Accuracy in KSA: How to Judge a CNC Machining Company Name
This page is for engineers and buyers in Saudi Arabia who need to verify machining accuracy before placing an order. It covers what tolerance figures actually mean on a drawing, which inspection documents to request, and how certifications map to aerospace, automotive and medical work.
What accuracy means on a real purchase order
A tolerance number is only half the story. The other half is how the shop proves it, part after part.
Read the tolerance before you read the supplier list
A drawing that says ±0.005 mm on every dimension is not a drawing that needs a five-axis machine. It needs a shop that will tell you which features actually drive the cost. On most parts, two or three dimensions carry the function: a bearing bore, a mating face, a bolt pattern. The rest can sit at ±0.1 mm and nobody will notice. When a supplier quotes the whole part at the tight number, you pay for grinding and CMM time you do not need.
The first useful question is which features are datum-controlled. A face called out as datum A tells the machinist where to hold the part and where to measure from. Without datums, an inspector can measure the same part twice and get two answers. Both are technically correct. Neither is repeatable.
Wall thickness matters as much as the tolerance block. A 0.8 mm wall on an aluminum housing will move during clamping, and it will move again after anodizing. If the wall is thin because the design is tight, say so on the RFQ. The shop can adjust fixturing and cutting sequence instead of discovering the problem at final inspection.
Which process holds which tolerance
Three-axis milling holds ±0.02 mm comfortably on flat plates and prismatic parts. It struggles when you need five faces in one setup, because each re-clamp adds position error. For housings with bores on two or more sides, a four-axis or five-axis machine removes that error by keeping the part still.
Five-axis machining is not automatically more accurate. It is more capable. It reaches undercuts, angled holes and contoured surfaces that a three-axis machine cannot touch without custom fixturing. On a simple bracket, five-axis work costs more and gains nothing. On a turbine blade root or a medical implant with compound angles, it is the only realistic route.
Turning and mill-turn centers handle round parts with tight concentricity. When a shaft needs a bearing journal, a thread and a cross-hole all held to the same axis, a mill-turn center does it in one operation. That single setup is often worth more than a tighter tolerance figure quoted on paper.
- 1Prismatic partsThree-axis milling, ±0.02 mm is routine.
- 2Multi-face housingsFour- or five-axis, one setup, no re-clamp error.
- 3Round and cross-feature partsMill-turn centers keep concentricity in one operation.
- 4Thin wallsFlag them on the RFQ; fixturing decides the result.
Tolerance, finish and the process that delivers it
Use this as a starting point when you write the RFQ. Actual values depend on material, geometry and feature size.
| Feature type | Typical tolerance | Achievable finish | Process note |
|---|---|---|---|
| Flat plate, simple profile | ±0.02 mm | Ra 1.6–3.2 μm | Three-axis milling, one or two setups |
| Housing, bores on 3+ faces | ±0.01 mm | Ra 0.8–1.6 μm | Four- or five-axis, single setup |
| Bearing bore, press fit | ±0.005 mm | Ra 0.2–0.8 μm | Boring or fine milling, then gauge check |
| Shaft with cross-hole | ±0.01 mm | Ra 0.8–1.6 μm | Mill-turn, concentricity held in one op |
| Thin-wall aluminum cover | ±0.05 mm | Ra 1.6–3.2 μm | Light clamping, sequenced cuts, stress relief |
| Contoured or angled surface | ±0.01 mm | Ra 0.8–1.6 μm | Simultaneous five-axis, ball-nose finishing |
What inspection paperwork should show up with the parts
A certificate of conformance with a signature and a date is the minimum. It tells you the shop believes the parts meet the drawing. It does not tell you which dimensions were measured or what the readings were. For anything functional, a first article inspection report is the document that matters. It lists every drawing dimension, the nominal, the actual reading and the instrument used.
In-process checks close the gap between the first article and the last part. Tool wear, thermal drift and chip buildup all shift dimensions over a run. A shop that measures only the first part and the last part is guessing about the middle. In-process monitoring on critical features catches drift before a batch is scrapped.
Material traceability belongs in the same packet. Mill certificates tie the raw stock to a heat number and a chemistry. Without them, a failed part gives you nothing to investigate. If the part goes into a regulated assembly, the traceability chain is part of the product, not paperwork.
Which certificate actually applies to your part
ISO 9001:2015 covers a quality management system. It says the shop documents its processes and follows them. It does not say the shop can hold ±0.005 mm. Those are different claims, and buyers in Saudi Arabia often treat them as one.
IATF 16949:2016 is the automotive standard. It adds requirements around part approval, traceability and change control that matter for production programs. ISO 13485:2016 is the medical device standard, aimed at risk management and design control. ISO 27001:2022 covers information security, which is relevant when your drawings and CAD files sit on a supplier's server.
Match the certificate to the end use. A bracket for an industrial machine does not need IATF. A component that ships inside a vehicle does. A patient-contact part follows the medical route. Asking for all four on every job adds audit cost that shows up in your unit price.
Questions engineers send before a first order
Can you hold ±0.005 mm on every dimension of my part?
No, and no shop can on a normal production run. ±0.005 mm is realistic on specific features such as a bored bearing seat, measured with the right instrument in a temperature-stable room.
On general dimensions we work to ±0.02 mm, and we will mark on the quote which features carry the tight number so you can see where the cost sits.
What do you need from me to quote accurately?
A 3D model plus a 2D drawing with datums, tolerances and surface finish callouts. Material grade, quantity and any post-processing go on the RFQ.
If the drawing is incomplete, we return a DFM analysis within 12 hours listing what is missing and where tolerances look tighter than the function requires.
How do certifications map to industries served in Saudi Arabia?
ISO 9001:2015 fits general industrial and machinery work. IATF 16949:2016 fits automotive and EV programs. ISO 13485:2016 fits medical devices. ISO 27001:2022 covers how we handle your files.
Tell us the end use on the RFQ and we will confirm which standard applies before production starts.
Can you start before an NDA is signed?
We can review a drawing for quoting, but production does not start until the confidentiality terms are settled. An NDA is available on request.
Uploads are held as secure and confidential, and access is limited to the engineers on your job.
What is the smallest quantity you will run?
There is no minimum order quantity. We run single prototypes up to 10,000+ part runs on the same equipment.
For one-off parts, the setup cost dominates. For runs above a few hundred, we will suggest fixtures that cut cycle time and improve repeatability.
How fast can parts ship?
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours of approval, and parts ship in 3–5 days for standard work.
Historical late-delivery probability is below 2%. Sequence and material availability can extend the window, and we will say so on the quote.
Send the drawing and get a tolerance review
Upload your model and 2D drawing. We return a quote with a free DFM analysis inside 12 hours, and we flag any tolerance that costs more than it needs to.
12-hour quoteDFM analysis included100% inspection before shipmentNDA on request
