Machining Methods

Face Turning | External Turning | Internal Hole Turning

External Turning

Ordinary external turning is to process the external surface of the part to obtain the required dimension accuracy and surface quality. Ordinary cylindrical turning tools are divided into 95°, 90°, 75°, 60°, 45°, etc. according to the tool’s main declination angle, 90° and 95° main declination tools have large axial force and small radial force during cutting , Suitable for turning slender shaft parts, 75°, 60°, 45° main angle cutters are suitable for Swiss Machining the outer circle of short and thick parts, of which 45° main angle cutters can also be used for 45° chamfer turning.

The economical efficiency of negative-angle blade turning tools is better than that of positive-angle blade turning tools, while positive-angle blade turning tools have sharp edges and light cutting, but the size of positive-angle blades is generally small, which is only suitable for small back-feeding and small feed The size of negative-angle blades can be made larger, which can be used for large back-feeding and large-feedage processing. The strength of the blade tip is also better than that of positive-angle blades (blades with the same shape, size, and circular arc). Different shapes of blades have different edge strengths, effective cutting edge lengths are different, and the number of available tool tips is also different.

Face Turning

Face turning refers to the main cutting edge cutting the end face of the workpiece.

1. Matters needing attention in the end of the car

  • 1) The tip of the turning tool should be aligned with the center of the work piece, so as not to leave a boss on the center of the end surface of the turning tool.
  • 2) The end face of the partial knife car, when the amount of knife eaten by the back is large, it is easy to pierce the knife. The choice of the amount of ap to eat the knife: ap=0.5~3mm when rough turning,
    During finishing, ap=0.05~0.2mm.
  • 3) The diameter of the end face changes from the outside to the center, and the cutting speed also changes. When calculating the cutting speed, it must be calculated according to the maximum diameter of the end face.
  • 4) If there is a concave or convex belly on the end of the vehicle with a larger diameter, check whether the turning tool and the square tool holder and the large sliding plate are locked. In order to feed the swiss cnc machining tool accurately laterally, the middle slide plate should be fastened to the bed, and the amount of knife eaten by the back should be adjusted with a small tool holder.
  • 5) When the quality of the end face is high, the last knife should be cut from the center outward.

2. Quality analysis of the car surface

  • 1) The end face is not flat, there is a convex or concave phenomenon, or the “small head” is left in the center of the end face; the reason is that the lathe tool is not installed correctly, the tip of the tool is not aligned with the center of the workpiece, the back-feeding knife is too large, and the lathe has a gap.
  • 2) Poor surface roughness. The reason is that the turning tool is not sharp, the manual tool is not shaken evenly or too fast, and the automatic feed is not selected properly.

Inner Hole Turning

The turning characteristics of the inner hole are: in a semi-closed state, it is not easy to observe the chip evacuation and affect the processing quality. Deep hole cutting often causes the vibration of the arbor, which causes the cutting edge to wear quickly. The carbide drill arbor is used for small-diameter hole cutting, and the vibration arbor is used for the medium diameter and above. When performing external swiss machining, the length of the workpiece and the size of the selected shank will not affect the tool overhang, so it can withstand the cutting forces generated during machining. When boring and internal hole turning, the depth of the hole determines the overhang, so the hole diameter and length of the part have a great restriction on the choice of tool.

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