CNC Machining
Turning, milling and drilling on multi-axis CNC machines with ±0.01mm tolerance. Delivery with CMM measurement and PPAP documentation.
CNC (Computer Numerical Control) machining is the process of bringing steel semi-finished products to precise dimensional and form tolerances through metal cutting on computer-controlled machines. This process covers turning, milling, drilling, reaming, and grinding operations, providing precision up to ±0.01 mm.
On multi-axis CNC turning centers (2–5 axis), cylindrical parts — shafts, bushings, pins, flange necks — are produced with high efficiency. Complex geometries are achieved in a single setup with automatic tool changing and live tooling features. G-code is generated directly from 3D models through CAD/CAM software.
Block-form parts — valve bodies, pump covers, die plates — are machined on vertical and horizontal machining centers. With 5-axis machining centers, inclined surfaces and complex pocket geometries are completed in a single setup, reducing total machining time by up to 40%.
Each production batch is 3D verified with CMM (Coordinate Measuring Machine). Under PPAP (Production Part Approval Process), first article inspection (FAI), measurement reports, material certificates, and process capability (Cpk) data are presented to customers. Process stability is continuously monitored with SPC system, targeting Cpk ≥ 1.67.
This process is carried out at partner mills across our supply network. Aktif Çelik is responsible for grade selection, conformity to specification, inspection documentation (EN 10204) and shipment follow-up.
Technical Parameters
CNC Machining — Key technical data of the process
Equipment & Facilities
- CNC turning centers (2–5 axis)
- CNC vertical machining centers
- CNC horizontal machining centers
- 5-axis machining center
- CNC cylindrical grinding
- Coordinate Measuring Machine (CMM)
- Tool presetter
- CAD/CAM software system
Quality Control Points
- CMM (Coordinate Measuring Machine) 3D measurement
- Surface roughness profilometer
- Optical measurement (projector / vision system)
- SPC (Statistical Process Control)
- PPAP (Production Part Approval Process)
- FAI (First Article Inspection)
- In-process control with gauges and calipers
Reference Standards
Related Products
Products obtained or used in this production process
Technical Support & Quote
CNC Machining — For detailed technical information, capacity details and custom production requests, contact our expert team.
What is CNC machining?
CNC (Computer Numerical Control) machining produces parts by removing material with computer-controlled machine tools (lathes, mills, machining centres). The program (G-code) defines the toolpath, delivering repeatable precision in the ±0.01 mm range, complex geometry and serial-production consistency. For steel bars, the most common operations are turning (cylindrical) and milling (prismatic).
Turning, milling and the effect of material choice
In turning the workpiece rotates and the tool feeds — producing rotational parts like shafts, bushings and flanges. In milling the tool rotates — cutting slots, faces and hole patterns. Achievable tolerance and surface finish (Ra) depend on the machine but also the material: free-cutting steels (11SMn30/11SMnPb30) are best for chip breaking and finish; Q&T 42CrMo4 machines harder but gives a stronger finished part. The right starting stock (bright steel h9/h11) reduces machining time and scrap. Dimensions are verified with CMM or micrometers, and with SPC in serial work.
Frequently Asked Questions
What is the difference between CNC turning and milling?+
In turning the workpiece rotates (cylindrical parts: shafts, bushings); in milling the tool rotates (prismatic faces, slots, holes).
What precision can CNC machining achieve?+
±0.05 mm in standard work, ±0.01 mm and below in precision work; grinding reaches micron level.
Which steel machines best on CNC?+
Free-cutting steels (11SMn30, 11SMnPb30) — the sulphur addition breaks the chip, improves finish and extends tool life. The standard for serial machining.
Which starting stock should be chosen for machining?+
Tight-tolerance bright steel (h9/h11) reduces roughing; for large sections, peeled bar guarantees a defect-free surface.
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