Mequon CNC Processing Service Guide
This guide is for engineers and purchasing teams in Mequon and the Milwaukee area who are selecting a CNC partner. It covers the checks that decide whether a shop can actually hold your print: tolerance, 5-axis capability, materials, inspection, lead time, and MOQ. Read it before you send an RFQ.
In this article
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What matters most when choosing a shop
Matching the process to the part
Use the left column to find your part type, then read across for the process and the reason.
| Part type | Recommended process | Why |
|---|---|---|
| Prismatic bracket, 6 faces | 3-axis with two setups | Lowest cost when faces are orthogonal |
| Angled ports, undercuts | 4-axis or 5-axis | Reaches features without repositioning |
| Impeller, turbine blade | Simultaneous 5-axis | Continuous tool vector, no witness marks |
| Long rail, 4,000 mm | Large-travel 3-axis | Fits 4,000 × 400 × 150 mm travel |
| Turned shaft with milled flats | Mill-turn center | One chucking, concentricity held |
| Thin-wall housing | 5-axis with light finishing passes | Fewer re-clamps, less distortion |
| Prototype, 1 to 20 pcs | 3-axis or 5-axis, no MOQ | No tooling commitment before validation |
| Production run, 10,000+ pcs | 5-axis or mill-turn with fixtures | Cycle time and repeatability dominate |
What a Mequon CNC processing service can hold
Tolerance is the first number engineers compare, and it is the easiest to misread. A shop quoting ±0.005 mm is stating a best-case capability, not a promise on every feature of every part. That number depends on machine condition, fixture rigidity, tool wear, thermal drift, and how many setups the part needs. Ask which machine holds it and on what envelope.
At GreatLight, the tightest routine tolerance is ±0.005 mm (±0.0002 in). That applies to features cut in a single setup on a rigid fixture, with finishing passes kept light. On long parts, tolerance interacts with travel: a 4,000 mm rail does not hold the same number as a 100 mm bracket because thermal expansion and machine geometry stack up over length.
Surface finish follows the same logic. As-machined finish runs Ra 1.6–3.2 μm. A high-quality finish is Ra 0.8–1.6 μm, and fine finishing reaches Ra 0.2–0.8 μm. Getting below Ra 0.8 μm usually means a separate finishing pass with a smaller stepover, which adds cycle time. If your print only calls out Ra 1.6 μm, do not pay for Ra 0.4 μm.
A useful test: send a drawing with one tight bore and the rest open. See whether the quote flags the tight feature and explains how it will be held. A shop that treats the whole part as equally critical has not read the print.
- 1±0.005 mmRoutine tight tolerance on rigid single-setup features
- 2Ra 0.8–1.6 μmStandard high-quality finish for sealing and sliding surfaces
- 3Ra 0.2–0.8 μmFine finish, adds a dedicated finishing pass
- 4Report on requestDimensional reports available with the shipment
Five-axis capability and when it changes the quote
Five-axis machining is not automatically better. It becomes the right call when a part has features that a 3-axis mill cannot reach in one orientation, or when repositioning the part would introduce error. Angled faces, compound holes, deep pockets with tapered walls, and organic contours all fall into that group.
Simultaneous 5-axis means the rotary axes move while the tool cuts. The tool vector stays continuous, so you avoid the scallops and witness marks that come from stopping, indexing, and restarting. The trade-off is programming time and machine hour rate. For a simple bracket, that extra cost buys nothing.
GreatLight runs 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines, and 16 mill-turn centers, 127 high-precision CNC machines in total across three wholly-owned plants. That mix matters because the shop can quote the process your part actually needs instead of forcing every job onto a 5-axis spindle.
Size decides the machine too. Travel options include 4,000 × 400 × 150 mm for long parts, 750 × 1,150 × 550 mm and 600 × 600 × 600 mm for mid-size work, and 500 × 500 × 450 mm plus 500 × 310 × 200 mm for compact parts. A Ø400 mm rotary table handles round work that needs indexing. If your part does not fit an available envelope, the process changes.
