METHOD AND SYSTEM FOR MACHINE CUTTING IN SHEET MATERIAL

Abstract

The invention relates to a method (100) for preparing machine cutting in sheet material, comprising the steps of obtaining (101) a set of geometries to be cut, positioning (102) the set of geometries for cutting, and thereafter deciding (104) on a format of sheet material based on the positioned geometries. The invention further relates to a corresponding system for machine cutting in sheet material, and a corresponding computer program product.

Claims

1. A method for preparing machine cutting in sheet material, comprising the steps of: obtaining a set of geometries to be cut, positioning the set of geometries for cutting, presenting at least one format of sheet material based on the positioned geometries that would result in low amount of scrap, controlling the accessibility of the at least one presented format of sheet material via a central computer that is connected or connectable to one or more providers of sheet formats, and deciding on a format of sheet material based on the presented formats and their accessibility.

2. The method according to claim 1, wherein the central computer is connected or connectable to one or more storages for storing sheet formats for controlling accessibility in said one or more storages,

3. The method according to claim 1, wherein the accessibility may be dynamically adjusted depending on decisions in connected processes and/or systems such as ERP, MES or other management systems.

4. The method according to claim 1, wherein deciding on a format of sheet material is based on: the extension of the positioned geometries in relation to the size of the format of sheet material; the amount of scrap material not belonging to the set of geometries to be cut obtained by the format of sheet material; and/or cost of different formats of sheet material.

5. The method according to claim 1, wherein deciding on a format of sheet material comprises selecting a best fit of format from a candidate set of formats.

6. The method according to claim 1, comprising repeatedly altering the positioning of the set of geometries, and deciding on the best fit of format to the altered positioning of the set of geometries, to obtain a candidate set of positioning and format of sheet material combinations.

7. The method according to claim 1, further comprising creating a machining plan for cutting of the positioned geometries, prior to or after deciding on the format of sheet material.

8. The method according to claim 1, wherein the set of geometries comprises at least one cluster of parts of free form shape, the parts being positioned so close to one another so that only the thickness of one cut of the cutting device is found between adjacent parts whenever the shape of the parts allows it.

9. The method according to claim 8, wherein the set of geometries are a plurality of clusters of parts of free form shape.

10. The method according to claim 1, comprising machine cutting of geometries in sheet material with a beam cutting technology.

11. The method according to claim 1, implemented as a tool for computer aided design (CAD) or computer aided manufacturing (CAM).

12. A method for machine cutting several parts out of a piece of material according to claim 1, further comprising cutting the positioned geometries from the decided format of sheet material.

13. A system for machine cutting several parts out of a piece of material, comprising a processing unit configured to obtaining a set of geometries to be cut, positioning the set of geometries for cutting, and thereafter deciding on a format of sheet material based on the positioned geometries, a cutting device, a central computer for controlling the accessibility of formats of sheet for the processing unit to decide between, and a control unit, wherein the control unit is configured to controlling the cutting device to cut the positioned geometries from the decided format of sheet material.

14. The system according to claim 13, wherein the cutting device is a beam cutting device.

15. The system according to claim 13, wherein the processing unit is further configured to create a machining plan for the cutting of the positioned geometries, and wherein the control unit is configured to controlling the cutting device to cut the positioned geometries according to the machining plan.

16. Computer program product comprising computer program code, which when executed enables a processor in a computer to perform the method according to claim 1.

17. A non-transient computer-readable medium or media comprising data representing coded instruction sets configured for execution by a processor in a computer, the instructions comprising the method according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0051] Various embodiments and examples related to the invention will now be described with reference to the appended drawing, where;

[0052] FIG. 1 shows a method of preparing machine cutting in sheet material.

[0053] FIG. 2 shows steps of a method of preparing machine cutting in sheet material.

[0054] FIG. 3 shows a system for machine cutting in sheet material.

DETAILED DESCRIPTION OF EMBODIMENTS

[0055] In FIG. 1 a method 100 of preparing machine cutting in sheet material is disclosed. The method first comprises obtaining 101 a set of geometries to be cut. The geometries may be any kind of shape or cluster of parts. The set of geometries are positioned 102 for cutting, preferably to minimize scrap between adjacent parts. Based on the positioned set of geometries a format of sheet material is thereafter decided 104.

