１．緒論 ｜ ２．圧粉体電極を用いた液中放電加工による砥粒層の形成法 ｜ ３．基礎実験 ｜ ４．各種砥粒材料の適用 ｜ ５．堆積層の評価 ｜ ６．円板状被加工物を用いた研削性能評価 ｜ ７．軸付砥石の試作 ｜ ８．結論 ｜ 参考文献
This document deals with a fabrication method for a grinding wheel by electrical discharge machining (EDM) and its evaluation through practical grinding.
A grinding wheel should be frequently dressed and as a result its total life becomes shorter. When the total life of the grinding wheel has ended, the grinding wheel is disposed of even if its core is still usable. To extend the total life of the grinding wheel by recycling, a fabrication process of an abrasive layer by EDM is proposed. The layer deposited by EDM with a green compact electrode is porous due to the electrical conditions. The green compact electrode was made by compressing a mixture of WC, Co and an abrasive, which is generally an insulating material. The layer produced with the dispersed abrasive powders with a size of 20-100 mm could be deposited on a plate. The grain size and the thermal conductivity mainly affect the layer properties. Each grain volume percentage was evaluated with a partial section analyzed by energy dispersive X-ray spectroscopy. The volume percentages of #150 and #400 SiC grains were 6% and 10%, respectively, when the volume ratio of the SiC grains in each electrode was 32%. These ratios are much smaller than that of conventional grinding wheels, 34-62% in nominal. The hardness of the WC-Co layer without abrasive was 102 HRRS, harder than a general vitrified bond wheel. Because the deposit of the WC-Co layer was very hard, tight gripping of grits can be also expected.
When the total life of the grinding wheel has ended, the grinding wheel is thrown away although its core is still usable. Depositing an abrasive layer by EDM with a green compact electrode is proposed to fabricate a recyclable grinding wheel for cost reduction. Some metallic disks were practically ground with a #400 SiC abrasive layer. The grinding ratio against steel was 6.9. Then the deposit process for a cylinder was proposed to fabricate and recycle a mounted wheel. The maximum difference for a thickness of 300 mm was 10 mm by the shape feedback machining method. Although the additional layer was deposited without any cleaning in the recycle process, it performed as well as a new one. Therefore, the abrasive layer fabricated by EDM can be used for grinding.
Key words: deposit, grinding wheel, abrasive, insulating powder, recycle
Last modified on 07/26/2003 at 08:46:30 by Katsushi Furutani