Trepanning tools

Where large-diameter holes are required in sheet metal, they can be conveniently cut using a trepanning tool. Fig. 8.17(a). 

The arm can be adjusted to any diameter within the range of the trepanning tool, which may be as large as 300 mm. The cutting tool can be ground to any angle to suit the material being cut. 

Large holes in sheet material can be produced using a trepanning tool. 

The trepanning tool reduces the thrust force and torque during drilling of GFRP composites as compared with the twist drill. The torque behaviour was similarly influenced by the drill point geometries and the feed rate. A decrease in the feed rate reduces the thrust force, which can reduce the... 

Mathew, J., Ramakrishnan, N. and Naik, N.K. (1999) Investigations into the effect of geometry of trepanning tool on thrust and torque during drilling of GFRP composites. J Mater Process Technol, 91 1-11. 

S.K. Chark, P.V. Rao Trepanning of A1203 by electro-chemical discharge machining (ECDM) process using abrasive electrode with pulsed DC supply. International Journal of Machine Tools Manufacture 47 (2007), pp. 2061-2070. 

A wide range in hole sizes can be drilled or trepanned by ECM diameters as small as 0.05 mm to as large as 75 mm have been achieved. For fine holes of 0.5 to 1.0 mm diameter, depths of up to 110 mm have been produced. Drilling by ECM is not restricted to round holes the shape of the workpiece is determined by that of the tool-electrode. 

---