Solutions to common problems in machining and turning of precision parts of multi-turn crankshaft

When precision parts are processed for turning crankshaft workpieces, due to the complex shape of the crankshaft and the longer crank arm, the extension length of the turning tool should be longer. Due to the long overhang of the turning tool, it is prone to deterioration in the stiffness of the tool holder. Coupled with the impact load during cutting, the rigidity of the process system is low, and vibration and deformation are prone to occur. Therefore, try to improve the crankshaft and the tool during processing. Stiffness.

  1. Maw-shaped turning tool. The protruding part of the turning tool is made into a fish belly shape, which not only ensures that the crank does not collide with the tool holder when the crank rotates, but also improves the rigidity of the protruding part of the knife body. The height h of fish maw is generally (0.6~0.8)L, and the height H of the clamping part of the knife body should be as large as possible.
  2. Row type turning tool. The turning tool consists of a high-rigidity tool row and a tool head, and screws are used to fasten the tool head. This structure makes it easier to sharpen and replace tools, and saves the tool body material. However, when precision parts are processed for turning rigid parts, chip removal is not smooth, and the cutting is easy to squeeze into the gap between the front of the tool head and the tool row. Observe the processing conditions It is also not right, so it is mostly used for roughing.
  3. Auxiliary support for turning tools. A screw hole is pre-processed at the bottom of the turning tool head, and the screw is supported on the middle sliding plate. The supporting length is adjusted and locked with a nut to improve the rigidity of the turning tool during rough machining. When this method is adopted, it is not convenient to rotate the tool post.
  4. Improve the machining rigidity of precision crankshaft parts. Install supporting bolts between the crank neck or the main journal; when the distance between the two crank arms is large, they can be supported by harder wood blocks or sticks; when the inner sides of the two cranks are arc or inclined, a pair of splints can be used To clamp the crank arm.