Drilling Processes Machines

G.E. Baker, Hole drilling processes experiences, applications and selection, in SME Non-traditional Machining Symposium, Orlando, Florida, 3rd-5th, Amchem Company, 1991, pp. 6-12. 

The drill milling process leads to a low burr formation and a low delamination of the CFRP layers (Brinksmeieretal. 2008). Furthermore, the produced chips are small compared to conventional drilling processes. Because the bore diameter is bigger than the tool diameter, the chips can be evacuated easily. In conventional drilling, the chip transport in the flutes of the tool leads to friction at the wall of the borehole. Especially when the CFRP layer is machined prior to the titanium or aluminum layer, the hot chips of the metallic material can destroy the surface in the CFRP layer. This can be avoided using the drill milling process. 

The main disadvantages of this process are the higher machining time compared to a conventional drilling process as well as the complicated feed path (Brinksmeier et al. 2008). To cope with the complicated tool path, special machine tool systems have been developed, for example, by the company Novator. These systems can be applied in conventional machine tools or used manually. 

Materials based on copol5nners of alkylene oxides and modified by ROMP of cycloolefins possess valuable properties recommending them for special applications in the automotive industry (hoses, fittings, and complex assemblies), in the oil industry (drilling and oil processing), machine building, defence, aviation, and aeronautics. 

These systems are at their most useful when there are no tramlines, i.e. before the crop has been drilled and during the drilling process. They can be used in conjunction with the drill to provide very accurate tramlines which can then be used with or without auto-steering options. A full system which will control not only steering and positioning, but also ground speed, engine speed, rates of application, etc., is called automatic machine control. 

For the past 2 years the output of analyses has been increased greatly, particularly with penetration studies, by utilization of wet-processing techniques and development of several new pieces of apparatus. This equipment includes the revolving drum-type stripping machine and especially adapted drill press used also for parathion studies. A detailed description of this press has been published ( ), and the stripping machine and accessory equipment have been described (5). 

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