Online Free CNC Quotation: What the Price Actually Tells You

• 1
  How an online free CNC quotation is priced
• 2
  What your CAD file must contain for the number to hold
• 3
  Where fast quoting engines break down
• 4
  How the shop turns that estimate into a real price
• 5
  Five checks before you accept an online free CNC quotation
• 6
  When an online free CNC quotation holds, and when it moves

A quoting engine does not look at your part the way a machinist does. It reads the STEP or IGES file, rebuilds the solid, then walks every face looking for features it recognizes: through holes, blind holes, pockets, bosses, chamfers, fillets, threads, undercuts. Each recognized feature carries a rule for the tool that can cut it and the passes needed. Holes below Ø3 mm, deep pockets with an aspect ratio past 4:1, and thin walls under 1 mm all trigger warnings.

From there the engine assigns stock. It picks the smallest standard bar or plate that contains the part plus machining allowance, looks up the density and per-kg price for the material you selected, and adds the cut-off and facing waste. This is why two near-identical parts in 6061 and 316L can differ by a factor of three. The material line is usually the single largest number on a fast online free CNC quotation.

Machining time comes next. Cycle time is estimated from the volume removed, the material removal rate for that alloy, the number of tool changes, and the number of setups. Five-axis parts with features on four or five faces get a setup multiplier. So do parts that need soft jaws or a custom fixture. The engine's cycle estimate is a median, not a best case. On a well-modeled part with clean geometry it often lands within 15 to 25 percent of the actual run time.

Finally, overhead and margin are applied, plus finishing, inspection, and shipping. That stack is why the number you see is a budget figure, not a contract price. It is accurate enough to compare designs and materials. It is not accurate enough to argue about a 5 percent delta between two suppliers.

Garbage in, garbage price out. A solid model with true arcs, proper threads, and no overlapping surfaces quotes reliably. A mesh exported from a scan, or a model with hundreds of tiny facets, forces the engine to guess. Faceted geometry inflates surface area, which inflates cycle time, which inflates the quote. If your file is a mesh, expect the number to be high and to move once a human looks at it.

Tolerance is the second input most people get wrong. If the title block says ±0.005 mm across a 300 mm part, the shop must plan for grinding or a temperature-controlled finishing pass, and the price reflects that. If only two bores actually need that tolerance, say so. The quote drops. General tolerances of ±0.1 mm on non-critical faces cost far less to hold, and the engine usually cannot tell the difference without your notes.

Specify material by standard grade, not by trade name. 7075-T6, 17-4PH, Ti-6Al-4V and Inconel all machine differently and price differently. Vague inputs like aluminum or stainless steel push the engine toward a default that may not match your intent. Include the temper or condition, the stock form if it matters, and any certification requirement such as a material certificate with the shipment.

Surface finish drives the last input. As-machined at Ra 1.6-3.2 μm is the baseline. Ra 0.8-1.6 μm adds a finishing pass. Ra 0.2-0.8 μm on a functional sealing face adds more. Anodizing, plating, and bead blasting are priced per part and per batch, so quantity changes the finish cost curve more than it changes the machining cost.

Automated quoting struggles with parts whose cost is dominated by setup, not by cutting. A one-off bracket with a complex fixture, a part that needs a soft jaw machined first, or a casting that must be located on a machined datum, all take longer to set up than to cut. The engine sees the cutting volume and prices that. It cannot see the four hours of fixturing.

It also struggles with inspection cost. A part with ten true-position callouts and a first-article requirement is not just a machining job. It is a metrology job. If your drawing references GD&T that needs a CMM program, the quote may not include that line item. Ask. At GreatLight, 100% inspection before shipment is standard, and dimensional reports are available on request, but the report format should be agreed before the run starts.

Assembly and secondary operations are another blind spot. Press fits, dowel pinning, helicoils, laser marking with a minimum character height of 1.5 mm, and serialized engraving all add steps. Some are priced, some are quoted separately. A fast online free CNC quotation is a machining estimate. It is not a full turnkey estimate unless the platform says so.

Finally, quantity breaks behave differently than most buyers expect. Going from 1 to 10 parts cuts the per-part price sharply because programming and setup amortize. Going from 1,000 to 10,000 parts cuts far less, because at that point you are paying for material, cycle time, and inspection. If a quote shows a dramatic drop at high quantity, check whether it is quoting a different process, such as die casting or vacuum casting instead of CNC.

A reliable quote has to connect to real capacity. GreatLight runs 127 high-precision CNC machines across three plants, including 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines, and 16 mill-turn centers. Maximum processing size is 4,000 mm, with travel envelopes at 4,000 × 400 × 150 mm for large work and 500 × 500 × 450 mm for compact parts. Those numbers decide whether your part can be made in one setup or four.

The tolerance the shop can hold is the tolerance the quote should reflect. We work to ±0.005 mm (±0.0002 in) where the drawing calls for it, with finishes from Ra 0.2-0.8 μm on sealing faces up to Ra 1.6-3.2 μm as-machined. If the automated estimate assumed a looser tolerance than your drawing shows, the price will climb after DFM review. Better to flag the tight features up front.

Lead time is the other half of the quote. Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours of a released order, and parts ship in 3-5 days depending on quantity and finishing. Historical late-delivery probability sits below 2%. No platform can promise a delivery date from a CAD file alone, but a shop with known capacity can give you a range that holds.

Certifications matter when your part feeds a regulated line. GreatLight holds ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. The information security certificate is the one buyers overlook. It covers how your drawings and models are stored and who can access them. Uploads are kept secure and confidential, and an NDA is available on request.