Large fabricated parts often do not need every surface machined. They need the right surfaces machined. A bearing hole, a flat mounting face, a slot, a datum edge, or a bolt pattern can decide whether the finished assembly fits when it reaches the job.
That is why CNC machining should be planned before cutting and welding are finalized. If the drawing has tolerance notes, we need to know which features are functional and which dimensions are only reference.
Current capacity reference: CNC machining up to about 2 m W x 4 m L x 1 m H. Final feasibility depends on part weight, fixturing, datum access, tool reach, tolerance, and the machining allowance left from cutting or welding.
What CNC machining is used for
On heavy plate and welded components, CNC machining is often used after rough cutting or welding. The part may need drilled and bored holes, milled faces, slots, pockets, counterbores, or a cleaned-up datum surface. The goal is not to make the whole part shiny. The goal is to control what the assembly actually uses.
The most useful drawing separates critical dimensions from non-critical ones. If every dimension is treated as tight, the quote gets slower and more expensive than needed. If the functional features are marked clearly, the process route is easier to plan.
What we review before machining
| Drawing item | Why it matters |
|---|---|
| Datum references | The part must be fixtured from surfaces that match the inspection plan. |
| Tolerance notes | Hole position, flatness, parallelism, and fit-up notes change the machining route. |
| Machining allowance | Cut or welded parts need enough stock left for cleanup after stress and distortion. |
| Part size and access | Tool reach, clamping, lifting, and part orientation can limit what can be machined in one setup. |
Post-weld machining needs more planning
Welding can move a part. Even a strong fixture cannot remove every effect of heat and shrinkage. If a part will be machined after welding, the drawing should leave realistic allowance on the surfaces that need cleanup.
For heavy weldments, we usually look at weld sequence, stress relief requirement if any, setup access, and inspection method. If a machined feature is too close to a weld or hard to reach after assembly, it may need to be changed before production.
What to send
- 3D model or STEP file when available.
- 2D drawing with tolerance and datum notes.
- Material grade and heat treatment or stress relief requirement, if any.
- Features that must be inspected before shipment.
- How the part will mount or mate with other parts.
Need a CNC feasibility check?
Send the model, drawing, material, tolerance notes, and quantity. EONE can review which features should be machined and what allowance should be left before the part is cut or welded.