is oriented such that the movement of the bracket 64a is along the X-axis. Furthermore, the sliding mechanism 62a is fixed to the Y-direction bracket 54a, such that the first X-direction linear alignment mechanism 60a is mounted on the first Y-direction linear alignment mechanism 50a to achieve movement in the XY plane. The adjustment mechanism 66a may include a knob with a digital readout 68a to enable the first X-direction linear alignment mechanism 60a to be set to its desired position.

[0068] The first angle alignment mechanism 70a includes a rotary alignment mechanism 74a and a gun mounting plate 76a mounted to the alignment mechanism 74a. The rotary alignment mechanism 74a provides pivoting or rotational movement relative to the mounting plate 76a. Furthermore, the first angle alignment mechanism 70a is fixed to a bracket 64a of a first X-direction linear alignment mechanism 60a, allowing the first angle alignment mechanism 70a to be positioned at any location in the XY plane. The rotary alignment mechanism 74a may include a knob with a digital readout 78a to enable the first angle alignment mechanism 70a to be set to its desired position.

[0069] The lower or second alignment component 40b includes a second Y-direction linear alignment mechanism 50b, a second X-direction linear alignment mechanism 60b, and a second angle alignment mechanism 70b.

[0070] The second Y-direction linear alignment mechanism 50b includes a sliding mechanism 52b, a bracket 54b, and an adjustment mechanism 56b. The second Y-direction linear alignment mechanism 50b is oriented such that the movement of the bracket 54b is along the Y-axis. The adjustment mechanism 56b may include a knob with a digital readout 58b to enable the second Y-direction linear alignment mechanism 50b to be set to its desired position, as described below.

[0071] The second X-direction linear alignment mechanism 60b includes a sliding mechanism 62b, a bracket 64b, and an adjustment mechanism 66b. The second X-direction linear alignment mechanism 60b is oriented such that the movement of the bracket 64b is along the X-axis. Furthermore, the sliding mechanism 62b is fixed to the Y-direction bracket 54b, such that the second X-direction linear alignment mechanism 60b is mounted on the second Y-direction linear alignment mechanism 50b to achieve movement in the XY plane. The adjustment mechanism 66b may include a knob with a digital readout 68b to enable the second X-direction linear alignment mechanism 60b to be set to its desired position.

[0072] The second angle alignment mechanism 70b includes a rotary alignment mechanism 74b and a gun mount plate 76b mounted to the rotary alignment mechanism 74b. The rotary alignment mechanism 74b provides pivoting or rotational movement relative to the gun mount plate 76b. Furthermore, the second angle alignment mechanism 70b is fixed to a bracket 64b of the second X-direction linear alignment mechanism 60b, allowing the second angle alignment mechanism 70b to be positioned at any location in the XY plane. The rotary alignment mechanism 74b may include a knob with a digital readout 78b to enable the second angle alignment mechanism 70b to be set to its desired position.

[0073] The first spray gun 20a is fixed to the gun mounting plate 76a, and the second spray gun 20b is fixed to the second gun mounting plate 76b.

[0074] Optionally, the manual (i.e., hand-operated) knob adjustment device of the alignment mechanisms 50a, 60a, 70a, 50b, 60b and 70b can be replaced or enhanced with an actuator (e.g. a stepper motor) having an encoder capable of performing the registration function.

[0075] Figures 7 to 12 The alignment process for setting a process-based reference position for the spray gun assembly used to coat the sidewall of a beverage can is shown. For ease of description and clarity, spray gun 20a and its corresponding alignment and movement device are used. Spray gun 20b is set in the same manner as spray gun 20a, so for the sake of brevity, repeated descriptions are omitted. Thus, the second spray gun is aligned after the first spray gun is aligned, while the support rail remains fixed.

[0076] Figure 7 The spray gun 20a is shown in its retracted position, perpendicular to the face of the star wheel 121. A protractor (or similar reference tool) is placed against the surface of the star wheel 121 to confirm the vertical orientation of the spray gun 20a relative to the star wheel face 121, thus parallel to the tank centerline. In this respect, the face of the turntable star wheel 121 establishes a reference plane that represents a plane perpendicular to the longitudinal axis of the tank. At this point, the operator can set the digital readout 78a of the angle alignment mechanism 70a to zero to indicate that the spray gun's orientation is aligned with the longitudinal axis of the tank.

