Burr formation in drilling miniature holes

The exit burrs in the drilling of precision miniature holes of diameters less than 1 mm are of interest. The burrs from these processes can be difficult to remove. This paper describes the results of a study on the burr formation in drilling miniature holes. Most existing studies focus on holes in the 3 mm to 12 mm size range. This data is not transferable to smaller diameter holes. We report here on the study of burr height, thickness and geometry observed in the drilling of 0.91 mm diameter through holes in stainless steel 304L. The sensitivity of feed, speed and drill wear as well as the exit surface geometry (i.e. for intersecting holes) was determined. A proposal for using the drilling burr data as part of a process planning methodology for burr control is presented.