Study on Reduction of Burrs in Micro Slotting of Oxygen-Free Copper by Multistep Milling

This study deals with a reduction of burr height on edge of micromilled channels. The microchannels were cut in oxygen-free copper by using cemented carbide end mill under semidry condition. The oxygen-free copper with superior conductivity is an electrode material for EDM, but it is a material difficult to cut. The microchannels of 50μm depth were cut by multistep slotting to reduce burr height. Axial depth of each slotting was set so that total depth became 50μm. Each slotting was carried out in recommended cutting conditions. The micro burr height was measured by SEM. The mechanism of burr formation at the edge of the micromilled channel is similar to entry burr formation in drilling. In drilling, entry board is often used to prevent entry burr formation. In multistep slotting, the edge of mere several micron thickness which made by preceded slotting acted as entry board in following slotting. This study shows the multistep slotting was effective in reducing the burr height by setting appropriate combination of axial depths.