GB2583099A

GB2583099A - Precision machining apparatus

Info

Publication number: GB2583099A
Application number: GB1905322.2A
Authority: GB
Inventors: Stewart Hall James; Graham Hall James
Original assignee: Tannlin Technology Ltd
Current assignee: Tannlin Technology Ltd
Priority date: 2019-04-15
Filing date: 2019-04-15
Publication date: 2020-10-21
Anticipated expiration: 2039-04-15
Also published as: GB201905322D0; WO2020212687A1; GB2583099B

Abstract

A precision laser machining apparatus 1, comprising; i) a linear track 5; ii) a machining head 7 moveable along the linear track, the machining head comprising a laser 9 operable to emit a beam which intersects an R-axis wherein movement of the machining head along the linear track causes the intersection of the beam and the R-axis to move along the R-axis, and, iii) a workpiece support platform rotatable around a Theta-axis, wherein the Theta-axis and R-axis intersect with, and are orthogonal to, one another. The machining head may move between two end stops, defining first and second limit points of the intersection of the beam and the R-axis along the R-axis (the first and second limit points are optionally equidistant from the intersection between the two axes). The apparatus may be configured to machine a workpiece formed of a sheet material and may comprise a loading arrangement (such as a robotic arm) for grasping a workpiece and placing the workpiece on the support platform. A second aspect is directed towards a method of laser machining a workpiece.

Description

PRECISION MACHINING APPARATUS

Field of the Invention

The invention relates to precision machining apparatus, and laser machining in particular.

Background to the Invention

Precision machining, such as laser machining, is commonly used to form surface patterns or to cut through blank work pieces, to form precision parts for use in a wide range of industries. Precision machining is used for example to form stencils or masks for solder paste printing of circuit boards, or templates for use in making other electronics components. Laser machining is also used to manufacture precision mechanical parts for the automotive, aerospace, personal care, medical and other industries.

Laser machining in particular may also be applied to a wide range of materials, including metal workpieces, ceramics and plastics.

Precision laser machining requires precise positioning and support of a workpiece, and precise control over the position of the laser and the work piece.

Conventionally, a workpiece is supported in a fixed position and a machining head is movable along two orthogonal linear axes. The head is normally moveable along a gantry which bridges the work piece and any supporting or ventilation structures. The gantry has a track which defines one axis and itself is moveable along parallel rails either side of the machining apparatus, which run perpendicular to the gantry.

The precise position of the machining head and its trajectory is sensitive to any deviance from orthogonality of the axes, which might for example be caused by one end of a gantry experiencing greater friction than the other.

Whilst these can be addressed in some situations by increasing rigidity of the apparatus, this can increase costs to make and run the machining apparatus. In addition, an increased moving mass normally compromises the speed at which the apparatus can operate.

The machining head and gantry typically role along a track or rails, driven by a servomotor. Any discrepancy between positive and negative motions along the track axes can also introduce errors and lead to greater manufacturing tolerances. This can be exacerbated where machining patterns require complex combinations of ±X and ±Y actuations to follow a given path, for example to follow a curved path.

There remains a need to address or mitigate one or more of these issues.

Summary of the Invention

An aspect of the invention relates to a precision laser machining apparatus, comprising: a linear track and a machining head moveable along the linear track; the machining head comprising a laser operable to emit a beam which intersects an R-axis; wherein movement of the machining head along the linear track causes the intersection of the beam and the R-axis to move along the R-axis; and a workpiece support platform rotatable around a Theta-axis; wherein the Theta-axis and R-axis intersect with, and are orthogonal to, one another.

In comparison to a conventional XY-axis gantry system, the precision laser machining apparatus requires fewer moving components and so a lower moving mass, to facilitate two-dimensional movement of the machining head in relation to a workpiece on the support platform. Lower moving mass may be moved more rapidly and/or with a lower power requirement.

Moreover, since neither axis is required to move, reducing machining tolerances are possible. The apparatus is of particular utility in machining patterns having an axial symmetry, or patterns wherein a predominance of the features to be machined have an axial symmetry.

