TOOLING MATERIALSApplication / Composite machining
A trimming fixture supports a composite part in a defined position while leaving clearance for the cutting tool. Reliable vacuum holding depends on the contact surface, seal layout, stiffness and stable datums—not simply on the material used for the body.
Engineering requirements
01 / REFERENCE METHOD
A metal reference route for stiffness, durability and established fixture practice. Compare casting and machining lead time, stock removal, handling mass and dimensional movement at the working temperature.
02 / BONDED BOARD
Bond PUBOARD or EPBOARD into a blank, then machine the support surface, vacuum features and datum interfaces. Qualify bondline sealing, inserts and local support before accepting the completed fixture.
03 / NEAR-NET CASTING
Cast a filled PU or epoxy blank close to the required shape, then machine the final geometry. This can reduce excess stock; blank design, resin heat build-up, cure and machining allowance remain critical.
04 / REPLICATED SHELL
Reproduce the contact surface from a controlled master, then build the shell and backing structure. The tool surface, part-thickness offset, shell stiffness, cure and frame attachment determine the final fit.
Engineering requirements
| Route | EPTEK product family | What to verify |
|---|---|---|
| Board machining | PUBOARD tooling boards / EPBOARD | Bondline airtightness, insert retention, machining and dimensional stability |
| Precision casting | PUCAST / EPCAST | Casting thickness, fillers, void control, cure and remaining machining stock |
| Replicated shell | Compatible gelcoat + EPMOLD LP70 and selected EPLAM / EPMOLD backing systems | Layer compatibility, shell thickness, cure, reinforcement and frame attachment |
| Aluminium reference | Metal fixture design and machining | Use the same part, tolerance and acceptance criteria when comparing alternatives |
Engineering requirements
| Check | Acceptance focus |
|---|---|
| Fit and geometry | Inspect after cure and assembly. Include the part-thickness offset and springback where the tool is replicated. |
| Vacuum integrity | Check pull-down time and isolated pressure rise; separate leakage through the body, joints, seals and connections. |
| Location and support | Verify repeatable datums, seal compression, local stiffness and access for the cutting tool. |
| Temperature and machining | Assess expansion with the actual tool size and temperature change; confirm the first machined part against the drawing. |
| Whole-life cost | Compare usable blank volume, machining, joining, sealing, support structure, rework and expected service life. |