[0077] like Figure 8 As shown, after the can is placed in the recess 124 of the turntable 120, the operator moves the angle alignment mechanism 70a to the desired angle relative to the centerline of the can. The desired angle is selected based on the operator's experience using the paint spraying machine. Determining the desired angle may include trial and error, recommendations from the spray gun manufacturer and / or coating manufacturer, etc.

[0078] In the embodiment shown in the accompanying drawings, the longitudinal axis of the can is horizontal, so the orientation of the spray gun is horizontal both before and after the spray gun moves via the angle alignment mechanism 70a. In this respect, a horizontal orientation of the spray gun 20a is not necessary, as a non-horizontal orientation can be considered depending on the specific parameters of the application.

[0079] like Figure 9 As shown, after achieving the desired angular orientation of the spray gun 20a, the operator moves the X-direction and Y-direction linear alignment mechanisms 50a and 60a until the tip of the nozzle 22a of the spray gun 20a just leaves the inner edge of the tank 99a. Figure 10 This is an enlarged top view showing the relationship between the tip of the spray gun 20a and the edge of the can. The tip of the nozzle 22a is close to the edge of the can but does not touch it because the can is easily bent. The operator zeroes the digital readouts 58a and 68a of the X and Y direction linear alignment mechanisms 50a and 60a.

[0080] Next, the operator actuates the Y-direction sliding mechanism 52a to position the nozzle 22a at the desired radial position (i.e., the position relative to the longitudinal axis of the tank), such as... Figure 11 As shown, the Y-direction digital reading 58a is recorded. Next, the operator actuates the X-direction sliding mechanism 62a to position the nozzle 22a at the desired axial position, as shown. Figure 12 As shown, the X-direction reading 68a is recorded. After recording the linear and angular values, the process-based reference position of the spray gun 20a is set. Once the spray gun assembly 20a undergoes any movement, such as maintenance of the paint spraying machine, it can be reliably reset to its desired position by moving the alignment mechanisms 50a, 60a, and 70a to this predetermined process-based reference position reading. Furthermore, readings can be established for each can type (i.e., diameter and height), thereby significantly improving the speed and accuracy of switching from production of one can type to production of another. In this regard, the term "predetermined" as used herein refers to the target position or orientation of the setup steps for a specific can type.

[0081] It has been found that the above methods are limited in certain situations, for example, due to... Figure 7The limitations of precisely determining the perpendicularity of the spray gun assembly shown are as follows. In this regard, the outer contours of some spray gun assemblies may be irregular, making it difficult or prone to error to align the protractor or straight edges; the operator's skill level may introduce variability in alignment; and / or obtaining an unobstructed vertical view may be difficult or infeasible. Furthermore, as... Figure 9 and Figure 10 As shown, contact between the spray gun tip and the can may damage the nozzle spray tip and / or the determination of the nozzle's position relative to the edge of the can may introduce uncertainty.

[0082] Figures 13 to 26 Structures and methods for aligning support rail 34 and corresponding supports 36a and / or 36b are shown. Alignment structure 210 includes a support 236, a laser device 220, and a target device. Support 236 can be one or both of supports 36a and 36b, or other support structures of known dimensions. Laser device 220 can be a conventional laser alignment tool, such as a self-leveling laser type that produces a horizontal line H and a vertical line V regardless of device orientation. Alignment structure 210 will be described using a coordinate system including an X′ axis defined as parallel to the axis of rotation of the turntable and extending through the center line of the chuck 126 and the tank 99. The X′ axis is... Figure 14 The accompanying drawing shows a laser device 220, which is a crosshair. As explained more fully below, the invention is not limited to the use of a crosshair device.

[0083] The target device shown in the accompanying drawings includes a base 232 that engages with a vacuum chuck 126 or a similar device for holding the canister 99. Alternatively, the base 232 may be fixed to a turntable 120 or any other device for securing the target device; or a portion of the sprayer 110 may perform the function of the base, thus constituting a base.

[0084] The target device includes an arched target component 230a, a short-necked stepped target component 230b, and a long-necked stepped target component 230c. Each target component 230a, 230b, and 230c is mounted in a manner that aligns with the notch 124 (i.e., repeatable and accurate alignment), such that the center point C of the target component is aligned with the centerline of the tank 99. In the embodiment shown in the figures, each target component 230a, 230b, and 230c is fixed in its respective base 232.