In the interests of minimising moving mass during machining, the precision laser machining apparatus advantageously includes the movement along the R-axis and the Theta-axis, and no other degrees of freedom of movement of the laser machining head.

By patterns wherein a predominance of features to be machined have an axial symmetry, we refer to machining patterns in which a high proportion (for example at least 50%, 60%, 70%, 80% or 90%, or in some embodiments all) of the features of the machining pattern are one or other of radial features (i.e. extending radially from the Theta-axis), or curves defined in relation to the Theta-axis, such as circular features or portions thereof (e.g. radiused curves), or oval features or portions thereof.

By precision laser machining we refer to a process by which a machining pattern is made onto, into or through a workpiece by a laser machining head. The position of the machining head is robotically movable under computerised control. Such methods may be generically referred to as "CNC" (which stands for computer numerical control) laser or plasma machining. Precision laser machining may be required to machine a machining pattern within a tolerance (of the dimensions of the machined features) of less than 10 pm, or less than 5pm or less than 1 pm (i.e. sub-micron precision).

The machining head may comprise any suitable type of laser. The type and power can be selected according to the requirements of a particular workpiece material. For example the laser may be a CO2 laser, a neodymium (Nd) laser or a neodymium yttrium-aluminium-garnet (Nd:YAG) laser.

The machining head typically moves between two end stops. The end stops will define first and second limit points of the intersection of the beam along the R-axis.

The first limit point may be closer to the intersection the second limit point.

For example, the apparatus may be configured to allow the intersection of the beam and the R-axis to move, during a machining process, radially along only a positive radius in relation to the Theta-axis (i.e. along a radius extending between the Theta-axis and the second limit point).

Since the support platform is continuously rotatable around 360 degrees, an apparatus so configured to move the beam only along a positive radius provides for a maximum available machining area for a given length of linear track.

It should be understood that embodiment the apparatus which are configured in this way, the first limit point is close to, but desirably slightly beyond the intersection (for example by between around 0-10 mm) along a negative radius, so as to allow the apparatus to be calibrated. In some embodiments, the first limit point is sufficiently far from the intersection for the machining head to partially or fully clear the support platform (i.e. when viewed in a direction along the Theta-axis), for example to facilitate placement of a workpiece on the platform, and/or removal of a machined workpiece therefrom.

A small amount of travel along the negative radius may also assist in minimizing the required movements for certain machining patterns. For example, the distance along the positive radius between the Theta axis and the second limit point may be around 5, 10, 20 or 30 times or more than the distance along the negative radius between the Theta-axis and the first limit point.

The apparatus may be configured to allow the intersection of the beam and the R-axis to move radially along a positive and a negative radius in relation to the Theta-axis.

In further embodiments, the first and second limit points may be equidistant from the Theta-axis.

The machining head may be oriented to project the beam parallel to the Theta-axis.

The apparatus may be configured to machine workpiece formed of a sheet material, such as a metal sheet.

The apparatus may therefore be configured such that the R-axis can therefore notionally be defined along a surface, or a plane defined by the sheet material of a workpiece supported on the support platform.

Accordingly, the support platform, or turntable, may comprise a generally planar support surface or include a collection of vertices or surfaces together defining support plane.

The support platform may be vented. The support platform may include a plurality of apertures therethrough to allow machining debris and gasses to move away from the workpiece and to assist in irrigating the workpiece to clear such material.

The support platform may be configured to receive a material fixture, wherein a said material fixture in use defines the support plane. The support platform may for example include a recessed portion in which a material fixture can be placed, or raised lips or the like, to retain the position of a material fixtured placed therebetween.

A material fixture may include an interlocking lattice of metal "blades" formed from a sheet material such as mild steel, or in some circumstances nickel or stainless steel.

Conventionally, each blade is provided with regular triangular crenallations, the tips of which are co-planar, to support a workpiece. A material fixture may comprise a network of cast or moulded support members, the upper portions of which may optionally be provided with such crenellations.

