Dalang CNC Factory Overview: How to Judge One Before You Send an RFQ

• 1
  Key takeaways
• 2
  What to compare when you screen a Dalang CNC factory
• 3
  What a Dalang CNC factory actually is
• 4
  Machine capability: which parts fit which machine
• 5
  Tolerance and surface finish: what the numbers mean
• 6
  Certificates, confidentiality and the paperwork trail
• 7
  Lead time, MOQ and the real cost of a cheap quote
• 8
  How to screen a Dalang CNC factory in 6 steps

Dalang is a town inside Dongguan, and Dongguan is one of the densest machining clusters in southern China. A single industrial street can hold dozens of shops running three-axis mills, lathes and surface grinders. Because the supply chain sits within a few kilometers, tooling, material and finishing all move quickly between vendors. That density is the real advantage of the area.

The catch is that 'Dalang CNC factory' describes a location, not a capability level. Two buildings on the same road can differ by an order of magnitude in equipment. One shop runs 127 high-precision CNC machines and 16 simultaneous 5-axis machining centers. The next one brokers your job to a third party and adds a margin. Both call themselves a CNC factory.

So the useful question is not where the shop is. It is which machines it owns, who programs them, and how it proves the parts are correct. A Dalang CNC factory that answers those three questions in writing is worth a quote. One that answers with adjectives is not.

GreatLight has operated from Dongguan since 2011, with 3 wholly-owned plants covering 7,600 m² and about 150 technicians. We also run a factory in Singapore at No.3 Joo Koon Circle. That combination matters for buyers who need a second shipping origin or a Southeast Asia production base.

• 1
  Cluster advantageMaterial, tooling and finishing vendors within a short drive
• 2
  Cluster riskLocation is often sold as if it were capability
• 3
  What to verifyOwned machines, in-house programming, documented inspection

Axis count is the first filter. A three-axis mill cuts prismatic parts from up to six sides with refixturing. A four-axis mill adds a rotary table, so holes and slots around a cylindrical body can be cut in one setup. A five-axis machine tilts the tool or the table, which lets it reach undercut features and steep walls without moving the part.

Typical travel sizes tell you the part envelope. Large five-axis machines in the cluster run travels around 4,000 × 400 × 150 mm. Mid-size machines run 750 × 1,150 × 550 mm and 600 × 600 × 600 mm. Compact machines sit at 500 × 500 × 450 mm and 500 × 310 × 200 mm. A Ø400 mm rotary table sets the practical limit for turned-and-milled round parts.

Choose five-axis when one setup saves real money. A part with five angled faces, deep pockets on a curved surface, or tight position tolerance between features on different sides is a good candidate. Choose three-axis when the part is flat, the volumes are high, and a fixture costs less than the extra machine hour.

Neither is automatically better. A simple bracket on a five-axis machine is an expensive bracket. A complex impeller on a three-axis machine becomes five setups and five chances to lose datum. Match the geometry to the machine, then check the tolerance.

• 1
  5-axisAngled faces, undercuts, tight feature-to-feature position
• 2
  4-axisCylindrical bodies with radial holes or slots
• 3
  3-axisPrismatic, flat, high-volume parts with simple fixtures
• 4
  Mill-turnShafts and housings finished in one program

±0.005 mm (±0.0002 in) is a tight number, and it is not a shop-wide default. It is achievable on specific features, on specific machines, with the right material and a controlled thermal environment. Aluminium 6061 and 7075 hold it more easily than 316 stainless or Ti-6Al-4V, which move more during and after cutting.

Ask which features carry the tight tolerance and how the shop verifies them. A good answer names the machine, the fixture, the gauge and the inspection routine. A vague answer means the number came from a template. Some shops quote ±0.005 mm on the front page and then ask for a tolerance relaxation after the first article.

Surface finish is a separate axis of cost. As-machined surfaces land around Ra 1.6–3.2 μm. A high finish sits at Ra 0.8–1.6 μm and usually needs a finer stepover or a finishing pass. Fine finish at Ra 0.2–0.8 μm often means polishing or lapping after machining, which adds a process step and a handling risk.

Specify finish only where it does a job. A sealing face, a bearing seat or an optical mount needs it. A cosmetic cover usually does not, and paying for Ra 0.4 μm on a non-functional surface just moves budget away from the features that matter.

• 1
  Material effectAluminium holds tight tolerance more easily than titanium
• 2
  VerificationAsk for the gauge and the inspection routine, not just the number
• 3
  Finish costFiner Ra means more machine time or an added polishing step

Certificates are only useful when the scope matches your part. ISO 9001:2015 covers a general quality management system. IATF 16949:2016 addresses automotive production, including traceability and change control. ISO 13485:2016 applies to medical devices and carries validation requirements. ISO 27001:2022 covers information security, which matters when you send CAD files and drawings.

A shop may hold one and not the others. That is normal. What is not normal is presenting all four as if they applied to every job. Ask which certificate covers the process that will run your part, and ask for the current document with scope and expiry visible.

Confidentiality is the other half of the paperwork. Uploads should be secure and confidential, and an NDA should be available on request. If your drawings go to a broker who forwards them to three shops, your design is circulating before you have a purchase order.

Traceability matters most in regulated work. For automotive and medical programs, ask how material lots, machine logs and inspection records link to the part serial. If the shop cannot describe that chain, it is not set up for the program.

• 1
  Match scopeIATF 16949 for automotive, ISO 13485 for medical
• 2
  Information securityISO 27001:2022 covers how your files are stored and shared
• 3
  NDAAvailable on request, before files move
• 4
  TraceabilityMaterial lot, machine log and inspection record linked to the part

Lead time has three parts: quoting, production start and shipping. Quotation and free DFM analysis within 12 hours is a reasonable benchmark. Production can start within 24 hours once the drawing and material are confirmed. Parts ship in 3–5 days for standard work. A shop that cannot separate those three stages is usually guessing.

MOQ is a strong signal about workflow. No minimum order quantity, from one prototype to 10,000+ part runs, means the shop has a setup routine for single parts and a separate one for volume. A high MOQ means your prototype is an interruption, and it will be scheduled after the production jobs.

Price gaps between Dalang shops are usually explained by what is excluded. Watch for material certificates charged as an extra, inspection reports billed separately, or finishing subcontracted with no incoming check. None of these are wrong on their own, but they belong in the quote so you can compare like for like.

The cheapest quote often carries the largest hidden cost: a tolerance relaxation request, a second setup, or a rework loop that pushes your build date. On regulated programs, a single rejected lot can cost more than the difference between the low and high bid.

• 1
  Quote stageQuotation and free DFM analysis within 12 hours
• 2
  Start stageProduction can start within 24 hours after confirmation
• 3
  Ship stageParts ship in 3–5 days for standard work
• 4
  ExclusionsMaterial certs, inspection reports and finishing should be visible