milling spindle fan

Abstract

A milling fan comprises fan blades with a radially inner end and a radially outer end, and a mounting sleeve with a radially inner surface and a radially outer surface. The radially inner surface forms a tool contact surface, and the radially outer surface engages with the radially inner ends of the fan blades. The milling fan also includes an outer sleeve that connects the radially outer ends of the fan blades, forming a ring.

Description

[0001] The present description relates to the field of machining and in particular to a milling machine with a fan for removing deposits.

[0002] Milling machines are used in various industries for shaping and cutting materials such as metals, plastics, and composites. These machines typically use a rotating cutting tool, called a milling cutter, to remove material from a workpiece. The workpiece is fixed to a table. The table can move relative to the milling cutter, or the milling cutter can move relative to the table, to allow for precise positioning and feeding of the workpiece into the cutting tool. On some milling machines, the movement of the milling cutter relative to the workpiece can be controlled manually by an operator or with a numerical control unit (CNC).

[0003] Depending on the type of workpiece being machined, a fluid can be applied to the milling tool and the workpiece to reduce friction and the heat generated during the machining process. Additionally, a vacuum source can be used with some materials to collect the waste material produced by the milling cutter.

[0004] EP 1 872 901 A1 describes a rotating machining tool with a device for removing machining chips. The tool has a body comprising complementary structural elements that form a suction turbine equipped with radial blades. Each blade is bounded by front and rear free edges, with the blades extending between a central tubular ring and a cylindrical circumferential ring. The edges are each oriented towards one side of a front cutting portion and a rear mounting portion of the body, with the tool being rotated to generate an edge-to-edge airflow.

[0005] US 2023 / 0201985A1 describes a milling tool for a dental milling machine and the arrangement of a milling spindle and a milling tool. The milling tool for a dental milling machine comprises a base body with a rotary axis. A shank for clamping the milling tool is provided at a first end of the base body. A cutting edge is arranged at a second end of the base body. A receiving section is provided on the base body between the shank and the cutting edge. A fan wheel is arranged on the receiving section of the base body. The fan wheel is designed such that, when the milling tool is driven in a direction of rotation intended for chip removal, an airflow is generated by the fan wheel in the direction from the fan wheel toward the cutting edge of the milling tool.

[0006] US 5,772,367 A describes a device for a rotating tool attachment that provides an airflow near a work area without requiring a separate vacuum or compressed air supply. The device is mounted on the shaft of the rotating tool attachment and is provided with a plurality of vanes that direct the airflow through a cylindrical housing toward or away from the work area. A central opening allows the attachment to be elastically mounted to the tool. The attachment can provide both suction and compressed air to the work area. Several embodiments are disclosed to direct the exhausted air in different directions depending on the tool application and the operator's orientation. A filter can be integrated into the attachment to capture dust and debris carried away from the work area by the airflow.

[0007] DE 20 2015 004 924 U1 describes a fan-like screw nut with dynamic equilibrium. The screw nut comprises: a screw part that is hollow cylindrical and has a front end face, an outer circumferential surface, a mounting opening, a plurality of tool positioning holes, and more than one counterweight hole, wherein the mounting opening extends through the center of the front end face and is stepped, wherein the mounting opening forms a circular cone surface near the front end face, wherein a thread is arranged circumferentially in the rear section of the mounting opening, wherein a retaining ring is arranged between the circular cone surface and the thread of the mounting opening, enclosing half the inner circumference of the mounting opening, wherein eccentric holes are formed on the retaining ring and the inner wall of the mounting opening.wherein the tool positioning holes and the more than one counterweight hole are spaced apart and distributed over the front end face, the more than one counterweight hole and the retaining ring being located on the same side of the screw part; - a plurality of blade parts distributed over the outer circumferential surface of the screw part, with an airflow space formed between each pair of blade parts, the blade parts being spirally shaped; and - a ring frame part, which is a frame integrally connected to the respective front outer edge of the blade parts, the inner circumferential wall of the ring frame part enclosing the airflow spaces, thereby creating a plurality of through-holes.

