Generation of holding tabs for fixing a part during machining
Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design and manufacture of physical structures using subtractive manufacturing systems and techniques include, in one aspect, a method including: obtaining a toolpath specification for a three dimensional model of geometry of a part to be machined from a workpiece; calculating predicted cutting forces to be applied to the workpiece when machining the part; generating a set of holding tabs for the part based on the predicted cutting forces, wherein each of the holding tabs bridge from the part to the workpiece so as to keep the part fixed, in situ, within the workpiece during the machining, and at least one position of a holding tab from the set is determined in accordance with the predicted cutting forces; and providing the set of holding tabs for use by a computer-controlled manufacturing system.
1. A computer-implemented method comprising:
obtaining a toolpath specification for a three dimensional model of geometry of a part to be machined by a computer-controlled manufacturing system from a workpiece;
calculating predicted cutting forces to be applied to the workpiece when machining the part using the toolpath specification;
generating a set of holding tabs for the part based on the predicted cutting forces, wherein each of the holding tabs bridges from the part to the workpiece so as to keep the part fixed, in situ, within the workpiece during the machining of the part from the workpiece, and wherein at least one position of a holding tab from the set of holding tabs is determined in accordance with the predicted cutting forces; and
providing the set of holding tabs for use during the machining of the part by the computer-controlled manufacturing system.
2. The method of claim 1 , wherein positions of the holding tabs of the set of holding tabs and a quantity of the holding tabs are determined in accordance with the predicted cutting forces and one or more directions of the predicted cutting forces.
3. The method of claim 2 , wherein the holding tabs are defined with sizes in accordance with the predicted cutting forces.
4. The method of claim 2 , wherein a shape and an attachment angle defined for a holding tab from the set of holding tabs is determined based on the predicted cutting forces and the one or more directions of the predicted cutting forces.
5. The method of claim 1 , wherein generating the set of holding tabs comprises generating a plurality of sets of holding tabs defining different holding tab options to keep the part fixed, in situ, within the workpiece during the machining of the part.
6. The method of claim 5 , further comprising:
receiving a user selection of one of the different holding tab options from the plurality of sets of holding tabs, and
wherein providing the set of holding tabs for use during the machining of the part comprises providing the selected one of the different holding tab options as the set of holding tabs to be used when performing the machining of the part.
7. The method of claim 1 , further comprising:
receiving input comprising a selection of one or more regions of the three dimensional model of geometry of the part to be excluded for placing of holding tabs,
wherein generating the set of holding tabs comprises excluding the one or more regions at the three dimensional model from regions of the part available for connection to holding tabs.
8. The method of claim 1 , wherein a size of a holding tab is defined based on a type of machining operation to be performed at an area where the holding tab is to be placed, wherein the type of machining operation is associated with a corresponding predicted cutting force to be induced on the part when performing the type of machining operation.
9. The method of claim 1 , wherein generating the set of holding tabs comprises:
defining a first sub-set of holding tabs from the set of holding tabs by removing one or more holding tabs from the set of holding tabs, wherein the first sub-set of holding tabs is defined to hold the part, in situ, in the workpiece during a semi-finishing operation of the machining to be performed after a roughing operation and before a finishing operation on the part from the workpiece.
10. The method of claim 9 , wherein generating the set of holding tabs further comprises:
removing one or more holding tabs from the first sub-set of holding tabs to define a second sub-set of holding tabs for use when performing the finishing operation of the machining to provide a finished surface of the part, wherein the second sub-set of holding tabs maintains the part, in situ, within the workpiece during the finishing operation.
11. A system comprising:
a data processing apparatus including at least one hardware processor; and
a non-transitory computer-readable medium encoding instructions of a computer-aided design or manufacturing program, the instructions being configured to cause the data processing apparatus to
obtain a toolpath specification for a three dimensional model of geometry of a part to be machined by a computer-controlled manufacturing system from a workpiece;
calculate predicted cutting forces to be applied to the workpiece when machining the part using the toolpath specification;
generate a set of holding tabs for the part based on the predicted cutting forces, wherein each of the holding tabs bridges from the part to the workpiece so as to keep the part fixed, in situ, within the workpiece during the machining of the part from the workpiece, and wherein at least one position of a holding tab from the set of holding tabs is determined in accordance with the predicted cutting forces; and
providing the set of holding tabs for use during the machining of the part by the computer-controlled manufacturing system.
12. The system of claim 11 , wherein positions of the holding tabs of the set of holding tabs and a quantity of the holding tabs are determined in accordance with the predicted cutting forces and one or more directions of the predicted cutting forces.
13. The system of claim 11 , wherein the instructions configured to cause the data processing apparatus to generate the set of holding tabs comprise instructions configured to cause the data processing apparatus to:
generate a plurality of sets of holding tabs defining different holding tab options to keep the part fixed, in situ, within the workpiece during the machining of the part.
14. The system of claim 13 , wherein the non-transitory computer-readable medium encodes the instructions configured to cause the data processing apparatus to:
receive a user selection of one of the different holding tab options from the plurality of sets of holding tabs, and
wherein the instructions to provide the set of holding tabs for use during the machining of the part comprises instructions configured to cause the data processing apparatus to provide the selected one of the different holding tab options as the set of holding tabs to be used when performing the machining of the part.
15. The system of claim 11 , wherein the non-transitory computer-readable medium encodes the instructions configured to cause the data processing apparatus to:
receive input comprising a selection of one or more regions of the three dimensional model of geometry of the part to be excluded for placing of holding tabs,
wherein the instructions to generate the set of holding tabs comprises instructions configured to cause the data processing apparatus to exclude the one or more regions at the three dimensional model from regions of the part available for connection to holding tabs.
16. A non-transitory computer-readable medium encoding instructions operable to cause data processing apparatus to perform operations comprising:
obtaining a toolpath specification for a three dimensional model of geometry of a part to be machined by a computer-controlled manufacturing system from a workpiece;
calculating predicted cutting forces to be applied to the workpiece when machining the part using the toolpath specification;
generating a set of holding tabs for the part based on the predicted cutting forces, wherein each of the holding tabs bridge from the part to the workpiece so as to keep the part fixed, in situ, within the workpiece during the machining of the part from the workpiece, and wherein at least one position of a holding tab from the set of holding tabs is determined in accordance with the predicted cutting forces; and
providing the set of holding tabs for use during the machining of the part by the computer-controlled manufacturing system.
17. The non-transitory computer-readable medium of claim 16 , wherein positions of the holding tabs of the set of holding tabs and a quantity of the holding tabs are determined in accordance with the predicted cutting forces and one or more directions of the predicted cutting forces.
18. The non-transitory computer-readable medium of claim 16 , wherein generating the set of holding tabs comprise instructions operable to cause the data processing apparatus to:
generate a plurality of sets of holding tabs defining different holding tab options to keep the part fixed, in situ, within the workpiece during the machining of the part.
19. The non-transitory computer-readable medium of claim 18 , wherein the operations comprise:
receiving a user selection of one of the different holding tab options from the plurality of sets of holding tabs, and
wherein providing the set of holding tabs for use during the machining of the part comprises providing the selected one of the different holding tab options as the set of holding tabs to be used when performing the machining of the part.
20. The non-transitory computer-readable medium of claim 18 , wherein the operations comprise:
receiving input comprising a selection of one or more regions of the three dimensional model of geometry of the part to be excluded for placing of holding tabs,
wherein generating the set of holding tabs comprises excluding the one or more regions at the three dimensional model from regions of the part available for connection to holding tabs.