Material range and what it does to the process
Material choice drives tooling, speed, and sometimes the finishing route. Aluminum is the most forgiving: 6061, 6061-T6, 2024, 5052, 5083, 6063, 6082, 7075, and ADC12 all machine cleanly, though 7075 and 2024 need sharper tools and better chip evacuation. Stainless 303 and 304 cut well; 316L and 17-4PH work-harden, so keep the tool engaged and avoid dwelling.
Steel grades 1018, 1045, 4130, 4140, 4340, A36, and tool steel cover most structural and wear applications. Titanium TA1, TA2, TC4 (Ti-6Al-4V), Inconel, and magnesium AZ31B or AZ91D are also in the range, but they slow the process. Titanium and Inconel generate heat at the cutting edge, so feeds and speeds drop and cycle time rises. Magnesium needs coolant discipline because chips ignite.
Plastics are their own discipline. ABS, PC, PMMA, POM, PA, PEEK, PP, HDPE, and carbon fibre all behave differently. POM machines like brass with sharp tools and no coolant flood. PEEK and carbon fibre are abrasive, so tool life is shorter and the quote reflects it. Thin plastic walls deflect, which limits how aggressively you can rough.
A note on finishes: anodizing, electroless nickel, zinc, silver and gold plating, powder coating, black oxide, bead blasting, tumbling, brushing, polishing, and laser marking are all available. Laser marking has a minimum character height of 1.5 mm, so plan your part number and QR code layout around that.
- 1Aluminum6061, 7075, 2024, 5052, 6082, ADC12
- 2Stainless303, 304, 316L, 17-4PH, 440C
- 3Steel1018, 1045, 4130, 4140, 4340, tool steel
- 4SpecialTi-6Al-4V, Inconel, magnesium AZ31B
Inspection, certification, and what the paperwork proves
Inspection is where a supplier relationship is won or lost. A shop that measures only the first and last part leaves the middle of a run unverified. GreatLight inspects 100% of parts before shipment and runs raw material checks, in-process monitoring, and final inspection. Reports go out on request. For a medical or aerospace part, those records are not optional.
Certifications tell you which industries a shop is set up to serve. ISO 9001:2015 is the quality baseline. IATF 16949:2016 covers automotive production and the traceability that goes with it. ISO 13485:2016 covers medical devices. ISO 27001:2022 covers information security, which matters when you send proprietary CAD files and NDAs are involved.
The reported qualification rate is 99.99%. Treat that as a process indicator, not a guarantee on your specific geometry. The useful question is what happens when a dimension drifts: does the shop stop the run, quarantine parts, and tell you before shipment? Ask that during selection, not after a failed inspection.
For confidential work, uploads are secure and confidential, and an NDA is available on request. If your program requires one, sign it before sending models. It costs nothing and removes an argument later.
Lead time, MOQ, and how to read a quote
Lead time is a function of process, material, and finishing, not a single published number. At GreatLight, quotation and free DFM analysis come back within 12 hours, production can start within 24 hours, and parts ship in 3–5 days. The historical late-delivery probability is below 2%. Those figures assume the drawing is complete and the material is in stock.
MOQ is where smaller buyers get squeezed. No minimum order quantity means one prototype is a valid order, and a 10,000+ part run is handled on the same process. That matters for validation: you can prove the design before spending on fixtures and tooling.
When you compare quotes, compare the scope, not just the number. Does the price include material certification, in-process inspection, final dimensional report, and finishing? A low quote that adds inspection and deburring as line items is not actually lower. Ask for the inspection plan in writing.
Be cautious with quotes that promise delivery dates far shorter than the process allows. Anodizing, heat treating, and plating add calendar time that no machine shop can compress. A supplier who admits that is more useful than one who does not.