In laser cutting processes, the underlying support for a workpiece may become damaged under the action of the laser. The use of a replaceable or consumable material fixture supported by the support platform (for example on top of or within a well defined by the support platform) may therefore be desirable for some applications.

The support platform of plane may be horizontal, in normal use of the precision laser machining apparatus.

In use, each workpiece may be manually loaded on to the support platform.

The precision laser machining apparatus may alternatively be configured for automated loading of each workpiece. The apparatus may for example include a 6-axis robotic arm system for loading (and typically also unloading) of each workpiece, for example. Other robotics may alternatively be used for loading and/or unloading of a workpiece, such as a cartesian, or gantry, robot or a SCARA (selective compliance assembly robot arm) or the like.

Such robots or robotic arms may be configured to pick a workpiece from a supply (e.g. a stack) of blank workpieces, remove a machined workpiece to a different location, and select a further blank workpiece (said sequence being potentially repeated multiple times).

In some embodiments, the apparatus includes a loading arrangement, for automated loading of workpiece onto the support platform.

It may be required to portion sheet material into smaller workpieces, for example by cutting lengths from a roll of sheet material. The loading arrangement may therefore comprise a sheet inlet for receiving sheet material (e.g. from a roll), and/or a segmenting apparatus, for separating each workpiece from the sheet material. Each workpiece may be separated for example by cutting (including laser cutting, or mechanical means), stamping or the like.

The loading apparatus may be configured to advance the sheet material over the support structure, to separate a workpiece therefrom, and then to withdraw the remaining sheet material sufficient to allow the workpiece to be freely rotated during machining.

The machining head may be used as the segmenting apparatus.

The loading arrangement may further include a removal arrangement for removing a machined workpiece from the support structure. Robotic arrangements for lifting and moving articles, by gripping, suction, magnetism or the like are well known in the art.

In some embodiments, a machined workpiece may be displaced by advancing the sheet material (i.e. by pushing the workpiece from the support structure).

The precision laser machining apparatus may be configured to allow for fine adjustment of the orientation and/or position of one or both axis (i.e. to ensure that the axes are orthogonal and intersect, for example on initial setup of later recalibration). Adjustment of the or each axis may be facilitated by shims, worm drives, precision grub screws and the like.

The precision laser machining apparatus may comprise a control system, operable to control the positions of the machining head and the support platform and regulate operation of the laser, to execute a desired machining pattern. The control system may be further operable to control automated loading, segmenting and removal operations as discussed herein.

The control system may comprise suitable robotic actuators to facilitate precise movement of the machining head along the R-axis and the support platform around the Theta-axis. The componentry for such control systems are well known in the art.

For example, in some embodiments, the machining head moves along the track driven by a linear motor or motors, which may provide sub-micron or sub nanometre positioning accuracy of the laser machining head. In other embodiments, the apparatus comprises a belt drive to translate rotary motion of a precision rotary motor into linear motion along the linear track, or a ball screw drive (wherein the laser machining head is coupled to a helical raceway, and a threaded drive rod is driven by a rotary motor to translate rotary motion into linear motion along the track).

Any suitable rotary device may be used to drive rotation of the support platform around the Theta-axis, including but not limited to a direct drive motor, a servo motor, a stepper motor or the like.

The control system will be controlled by a computer processing resource. The computer processing resource may form part of the precision laser machining apparatus or may be a separate system communicating therewith.

The computer processing resource may include a coordinate transform module, operable to convert a machining pattern from cartesian coordinates (typically a 2-D, "XY" coordinate system) to polar coordinates (typically a 2-D, "R-Theta" coordinate system, were R values correspond to a distance along the R-axis from the intersection and Theta values correspond to rotation angle around the Theta-axis from a predetermined zero point -conveniently aligned with the R-axis).

The control system may include a data store, to receive machine and store machining patterns.

