Development and analysis of a mechatronic system for in-process monitoring and compensation of straightness deviation in BTA deep hole drilling

In BTA deep hole drilling straightness deviation of the bore is a very important quality criteria. The avoidance of straightness deviation is not possible due to the many influencing variables. Currently used methods for compensation require significant additional time, as they either require the interruption of the drilling process, or require an additional boring process. By using a newly developed, manufactured and tested compensation unit, which is mounted between the drill head and the drill pipe, a targeted tilting of the drill head and thus a targeted influencing of the straightness deviation in the running process is possible with the use of a radially adjustable control pad and an innovative actuator concept. The developed measuring system offers the possibility to record the straightness deviation during the drilling process. On the basis of experimental test series, a control system was developed and applied to the BTA deep drilling process. After a drilling path of 1,000 mm, a maximum straightness deviation reduction of approx. 51 % can be realized. Compared to the process without control and compensation unit, the progressive increase of the straightness deviation was significantly reduced.