[0008] EP 2 422 925 A1 describes a removal device for removing particles from a machining tool, in particular a tool or assembly, with a vane wheel which is designed to generate an airflow for removing particles that arise during machining with the machining tool, and with a separator upstream of the vane wheel which separates particles from the air drawn in by the vane wheel before passing the vane wheel, wherein at least the vane wheel can be attached to the machining tool in such a way that the vane wheel rotates with the machining tool about its machining axis.

[0009] US 2017 / 0341115 A1 describes a machine tool accessory for chip removal. In a preferred embodiment, a set of angled vanes attached to a rotating part of the machine tool, when that rotating part is facing the workpiece, removes chips from the workpiece during machine operation without the need to add other expensive chip removal parts or integrate complicated chip removal systems into the machine tool. The vanes on the rotating part utilize the motion of that rotating part to generate the necessary air force to blow chips out of and away from the workpiece. Among the many different possibilities considered, the rotating part could be a spindle, a tool holder, a milling cutter, or any other rotating part of a machine tool that is facing the workpiece during machine operation.Additionally, the set of angled wings can be attached to an inner hub mounted around or on the rotating part. The angled wings can rotate freely from other parts if their composition, whether metallic or non-metallic, makes them sufficiently rigid to exert the necessary air force on the workpiece during machine operation and at high rotational speeds. Furthermore, the outer edge of the angled wings can be connected to a surrounding cover to hold them in the required angled position, thus ensuring the necessary air force is applied to the workpiece. O-rings can also be used to secure the inner hub to the rotating part, providing another way to firmly and securely attach the machine tool's chip removal device to the rotating part.

[0010] CN 1 10 465 807 A describes a turning and milling machine for valve machining. Structurally, the turning and milling machine comprises an alarm lamp, a numerical control panel, a lathe base, a sliding safety door, and a composite machine body. Since the turning and milling machine is equipped with a chip collection device, machining a valve generates an upward airflow within the safety cover, causing iron chips to flow upwards in a milled slot in the valve along with the airflow and be adsorbed on the underside of a magnetic adsorption block.When a hole in a workpiece is machined upwards, the iron chips from the milling process remain in the bore and accumulate, the iron chips and a milling spindle become entangled, and the iron chips are thereby sprayed everywhere, injuring workers; this is avoided, and the quality and safety of valve machining are improved.

[0011] Accordingly, the object of the present invention is to provide a device with improved, wear-free and simplified flow guidance without the use of additional components, such as air or vacuum sources.

[0012] The problem is solved by the subject matter of the independent claim.

[0013] The invention describes a milling fan. The milling fan comprises fan blades with a radially inner end and a radially outer end, as well as a mounting sleeve with a radially inner surface and a radially outer surface. The radially inner surface comprises a tool contact surface, and the radially outer surface engages with the radially inner ends of the fan blades. The milling fan also includes an outer sleeve that connects the radially outer ends of the fan blades and forms a ring. The mounting sleeve extends over a first axial length relative to an axis of rotation of the milling fan, and the outer sleeve extends over a second axial length relative to the axis of rotation of the milling fan, the second axial length being greater than the first axial length. The mounting sleeve is partially axially offset from the outer sleeve relative to an axis of rotation of the milling fan.Furthermore, the mounting sleeve is offset from the outer sleeve by at least % of the axial length of the mounting sleeve. Additionally, an upstream end of the mounting sleeve, adjacent to an inlet, is recessed into the outer sleeve, such that the upstream ends of the mounting sleeve and the outer sleeve are at least partially axially offset from each other. Furthermore, a downstream end of the mounting sleeve projects axially beyond an axial end of the outer sleeve at the outlet, such that the downstream ends of the mounting sleeve and the outer sleeve are at least partially axially offset from each other.

[0014] In one embodiment, the outer sleeve has a conical shape.

[0015] In one embodiment, the radially inner end of each of the fan blades is offset relative to a corresponding radially outer end of the fan blades.

[0016] In one embodiment, the majority of the fan blades have a radially inner chord length near the radially inner end of each fan blade that is smaller than a radial chord length near the radially outer end of each fan blade.

