Machining 2
Customized according to drawings and quantities
I. Core Technology System
Traditional processing techniques
Turning: By rotating the workpiece and feeding the tool, it processes cylindrical surfaces, end faces, threads, etc., and is suitable for shaft and disc parts. For instance, in the turning of automotive crankshafts, it is necessary to control the roundness error to be ≤0.01mm and the surface roughness Ra to be ≤0.8μm.
Milling: By using a rotating multi-edge cutting tool to cut, it can process planes, curved surfaces, grooves, gears, etc. Five-axis linkage milling can achieve precise machining of complex curved surfaces (such as aero engine blades), with a tolerance control of ±0.02mm.
Drilling/Boring: It is used for hole processing. For example, the hole system of the engine cylinder block needs to meet the positional accuracy ≤0.05mm and the straightness ≤0.02mm.
Grinding: By removing materials through abrasive grains, high-precision surfaces are achieved (such as Ra≤0.2μm in bearing raceways), and it is suitable for difficult-to-machine materials like cemented carbide and ceramics.
Special processing technology
Electrical discharge machining (EDM) : It processes hard and brittle materials (such as die steel and titanium alloys) based on the principle of electrical erosion. It can process complex structures such as deep holes and narrow slots, with a surface roughness of Ra≤0.1μm.
Laser cutting/engraving: High-precision cutting of thin plates (such as 0.1mm stainless steel), with a small heat-affected zone, suitable for manufacturing precision parts.
Ultrasonic processing: Suitable for micro-hole and cavity processing of non-metallic materials such as glass and ceramics.
Ii. Material Compatibility and Process Selection
Metallic materials
Stainless steel (304/316L) : Strong corrosion resistance, suitable for medical and food equipment. During processing, the cutting speed should be controlled (Vc=60-100m/min), and hard alloy tools should be used in combination with coolant to prevent the workpiece from overheating.
Aluminum alloy: Lightweight and with good thermal conductivity, it is used in aerospace and automotive structural components. High-speed milling (Vc=300-800m/min) can reduce cutting force and prevent deformation.
Titanium alloy: High strength and excellent biocompatibility, used in aero engines and medical implants. Low cutting force processes (such as low-speed turning) should be adopted to prevent work hardening.
High-temperature alloys (such as Inconel 718) : resistant to high temperatures and fatigue, used in gas turbine blades. CBN tools should be used in combination with high-pressure coolant to extend the tool life.
Non-metallic and composite materials
Engineering plastics (PC/ABS) : Easy to process and low in cost, they are used in electronic casings and automotive interiors. High-speed milling (Vc=200-400m/min) is adopted to avoid melting and adhesion.
Carbon fiber composite materials: high strength and lightweight, used in aerospace structural components. The cutting Angle needs to be controlled to prevent delamination, and diamond tools should be used to improve the surface quality.
Iii. Process Optimization and Quality Control
Precision control
Dimensional tolerance: High-precision positioning (repeat positioning accuracy ±0.005mm) is achieved through the CNC numerical control system, meeting the tolerance requirements of IT5-IT7 grades.
Surface roughness: By adopting multi-axis linkage, small cutting depth and high-speed process, combined with polishing/grinding post-treatment, a mirror-like effect of Ra≤0.2μm is achieved.
Form and position tolerances: Parallelism, perpendicularity, coaxiality, etc. are controlled through fixture design (such as hydraulic clamping) and online measurement (such as laser tracker).
Quality control measures
Online detection: CNC machine tools are integrated with probe detection and vision systems to monitor dimensional deviations in real time. The three-coordinate measuring machine (CMM) is used for offline accuracy verification.
Non-destructive testing: Ultrasonic testing (weld thickness), magnetic particle/penetrant testing (surface cracks), X-ray flaw detection (internal defects).
Material analysis: Grain structure was observed under a metallographic microscope, material properties were tested with a hardness tester (HV/HRC), and composition consistency was verified by a spectrometer.
Iv. Industry Application Cases
Automobile manufacturing: The engine block/cylinder head adopts CNC milling + honing process, with the hole system position accuracy ≤0.05mm. The gears of the transmission are processed by hobbing and grinding, and the tooth profile accuracy reaches DIN grade 5.
Aerospace: The blades of aero engines are processed by five-axis linkage milling and electrical discharge polishing, with a surface roughness Ra≤0.4μm. Titanium alloy structural components are processed through laser welding and CNC machining to meet the requirements of lightweight and high strength.
Medical devices: Surgical instruments (such as bone forceps) are made of stainless steel through a turning and grinding process, with a surface roughness of Ra≤0.4μm, meeting the ISO 13485 biocompatibility requirements. Implants (such as artificial joints) are processed through titanium alloy CNC machining and anodizing to enhance corrosion resistance.
Electronic equipment: The middle frame of the mobile phone is made of aluminum alloy through CNC milling and anodizing, with a dimensional tolerance of ±0.02mm and a surface hardness of HV≥300. Semiconductor equipment parts achieve nanoscale surface quality through ultra-precision turning (Vc=500m/min).
