What are the factors that affect the surface roughness of cutting in precision parts machining??
1. The influence of cutting force and friction. When precision parts are machined and cut, the rounded corners of the cutting edge of the tool, as well as the compression and friction on the side facing the workpiece, can cause plastic deformation of the metal material, resulting in distortion or deepening of the existing residual areas, increasing surface roughness and causing brittle materials to be processed. At this time, the chips become broken particles, and the processed surface often shows signs of particle collapse, leaving many pits, making the surface rough.
2. The impact of debris accumulation tumors. When the cutting tool cuts plastic at a certain speed, some small particles on the chip will adhere to the tip of the front cutting surface, forming high hardness stacked edges that can replace the front cutting surface and cutting edge for cutting.
When the frictional force between the chips and the edge of the pile is greater than the cold welding strength between the pile edge and the front cutting surface, or when it is subjected to impact or vibration, the pile edge will fall off, and a new edge will gradually form in the future. The formation, growth, and detachment of stacked edges can seriously affect the surface roughness of the parts.
3. The influence of scales and thorns. During the cutting process, due to the friction and cold welding of chips on the cutting surface during precision part machining, the chips will periodically stay on the front cutting surface, thereby squeezing the newly machined surface. In severe cases, the surface may tear. Scaly spines form on the surface, making it rough and uneven.
Due to the influence of the aforementioned physical factors on roughness, in order to reduce surface roughness, in addition to reducing plastic deformation caused by cutting forces, the generation of accumulated tumors and scales should be avoided during precision part machining.
The main process measures are: selecting cutting speed that is not prone to producing accumulation edges and spikes, improving the cutting performance of materials, and selecting cutting fluid correctly.