Modular workholding apparatus
A workholding apparatus for components having complex geometries or surfaces, which components are difficult constrain for the purpose of inspection, addresses the problem of adequately constraining such components in a convenient and cost-effective manner so that they do not move during inspection, while also making all or most critical features accessible to the inspection instruments being used. A method teaches how to eliminate setup changes between different components through the use of inexpensive modular attachments. These attachments are in the form of a single piece thermoplastic part which is affixed to each component having also reference features that can be interlocked into a common base fixture for more efficient inspection operations.
1. A fixture for holding a workpiece during inspection by a coordinate measuring machine, the workpiece having a target portion having a target portion shape, the fixture comprising:
a workpiece interface having a fixed shape, the workpiece interface adapted to couple to the target portion of the workpiece wherein the workpiece interface has a contour that is the complement of the target portion shape of the target portion such that the contour is complementary to the shape of the target portion, and wherein the workpiece interface is flexible so as to accept the target portion of the workpiece and so as to provide a compressive force on the target portion of the workpiece when the workpiece is disposed in the workpiece interface so as to hold the target portion via compression fitting; and
a base having a second interface configured to securely couple to a clamping system.
2. The fixture of claim 1 wherein the base has a bottom face, the fixture further comprising a plurality of cavities in the bottom face, the plurality of cavities arranged in a pattern to match a corresponding pattern of dowels on a storage plate.
3. The fixture of claim 1 , further comprising a plurality of base magnets coupled to the base, the plurality of base magnets arranged in a base pattern to match a corresponding pattern of storage magnets arranged on a storage plate.
4. The fixture of claim 1 , further comprising:
a first set of base features, which first set of base features is configured to interlock with counterpart features on a robotic gripper; and
a second set of base features, which second set of base features is configured to interlock with counterpart jaw reference features of a clamp,
wherein the first set of base features is not identical to the second set of base features.
5. The fixture of claim 1 , further comprising base features, which base features are configured to interlock with counterpart features on a robotic gripper, and the same base features are configured to interlock with counterpart jaw reference features of a clamp.
6. The fixture of claim 1 wherein the target portion shape has a complex geometry defined by a plurality of curved surfaces, and the workpiece interface is shaped and sized to have a contour that is the complement of said complex geometry, to provide a compressive force on the target portion of the workpiece when the workpiece is disposed in the workpiece interface.
7. The fixture of claim 1 wherein the workpiece interface comprises thermoplastic.
8. The fixture of claim 1 , wherein the workpiece interface is pliable so that it can flex when accepting the workpiece.
9. A workholder for holding a workpiece during inspection by a coordinate measuring machine, the workpiece having a target portion having a target portion shape, the workholder comprising:
base means for securely coupling to a clamping system; and
means for receiving and securing the target portion of the workpiece, said means having a workpiece interface having a fixed shape comprising a contour that is the complement of the target portion shape of the target portion such that the contour is complementary to the shape of the target portion, wherein the workpiece interface is flexible so as to accept the target portion of the workpiece and so as to provide a compressive force on the target portion of the workpiece when the workpiece is disposed in the workpiece interface so as to hold the target portion via compression fitting.
10. The workholder of claim 9 wherein the base means has a bottom face, the base means further comprising a plurality of cavities in the bottom face, the plurality of cavities arranged in a pattern to match a corresponding pattern of dowels on a storage plate.
11. The workholder of claim 9 , further comprising a plurality of base magnets coupled to the base means, the plurality of base magnets arranged in a base pattern to match a corresponding pattern of storage magnets arranged on a storage plate.
12. The workholder of claim 9 , wherein the workpiece interface is pliable so that it can flex when accepting the workpiece.
13. The workholder of claim 9 , wherein the target portion shape has a complex geometry defined by a plurality of curved surfaces, and the workpiece interface is shaped and sized to have a contour that is the complement of said plurality of curved surfaces of said complex geometry to provide a compressive force on the target portion of the workpiece when the workpiece is disposed in the workpiece interface.