Increase of chip removal rate in single-lip deep hole drilling at small diameters by low-frequency vibration support

Due to the enclosed chip evacuation space in deep hole drilling process, chips are accumulated in drill flutes as drilling depth increases, resulting in the increase of drilling torque and lead to drill breakage. Peck drilling is a widely used method to periodically alleviate the drilling torque caused by chip evacuation; the drilling depth in each step directly determines both drill life and machining efficiency. The existing drilling depth optimization methods face problems including low accuracy of the prediction model, the hysteresis of signal diagnosis, and onerous experiments. To overcome these problems, a novel drilling depth optimization method for peck drilling based on the iterative learning optimization is proposed. First, the chip evacuation torque coefficients (CETCs) are introduced into the chip evacuation torque model to simplify the model for learning. Then, the effect of chip removal process in peck drilling on drilling depth is analyzed. The extended depth coefficient by chip removal (EDCbCR) is introduced to develop the relationship between the extended depth in each drilling step and drilling depth. On the foundation of the modeling above, an iterative learning method for drilling depth optimization in peck drilling is developed, in which a modified Newton's method is proposed to maximize machining efficiency and avoid drill breakage. In experiments with different cutting parameters, the effectiveness of the proposed method is validated by comparing the optimized and measured results. The results show that the presented learning method is able to obtain the maximum drilling depth accurately with the error less than 10%.

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Experimental Research on the System Performance in Near-Dry Deep Hole Drilling

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.455.98 ◽

2010 ◽

Vol 455 ◽

pp. 98-102 ◽

Cited By ~ 1

Author(s):

H.B. Zhao ◽

Y.F. Nan

Keyword(s):

Surface Quality ◽

System Performance ◽

Cutting Fluid ◽

Hole Drilling ◽

Drilling Process ◽

Deep Hole ◽

Deep Hole Drilling ◽

Ideal System ◽

Drilling System ◽

Chip Removal

The near-dry deep hole drilling system was taken as object in this study，and the contrast experiment between the deep hole drilling system and the traditional（wet）deep-hole drilling system，including the cutting force，the tool wear，the surface quality and the chip-break have been done. The results show that the near-dry system drill stability and have better effort in cooling，lubrication，chip removal effective. The tool life and surface quality within the hole are better，at the same time，it can greatly reducing the amount of cutting fluid，the costs and the pollution of the environment. So we can get a conclusion that it is an ideal system in green drilling process.

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A Thin and Deep Hole Drilling Using a Fuzzy Discrete Sliding Mode Control with a Woodpeckering Strategy

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1243/pime_proc_1995_209_395_02 ◽

1995 ◽

Vol 209 (4) ◽

pp. 281-292 ◽

Cited By ~ 8

Author(s):

C L Hwang ◽

C W Hsu

Keyword(s):

Sliding Mode Control ◽

Sliding Mode ◽

Hole Drilling ◽

Deep Hole ◽

Deep Hole Drilling ◽

Mode Control ◽

Invariant Properties ◽

Discrete Sliding Mode Control ◽

Chip Removal ◽

Heat Buildup

In this paper, a thin and deep hole drilling (TDHD), which is one of the difficult operations in metalworking, is accomplished by a fuzzy discrete sliding mode control (FDSMC) which is a combination of the fuzzy control and the discrete sliding mode control. The kernel problems of TDHD are chip removal, heat buildup, drill life, drill vibration, hole finish, drill breakage, difficulties in modelling the dynamic system, and so forth. The advantageous features of the FDSMC are that it does not require a mathematical model and that it has the invariant properties to resolve uncertainties when the system state is on the sliding surface. Moreover, a woodpeckering strategy can help prevent chip congestion and drill breakage. Finally, the experimental results for a thin and deep hole drilling by the proposed fuzzy discrete sliding mode control using a woodpeckering strategy are presented to verify the usefulness of the system.

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