Machining & Assembly / Purchasing guide
A CNC quotation becomes easier to assess when the drawing separates geometry, material, finish and acceptance requirements. The CAD model communicates shape, while the drawing communicates the conditions that make the part acceptable. Send a coordinated package and identify the controlling revision before asking a supplier to commit to production.
Catalogue reference image. Confirm the quoted configuration against the agreed drawing.
Make the document set coherent
Use consistent units, part numbers and revisions across the model and drawing. Identify the document that governs a conflict. Remove obsolete attachments from the enquiry or clearly label them as reference only. A supplier should not be expected to infer which of several similarly named files represents the current design.
Highlight the functional features
Identify datums, mating holes, slots, contact surfaces and any areas that require particular attention. Explain which features locate the part in its assembly. Distinguish reference dimensions from acceptance dimensions so inspection effort is directed to the actual requirement.
Request a written manufacturing review
Ask the supplier to record proposed changes, exceptions and unresolved points before the order. Resolve those items through a revised drawing or an agreed deviation, rather than leaving them in an informal message. Keep the approved manufacturing scope attached to the purchase record.
Information to include in your enquiry
| Review item | Information to provide |
|---|---|
| Identity | Part number, units and revision |
| Geometry | Model, drawing and precedence rule |
| Function | Datums and critical mating features |
| Acceptance | Inspection and finish requirements |
Frequently asked questions
Can a model replace every drawing note?
A model may define geometry, but material, finish, tolerances and acceptance still need a clear agreed definition.
Should supplier suggestions be left in email only?
Carry approved changes into controlled documentation so later batches do not rely on reconstructing a conversation.
Discuss your carbon fiber component
Send your drawing revision, intended application, quantity and acceptance requirements to Litian Yunde for a project review.