粉末混入加工液中の放電を利用した潤滑面形成法

抄録

Solid lubricants, such as molybdenum disulfide (MoS₂), gold, silver or polytetrafluoroethylene (PTFE) are often used on the sliding parts exposed in the space environment. When MoS₂ powder is mixed in the working oil, MoS₂ layer can be deposited on stainless steel during the finishing electrical discharge machining (EDM) process. The deposition process must be clear to improve the endurance of the lubricant layer. When the electric field was applied between the electrodes, MoS₂ powder reciprocated. Eventually, the powder was concentrated on the positive electrode side. Therefore, the positive polarity is preferable for the tool electrode. Then, the influence of the working oil flow was investigated by rotating a copper disk electrode. MoS₂ was observed on steel under all conditions. The reciprocating friction test in air was carried out to investigate the influence of machining time and measured point of the deposited layer. The lubrication duration was decreased with an increase of the rotation speed of the electrode. Because the lubrication duration was saturated over 30 min, the deposited MoS₂ was removed during deposition in the case of machining for a long time. The influence of the thermal properties of the specimen was also investigated. MoS₂ could be deposited on the metals with lower melting point than MoS₂.