Mounting plate rework fixture
Three parametric fixture configurations, exported STEP solids, drilling inserts, and a worst-case locating calculation.
Completed commissioning study
Flanged bushes and screw-retained caps; 40 N lateral force plus 0.6 N m drilling torque, 150 N pullup, 350 N thrust; toe-clamp torque 2.8-3.2 N m, friction>=0.12, fixture 10-35 C. Unworn radial position budget<=0.20 mm.
Executed synthetic/theoretical results, rejected cases and acceptance matrix. Source: complete_validation.py.
Reference inputs
- All dimensions are millimetres; files are in outputs/cad.
- Round pin at (-40,0), relieved diamond pin at (40,0); three bottom supports establish datum A.
- The removable insert locates in a stepped pocket; the guide sits 12 mm above the workpiece.
Tolerance results
| variant | worst_case_radial_mm | allowed_radial_mm | radial_margin_mm | rotation_rad |
|---|---|---|---|---|
| A | 0.182756 | 0.2 | 0.017244 | 0.000813 |
| B | 0.184653 | 0.2 | 0.015347 | 0.000813 |
| C | 0.187118 | 0.2 | 0.012882 | 0.000813 |
Assembly and inspection
- Deburr and clean support pads and both datum holes. Seat the plate on the round pin first, then the diamond pin.
- Fit the correct A/B/C insert; check its mark against the plate variant before tightening the four M3 retainers.
- Tighten the two toe clamps evenly. Verify all three pads contact the plate and the guide/drill path is clear.
- Inspect the first reworked plate relative to the same A/B/C datums. Gauge datum pins and bushing bores at each setup.
- Physical trial: 3 operators x 10 remove/reseat cycles per variant; measure X/Y hole centers and report radial error, not just the mean.
BOM
| item | qty | spec | type |
|---|---|---|---|
| Base | 1 | 200 x 140 x 12, 6061-T6 | Make |
| Guide frame | 1 | 180 x 120 x 12, 6061-T6, stepped pocket | Make |
| Guide inserts A/B/C | 3 | 100 x 70 x 8, 6061-T6 | Make |
| Support pads | 3 | Diameter 12 x 4, hardened steel | Make |
| Round and diamond locators | 2 | 5.975-5.985 working diameter; diamond relieved to 5.4 in X | Make |
| Posts | 4 | OD16 x 24, M6 mounting, steel | Make |
| Toe clamps and heels | 2 | Stepped low-profile clamps; see STEP and setup drawing | Make |
| Drill bushings | 9 | OD10 x12 stem, ID4.2, OD14 x2 flange; hardened steel, replaceable | Purchase to stated limits |
| Bushing retention caps | 9 | Steel 30 x14 x3 with two OD5 x2 feet; drawing bushing-retainer.svg | Make |
| M3 cap screws | 18 | M3 x10 class8.8; 5 mm insert engagement; 0.25 N m +/-0.03 seating torque | Purchase |
| M6 screws | 6 | Length selected for >=9 mm base engagement, avoid bottoming | Purchase |
| M3 insert screws | 4 | 8 mm insert clearance plus 4 mm thread engagement; head clearance verify | Purchase |
Verification
- 22 executed geometry, tolerance, and file round-trip checks passed.
- Run python test_project.py for regression and invalid-input checks.
Limits
- Dimensions define a self-contained reference plate family, not an existing customer part.
- Tolerance budget is worst-case, not a statistical capability claim. The 0.04 mm drill-walk allowance is an unverified process assumption.
- Complete the supplied numerical commissioning study for clamp, pad and bushing-retention calculations. These are reference load checks; no fatigue or physical qualification is claimed.
- Threaded and purchased hardware is represented by envelopes or hole callouts, not supplier-certified thread models.
- STEP exports use nominal geometry. Drawing tolerances govern the intended fit; verify bushing installation and the diamond-pin relief physically.
References
CadQuery STEP/STL export documentation. Material and tolerance values are declared reference inputs, not measured properties.
Reference design by CJ Ackley. Numerical and geometry checks are not a physical qualification.