[0017] In one embodiment, the radially inner ends of the fan blades are axially offset outwards relative to the axis of rotation of the milling fan from an axial end of the outer sleeve.

[0018] In one embodiment, the radially outer end of each fan blade is offset axially outwards from an axial end of the mounting sleeve relative to an axis of rotation of the milling fan.

[0019] In one embodiment, the mounting sleeve includes a mounting opening for receiving a fastening element, and the mounting opening is located axially outside an axial end of the outer sleeve with respect to an axis of rotation of the milling fan.

[0020] In one application example, a milling machine is described. The milling machine comprises a drive motor engaged with a spindle, a tool mounted on the spindle and configured to rotate with the spindle, and a milling fan according to the invention, mounted on the tool and configured to rotate with the tool. The milling fan comprises fan blades with a radially inner end and a radially outer end, as well as a mounting sleeve with a radially inner surface and a radially outer surface. The radially inner surface comprises a tool contact surface, and the radially outer surface engages with the radially inner ends of the fan blades. The milling fan also comprises an outer sleeve that connects the radially outer ends of the fan blades, forming a ring.

[0021] In one embodiment, the outer sleeve has a conical shape.

[0022] In one embodiment, the radially inner end of each of the fan blades is offset relative to a corresponding radially outer end of the fan blades.

[0023] In one embodiment, the fan blades have a radially inner chord length near the radially inner end of each fan blade that is smaller than a radial chord length near the radially outer end of each fan blade.

[0024] In one embodiment, the mounting sleeve extends over a first axial length relative to an axis of rotation of the milling fan, and the outer sleeve extends over a second axial length relative to the axis of rotation of the milling fan, the second axial length being greater than the first axial length.

[0025] In one embodiment, the mounting sleeve is partially axially offset from the outer sleeve relative to a rotational axis of the milling fan.

[0026] In one embodiment, the mounting sleeve includes a mounting opening for receiving a fastening element, and the mounting opening is located axially outside an axial end of the outer sleeve with respect to an axis of rotation of the milling fan.

[0027] In one application case, a method for operating a milling machine to produce a workpiece is described. The method comprises receiving a toolpath representative of a component with a control unit and instructing a tool to engage the workpiece and selectively remove material from it while following the toolpath. The method also includes generating an airflow with a milling fan according to the invention in an interface between the tool and the workpiece to remove deposits from the toolpath by selecting a rotational speed for the tool based on the workpiece material and a feed rate of the tool.The milling fan comprises fan blades and a mounting sleeve with a radially inner surface and a radially outer surface, wherein the radially inner surface has a tool mounting surface in direct contact with the tool, and the radially inner ends of the fan blades extend radially outward from the radially outer surface of the mounting sleeve. The milling fan also comprises an outer sleeve that connects the distal ends of the fan blades, forming a ring. Fig. Figure 1 is a schematic representation of an exemplary milling machine with a milling fan. Fig. Figure 2 is a schematic representation of a top view of the milling fan of Fig. 1. Fig. Figure 3 is a schematic representation of a side view of the milling fan of Fig. 1. Fig. Figure 4 is a schematic representation of a perspective top view of the milling fan of Fig. 1. Fig. Figure 5 is a schematic representation of a lower perspective sectional view of the milling fan. Fig. 1. Fig. Figure 6 is a flowchart of an exemplary procedure for operating the milling machine of Fig. 1.

[0028] Fig. Figure 1 shows a schematic view of a milling machine 20, where identical numbers denote identical parts that refer to the drawings, and identical reference numbers refer to identical components. The milling machine 20 enables the movement of a milling cutter, e.g., a tool 38, relative to a workpiece 39 on a workpiece carrier 41. In the example shown, the workpiece 39 is made of a clay-based material. A characteristic of milling a clay-based material is that deposits generated during milling can accumulate along a toolpath of the tool 38 or become embedded in a finished surface of the workpiece 39. This impairs the surface quality of the workpiece 39 and can lead to wear of the access tool. Furthermore, the size and volume of the particles that accumulate can vary depending on the feed rate of the tool 38.Furthermore, this disclosure is applicable to the milling of workpieces that contain materials other than clay, such as materials or metal.