[0085] like Figure 15The target device 230a shown includes a base 232a and an outwardly projecting dome 236a. The dome 236a includes a forward-facing surface 240a (i.e., the surface that the laser device 120 points to or is visible from). The dome 236a can be a hemisphere with a circular cross-section (cut in either or both of the vertical and horizontal planes), or it can have other arcuate shapes in its cross-section. Preferably, the dome 236a is symmetrical about both the horizontal and vertical planes. Asymmetrical target devices are also possible.

[0086] The target device of the second embodiment, such as Figure 21 The illustrated short-necked stepped target part 230b includes a base 232b, a base surface 235b, a neck 237b, and a front surface 240b located at the distal end of the neck 237b. In the embodiment shown in the figures, the base surface 235b is flat and perpendicular to the centerline of the can 99 (when in the spraying position). The neck 237b is cylindrical and extends forward relative to the base surface 235b, terminating at the front surface 240b. The front surface 240b is flat and perpendicular to the centerline of the can 99, and therefore parallel to the plane defined by the base surface 235b. In the embodiment shown in the figures, the center point C of the front surface 240b coincides with the X′ axis.

[0087] The target device of the third embodiment, such as Figure 25 As shown, the long-necked stepped target part 230c includes a base 232c, a base surface 235c, a neck 237c, and a front surface 240c located at the distal end of the neck 237c. In the embodiment shown in the figures, the base surface 235c is flat and perpendicular to the centerline of the can 99 (when in the spraying position). The neck 237c is cylindrical and extends forward relative to the base surface 235c, terminating at the front surface 240c. The front surface 240c is flat and perpendicular to the centerline of the can 99, and therefore parallel to the plane defined by the base surface 235c. In the embodiment shown in the figures, the center point C of the front surface 240c is located on the X′ axis.

[0088] The long-necked stepped target 230c is functionally similar to the short-necked stepped target 230b; the distance between surfaces 235c and 240c is greater than the distance between surfaces 235b and 240b. In other words, the target device 230c of the third embodiment has a longer neck than the neck of the target device 230b of the second embodiment.

[0089] To position the support rails 34 and / or brackets 36a, 36b, and thereby position the pre-positioned spray gun assemblies 20a and / or 20b, the laser device 220 is secured to the bracket 236. The self-aligning characteristic of the laser device 220 generates a horizontal line H and a vertical line V pointing towards the dome surface 240a, such as... Figure 14As shown. If lines H and V are perfectly linear and orthogonal to each other on the arch surface 240a, and their intersection point O coincides with point C on the arch surface 240a, then the position and angular relationship of the support 236 relative to the arch 236a in the YZ plane is correct, and therefore the track 34 is in proper alignment, which is referred to herein as the “alignment position”.

[0090] If the intersection point O of the crosshairs of laser lines H and V deviates from the center C of the vault surface 240a, then the laser 220 is not in position relative to the X′ axis, that is, the laser 220 is not in position in the YZ plane. Therefore, the position of the support 236 can be adjusted in the YZ plane toward the alignment point O located at the center C of the vault surface. After the intersection point O of the laser crosshairs is aligned with the center C formed on the vault surface 240a, the straightness of lines H and V can be evaluated. Any deviation of lines H or V from a straight line indicates that the laser device 220 is not angularly aligned with the vault 236a. Figure 16 Lines H and V are shown in the angular alignment position.

[0091] Figure 17 The line V is shown to deviate from the straight line, and it indicates that the laser device 220 is misaligned with the X′ axis by one degree, while points O and C coincide. Figure 18 , 19 Figures 20 and 20 show deviations of line V from a straight line of two, five, and ten degrees, respectively, indicating that as the misalignment of laser 220 relative to vault 236a about the vertical axis increases, the vertical line V becomes increasingly nonlinear. Therefore, the magnitude of the deviation from the straight line can be used as an estimate of the required movement of track 34. It is anticipated that angular movement of laser device 220 can alter the alignment in the YZ plane, making the alignment process described herein iterative.

