Effects of Mask Gap and Etching Temperature on Etching Rate of Die Steel 738

Micro-etching of die steel 738 was processed in spray etching. The effects of mask gap and etching temperature on undercut were studied. Using one-way analysis of variance process experimental data got the significance testing, the fitted equations showing the relationships of undercut with mask gap and etching temperature were also got in linear fitting. It is found that the mask gap and etching temperature have significant impact on undercut. The undercut first increases, and then decreases gradually with the rise in mask gap at 30 ℃. When the mask gap is 150 μm, the undercut grows as temperature increases.