The computer processing resource may include a CAD design module, operable to generate a machining pattern (in cartesian coordinates, for later transform to polar coordinate, or directly in polar coordinates).

The computer processing resource may include multiple computer processors, each comprising one or more of the above modules. For example, a computer processor may be dedicated to driving the machining apparatus to execute a machining pattern in polar coordinate form received from a further computer processor in communication therewith.

In some embodiments, for example, a machining pattern is externally generated by one computer processor (such as a PC running suitable CAD software) and transmitted to a second computer processor, for example forming part of the machining apparatus, which then executes control software to run the control system. The coordinate transform module may form part of one or other of the first and second processors (i.e. in the form of software executed by a said processor).

The invention is not limited to any particular arrangement of computerised software and hardware control, and the skilled person will appreciate that further arrangements and allocations of resource may be possible in order to cause the control system to effect control over the positions of the machining head and support platform, and the actuation of the laser, to execute a desired machining pattern.

The invention therefore extends in further aspects to a computer processing resource configured to the control system to effect control over the positions of the machining head and support platform, and the actuation of the laser, to execute a desired machining pattern; and to computer readable storage media storing software for so doing.

In another aspect of the invention there is provided a method of precision laser machining a workpiece according to a machining pattern, the method comprising: providing a workpiece on a support platform; providing a machining head comprising a laser; laser machining the workpiece with the laser by; emitting a beam from the laser to intersect an R-axis; moving the machining head linearly to cause the intersection of the beam and the R-axis to move along the R-axis; and rotating the support platform around a Theta-axis that is orthogonal to, and intersects with, the R-axis.

The method may comprise precision laser machining a workpiece formed of a sheet material. The R-axis may extend along a surface of, or parallel to, the workpiece formed of a sheet material.

The method may comprise emitting the beam parallel to the Theta-axis.

The method may comprise laser machining, including etching, into a surface of the workpiece. The method may comprise laser cutting through the workpiece.

The method may comprise rotating the support platform in only one direction, in order to execute the machining pattern.

During machining, the method may comprise moving the machining head to cause the intersection of the beam emitted by the laser and the R-axis to move along an R-axis only along a single (i.e. "positive) radius, in relation to the Theta-axis.

For example, the machining head may be moveable away from a first position which places the beam at the Theta-axis, towards a second limit point, and vice versa, to thereby move the beam along the positive radius. As explained above, a small amount of movement beyond the first position along a negative radius to a first limit point, may be allowed, to facilitate calibration.

The method may comprise moving the machining head to cause the intersection between the beam and the R-axis to move along both a positive and a negative radius, in relation to the Theta-axis.

The method may comprise machining one or more radial features and/or one or more curved features defined in relation to the Theta-axis.

A method in which machining is conducted along an R-axis and around a Theta-axis provides for machining of such radial or curved features with particularly low tolerances (as compared for example to machining along X and Y axes), since comparatively few movements of the support platform and machining head are required.

The method may comprise machining according to a machining pattern wherein a predominance of features have an axial symmetry (i.e. radial of curved features, extending from or defined in relation to the Theta-axis).

The method may comprise providing a machining pattern. A machining pattern may for example be downloaded to computer processing apparatus, for example running suitable CAD software. The machining pattern may optionally be stored on a data store thereof.

The method may comprise generating a machining pattern (for example using said CAD software).

The provided machining pattern may be in Cartesian coordinates.

The method may comprise transforming a machining pattern in XY cartesian coordinates into R-Theta polar coordinates.

The method may comprise machining more than one workpiece. Due to lower moving mass, the machining of multiple workpieces can be conducted more rapidly, or using less energy. Moreover, high repetitions of a given pattern, or a given movement along or around the axes may allow for iterative refinement of machining accuracy. This is of particular benefit where the machining pattern includes a predominance of features having an axial symmetry.

Such self-calibration of motor controlled apparatus is well known in the art.

The method may comprise loading a workpiece onto the support platform, and unloading a machined workpiece, after a machining pattern has been executed. Loading and unloading may be conducted multiple times.