[0092] Referring to the target device of the second embodiment, the short-necked stepped target 230b, Figure 22 The intersection point O of laser lines H and V is shown to be located at the center of front surface 240b. The coincidence of point O with the center C of front surface 240b indicates that the laser device 220 (and therefore the support 236) is correctly aligned. The portion H-235b of laser line H that hits the base surface 235b is aligned with the portion H-240b of laser line H that hits the front surface 240b. In this respect, when coplanar (e.g.) Figure 22 When (as shown), lines H-235b and H-240b are aligned, or when lines H-235b, H-240b, and the X′ axis are coplanar, lines H-235b and H-240b are aligned in three dimensions. The portion V-235b of the laser line V that hits the base surface 235b is aligned with the portion V-240b of the laser line V that hits the front surface 240b. When coplanar (as shown) Figure 22As shown, lines V-235b and V-240b are aligned, or lines V-235b and V-240b are aligned in three dimensions when lines V-235b, V-240b and the X′ axis are coplanar. Therefore, Figure 22 The laser 220 is shown to be aligned with the short-necked stepped target 230b in both the YZ plane and angle.

[0093] Figure 23 The misalignment of the base section line V-235b with the front section line V-240b is shown, indicating an angular misalignment, which can be clearly seen from the offset of line V-235b relative to line V-240b. Figure 23 The laser 220 is misaligned by one degree relative to the X′ axis, as observed on the short-necked stepped target 230b, while the intersection O of laser lines H and V coincides with the center C of the front 240b. Figure 24 The diagram shows a 10-degree misalignment of laser 220 relative to the X′ axis, demonstrating that as the misalignment of laser 220 relative to the X-axis increases, the displacement of vertical line V-235b relative to line V-240b increases. Therefore, the magnitude of the deviation between lines V-235b and V-240b can be used as an estimate of the required movement of track 34. It is anticipated that angular movement of laser 220 can alter the alignment in the YZ plane, making the alignment process described herein iterative.

[0094] It should be understood that the description of the alignment process of the long-necked target device 230c will be the same as the description of the alignment process of the short-necked stepped target 230b described above. Compared with the displacement of the target device 240b in the second embodiment described above, the larger neck length of the device 230c in the third embodiment provides a larger displacement between line V-235c and line V-240c, such as Figure 26 As shown.

[0095] A system for aligning spray guns of paint spraying machines in a can manufacturing production line allows the spray guns to be oriented at an angle relative to the longitudinal axis of the beverage can, with the spray gun nozzle adjacent to the lip of the beverage can. In this regard, a spraying system 10 can be employed as described above, wherein the gun mounting plate 76a and spray gun 20a are replaced with a reference fixing device 320 and a laser device (e.g., the laser device 220 described above). This alignment process is referred to as machine-based reference setting. The advantages are numerous: consistency between machines, consistency of setup and reset on each machine, reduced downtime between can type changes, operator-independent spray gun setting (quality improvement), non-contact spray gun setting (reduced nozzle damage), and repeatability of spray gun position.

[0096] refer to Figure 27The dimensions of the reference fixing device 320 are configured relative to the gun mounting plate 76a such that, when the laser device 220 is aligned with any target device described herein, replacing the reference fixing device 320 with the gun mounting plate 76a will place the spray gun assembly 20a in the desired predetermined position, for example... Figure 10 The position shown is such that the spray gun assembly 20a is oriented at an angle relative to the longitudinal axis of the beverage can, and the spray gun nozzle 22a is adjacent to the lip of the beverage can. The adjustment mechanism can then be zeroed or otherwise set. Figure 28 The spray gun assembly 20a is shown after the reference fixing device has been replaced with mounting plate 76a.

[0097] Machine-based baseline settings offer numerous advantages: consistency between machines within a spraying unit, consistent settings and resets on each machine, reduced downtime between can type changes, operator-independent spray gun settings (quality improvement), non-contact spray gun settings (reduced nozzle damage), and repeatability of spray gun positions.

[0098] This invention is disclosed through the use of embodiments, which are not intended to be limiting. Rather, the inventors intend that the invention be given the full scope defined by the claims. Several exemplary embodiments and / or alternatives are provided, and are not intended to be limiting. Therefore, any use of the terms “for example,” “such as,” and any other terms associated with examples or alternatives does not constitute a waiver of any manner of unnamed structures or functions.

Claims

1. A method for reproducibly aligning a spray gun of a paint spraying machine in a can manufacturing production line, the method comprising the steps of: Determine the angular orientation of the spray gun corresponding to the desired angle alignment with the spray gun; Determine a linear reference point and determine the linear position of the spray gun corresponding to the desired linear alignment of the spray gun; and Record the alignment coordinates of the spray gun relative to the angular orientation and the linear reference point; The subsequent alignment of the spray gun is achieved by resetting the spray gun to the recorded alignment coordinates.

