Important processing technology of camshaft;

Generally, the first working procedure is milling the end face and drilling the center hole-CNC lathe-quenching-center hole grinder-fine grinding.

3. 1 center hole machining

Generally, the standard center is used for machining center holes (special center holes are treated differently), and the process arrangement is divided into two times.

Before and after heat treatment. The key of this process is to control the tolerance of 60 positioning cone (15 ′ ~ 20 ′) and check it all with special tools (simulating the positioning thimble of subsequent machine tools), so as to control the axial gear opening accuracy of camshaft (0.2 ~ 0.5 mm) and prevent unmapped burrs from appearing during cam milling.

3.2 Heat Treatment +0 Quenching

Induction quenching should be based on different workpiece materials. On the premise of meeting the hardness requirements, find out the boundary conditions of quenching, control the maximum and minimum voltage and current range of output, control the concentration, flow rate and temperature of quenching liquid at the same time, and analyze the cooling rate of quenching liquid regularly as the basis for replacing quenching liquid.

3.2.2 Various camshaft materials and heat treatment processes

With the reduction of grinding allowance and the increase of grinding speed (from the traditional 35 ~ 60m/s to 125 ~ 200m/s), it will be an inevitable trend to adopt high-speed grinding. The grinding speed of resin bonded corundum, silicon carbide and cubic boron nitride grinding wheel can reach 125m/s, and the grinding speed of ceramic bonded grinding wheel can reach 200m/s. When grinding with CBN grinding wheel, attention should be paid to selecting appropriate grinding wheel width, concentration, hardness and cutting fluid. The correct selection of cutting fluid types and cooling process parameters will have a great influence on the degree of mechanical wear, chemical erosion and thermal damage of grinding wheels during grinding. Especially when there are concave-convex wheels (also known as negative radius of curvature (NROC) cams) on the camshaft, equipment suppliers generally recommend the use of double-grinding-head CNC grinders. As for the grinding process design of cam, the general users rely on equipment suppliers to solve it. According to the 0 ~ 360 discrete points of the cam provided by the user, the supplier mainly solves the following problems by selecting the appropriate numerical control system: 1) Turn the discrete points into a continuous closed curve. 2) Turn the generated curve into a grinding curve. Because the grinding point and the generating point are not at the same point when grinding the cam, it is necessary to change the mold mathematically, and this transformation is also related to the measurement method of the cam. 3) Establish the C-axis speed regulation curve. In cam grinding, in order to ensure the constant cam acceleration, the speed regulation curve of C-axis speed must be adjusted according to the angle of C-axis. Among them, before the NC program of cam grinding is generated, the key is to compile the calculation program of cam generation curve (discrete points form closed curve through data smoothing) and speed curve, that is, to convert the given cam generation table into grinding curve (C coordinate value and X coordinate value) for grinding.