Machining for industrial automation and robotics
Automation buyers care about one thing above all: the part that arrives in month six must locate the same way as the first article. A line stopped by a 0.02 mm bore error costs more than the part ever will.
Part families
Housings carrying a crossed-roller or harmonic bearing on two faces. Bore-to-face perpendicularity usually matters more than the bore diameter, because a tilted bearing shows up as runout at the end of the arm.
Motor plates, linear rail seats and frame plates. Rail seat flatness and parallelism decide whether the axis runs smoothly at speed; the individual hole positions matter less than the relationship between them.
Finger bodies, jaw mounts and sensor brackets where 2 mm features are normal. Usually the cheapest parts in the cell and the most frequently redesigned, so tooling stays minimal.
Custom tooling for the cell itself. Short runs, fast turnaround, and dimensions that follow the workpiece rather than a drawing standard.
Folded frames with machined mounting pads. The folded structure carries the stiffness; the machined pads carry the precision, and combining them in one order avoids a tolerance argument between two suppliers.
Tolerances that decide whether the machine repeats
Repeatability complaints rarely come from one dimension being wrong. They come from relationships: a bore that is round but not perpendicular to its mounting face, two dowel holes that are individually correct but 0.02 mm apart in the wrong direction, a plate that is flat alone and twisted when bolted down.
So the drawing should carry the relationships, not just the sizes: position and perpendicularity at the joint interface, profile on the mounting face, and a datum reference frame that matches how the part sits in the assembly.
| Control | Value |
|---|---|
| Bearing bore diameter | H7, Ø20–120 mm |
| Perpendicularity, bore to face | 0.01–0.02 mm |
| Position, dowel holes | Ø0.02 mm M |
| Flatness, mounting face | 0.02 mm |
| Parallelism, rail seats | 0.01 mm over 200 mm |
Three habits that cost money
A housing where all six faces carry 0.02 mm flatness gets ground on all six. Two functional faces and four general ones usually perform identically for 30% less.
A shoulder corner with no radius cannot be machined. Specify 0.5 mm or a relief groove and the part becomes straightforward.
Tightening one part's tolerance to solve a stack problem moves cost into the wrong place. A stack check before release usually finds the clearance in a cheaper component.
Spares and short-cycle replenishment
Automation lines do not stop politely. When a gripper finger breaks, the replacement is needed in days, not weeks. Because the program, fixture and inspection plan are stored against the part number, a short-cycle reorder runs from the existing setup rather than starting from the model again.
That is also why the sample, small-batch and volume lines are separated: a five-piece spare order does not queue behind a fifty-thousand-piece production run.
| Single spare part | Machined from stock, 3–7 days typical |
|---|---|
| Set of gripper fingers | 5–20 pcs, 7–10 days |
| Production batch | 100–2,000 pcs, 7–15 days |
| With finishing | Add 3–7 days for anodizing or plating |
Industry questions
Yes, with boring rather than interpolation and an in-process check at a defined interval. The bore is gauged on the floor and measured on the CMM at first-off, mid-batch and last-off.
Yes. Aluminium for links and plates, pre-hardened 4140 for wear surfaces and gearbox bodies, stainless where washdown rules out aluminium.
The program, fixture and inspection plan are stored against the part number. A repeat order runs the same route; if a fixture is remade, the first article is re-run and compared with the original report.
For simple assemblies with pressed bearings or inserts, yes. Full electromechanical assembly with motors and encoders is outside what the plant does, and saying so early avoids a bad quote.
Send the joint or rail-seat drawing with its datum scheme.
The quote will confirm which callouts drive the fixture and whether the bore-to-face relationship is achievable in one setup.
From the shop notes
Longer answers to the questions these pages raise.