What is the best Angle for a car knife
Reasonable use of cutting. With smaller cutting depth ap and quantity f, the residual area can be reduced, reducing the Ra value. (2) reduce the residual area and reduce the amount of the Ra by reducing the par-angle krypton, or the tip of the knife. (3) increase the front Angle gamma 0 and sharpen the blade. (4) it is effective to reduce the amount of Ra at the surface of the workpiece by grinding the front and back of the tool with oil, and then the rear edge of the tool is made up of 0.2 ~ 0.1 mu m. (5) the rational use of cutting fluid may also reduce the roughness of the machining surface. Low speed precision vehicles use emulsion or oil; If the cast iron should use kerosene, high speed fine steel and high cutting speed fine cast-iron parts, it is not normally used to use the cutting fluid.
The distance that the tool moves at each turn of the workpiece, called the quantity of feed, is expressed in terms of f (mm/r). The thickness of the metal layer, which is cut each time, is called cutting depth, which is represented by the ap (mm). In order to ensure the quality of processing and improve the productivity, the parts process should be phased in, the parts of the medium precision are carried out in the plan of the cart. The purpose of the rougher is to cut the bulk of the machining from the blank as quickly as possible, and make the workpiece in the shape and size of the requirement. Coarse car give priority to in order to improve the productivity, increase the cutting depth in the production, to improve the productivity in the most favourable, followed by appropriate increase feed, and adopts medium or medium to low cutting speed. Using high speed steel lathe tool for rough turning cutting dosage recommendations are as follows: cutting depth ap = 0.8 ~ 1.5 mm, feeding the f/r = 0.2 ~ 0.3 mm, cutting speed v take 30 to 50 m/min (steel).
The first cut should be greater than the thickness of the hard skin because of the hard skin on the surface of the workpiece and the tip of the blade. If the length of the workpiece is shorter or the surface is uneven, the cutting amount should not be too big. The coarse car should be left with 0.5 ~ 1mm as the spare quantity of the fine car. The accuracy of the coarse car is it14-it11, and the surface roughness Ra is usually 12.5 ~ 6.3 mu m. The purpose of the fine car is to ensure the accuracy and surface roughness of the parts, and the productivity should be raised as far as possible. The accuracy of the average precision car is IT8 ~ IT7, the surface roughness value Ra = 3.2 ~ 0.8 mu m, so the fine car is mainly the processing quality of improving the workpiece. The cutting dosage should be used for the smaller cutting depth ap = 0.1 ~ 0.3 mm and the smaller quantity of feed f = 0.05 ~ 0.2 mm/r, the cutting speed is preferable. Another outstanding problem with the fine car is the requirement for surface roughness. The main measures for reducing the surface roughness Ra are as follows. (1) the use of cutting is reasonable. With smaller cutting depth ap and quantity f, the residual area can be reduced, reducing the Ra value.
Under normal circumstances, when turning turning parts, if there are any blank contains a large number of hard material, easy to make the collapse of the cutting tools, in order to protect the blade, the blade and blade Angle, pour round processing. A little bit more, and less round. In addition, through the reverse Angle processing of the car knife, it can also get the actual front Angle bigger car knife, it is the turning performance of the car knife improved.
