Franklins Expert CNC Machining Services: How to Pick a Supplier

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  Five checks that decide the supplier
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  Franklins expert cnc machining: what to compare
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  Tolerance and geometry decide the machine
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  Lead time, capacity and where the parts are made
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  MOQ, tooling and the prototype-to-production jump
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  Certifications, material traceability and inspection
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  How the quote is written and what it leaves out
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  Match the alloy to the process before you compare prices
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  How to run the comparison

Start with the tightest tolerance on the print, not the general block tolerance. If the drawing calls for ±0.005 mm on a bore position, a 3-axis mill with three setups adds stack-up error at every refixture. A 5-axis center cuts the part in one setup and holds the relationship between features.

Geometry matters just as much. Deep pockets, compound angles and features on five faces push work toward simultaneous 5-axis. Simple plates, brackets and turned shafts run faster and cheaper on 3-axis or mill-turn equipment. Paying 5-axis rates for a flat plate is a common waste.

Surface finish is the third input. Ra 0.8–1.6 μm is a normal machined finish. Ra 0.2–0.8 μm needs slower passes, sharper tooling and often a finishing operation. Ask the shop which of these ranges it quotes as standard, because the answer changes both price and schedule.

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  Send the real toleranceA blanket ±0.1 mm title block hides the two features that actually matter.
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  Name the datumInspection disputes usually start with an unclear datum callout.
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  Flag thin walls earlyWalls under 0.8 mm on aluminium deflect unless the toolpath is adjusted.

A lead time number means little without the start point. Ask when chips start flying. A shop that confirms an order on Monday and starts cutting on Tuesday is different from one that queues for a week. At GreatLight, quotation and free DFM analysis come back within 12 hours and production can start within 24 hours of approval.

Capacity also tells you whether the shop can absorb a schedule slip. Machine count and axis mix matter more than a website claim. Sixteen simultaneous 5-axis centers plus 12 four-axis mills and 27 three-axis machines give a shop room to move work between cells when one job runs long.

Part size sets the floor. A 4,000 mm maximum processing size covers long rails and frames that many regional shops cannot hold. If your part is under 500 mm, you are paying for travel you do not need, which is fine as long as the price reflects it.

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  Ask for the spindle start dateIt is the only date that reflects real capacity.
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  Check the axis mixA shop with only 3-axis machines will subcontract your 5-axis work.
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  Confirm shipping termsParts ship in 3–5 days after machining, not after the order date.

Minimum order quantity reveals the shop's business model. A high MOQ usually means dedicated fixtures and long setup times that only pay off in volume. No minimum order quantity means the shop can quote one prototype and a 10,000+ part run on the same drawing.

The risk sits in the middle. A prototype made on a 3-axis machine with hand finishing may not match the production part made on a different machine with a different fixture. Ask whether the prototype and the production run use the same process plan, or at least the same datums.

Tooling cost is the other hidden line. Soft jaws, custom fixtures and form tools belong to your program. Ask who owns them and whether they are stored for repeat orders. If the shop cannot answer, expect to pay for them twice.

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  Quote the prototype and the batch togetherIt exposes process changes that a single quote hides.
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  Ask about fixture storageRepeat orders are cheaper when soft jaws are kept.

Certifications are a filter, not a ranking. ISO 9001:2015 covers general quality management. Automotive work usually needs IATF 16949:2016. Medical device parts push toward ISO 13485:2016. If your data leaves your building, ISO 27001:2022 covers information security.

Material traceability matters for regulated parts. Ask whether the shop records heat numbers and keeps mill certificates on file. For titanium and Inconel work, traceability is often the difference between a usable part and scrap at incoming inspection.

Inspection scope is the last question. A shop that checks a sample and writes a report is not the same as one that inspects 100% of parts before shipment. For a first article or a safety-critical run, ask for the inspection plan and the report format before the order, not after.

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  Match the cert to the industryA medical part quoted without ISO 13485 needs a second look.
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  Request reports up frontInspection reports are easier to define before machining starts.

A quote is a process document. If it lists material, setup, machining, finishing and inspection as separate lines, you can see where the money goes. A single lump sum hides the parts you cannot control, and it makes change orders harder to price later.

Watch for finishing exclusions. Anodizing, plating, powder coating and laser marking are often quoted separately. Ask whether the finish house is in the same building or a subcontractor, because that adds transit time and a second tolerance chain. Laser marking also has a limit: minimum character height is 1.5 mm.

Finally, look at how the shop handles changes. A revision after the first article is normal. What matters is whether the quote states how a revision is priced and how long it adds. Shops that answer this in writing are usually easier to work with on a long program.

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  Read the exclusionsMost surprises live in the last three lines of a quote.
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  Ask about revision policyIt predicts how the next six months will go.

Material choice sets the cutting parameters and the price. Aluminium 6061 and 7075 machine fast and hold tight tolerances well. Stainless 304 and 316 work-harden, so light passes and sharp tooling matter. Titanium TC4 (Ti-6Al-4V) and Inconel generate heat at the cutting edge and need slower feeds, which raises cost per part.

Plastics behave differently again. POM and PEEK cut cleanly but move with temperature. ABS and PC scratch easily during handling, so bead blasting or a protective film may be worth the extra step. If the drawing does not name an alloy, ask the shop to propose one and explain the trade-off.

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  Name the temper6061-T6 and 6061-O machine very differently.
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  Check post-machining movementThin plastic parts can warp after the fixture is released.