Let's take the XX90 cylinder head as an example. In order to ensure sufficient heat dissipation, the cylinder head has a total of 6 radiating blades with a spacing of 12mm and an outer edge thickness of 2mm. For the convenience of demolding, a draft angle must be added. The outer edge of each blade is different from the center. Therefore, the blade profile is a curved surface model with variable draft angle, and the draft angle varies from 1 ° to 3 °.
The mold adopts the parting structure of three-side core pulling, and the three-side core pulling requires electrodes. If an integral electrode is used for each core pulling, only a slender tool with a diameter of less than 5mm and a length of 100mm can be used, and it cannot be cut at all. Therefore, the method of single electrode combination is usually adopted. It is the mold and electrode model of the first blade. Each blade requires three electrodes. The XX90 cylinder head mold with 6 radiating blades requires 18 electrodes. Similarly, the XX250 cylinder head with 12 radiating blades requires 36 electrodes.
For the convenience of processing during manufacture, blanks of the same shape and size are usually adopted. First forge 18 identical cuboid blanks and mill the six sides of the blanks to ensure a thickness of 12mm. Each blank is drilled with two positioning holes with the same diameter and the same position. Then edit the CNC machining program in UG, process each blade separately on the CNC machine, and finally clamp each of the six electrodes in three directions through the positioning holes to form three electrode combinations, and process different three on the electric machining machine. Cores.
When designing and programming, the XX90 cylinder head needs to establish 18 three-dimensional geometric models and 18 blank models, and the XX250 cylinder head requires 36 3D geometric models and 36 blank models. Each blade electrode requires 3 programs, only XX90 cylinder head has 54 programs, the CNC programming and CNC processing time is long, and it is tedious and error-prone. Therefore, the design and processing of the blade electrode greatly affects the processing cycle and cost of the mold.