CNC Machining Quotes: 7 Pieces of Information to Send for the Right Solution
Prepare drawings, material, quantity, tolerances and acceptance requirements to get a CNC machining quote with a clear scope that is easy to compare across suppliers.
The price of CNC machining does not depend only on the size of the part. The same geometry with a different material, tolerance, quantity or inspection requirement may call for a different production approach. To receive quotes that are easy to compare, send a package that clearly shows the part to be made and the acceptance conditions.
Below are 7 groups of information to prepare before talking to a machining supplier.
1. Drawings and design revision
Send a 2D drawing with dimensions, technical requirements and the revision code. If you have a 3D model, attach it to make it easier to assess the geometry and tool access. The 2D drawing and the model must match; if they differ, confirm which data is the basis for manufacturing.
For parts without drawings, provide photos, a sample and a description of the part's function. In that case, the scope of the survey or the rebuilding of the documentation needs to be agreed separately before the machining requirements are finalized.
2. Material and traceability requirements
Specify the material grade instead of just writing "aluminum", "stainless steel" or "steel". If you require material certificates, heat treatment or lot traceability, state this in the order documents from the start.
Material not decided yet? Describe the operating environment, loads, contact surfaces and corrosion resistance requirements so the options can be discussed. Do not substitute a material just because it is cheaper without approval from the person responsible for the design.
3. Quantity and ordering plan
Distinguish between the prototype quantity, the first order quantity and the expected repeat demand. Programming, tooling and fixturing costs may be allocated differently for a one-off part than for a production lot.
If you need a trial fit first, ask for a quote that separates the prototype phase from the production phase. This helps clarify the cost of changes while the design is not yet frozen.
4. Tolerances at functional features
Identify fitted holes, locating faces, measurement datums and the dimensions that determine how the part works. Do not apply tight requirements to the entire drawing just to be "sure it is accurate" if the design does not need it.
Tolerances must come with a suitable inspection method. For geometric requirements such as flatness or position, the documents should clearly show the reference datums and acceptance criteria.
5. Surfaces and post-machining operations
Distinguish between cosmetic surfaces, mating surfaces and surfaces that only need sharp edges removed. If anodizing, plating, painting, heat treatment or polishing is involved, specify which operations are included in the quote.
Clarify when dimensions are inspected: before or after surface treatment. Areas that must be masked, left untreated or keep their fit characteristics should also be marked.
6. Acceptance documentation
Inspection requirements should be agreed before production: which dimensions are inspected, whether inspection is by sampling or of every part, which report format is required, and whether first article approval is needed.
When comparing two quotes, do not look only at the unit price. An offer that includes a measurement report and surface treatment is not equivalent to one that only delivers the parts as machined.
7. Required delivery date and delivery scope
State the required receipt date, the delivery location and packaging requirements. If delivery is split into several batches, give the quantity for each batch. Agree on how drawing changes after approval will be handled and when the schedule will be confirmed.
An estimated lead time should not be treated as a delivery commitment while the material, design and scope of work have not been confirmed.
Quote request information template
Part: Name, part number, drawing revision and attached files
Material: Material grade, heat treatment and certificates if required
Quantity: Prototypes, first lot and repeat demand
Technical: Tolerances, measurement datums, functional surfaces
Finishing: Surface treatment, deburring, packaging
Acceptance: Dimensions to measure, inspection scope, reports
Delivery: Required date, location, number of deliveries
Discuss your machining requirements with ZINITEK
Send your drawing along with the material, quantity and required receipt date to discuss the machining approach. If the design is still being finalized, mark the requirements that are not yet fixed so both sides can agree on them before the quote is prepared.
A clear package helps you compare the same scope of work, reduces back-and-forth and keeps requirements under control when you place the order.