[0029] In the example shown, the milling machine 20 comprises a frame 21 that supports the milling machine 20 on a floor surface. The milling machine 20 is configured to allow the movement of the tool 38 along an x-axis, a y-axis, and a z-axis. A vertical guide column 22 includes a motor 24 that moves a horizontal crossbar 26 along the z-axis in a track extending along the vertical guide column 22. The horizontal crossbar 26 includes a motor 28 that moves a second crossbar 30 along the x-axis in a track extending along the horizontal crossbar 26. Furthermore, the second horizontal crossbar 30 includes a motor 32 that moves the tool 38 along the y-axis in a track extending along the second horizontal crossbar 30. This configuration of the milling machine 20 is generally referred to as a three-axis milling machine, i.e., x-axis, y-axis, and z-axis.However, the milling machine 20 can be configured so that the workpiece 39 is moved along additional axes by manipulating the workpiece carrier 41, for example along at least a first rotary axis R1 that runs vertically through the workpiece 39, or a second rotary axis R2 that tilts the workpiece 39, as in . Fig. Figure 1 shows that using these additional axes would allow milling machine 20 to operate as a five-axis milling machine. Furthermore, this description also applies to milling machines with other configurations.

[0030] The milling machine 20 has a drive motor 34 that rotates the tool 38 at a predetermined speed. The tool 38 is attached to the milling machine by a chuck 36; however, other types of fixtures can also be used to attach the tool 38 to the drive motor 34. A milling fan 40 is attached directly to the tool 38, so that the milling fan 40 rotates at the same speed as the tool 38.

[0031] Furthermore, the milling machine 20 can be set up manually or with the aid of an electronic control unit 70. The electronic control unit 70 can be arranged in conjunction with the motors 24, 28, 32, and 34 to control the movement of the tool 38 along the x, y, and z axes. The electronic control unit 70 can alternatively also be referred to as a control module, control unit, control unit, computer, etc. The electronic control unit 70 can include a computer and / or processor 72 as well as software, hardware, memory, algorithms, etc., for managing and controlling the milling machine 20. Thus, a method described below and generally referred to in Fig. 2, which is represented as a program or algorithm that can be partially configured on the electronic control unit 70. The electronic control unit 70 can include a device capable of performing the necessary tasks for controlling the operation of the milling machine 20.

[0032] The electronic control unit 70 can be implemented as one or more digital computers or host machines, each comprising one or more processors 72, a read-only memory (ROM), a random access memory (RAM), an electrically programmable read-only memory (EPROM), optical drives, magnetic drives, etc., a high-speed clock, an analog-to-digital (A / D) circuit, a digital-to-analog (D / A) circuit, an input / output (I / O) circuit, I / O devices and communication interfaces, and signal conditioning and buffer electronics. The computer-readable memory can comprise a non-volatile / tangible medium involved in providing data or computer-readable instructions. The memory can be non-volatile or volatile. Non-volatile media can be, for example, optical or magnetic disks and other persistent storage media.An example of volatile memory is dynamic random-access memory (DRAM), which can represent main memory. Other forms of memory include, for example, a flexible disk, a hard disk, a magnetic tape or other magnetic medium, a CD-ROM, a DVD and / or other optical medium, as well as other possible devices such as flash memory.

[0033] The electronic control unit 70 comprises a tangible, non-transient memory 74 in which computer-executable instructions, including one or more algorithms, for controlling the operation of the milling machine 20 are stored. The algorithm(s) in question may, in particular, include an algorithm configured to instruct the milling machine 20 to follow a toolpath for the tool 38 that results in the formation of a finished workpiece, as explained in more detail below with reference to method 100.

