Reasonable setting of turning processing parameters is the key to ensuring processing quality, improving production efficiency and reducing tool wear. It should be comprehensively determined according to workpiece materials, tool performance, equipment operating conditions and processing requirements, instead of blindly adopting fixed parameters.
First, the workpiece material is the core basis. Non-ferrous metals such as aluminum alloy and copper are soft in texture, which allow high rotating speed and large feed rate, and DLC coated tools can be used to avoid built-up edges. Steel and stainless steel feature high hardness and toughness, requiring reduced rotating speed and optimized feed to prevent tool edge wear and chipping. For hardened materials, the cutting load needs to be further reduced.
Second, the substrate and coating performance of cutting tools determine the upper limit of processing parameters. Ultra-fine grain cemented carbide tools with excellent toughness and wear resistance are suitable for medium and high-speed finishing. PVD and DLC coated tools have low friction coefficient and good high-temperature resistance, which support appropriately increased rotating speed. Uncoated bare tools require reduced cutting parameters to protect the cutting edge.
Finally, fine adjustments should be made based on machine tool accuracy, processing procedures and production demands. For finishing, low cutting depth, small feed rate and high rotating speed are adopted to guarantee surface finish and dimensional accuracy. For roughing, large cutting depth and feed rate are applied to improve material removal efficiency. Meanwhile, machine tool rigidity must be fully considered to avoid vibration and deformation, achieving an optimal balance between processing quality and production efficiency.
Three Core Machining Parameters for Common Metal Materials
Different metal materials require matched cutting speed, feed rate, and cutting depth, which are the three essential elements of turning parameter setting. The standardized parameter configuration for steel, cast iron, and stainless steel is listed below for reference.
1. Carbon Steel & Alloy Steel
Cutting Speed: Medium to high speed is applicable. The conventional speed ranges from 120m/min to 350m/min. Lower speed is adopted for rough turning with heavy load, while higher speed is used for finishing to obtain smooth surfaces.
Feed Rate: Match the processing scenario. Rough turning adopts 0.2–0.5mm/r to improve removal efficiency; finishing adopts 0.08–0.15mm/r to ensure dimensional precision.
Cutting Depth: Rough cutting depth is controlled at 2.5–4.5mm for bulk material removal; finishing depth is reserved at 0.2–0.8mm to correct dimensional errors.
2. Cast Iron
Cutting Speed: Medium and stable speed of 130–380m/min is suitable. Cast iron produces abrasive chips, so excessive high speed will accelerate tool wear.
Feed Rate: Stable medium feed of 0.15–0.35mm/r for rough turning, and 0.08–0.15mm/r for finishing to avoid surface pitting and burrs.
Cutting Depth: Rough cutting depth is 2–5mm; finishing depth is 0.15–0.8mm, which effectively improves the flatness of cast iron surfaces.
3. Stainless Steel
Cutting Speed: Low to medium speed of 80–220m/min. Stainless steel has high toughness and is prone to work hardening, so high-speed cutting is prohibited to prevent tool chipping and built-up edges.
Feed Rate: Reasonable feed of 0.20–0.35mm/r for roughing and 0.05–0.15mm/r for finishing. Too small feed will aggravate work hardening.
Cutting Depth: Moderate cutting depth of 1–2.5mm for rough turning, and 0.2–0.6mm for finishing, which reduces cutting heat and avoids workpiece deformation.