Tungsten carbide grades serving the industry for over 40 years.
Industry leading grades proven in their application. We use a proprietary process which results in mechanical properties that resist corrosion, pitting and cracking commonly experienced during electrical discharge machining.
EDM Blocks are made by a proprietary stress-relieving sinter-HIP process. Optimized metallurgy ensures pits or cracks won't slow you down.
KR Grades feature a mix binder that provides corrosion resistance to help reduce EDM times and number of skim cuts.
Our proven grades ensure consistent, reliable performance while stamping a wide range of metals, from silicon steel to beryllium copper, and everything in between.
The principle of EDM is based on the electrical corrosion phenomenon between the tool and the workpiece (positive and negative electrodes) during the pulse spark discharge to remove excess carbide parts to achieve the predetermined processing requirements for the size, shape and surface quality of the workpiece. Only copper-tungsten electrodes and copper-silver electrodes can process carbide blanks.
In short, EDM does not utilize mechanical energy, does not depend on cutting forces to remove metal, but directly uses electrical energy and heat to remove the carbide part. Compared with mechanical cutting,
EDM has the following characteristics:
1. The material removal is achieved by the thermal erosion of the discharge. The processability of the material mainly depends on the thermal properties of the material, such as melting point, specific heat capacity, thermal conductivity (thermal conductivity), etc., almost independent of its mechanical properties such as hardness and toughness.
2. Can process special and complex shapes of parts.
3. The whole process can be automated.
4. Since EDM is not affected by the hardness of the material, it can be processed after quenching.
EDM has its unique advantages, but at the same time has certain limitations, which are manifested in the following aspects:
1. Processing efficiency is relatively low. In general, the processing speed per unit of machining current does not exceed 20 mm3 / (A · min). The material removal rate of EDM is relatively low compared to machining. Therefore, machining cutting is often used to remove most of the allowance, and then EDM. In addition, there is a prominent contradiction between the processing speed and the surface quality, that is, the processing speed during finishing is very low, and the rough processing is often limited by the surface quality.
2. The surface after EDM will have a metamorphic layer or even microcracks. Due to the instantaneous high heat generated on the machined surface during EDM, thermal stress deformation occurs, resulting in a deteriorated layer on the surface of the machined part.
3. Under normal circumstances, the minimum corner radius obtained by EDM is slightly larger than one by ECM, which is generally 0.02~0.03mm. If the electrode is worn, the corner radius will be larger than that value. There is no possibility for EDM to obtain completely right angle and utmost angular deviation.
4. The discharge part must be in the working fluid during EDM, otherwise, an abnormal discharge will happen also lead to trouble to observe the processing state.
5. Actually, the “glow” shows on the machined surface are consists of a number of pulsed discharge pits. Thus, the finished surface will never have the “glow”, which is the consequence of being polished by other processing methods.