The method may comprise segmenting a workpiece from a sheet material, for example by cutting lengths from a roll. The segmenting may be conducted using the laser.

It will be understood that further features of each aspect of the invention correspond to further features of each other aspect of the invention. For example, the precision laser machining apparatus, may be configured to perform one or more steps of the above method. The software code on the computer readable storage medium may, when executed, cause a computer processing resource or control system to cause suitable apparatus to perform one or more steps of the method. The computer processing resource may be configured to perform, or cause suitable apparatus to perform, one or more steps of the method. Conversely, the method may include the steps performed by further optional features of the precision laser machining apparatus, or the computer processing resource, or such steps as might be executed by software stored on the computer readable storage media.

Description of the Drawings

Example embodiments will now be described with reference to the following figures in which: Figure 1 shows a perspective view of a precision laser processing apparatus; Figure 2 shows a side view of the precision laser processing apparatus; Figure 3 shows a front view of the precision laser processing apparatus; Figure 4 shows a top view of the precision laser processing apparatus; and Figures 5 and 6 show steps of a method for precision laser machining.

Detailed Description

Figures 1-4 show a precision laser machining apparatus 1. The apparatus includes a base 3, and a gantry 4 mounted to the base. A linear track 5 is mounted to the front face (in the orientation shown in the figure) of the gantry 4.

A machining head 7, comprising a laser 9 (in the embodiment shown a YAG laser) is mounted to the linear track 5 and is moveable between first and second end stops 11, 13. In alternative embodiments, a green or a UV laser may be used, for example.

The machining head 7 moves under the action of a linear motor.

A support platform, or turntable, 15 is mounted centrally on the base 3. The support platform rotates around a Theta-axis (marked 0 in the figures) which extends vertically (in the orientation of the apparatus as shown in the figures) and which is perpendicular to the XY motion of the machining head 7 along the track 5. In use, the laser 9 emits a beam (not shown), onto a workpiece positioned on the support platform.

The rotation of the support platform 15 is powered by a conventional stepper motor (not shown) within the housing 17 which sits beneath the support platform. The rotational position of the support platform 17 and the linear position of the machining head are under CNC control. The details of convention CNC control, including electrical connection to a processing resource, CAD software for receiving a machining pattern and, in some embodiments, creating a machining pattern are well known in the art and will not be detailed here.

In the embodiment shown, the laser beam is projected vertically, and thus parallel to the Theta-axis. The beam intersects with an R-axis (marked "R" in the figures), which may be notionally defined in relation to the position of a workpiece, as discussed in further detail below.

Movement of the machining head along the track (in the directions X and Y) causes the intersection of the beam and the R-axis to move along the R-axis.

The R-axis R intersects with, and is orthogonal to, the Theta-axis, at point I. The track 5 (and thus the R-axis) is fixed in relation to the centre of the support platform (and thus the Theta-axis). During machining the moving mass is therefore limited to the mass of the machining head and support platform and workpiece. In comparison to conventional gantry systems, in which an entire gantry (of comparable size to the gantry 4) is required to move, the moving mass is therefore much smaller. In turn this allows for the apparatus to be more electrically efficient, require fewer parts to manufacture and also gives rise to lower tolerances in use. This is particularly the case for machining along a radius, or around a circumference or curve defined in relation to the Theta-axis, due to the inherent geometry of the apparatus 1.

As more clearly seen in the plan view of Figure 4, the support platform is vented, that is to say it is provided with a number of vent holes 19 between support members 21. In the embodiment shown, the support members are arranged in a generally circular array, but other arrangements are also possible.

The support members may form part of a removable support fixture 22, which sits within a supporting frame 23. The fixture 23 can be replaced when worn, due to overlap between the support members and machining patterns, in use.

In the embodiment shown, the support platform 15 defines a planar array of support members. The support platform is adapted to support a workpiece formed form a flat sheet material. The vertical position of the laser 9 is also selected for use with a relatively thin sheet material. In alternative embodiments, the apparatus may be configured to laser machine workpieces having other configurations -such as blocks of material, workpieces having an irregular shape.

