What Files Do I Need to Send for a CNC Quote?

The short answer

A 2D drawing or a 3D model is enough to price a CNC machined part — both is better. A 3D model fixes the geometry; a 2D drawing fixes the tolerances, surface finish and material that the model cannot carry. Send the pair and the quote needs no assumptions.

If you have only one, send the 3D model when the part is geometrically complex, and the 2D drawing when the part is simple but tolerance-critical. Either way, state material and quantity in the message — those two numbers move the price more than any other input.

What the drawing has to carry

A drawing that can be quoted without questions has six things on it. Missing any one of them turns a price into an email thread.

Detail	Why it decides the price
Material and grade	6061 aluminium and 304 stainless run at different speeds and tool wear; "aluminium" alone is not quotable.
General tolerance	Sets the process: a ±0.1 mm part and a ±0.01 mm part are not the same job on the same machine.
Critical tolerances	Only the dimensions that matter need a tight callout — marking everything tight raises cost with no benefit.
Surface finish	Ra value or a finish name (anodise, bead blast, passivate) changes both routing and lead time.
Quantity	One piece and one thousand pieces are quoted on different logic; setup is amortised only in the second case.
Target date	Allows a realistic promise instead of a hopeful one.

Which file formats are accepted

STEP is the safest 3D format because it carries solid geometry without vendor lock-in. IGES works but loses some feature information. For 2D, a PDF with vector lines and readable dimensions is enough; DWG and DXF are accepted when you have them. Photographs and screenshots are accepted for a first look, but a part cannot be cut from a picture.

If your file is in a format not listed, send it anyway. The real question is whether the geometry and the tolerance intent survive, not whether the extension matches a list.

What usually stalls a quote

In practice the same six gaps appear again and again: material named by trade name only, tolerances implied by "precision", surface finish left blank, quantity left as "to be confirmed", a model with no drawing, and a drawing whose revision does not match the model. Any of these forces a question, and a question costs a day.

Two habits remove most of it. First, mark tolerances only where they matter — a drawing with three deliberate callouts is faster to quote and cheaper to make than one with every dimension boxed. Second, keep the revision letter on both the model and the drawing identical, so the shop quotes the geometry you actually intend.

When you only have a photograph

A photo of a worn or imported part is a legitimate starting point for reverse work, provided you say what the part has to do. Dimensions can be reconstructed, but the tolerances cannot be guessed — they come from function. Tell us where the part fits, what moves against it, and what failed, and the drawing can be built from that.

What happens after you send the files

Files are reviewed against the machine park and the inspection plan, not just priced. On a first enquiry you normally get a quote plus notes on features that are expensive to hold and cheaper to relax. That review is the part of the process worth using: a tolerance that costs money but does not affect function is the most common finding.

Xiangying machines to ±0.005 mm on Mitutoyo inspection equipment, works to ISO 9001:2015, and ships prototypes in 3–5 days once files are released, with production runs in 7–15 days depending on quantity and finish. Drawings can be sent through the quote form; the capabilities page lists the processes and the quality page explains what is measured and reported.

Checklist before you hit send

• 3D model (STEP preferred) and/or 2D drawing with dimensions
• Material with grade, not just family
• General tolerance block plus the critical callouts only
• Surface finish or treatment named
• Quantity, and whether it is a prototype or a repeating order
• Target delivery date, and the destination country
• Revision letter identical on model and drawing