Tool sticking and work hardening are two major obstacles that affect precision in stainless steel parts processing, requiring solutions throughout the entire machining process. Tool sticking stems from the high toughness of stainless steel, which makes it prone to sticking to the tool during cutting. Work hardening occurs when the material's surface hardness increases dramatically after being squeezed by cutting forces. The combined effects of these two factors can exacerbate tool wear and part deformation, necessitating targeted optimization of the machining plan.
Tool selection is crucial for preventing tool sticking in stainless steel parts processing. Ultrafine-grain carbide tools are preferred, as their high hardness resists the sticky wear of stainless steel, and their sharp cutting edges reduce frictional heat generation. Coated tools, such as titanium aluminum nitrogen (TiAlN) coatings, create a low-friction surface that prevents chips from sticking to the tool face, facilitating smoother chip evacuation during stainless steel parts processing.
Adjusting cutting parameters is crucial for controlling work hardening in stainless steel parts processing. Excessively high cutting speeds can cause material overheating and increased stickiness, while too low speeds prolong tool-workpiece contact time, exacerbating work hardening. It's important to control the speed within a reasonable range, using a moderate feed rate, while also reducing the depth of cut to mitigate plastic deformation and reduce the degree of hardening in stainless steel parts processing.
A cooling and lubrication system is essential in stainless steel parts processing. The high temperatures generated during cutting intensify the material's viscosity and hardening tendency, necessitating the use of high-pressure cutting fluid directly in the cutting zone to dissipate the heat promptly. Selecting a cutting fluid containing extreme pressure additives not only lubricates the tool-workpiece interface but also forms a protective film on the stainless steel surface, inhibiting the growth of the hardened layer.
Tool geometry must be tailored to the specific characteristics of the stainless steel parts being processed. Increasing the rake angle reduces cutting resistance and minimizes material extrusion deformation. Properly designed clearance angles minimize friction between the tool and the machined surface, preventing secondary hardening. Keeping the cutting edge radius within a narrow range prevents excessive wear while minimizing compression of the stainless steel, achieving a balanced machining efficiency and quality.
Optimizing the cutting path can alleviate problems in stainless steel parts processing. Layered cutting distributes cutting forces, preventing continuous stress in the same area and the resulting accumulation of hardening. Arc transitions are used at corners instead of right-angle cuts to reduce sudden changes in cutting forces. Eliminating pauses during cutting prevents localized heat buildup that can cause tool sticking, ensuring smoother processing of stainless steel parts.
Material pretreatment removes obstacles to stainless steel parts processing. Annealing stainless steel before processing reduces its hardness and toughness, minimizing plastic deformation during cutting. Lubrication pretreatment of the blank surface reduces the initial friction coefficient. This improves cutting performance from the material itself, and, combined with process optimization during processing, completely eliminates tool sticking and hardening.