In use to machine a workpiece formed of a sheet material, the workpieces may be individually placed on the platform 15. Blank workpieces may be placed manually on the platform, or the apparatus may be provided with a robotic arm (not shown), for example a 6-axis arm, for grasping and lifting each workpiece, for example from a stack.

The apparatus may alternatively, or in addition, include means to cut each workpiece from a larger piece of sheet material, such as a roll or length of material. This may be achieved by introducing the sheet material from behind the apparatus (direction Z) and cutting or segmenting.

Machined workpieces may be manually removed from the platform 25. However, the apparatus may also include means for the automated removal of machined parts may also be provided. Conveniently, the robotic arm used for loading the workpiece may be used to remove the machined workpiece from the platform, and placed in another location (e.g. next to the stack of blank workpieces, or in a delivery package).

Machined parts may in some embodiments simply be pushed forward from the platform 15, by the next workpiece, for example into a hopper.

The relative terms "front", "above", "below", "behind" etc. are used with reference to the orientation of the apparatus shown in the figures and are not intended to be limiting.

A method of precision laser machining will now be defined with reference to Figures 5 and 6.

At step 100, a workpiece is provided on a support platform such as platform 15. A workpiece is typically in the form of a sheet material. The method may include loading the workpiece onto the platform (step 99), for example by sliding or rolling, and/or segmenting the workpiece from a larger piece of sheet material (at step 98) as disclosed herein. The method may include loading the workpiece by picking from a stack of blank workpieces and placing on the platform 15, either manually or using robotics, such as said robotic arm.

At step 110, a laser machining head is provided, such as machining head 7, configured to emit a beam onto the workpiece (for example emitted by the laser 9). The workpiece is then laser machined, at step 120, by emitting a laser beam so as to intersect with an R-axis coincident with the workpiece (e.g. across a surface thereof) -at step 122, and moving the laser machining head linearly (step 122a), for example by moving the machining head 7 along a track 5 running parallel to the R-axis, so that the beam moves linearly along the R-axis and rotating the support platform around a Theta-axis (step 122b). The Theta-axis and R-axis are orthogonal to one another and intersect one another.

The method may further include removing the machined workpiece, as step 130, for example using a robotic arm or the like.

The precision laser machining apparatus 1, discussed above with reference to Figs 1-4, may be used to carry out the method.

As indicated by the arrows, the method may be repeated on any number of workpieces, by returning to step 100 or, where applicable, preparatory steps 98 or 99.

In Figure 6 are shown the possible methods associated with the provision of a machining pattern (step 112), to be followed in step 120. As disclosed herein, the method may include generating a machining pattern (Step 114), using known in silico methods (E.g. using a processing resource running CAD software). Alternatively, a processing resource or control system of a machining apparatus, may receive a machining pattern (for example by downloading to a data store), at step 116.

CAD software used for generating machining patterns conventionally employ Cartesian coordinates. The machining pattern generated or received at steps 114 or 116 may therefore be in cartesian coordinates. The method may therefore additionally include a polar transform of such a machining pattern, into polar (R, Theta) coordinates, at step 118.

The machining patterns to which the method (and apparatus 1) is particularly suited are those which include a predominance of machining features extending axially from the Theta-axis, or around the Theta-axis (including radiused curved portions, or portions of an ovalized curve).

Whilst exemplary embodiments have been described herein, these should not be construed as limiting to the modifications and variations possible within the scope of the invention as disclosed herein and recited in the appended claims.

