More Detailed Explanation
Deep drilling is a machining method for the production and machining of bores. Deep holes are holes with a diameter of between about 1 mm to 1500 mm and a depth starting from about triple the width of the diameter.
It is not possible to make general definition of the deep drilling over other “conventional” drilling techniques using for example an overall valid definition. The following features characterize deep drilling:
– high quality drilling
– high productivity.
Drilling tools dominate the entire field of producible inner contours through drilling. Deep drilling techniques are particularly used almost exclusively in the field of deep drilling and drilling with large diameters.
Due to its high productivity and attainable drilling qualities, deep drilling is now being used increasingly for production tasks, in which the ratio between hole depth and hole diameter is lower than 10.
Also in the area of smaller tool diameters where naturally the majority of uses are for drilling, numerous instances of machining indicate the presence of deep drilling technique.
As a rule materials which are difficult to cut can be worked relatively well with deep drilling procedures.
Deep drilling has the following typical characteristics:
– Use of special carbide tools with an asymmetrical cutting edge in relation to the tool axis (when cutting).
– Self-guiding of the tool by means of three-point contact in the bore by means of guide rails and side cutter (circular grinding chamfer).
– Tool drilling guide in a drilling bush or a guide bore.
– Device for continuous coolant supply in larger quantities under pressure, steady chip discharge with no accumulation of chips.
The advantages of deep drilling procedures are the following:
– very high cutting performance
– ideal conditions for cooling and lubricating
– short waiting times
– high drilling quality regarding diameter tolerance. Surface quality and geometrical shape accuracy
– high alignment accuracy, short drilling path
– replacement of several operation processes – e.g. predrilling, cutting and grating by one single operation, deep drilling
– machining of materials which are difficult to cut
– large drilling depth in relation to the diameter (up to maximum of 250 times)
– profitability even with short drilling depths
– low burr formation during drilling and the drilling of over cross bores
Through deep drilling all kinds of metals as well as other materials, such as plastics, may be processed both in the mass production of small parts as well as in the individual production of large machine parts.
(Source: Explanations by Dr. Fuß www.tiefbohren.info )