CNC Machining Service Melbourne: What to Check Before You Order

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  What decides a good fit
• 2
  Six checks that separate capable suppliers from risky ones
• 3
  Matching tolerance to the machine, not the sales sheet
• 4
  Certifications that matter to Melbourne buyers
• 5
  How MOQ and quantity breaks change your real cost
• 6
  Lead time and shipping from Dongguan to Melbourne
• 7
  Inspection reports and what to ask for
• 8
  Step by step: vetting a CNC machining service in Melbourne

Every supplier will quote ±0.005 mm if you ask. The useful question is which machine holds it on your geometry. A 300 mm aluminium bracket with two bored holes is easy on a three-axis mill. A 900 mm housing with angled ports and a curved sealing face is not. That part needs simultaneous five-axis work so the tool reaches the feature in one setup.

Setup count drives your tolerance as much as the machine does. Each refixturing adds stack-up error. On a part with five tight features, three setups can push you past the limit before the spindle even moves. Ask the supplier how many setups they plan. If the answer is more than two for a tight part, request a datum strategy.

Tolerance also has a cost curve. Going from ±0.05 mm to ±0.005 mm on a small feature may add one finishing pass. Demanding it on a 4,000 mm frame adds fixturing, temperature control and inspection time. Sort your drawing by feature. Tight tolerance where it matters, standard tolerance everywhere else.

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  Ra 0.8–1.6 μmTypical fine-machined finish for sealing faces and bearing bores.
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  Ra 0.2–0.8 μmReserved for optical, hydraulic and sliding surfaces.
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  Ra 1.6–3.2 μmAs-machined surfaces that will be painted, coated or hidden.

A certificate on a website tells you the factory passed an audit. It does not tell you the audit covered your production line. Ask which plant and which line will run your parts, then confirm the scope. GreatLight holds ISO 9001:2015 for general quality management, IATF 16949:2016 for automotive work, ISO 13485:2016 for medical devices and ISO 27001:2022 for information security.

The medical and automotive certificates matter most when your part enters a regulated product. A medical housing needs traceable material, documented inspection and a process that survives an audit. An automotive bracket needs the same discipline with PPAP-style documentation. If your supplier cannot name the standard behind their inspection report, the certificate is decoration.

For defence, robotics and consumer electronics, ISO 27001 is the one buyers forget. It covers how your CAD files, drawings and revision history are stored and who can open them. If your design is the product, that matters more than the machine list. An NDA is available on request for projects that need it.

A no-MOQ policy is not a marketing line. It means the supplier can profitably run one prototype and still run 10,000 parts later without retooling the process. For Melbourne product teams, that removes the awkward step where a prototype shop hands off to a volume shop and the geometry changes.

Watch the setup cost per part. On a single prototype, setup can be most of the price. On a 500-part run, the same setup spreads thin and the per-part cost drops. If a supplier quotes a very low prototype price and a high production price, ask what changes between the two. Often it is the machine, the fixture or the inspection plan.

Material choice moves cost more than most engineers expect. Aluminium 6061 is standard and cheap to cut. Titanium TC4 and Inconel cut slowly, wear tooling and need slower feeds. A PEEK housing may cost more in raw stock than in machining time. Price the material and the cycle separately so you can see where the money goes.

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  One to ten partsPrototype quantities, often one-off setups on three-axis or five-axis mills.
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  Ten to 500 partsSoft tooling and fixtures start to pay back. Mill-turn centers shorten cycle time.
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  500 to 10,000+ partsDedicated fixtures, tighter cycle targets, and repeatable inspection routines.

Lead time has three stages: quote, production and transit. A supplier that quotes in 12 hours with a free DFM analysis gives you a day back before anything is cut. Production can start within 24 hours once the file and material are confirmed. Parts ship in 3–5 days for standard work.

Transit to Melbourne is the variable. Air freight runs a few days and suits prototypes and urgent spares. Sea freight runs weeks and suits larger runs where storage is available. Ask the supplier to quote the shipping terms separately so you can choose per order instead of locking into one mode.

The historical late-delivery probability at GreatLight is below 2%. That number only holds if your drawing is final and your material is in stock. When a buyer changes a revision after setup, the schedule resets. Freeze the drawing before you approve the quote, and keep a buffer on the first order.

A dimensional report is only useful if it names the instrument and the feature. A CMM report on a bearing bore tells you something. A caliper reading on an outside dimension tells you less. Ask for first-article inspection on the tight features, plus in-process checks on the rest.

GreatLight inspects 100% of parts before shipment and runs raw material checks, in-process monitoring and final inspection. Reports are available on request. For a first order, request the material certificate and the inspection report together. If they do not match the drawing revision, stop and clarify before shipping.

The qualification rate is 99.99%. That is a process number, not a promise that your part will be perfect. Use it to judge whether the shop controls variation, then use your own incoming inspection on the first batch. Once the process is stable, you can sample instead of inspecting every part.