Claims

CLAIMS1. A precision laser machining apparatus, comprising: a linear track and a machining head moveable along the linear track; the machining head comprising a laser operable to emit a beam which intersects an R-axis; wherein movement of the machining head along the linear track causes the intersection of the beam and the R-axis to move along the R-axis; a workpiece support platform rotatable around a Theta-axis; and wherein the Theta-axis and R-axis intersect with, and are orthogonal to, one another.
The precision laser machining apparatus of claim 1, wherein the machining head typically moves between two end stops, the end stops defining first and second limit points of the intersection of the beam and the R-axis along the R-axis.
The precision laser machining apparatus of claim 2, wherein the first limit and the second limit point are equidistant from the intersection between said axes.
The precision laser machining apparatus of claim 2, wherein the first limit point is closer to the intersection between said axes than the second limit point, wherein, during a machining process, the apparatus is configured to allow the intersection of the beam and the R-axis to move radially along only a positive radius that extends between the Theta-axis and the second limit point.
The precision laser machining apparatus of any preceding claim, wherein the machining head is oriented to project the beam parallel to the Theta-axis.
The precision laser machining apparatus of any preceding claim, configured to machine a workpiece formed of a sheet material, wherein the support platform comprises a generally planar support surface, or comprises a collection of vertices or surfaces together defining support plane.
The precision laser machining apparatus of any preceding claim, wherein the support platform is vented. 2. 3. 4. 5. 6. 7.
8. The precision laser machining apparatus of any preceding claim, wherein the is configured to receive a material fixture, wherein a said material fixture in use defines the support plane.
9. The precision laser machining apparatus of any preceding claim, configured for automated loading of each workpiece on to the support platform.
10. The precision laser machining apparatus of claim 9, comprising a loading arrangement for automated loading of a workpiece, the loading arrangement comprising a robotic arm for grasping a workpiece and placing the workpiece on the support platform.
11. The precision laser machining apparatus of claim 10, wherein the machining head functions as a said segmenting apparatus.
12. The precision laser machining apparatus of any preceding claim, comprising a control system, operable to control the positions of the machining head and the support platform and regulate operation of the laser, to execute a desired machining pattern.
13. The precision laser machining apparatus of claim 12, wherein the control system is be controlled by a computer processing resource, the computer processing resource forming part of the precision laser machining apparatus or in communication therewith.
14. The precision laser machining apparatus of claim 13, wherein the computer processing resource comprises a coordinate transform module, operable to convert a machining pattern from cartesian coordinates to polar coordinates.
15. The precision laser machining apparatus of claim 13 or 14, wherein the computer processing resource includes a CAD design module, operable to generate a machining pattern, in cartesian coordinates, for later transform to polar coordinate, or in polar coordinates.
16. A method of precision laser machining a workpiece according to a machining pattern, the method comprising: providing a workpiece on a support platform; providing a machining head comprising a laser; and laser machining the workpiece with the laser by; emitting a beam from the laser to intersect an R-axis; moving the machining head linearly to cause the intersection of the beam and the R-axis to move along the R-axis; and rotating the support platform around a Theta-axis that is orthogonal to, and intersects with, the R-axis.
17. The method of claim 16, comprising precision laser machining a workpiece formed of a sheet material.
18. The method of claim 16 or 17, comprising laser machining into a surface of the workpiece and or comprise laser cutting through the workpiece.
19. The method of any one of claims 16 to 18, comprising moving the machining head to cause the intersection of the beam and the R-axis to move along an R-axis only along a single positive radius, in relation to the Theta-axis.
20. The method of any one of claims 16 to 18, comprising moving the machining head to cause the intersection of the beam and the R-axis to move along an R-axis along both a positive radius and a negative radius, in relation to the Theta-axis.
21. The method of any one of claims 16 to 20, comprising machining one or more radial features and/or one or more curved features defined in relation to the Theta-axis. 25
22. The method of claim 21, comprising machining according to a machining pattern wherein a predominance of features have an axial symmetry.
23. The method of any one of claims 16 to 22, comprising machining more than one workpiece.
24. The method of claim 23, when dependent on claim 17, comprising segmenting a workpiece from a sheet material.
25. The method of claim 24, wherein the segmenting is conducted using the laser.
26. The method of any one of claim 16 to 25, comprising transforming a machining pattern in XY cartesian coordinates into R-Theta polar coordinates.