Product Design & Engineering Firms

A STEP model and a PDF print. Any file type is accepted, and IGES, SLDPRT, Parasolid, DXF, DWG, STL and ZIP all come through, and a ZIP of the whole assembly is fine for a multi-part project. STEP is the file format of ISO 10303, the standard for exchanging CAD data between systems (source 5). Export the model and the print from the same revision and put the revision on both, so the quote describes the part you mean.

Yes. A fully dimensioned 2D PDF is quoted without a CAD line. A sketch, photos or a new sample part also start a quote, and the CAD built from them is quoted as its own line. Photos with a ruler in frame help, and the quote lists what is still missing. The sample ships back with the parts.

Start from the function. Every dimension needs a tolerance, and a general note can supply it (source 6); tighten only the features that mate or locate, since the loosest tolerance that serves the function is the usual advice (source 1). Typical machined tolerance is ±0.005 in, which is also what a STEP file with no drawing is quoted to unless your notes name another. Position, perpendicularity and runout callouts are quoted from the print. CNC machining tolerances covers the bands.

A free design review comes with every quote. A person reads the design you send and notes what will cost more and what may not work: an inside corner with no radius, a thin wall, a deep pocket that needs a long cutter, a tight tolerance on a feature that does not need one, a finish that changes a fit. The notes come back with the quote. It is a review of your design, not a design service, so the changes stay with you and CAD work is quoted as its own line. CNC design mistakes lists the ones that come up most.

Ask for more than one quantity, such as 1, 25 and 100, and the quote shows each. Setup and programming time are spread across the quantity (source 1), so the quotes are worth reading side by side. One piece is a normal order (one-off CNC machining), there is no minimum, and quantities run from one piece to production runs of 10,000.

Iterate as many times as the design needs: each revision is quoted in 24-48 hours, so keep the revision letter on the print. When the design settles, validate with one or two pieces and run the same print at higher quantity, which is covered on small-batch CNC machining; prototype-only work is on prototype CNC machining. Reorders at the same revision: send the last quote or PO number and it’s requoted. Blanket orders are quoted too. Price, release schedule and lead time per release are set in the quote.

For aluminum, 6061 is a common choice: it is used from bicycle frames to flashlights and is worked more easily than 2024 (source 7). 6061 aluminum, 316 stainless, brass and Delrin acetal each have a grade page. Acetal is used for sliding and guiding parts, and machined acetal can be dimensionally unstable when wall thickness varies a lot, so even out the walls or add fillets or ribs (source 8). Other alloys and plastics quoted on request. Name the grade on the print.

Quotes come back in 24-48 hours. Rush: 1-2 weeks. Standard: 4-6 weeks (typical). Extended: 6-8 weeks, for jobs that aren't time-sensitive. Rush 1-2 weeks applies to machined parts with no secondary operations. Heat treat, grinding, EDM and finishing add time, and the quote gives the real date. Lead time starts at order approval. Put your need date in the part description and the quote answers it. Rush CNC parts has the detail.