Common mistakes when selecting a CNC supplier
The most common mistake is sending a PDF drawing without the 3D model. The model resolves ambiguous callouts and lets the shop check tool access before quoting. Without it, the quote is a guess and the first article becomes a negotiation.
The second is accepting a tolerance claim without a feature list. A shop that says it holds ±0.005 mm everywhere has not thought about the thin wall on your part or the 300 mm bore spacing. Ask for the exceptions, not the headline.
The third is ignoring the finishing chain. A part that machines perfectly can still fail because a coating added 0.02 mm or a heat treat moved a bore. If your print has a coating callout, ask how the shop compensates for it before cutting.
The fourth is skipping the NDA. If your design is proprietary, sign the agreement before you upload. It is a five-minute step that prevents a much longer conversation later.
How to vet a Mequon CNC processing service in seven steps
Work through these in order. Each step removes a category of risk before you commit to a purchase order.
- 1Send the full drawing set, not a screenshotInclude STEP or IGES models, 2D prints with GD&T, material spec, finish callouts, and any critical-to-function notes. A shop cannot quote tolerance it cannot see.
- 2Ask which machine and how many setupsThe answer tells you whether the shop read the print. One setup on a 5-axis center is different from four setups on a 3-axis mill, even if both claim ±0.005 mm.
- 3Confirm the tolerance is feature-specificShare your tightest bore or flatness callout and ask for the expected result. A shop that explains the fixture and the finishing pass is worth a second conversation.
- 4Check the material and finish routeAsk whether heat treating, anodizing, or plating happens in-house or at a partner. Outside processes add days and a second inspection point. Plan for both.
- 5Verify certification matchIf your industry needs IATF 16949 or ISO 13485, confirm the certificate covers the plant doing the work, not just the company name on a website.
- 6Ask about MOQ and run lengthNo minimum order quantity means you can order one prototype and then a 10,000+ part run without changing suppliers or re-qualifying the process.
- 7Agree on lead time and inspection paperworkQuotation and free DFM analysis come back within 12 hours, production can start within 24 hours, and parts ship in 3–5 days. Confirm what inspection records travel with the shipment.
Questions engineers ask before ordering
What tolerance can a Mequon CNC processing service actually hold?
The routine tight tolerance is ±0.005 mm (±0.0002 in) on rigid, single-setup features with light finishing passes. That is a capability statement, not a blanket guarantee.
Long parts, thin walls, and multi-setup geometry widen the realistic band. Send the critical callouts and the shop can confirm what applies to your part.
When is 5-axis machining worth the higher machine rate?
When the part has angled faces, compound holes, undercuts, or contours that a 3-axis mill cannot reach without repositioning. If repositioning would add two or more setups, 5-axis usually wins.
For a simple prismatic bracket with orthogonal faces, a 3-axis setup is cheaper and just as accurate.
Is there a minimum order quantity for prototypes?
No minimum order quantity. One prototype is a valid order, and the same process scales to 10,000+ part runs.
That lets you validate fit and function before committing to fixtures and production tooling.
Which certifications should I check for medical or automotive work?
Medical devices need ISO 13485:2016. Automotive production needs IATF 16949:2016. ISO 9001:2015 is the general quality baseline.
If you share proprietary CAD data, ISO 27001:2022 covers information security. Confirm the certificate applies to the plant running your job.
How fast can parts ship?
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours, and parts ship in 3–5 days.
External processes such as anodizing, plating, or heat treating add calendar time. The shop will flag that in the quote rather than hide it.
What should I include in the RFQ?
Send the STEP model, 2D print with GD&T, material grade, finish specification, quantity, and any inspection reporting requirements.
Flag the critical-to-function dimensions. That single step speeds up DFM feedback and reduces back-and-forth.
Ready to price your part?
Send your model and print. We return a quotation and a free DFM analysis within 12 hours, with the process route and inspection plan spelled out.
12-hour quoteNo MOQ100% inspectionNDA on request
More from the shop floor
We publish setup notes, tooling trials and inspection data from the factory floor.