[0056] A machining plan, e.g. a cutting plan, is created 103 for the cutting of the positioned geometries. The machining plan may be created prior to deciding on the format of sheet material, as illustrated in the figure, but it may alternatively be created after deciding on the format of sheet material. The machining plan defines how and in what order the cutting process will be conducted. The geometries are thereafter cut 105 according to the cutting plan, from the decided sheet format. A step of verifying 106 the accessibility of the sheet format is made before the final decision of the sheet format to be used. The step of verifying 106 the accessibility of the sheet format may however be made before the geometries are positioned 102. In such a case the step of positioning the geometries may be made on a set of different accessible formats, whereupon the most advantageous format is decided 104 to be used. The step of verifying 106 the accessibility of the sheet format may also be made before the set of geometries are obtained. In such an embodiment the step of verifying accessibility may be made continuously, e.g. by obtaining updates from the central computer on the accessibility of different sheet formats.

[0057] The step of deciding 104 on a format of sheet material is based on one or more of the extension of the positioned geometries in relation to the size of the format of sheet material, the amount of scrap material not belonging to the set of geometries to be cut obtained by the format of sheet material; and the cost of different formats of sheet material. The extension of the positioned geometries may be an approximation of the outer contour of the positioned geometries, e.g. by a polygon. The approximation of the outer contour may be a regular polygon, such as a rectangle, or an irregular polygon, having non-equal lengths of sides and/or angles. The amount of scrap obtained from the format of sheet material may be balanced to the cost of providing a particular format of sheet material, and/or cost per weight of the sheet material. The decided format of sheet material may have a regular or an irregular shape.

[0058] As one alternative the deciding on a format of sheet material comprises selecting a best fit of format for the geometries from a candidate set of formats. This may be provided by repeatedly altering the positioning of the set of geometries, and deciding on the best fit of format to the altered positioning of the set of geometries, to obtain a candidate set of positioning and format of sheet material combinations. From this candidate set of positioning and format of sheet material combinations the sheet format may be decided based on the criteria discussed above. Thus the best positioning and format of sheet material combination may be selected, which reduces the amount of scrap material and materials cost.

[0059] The set of geometries may comprise at least one cluster of parts of free form shape, the parts being positioned so close to one another so that only the thickness of only one cut of the cutting beam is found between adjacent parts whenever the shape of the parts allows it. Thus the amount of scrap between adjacent parts may be significantly reduced. As one alternative the set of geometries includes only a plurality of such clusters of parts of free form shape. Thus the sheet format may be utilized most efficiently.

[0060] In FIG. 2 some steps of the method is shown graphically. In FIG. 2(a), a set 200 of geometries 201, 201 and 201 is provided. The set of geometries illustrated shows a regular geometry in the form of a rectangle 201, and two free form, irregularly shaped, geometries 201 and 201. Both free form shaped geometries comprise concave portions along the circumference. The geometries 201, 201, 201 are represented by their respective actual shape during positioning, i.e. not represented by an approximated regular polygon such as a rectangle.

[0061] The set of geometries are positioned with respect to each other, in the example shown in FIG. 2(b) forming a cluster 202 of parts, including both free form shaped parts and a regular shaped part. Since the geometries are represented by their respective actual shape during positioning they may be positioned close to each other, as shown in FIG. 2(b). The forming and cutting of clusters of parts of free form shapes is further disclosed in WO 2011/042058 A1.

[0062] In FIG. 2(c), a format 203 of sheet material is decided based on the positioned geometries. The format of the sheet is defined as the extension of the positioned geometries in the plane of the sheet material, and in this case the format has a common rectangular shape. However, also irregularly shaped sheet formats may be decided based on the present invention. It should be noted that the illustration shown in FIG. 2 is simplified, and that in regular production scale processing, the number of geometries may very well exceed 10, 100 or 1000 parts.

[0063] Further, in FIG. 2d an example where a plurality of clusters 202 as shown in FIG. 2(b) are obtained as a set of geometries which are positioned, whereafter a format 203 of sheet material is decided based on the positioned geometries. This is in accordance with the invention done via a central computer which is connected to one or more providers of sheet formats and/or one or more storages for storing sheet formats.

[0064] In FIG. 3 a system 300 for machine cutting several parts out of a piece of sheet material 303 is shown. The system comprises a processing unit 301 configured to obtaining a set of geometries to be cut, positioning the set of geometries for cutting, and thereafter deciding on a format of sheet material based on the positioned geometries. As described above the decision of which format to use is preceded or followed by a step of verifying accessibility of sheet formats. The processing unit is further configured to create a machining plan for the cutting of the positioned geometries.

[0065] The system further comprises a cutting device 304, and a control unit 302, wherein the control unit is configured to controlling the cutting device to cut the positioned geometries from the decided format of sheet material, according to the machining plan. In the example shown in FIG. 3 the cutting device is a beam cutting device. As further alternatives, a system with a punch press as cutting device and a system utilizing knife cutting is also proposed.