Fixtures and jigs, designed around your part and built in Coimbatore

A jig holds the part and also guides the tool: a drilling jig has hardened bushes that steer the drill. A fixture locates and clamps the part while the machine or operator positions the tool. Most plants use the words interchangeably, as in “jigs and fixtures”; below, “fixture” covers both.

Assembly fixtures

An assembly fixture holds the parts in position while they are pressed, riveted, screwed or joined. Ours are usually pneumatic, with sensors that refuse to cycle on a wrong or missing part. For more than one station, see our assembly automation cells.

Pneumatic and manual clamping fixtures

Manual fixtures use toggle or cam clamps: no air supply, lower cost, suited to low volumes. Pneumatic fixtures clamp with cylinders, give the same force every cycle and can be interlocked with the next step. For each one we decide what holds when the air fails and what must release.

Checking fixtures

A checking fixture holds the part on its datums so an operator or a sensor can see whether the features that matter are within limits: a go/no-go pin, a dial indicator, a presence sensor. Where a sensor cannot see enough, we add machine vision.

ESD-safe PCB fixtures

ESD-safe work-holding fixtures that tilt a printed circuit board to a working angle, on aluminium-profile frames, as in the first clip. The stencil cleaning station clamps, tilts and cleans an SMT stencil at a fixed position.

Leak test fixtures and test-rig fixtures

A leak tester or test rig measures only what its fixture presents. The fixture must locate the part, seal every opening and hold the test pressure without moving. A good leak test fixture also fills empty cavities with blocks: less dead volume means a bigger pressure change from a leak, and a shorter test. See our leak testing machines and test rigs.

Poka-yoke

Poka-yoke means mistake-proofing. It starts with shape: a pin or block that stops a part going in backwards. Where shape is not enough, part-present and orientation sensors stop the clamp or press cycling until every check is made.

• Locate first, then clamp. A part has six degrees of freedom. The 3-2-1 principle restrains them with three points on the main datum face, two on the next and one on the third. Extra points over-constrain the part.
• Clamp onto the locators. Clamping force pushes the part onto its locating points, over a support so thin walls are not pulled out of shape, and clear of surfaces being worked on or measured.
• Design for the operator. A comfortable height, a clear view of the locators and a part weight a person can lift. A fixture that is awkward to load gets loaded wrongly.
• Plan the changeover. For several variants, one base with change parts that fit only one way, so the wrong part cannot be fitted.
• Treat wear as normal. Locating pins, bushes and pads are made hard and fitted as replaceable parts, so wear means changing a pin, not building a new fixture.
• Decide the failure case. If air or power is lost, the fixture either stays clamped to protect the part or releases to protect the operator.

You send

• The part drawing, or a sample or photos.
• The operation: an assembly step, a check or a test.
• The cycle time and the parts per shift.
• Every variant that will use the fixture.
• A phone video of the job today, if you have one.

Drawings are used only for your concept and quotation. Send an NDA with your enquiry and we sign it first.

You get

• A free first concept: how the part is located and clamped, a cycle-time estimate and a budget range. We reply within one working day; the concept is usually ready within a week.
• A design reviewed with you before anything is cut or bought.
• A trial with your parts in Coimbatore before dispatch.
• The documents and source files, as with every machine we build: drawings, the pneumatic circuit and, where there are sensors and a PLC, the electrical drawings and program.

A fixture alone is enough when loading is not the problem. If the part is held the same way every time, a person can do the rest. It costs less, and for low or changing volumes it is often right.

Add automation when the same press, insertion or check repeats very often, when every result must be recorded, or when no step may be skipped. The fixture then becomes one station of an automation cell.

A fixture is the wrong answer if the part design keeps changing, or if the real problem is a worn machine or an incapable process; we will say so after looking at the job. For one or two parts, a standard vice may cost less.

ElectronIx also builds leak testing machines, test rigs, automation cells and CNC retrofits, programs PLCs and HMIs, and writes DNC software for Fanuc CNCs.