[0034] As in the Fig. As shown in Figures 2-5, the milling fan 40 comprises a mounting sleeve 42, a plurality of fan blades 48, and an outer sleeve 50. In the illustrated example, the mounting sleeve 42 is cylindrical and has a radially inner surface 44 that forms a tool contact surface for direct engagement with the tool 38. The mounting sleeve 42 also comprises a radially outer surface 46 with radially inner ends of the fan blades 48 extending radially outward from this surface. The axial ends of the mounting sleeve 42 may also have a space 47 extending from the axial ends, with a radial thickness less than the radial thickness of a central portion of the mounting sleeve 42. In this description, the terms "radial," "axial," or "longitudinal" refer to the axis of rotation A of the milling fan 40 unless otherwise specified.

[0035] The mounting sleeve 42 also includes a mounting opening 43 for receiving a fastening element 45, e.g., an adjusting screw. The mounting opening 43 is located axially outside an axial end of the outer sleeve 50 with respect to axis A.

[0036] In the illustrated example, the fan blades 48 extend radially outwards from a proximal or radially inner end of the fan blade 48 at the mounting sleeve 42 to a distal or radially outer end at the outer sleeve 50. As shown in Fig. As shown in Figure 2, the fan blades 48 extend in the radial direction and in the circumferential direction, such that the radially outer ends of the fan blades 48 are offset relative to the radially inner ends of the fan blades 48.

[0037] As in the Fig. As shown in Figures 4-5, the fan blades also have a pressure or concave side 56 opposite a suction or convex side 58. Furthermore, the chord length between the leading and trailing edges of each fan blade 48 at the radially inner or proximal end is shorter than the chord length at the radially outer or distal end of each fan blade 48. The mounting sleeve 42 also has an axial length that is shorter than the axial length of the outer sleeve 50.

[0038] In the illustrated example, the outer sleeve 50 comprises a radially inner surface 52 and a radially outer surface 54. The outer sleeve 50 has a conical shape, tapering from an end near an inlet 60 of the milling fan 40, which draws in air during rotation, to an outlet 62 that expels air from the milling fan 40. Furthermore, as shown in the Fig. Figures 2 and 4-5 show that an upstream end of the mounting sleeve 42, adjacent to the inlet 60, is recessed into the outer sleeve 50, such that the upstream ends of the mounting sleeve 42 and the outer sleeve 50 are at least partially axially offset from each other. Furthermore, a downstream end of the mounting sleeve 42 projects axially beyond an axial end of the outer sleeve 50 at the outlet 62, so that the downstream ends of the mounting sleeve 42 and the outer sleeve 50 are at least partially axially offset from each other. In this description, upstream and downstream refer to a flow direction of air through the milling fan 40 during normal operation, which generates an airflow from the outlet end 62 and over the tool 38. Additionally, the radial inner ends of the fan blades 48 are at least partially offset in a downstream direction relative to the radial outer ends of the fan blades 48.

[0039] Furthermore, the axial length of the mounting sleeve 42 is less than the axial length of the outer sleeve 50. Additionally, the mounting sleeve 42 is axially offset from the outer sleeve 50 by at least 50% of its axial length, such that more than 50% of the axial length of the mounting sleeve 42 is spaced outwards from one of the axial ends of the outer sleeve 50. The radially inner ends of the fan blades 48 are also partially offset axially outwards from one of the axial ends of the outer sleeve 50.

[0040] Fig. Figure 6 shows an example of a method 100 for operating the milling machine 20 to bring the workpiece 39 into a desired shape. The method 100 begins in block 102 with the electronic control unit 70 receiving a toolpath representing the desired shape of the workpiece 39. The method then proceeds to block 104.

[0041] In block 104, the electronic control unit 70 instructs the tool 38 to engage the workpiece 39 and selectively remove material from it as it follows the toolpath. In addition to controlling the tool 38, the electronic control unit 70 selects a rotational speed for the tool 38 based on at least one material type of the workpiece 39 or a feed rate of the tool 38. In this way, the milling fan 40 can generate sufficient force to remove deposits in the area of ​​an intersection between the tool 38 and the workpiece 39. The process 100 then proceeds to block 106, where the milling fan 40 generates an airflow that removes the deposits produced by the tool 38 as the tool engages the workpiece 39.One feature of this configuration is that no additional energy source is required to generate the airflow, as it is generated directly by the rotation of the tool.

Images