Graphite is a very common black non-metallic raw materi […]
Graphite is a very common black non-metallic raw material in production and life. It has a relatively low density and has excellent properties such as high temperature resistance, electrical and thermal conductivity, lubricity, chemical stability, plasticity, and thermal shock resistance. And because it is a hexagonal crystal, the bonding force between layers is relatively weak, the internal porosity is large, and the tensile strength is low, which makes the mechanical processing performance of graphite very good.
Because of its excellent performance, graphite is often used to manufacture graphite parts such as graphite electrodes, graphite molds, 3D hot bending molds, etc. The structure of graphite mold parts is relatively complex, the precision requirements are high, and the quality requirements are strict. There are many hole processing requirements. The characteristics cause problems such as edge sawtooth, slag drop and corner chipping in the processing of graphite products, which brings more problems to machining.
Difficulties in machining of graphite electrode mold holes
Graphite material is a non-homogeneous brittle material, with relatively small macro hardness, easy to damage the reference surface during clamping, poor positioning accuracy, and large clamping error; especially for some slender holes processing, the product precision requirements are high, and the inner step hole processing is difficult; Moreover, graphite products are mostly mold parts, such as graphite electrodes, 3D hot bending molds, etc., which require high product consistency.
The processing quality of the slender graphite step hole directly affects the quality of downstream products and also seriously affects its own service life. Therefore, before processing, it is necessary to repeatedly conduct systematic analysis from the aspects of process plan, processing route, clamping method and process parameters. , Optimized design.
The difficulty in manufacturing slender graphite step hole products is boring and chip removal, as well as concentricity control. The processing error sources of its coaxiality mainly include reference error, clamping and alignment error, machine tool positioning error and so on. The process route of rough turning outer circle-cutting off-drilling-semi-finishing outer circle-boring-finishing outer circle is adopted.
In addition, the correct choice of graphite tools also directly determines the efficiency and quality of graphite products processing. Therefore, if you want to effectively control the quality of processing, you must choose a reasonable and effective graphite tool material.
Graphite mold electrode hole machining method and tool selection
There are many ways to process holes. Taking graphite electrode as an example, there are drilling, milling, turning, boring, etc. Each processing method is different, and the tool selected is also different.
For small holes below 3mm, cvd coated drills are recommended; for larger-sized holes, PCD drills are recommended. For the CNC milling of graphite products, for holes with high surface requirements and large diameters, milling cannot be used when machining on a lathe. Generally, CNC milling machines are used to process holes. The choice of drilling tools is the same, and according to the shape of the hole, Optional graphite flat end milling cutter or graphite ball end milling cutter.
Both boring and turning holes of graphite products can be machined on a lathe. For graphite products with a large diameter of 10mm or more and easy to clamp on the lathe, you can choose to use CNC blade turning to process the graphite inner hole; for the turning of small holes of 3-10mm , Generally choose a precision small boring tool for boring