||In this study, a square thread shape of conductive polymer (ESD 410C) was employed as a tool electrode to compositely electrolyze and abrasive polish the inner surface of bilnd hole workpiece whose diameter is 8, 6, 4 mm made of SKD61 hot work die steel using a polishing machine with multi-axis motions. The effects alumina abrasive particle size (3, 1, and 0.3 μm), load (0.3 ~ 0.5 N), current (0 ~ 400 mA), and polishing time (0 ~ 8 min) on the inner surface roughness of workpiece were investigated.|
In the abrasive polishing under a load of 0.4 N with a grit size of 1 μm in the electrolyte, the surface roughness Rmax and Ra decreased from 0.5 μm and 0.12 μm to 0.22 μm and 0.054 μm after 8 minutes, respectively.
In the electrolytic polishing under a current of 200 mA and a load of 0.4 N, the surface roughness Rmax and Ra decreased to 0.29 μm and 0.069 μm after 8 minutes, respectively.
The two-stage electrolytic abrasive polishing without feeding was conducted. In the first stage, the surface roughness Rmax and Ra decreased quickly to 0.26 μm and 0.052 μm, respectively under the load of 0.4 N, with the grit size of 1 μm and a current of 200 mA in electrolyte within 4 minutes of polishing time. In the second stage, Rmax and Ra decreased to 0.12 μm and 0.021 μm, respectively using the abrasive particle size of 0.3 μm for 4 minutes. The inner surface of the workpiece has achieved a bright mirror.
Finally, a electrolytic abrasive polishing process with feeding was conducted to the bilnd hole whose diameter is 8, 6, 4 mm.The surface roughness Rmax and Ra decreased quickly to 0.17 ~ 0.18 μm and 0.036 ~ 0.038 μm under a load of 0.4 N, with a grit size of 1 μm and a current of 200 mA in the electrolyte after 24 minutes. The inner surface of the workpiece has also achieved a bright mirror.
Keywords: Conductive polymer, Blind hole, Die steel, Electrolytic abrasive polishing, Mirror