2. The method according to claim 1, wherein, The step of determining the angular direction of the spray gun includes determining a reference plane, which is perpendicular to the longitudinal axis of the can at the position where the coating is to be sprayed.

3. The method according to any of the preceding claims, wherein, The steps of determining the angular orientation and the linear reference point include the following steps: (a) operating the spray gun to spray paint onto the interior of the can, (b) evaluating the characteristics of the paint coating on the interior of the can, (c) adjusting the position of the spray gun to improve the characteristics of the paint coating, and (d) repeating steps (a) to (c) until the desired alignment is achieved.

4. The method according to any of the preceding claims, wherein, The step of determining the angle of the spray gun includes the following steps: (e) adjusting the angle of the spray gun.

5. The method according to any of the preceding claims further includes the step of fixing the spray gun to the support at a desired angular direction.

6. The method according to any of the preceding claims, wherein, At least one of the steps of determining the linear reference point and determining the angular orientation of the spray gun includes adjusting the position of the spray gun by means of an alignment screw.

7. A system for reproducibly aligning a spray gun of a paint spraying machine in a can manufacturing production line, comprising: A support structure fixed relative to the base of the paint spraying machine, the support structure including a spray gun mounting component; A spray gun, which is fixed to the spray gun mounting; At least two linear alignment mechanisms adapted to move the spray gun mount relative to a reference point associated with the desired alignment of the spray gun; and An angle alignment mechanism adapted to move the spray gun mount relative to a desired angular direction of the spray gun; Specifically, after alignment is achieved at the reference point through iterative operations of the linear alignment mechanism and the angular alignment mechanism, the coordinates of the reference zero point can be recorded so that the spray gun can be subsequently aligned by locating the spray gun mounting component based on the coordinates.

8. The system according to claim 7, wherein, The linear alignment mechanism includes at least two linear actuators, wherein a first linear actuator is oriented to translate the spray gun mount along a first direction, and a second linear actuator is oriented to translate the spray gun mount along a second direction orthogonal to the first direction.

9. The system according to claim 7 or 8, wherein, The support structure includes a track that is angled relative to a vertical line, such that the first linear actuator and the second linear actuator can position the spray gun mount in the XYZ coordinates.

10. The system of claim 7, 8 or 9, further comprising a third linear drive assembly, wherein the first direction and the second direction define a horizontal XY plane, and the third linear drive is adapted to translate the spray gun mount along a vertical Z direction.

11. The system according to any one of claims 7 to 10, wherein, Each of the linear drives is a manual linear drive, which has a display indicating the position of the linear drive, wherein the position recorded by the display at the reference point enables subsequent alignment of the spray gun mount by resetting the linear drive to the recorded position.

12. The system according to any one of claims 7 to 11, wherein, Each of the linear actuators includes an actuator for moving the linear actuator, wherein, after determining the reference point, the control system is adapted to send a signal to the actuator to position the linear actuator at the reference point to achieve subsequent alignment of the spray gun.

13. The system according to any one of claims 7 to 12, further comprising an angle alignment mechanism assembly, said angle alignment mechanism assembly being a manual angle driver having a display indicating the angular position of said angle driver, wherein, The position recorded by the display allows for subsequent alignment of the spray gun mount by resetting the angle driver to the recorded position.

14. A system for aligning a spray gun of a paint spraying machine in a can manufacturing production line, comprising: A support structure fixed relative to the base of the paint spraying machine, the support structure including a spray gun mounting component; A reference fixing device, which is coupled to the spray gun mounting component; A laser device, which is fixed to the reference fixing device; as well as A target device, which is mounted at a predetermined position on the paint spraying machine, is positioned such that at least one laser line from the laser device irradiates the target device. The reference fixing device and the target device are configured to be replaceable by a spray gun fixing device, and the reference device is replaced by the spray gun fixing device and the spray gun after the laser device is aligned with the target device, thereby positioning the spray gun at a desired predetermined position.

15. The system according to claim 14, wherein, The support structure includes a track, and the laser device is coupled to the track via a bracket.

16. The system according to claim 14, wherein, The at least one laser line includes a horizontal laser line and a vertical laser line.

