The surface geometric characteristics of the CNC lathe workpiece include surface roughness, surface waviness, and surface processing texture.

Influencing factors of surface roughness

Surface roughness is the basic unit of geometric characteristics of the machined surface. When machining workpiece surface with metal cutting tools, surface roughness is mainly affected by geometric factors, physical factors, and CNC machining process factors.

• Geometric factors

From the point of view of geometry, the shape and geometric angle of the tool, especially the arc radius of the tooltip, the main deflection angle, the auxiliary deflection angle, and the feed rate in the cutting parameters have a great impact on the surface roughness.

• Physical factors

Considering the physical essence of the cutting process, the round corner of the cutting edge, and the extrusion and friction at the back of the tool make the metal material plastic deformation and seriously deteriorates the surface roughness. When plastic materials are processed on a numerical control lathe to form banded chips, it is easy to form a chip deposit with a high hardness on the rake face. It can replace the rake face and cutting edge for cutting so that the geometric angle and back feed of the tool change. The outline of the chip buildup is very irregular so the depth and width of the tool marks on the workpiece surface are constantly changing. Some chip nodules are embedded in the workpiece surface, which increases the surface roughness. The vibration during cutting makes the parameter value of workpiece surface roughness increase.

• Process factors

Considering its influence on the surface roughness of hardware parts from the point of view of technology, there are main factors related to cutting tools, workpiece materials, and NC machining conditions.

Clamping method for workpiece processed by CNC lathe

1. All fixtures of the workpiece processed by the CNC lathe are long horizontally and short vertically.

2. CNC lathe machining vice clamping: the clamping height should not be less than 10 mm. The clamping height and machining height must be indicated when machining the workpiece. The machining height shall be about 5mm higher than the three-dimensional jaw to ensure firmness and not damage the jaw. This kind of clamping is common, and the clamping height is also related to the size of the workpiece. The larger the workpiece, the higher the clamping height.

3. CNC lathe machining clamping of clamping plate: the clamping plate is placed on the task table with a code, and the workpiece is locked on the clamping plate with screws. This kind of clamping applies to workpieces that cannot be clamped high and have a large processing force, ordinary medium and large workpieces, and the effect is relatively good.

4. CNC lathe machining code iron clamping: when the workpiece is relatively large, the clamping height is not enough, and it is not allowed to lock the screw at the bottom, the code iron clamping is required. This kind of clamping requires secondary clamping, first code the four corners and process other parts, then code the four sides and process the four corners. During secondary clamping, the workpiece shall not be loosened, and it shall be loosened after stacking. You can also code both sides first and then process the other side.

5. Clamping of CNC lathe machining tools: the diameter shall be more than 10mm, and the clamping length shall not be less than 30mm; If the diameter is less than 10mm, the clamping length shall not be less than 20mm. The tool shall be firmly clamped, and it is forbidden to bump the tool and pull out the workpiece indirectly.