Iranian Industry Through CNC Processing: What Changes on the Shop Floor

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  Key takeaways
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  Where Iranian Industry Through CNC Processing Does the Most Work
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  Matching Material to the Cutting Route
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  Holding ±0.005 mm Without Overpaying for It
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  Choosing 3-Axis, 4-Axis, or 5-Axis for Your Part
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  What Inspection Actually Covers Before Shipment
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  How a Job Moves Through the Shop
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  Choosing a Machining Route by Part Type

Iranian industry through CNC processing matters most where a part has to fit something else. A pump housing, a gearbox cover, a valve body: these are not decorative. They carry a bolt pattern, a bore, or a sealing face that must line up on the first try. That is the point where subtractive machining earns its place over casting or hand finishing.

The work splits into three groups. Turning handles round parts: shafts, bushings, spacers, threaded fittings. Milling handles prismatic parts: plates, brackets, manifolds, housings. Mill-turn handles parts that are round and prismatic at once, such as a flanged shaft with a milled flat. Picking the wrong group is the most common reason a quote comes back higher than expected.

A practical first question: does the part have a rotational axis? If yes, a lathe or mill-turn center removes material far faster than a mill. If no, a 3-axis mill is often enough. Only when the part has features on four or five faces, or a compound angle, does a 4-axis or 5-axis center pay for itself.

The second question is size. A 4,000 mm maximum processing size covers long rails and beams, and the 4,000 × 400 × 150 mm travel envelope suits parts that are long and thin. Mid-size work sits in the 750 × 1,150 × 550 mm and 600 × 600 × 600 mm envelopes. Compact parts run in the 500 × 500 × 450 mm and 500 × 310 × 200 mm envelopes, usually on faster spindles.

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  Round partTurning or mill-turn, one setup where possible.
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  Prismatic part3-axis mill with two or three setups.
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  Features on five faces5-axis, one setup, fewer datum shifts.
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  Long and thin4,000 mm envelope, watch deflection.

Aluminium is the default for prototypes and light production. 6061 and 6061-T6 machine cleanly, hold tight tolerances, and take anodizing well. 7075 gives higher strength for brackets and fixtures but chips harder and can move after roughing, so leave stock and take a finishing pass. 2024 is strong but corrodes without coating.

Stainless steel behaves differently. 303 is free-machining and good for fittings and shafts. 304 and 316 resist corrosion and are common in food and medical hardware, but they work-harden, so the cut has to stay under the hardened layer. 17-4PH (SUS630) machines in the annealed state and then ages to high strength, which suits valve parts and pump components.

Steel grades 1018 and 1045 cover general shafts and plates. 4130, 4140, and 4340 are for loaded parts where fatigue matters. Titanium TC4 (Ti-6Al-4V) and Inconel are slow: low feeds, plenty of coolant, and sharp tooling. Expect more passes and longer cycle times rather than a failed cut.

Plastics are not a shortcut. POM and PA machine well and hold dimensions. PEEK needs sharp tooling and controlled heat. ABS and PC are soft and can smear if the feed is too light. Carbon fibre is abrasive and wears tooling fast, so it is quoted separately.

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  6061-T6Default for housings and brackets.
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  303 / 316LFittings, shafts, medical hardware.
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  4140 / 4340Loaded shafts, fatigue parts.
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  PEEK / POMInsulators, wear parts, seals.

A tolerance callout is a promise about the whole batch, not one part. ±0.005 mm is reachable on the right machine with the right setup, and it is also the fastest way to double a price. The rule we use: put the tight callout only on the features that need it, and leave the rest at general tolerance.

Datum choice decides whether the tight callout is repeatable. If a bore and a bolt pattern must line up, both should be machined in the same setup from the same datum. Adding a second setup adds a second source of error, and no amount of inspection removes it after the fact.

Surface finish follows the same logic. Ra 0.2–0.8 μm is a fine finish, usually reached by finishing passes or light polishing. Ra 0.8–1.6 μm covers most sealing faces and bearing seats. Ra 1.6–3.2 μm is as-machined and is fine for brackets and covers. Asking for a fine finish across a whole part rarely helps.

Thermal movement is the quiet failure mode. Aluminium grows roughly twice as fast as steel per degree, so a part measured hot can read different from the same part at 20 °C. For tight work, let the part settle before the final inspection rather than measuring straight off the machine.

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  Tight only where neededOne or two features, not the whole drawing.
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  Single datumBore and bolt pattern in one setup.
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  Finish by functionSealing faces fine, covers as-machined.

Three-axis milling is the most cost-effective route for a part that can be reached from one direction. Plates, covers, and brackets usually fall here. The limit is reach: a deep pocket with a vertical wall needs a long tool, and a long tool deflects. If the depth-to-diameter ratio passes about 4:1, expect to slow down or step out.

Four-axis adds rotation around one axis. This suits parts with features on several faces of a cylinder, such as a shaft with cross-drilled holes or a round flange with slots. It removes one or two setups, which matters more than the machine rate on small batches.

Five-axis adds tilt as well as rotation. It is the right answer when a part has undercuts, compound angles, or a surface that a ball nose cannot reach without a long tool. Sixteen simultaneous 5-axis machining centers in our shop carry this work. The gain is not only reach: a short, rigid tool cuts faster and leaves a better finish.

Five-axis is not always cheaper. Programming takes longer, and a part with simple geometry gains nothing. If a 3-axis job needs one extra setup and the tolerance is loose, that setup is usually cheaper than the 5-axis cycle.

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  3-axisPlates, covers, brackets, shallow pockets.
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  4-axisCylindrical parts, cross holes, slots.
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  5-axisUndercuts, compound angles, deep cavities.
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  Mill-turnRound and prismatic in one cycle.

Inspection is not a final gate. It starts with the raw material. Grade, condition, and certificate are checked before the first cut, because a wrong bar stock cannot be fixed later by tight machining. This is where most material mix-ups are caught.

In-process monitoring follows the critical features. On a first article, the operator checks the datum faces and the tight callout before the run continues. If a tool wears, the drift shows up in the in-process check rather than at final inspection.

Final inspection covers 100% of parts before shipment. Reports are available on request, and they list the measured values against the drawing callouts. For medical and automotive work, the report format follows what the customer's quality system expects.

The shops we work with hold ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, and ISO 27001:2022. The first two cover general and automotive quality, the third covers medical devices, and the fourth covers information security around customer drawings and files.

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  Raw materialGrade and certificate checked first.
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  In-processCritical features watched during the run.
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  Final100% inspection, reports on request.