17. The system according to claim 16, wherein, The target device includes an outwardly protruding domed surface adapted to receive illumination from the horizontal laser line and / or the vertical laser line.

18. The system according to claim 17, wherein, Linear deviation of the horizontal laser line illuminating the dome surface indicates that the laser device is misaligned relative to the target device, and / or linear deviation of the vertical laser line illuminating the dome surface indicates that the laser device is misaligned relative to the target device.

19. The system according to claim 18, wherein, The linear deviation of the horizontal laser line indicates that the laser device is misaligned around the horizontal axis, and the linear deviation of the vertical laser line indicates that the laser device is misaligned around the vertical axis.

20. The system according to claim 19, wherein, The deviation of the intersection of the horizontal and vertical laser lines relative to the center of the vault indicates a misalignment of the laser device relative to the vault in a plane perpendicular to the axis of the laser device.

21. The system according to claim 16, wherein, The target device is a stepped device comprising a base surface, a neck, and a front surface; wherein the neck extends forward relative to the base surface such that the front surface is formed at the distal end of the neck.

22. The system according to claim 21, wherein, The front surface is flat, and the base surface is flat and parallel to the front surface, such that the collinearity deviation of the horizontal laser line illuminating the base surface relative to the horizontal laser line illuminating the front surface indicates that the laser device is misaligned relative to the target device, and / or the collinearity deviation of the vertical laser line illuminating the base surface relative to the vertical laser line illuminating the front surface indicates that the laser device is misaligned relative to the target device.

23. The system according to claim 21, wherein, The deviation of the intersection of the horizontal and vertical laser lines relative to the center of the front indicates that the laser device is misaligned relative to the target device in a plane perpendicular to the central axis.

24. A method for aligning a spray gun of a paint spraying machine in a can manufacturing production line, comprising: At least one laser line from a laser device is directed onto a target device, which is positioned to receive the illumination from the at least one laser line. The position of the support structure for maintaining the laser device is adjusted based on the linearity of at least one laser line and / or based on the deviation of the center of the laser line. Determine the reference point and the angle of the spray gun to achieve the desired alignment of the spray gun; as well as Record at least the alignment coordinates of the aforementioned reference points; The subsequent alignment of the spray gun is achieved by resetting the spray gun to the alignment coordinates associated with the reference point.

25. The method according to claim 24, wherein, The support structure includes a track, and the step of adjusting the position of the support structure includes moving the track and / or moving the bracket supported by the track.

26. The method according to claim 24, wherein, The step of irradiating at least one laser line includes irradiating the target device with a horizontal laser line and a vertical laser line.

27. The method according to claim 26, wherein, The target device includes an outwardly protruding dome surface, and the step of irradiating at least one laser line includes irradiating the horizontal laser line and / or the vertical laser line onto the dome surface.

28. The method according to claim 27, wherein, Linear deviation of the horizontal laser line illuminating the dome surface indicates that the laser device is misaligned relative to the target device, and / or linear deviation of the vertical laser line illuminating the dome surface indicates that the laser device is misaligned relative to the target device.

29. The method according to claim 28, wherein, The linear deviation of the horizontal laser line indicates that the laser device is not aligned with the horizontal axis, and the linear deviation of the vertical laser line indicates that the laser device is not aligned with the horizontal axis.

30. The method according to claim 27, wherein, The deviation of the intersection of the horizontal and vertical laser lines relative to the center of the vault indicates that the laser device is misaligned relative to the vault in a plane perpendicular to the center.

31. The method according to claim 26, wherein, The target device is a stepped device comprising a base surface, a neck, and a front surface; and the neck extends forward relative to the base surface such that the front surface is formed at the distal end of the neck.

32. The method according to claim 31, wherein, The front surface is flat, and the base surface is flat and parallel to the front surface, such that the collinearity deviation of the horizontal laser line illuminating the base surface relative to the horizontal laser line illuminating the front surface indicates that the laser device is misaligned relative to the target device, and / or the collinearity deviation of the vertical laser line illuminating the base surface relative to the vertical laser line illuminating the front surface indicates that the laser device is misaligned relative to the target device.

33. The method according to claim 31, wherein, The deviation of the intersection of the horizontal and vertical laser lines relative to the center of the front indicates that the laser device is misaligned relative to the target device in a plane perpendicular to the central axis.

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