The Performance of Small Diameter Twist Drills in Deep-Hole Drilling

2006 ◽  
Vol 128 (4) ◽  
pp. 884-892 ◽  
Author(s):  
Robert Heinemann ◽  
Srichand Hinduja ◽  
George Barrow ◽  
Gerhard Petuelli

This paper investigates the performance of small diameter high-speed steel twist drills drilling boreholes with a depth of ten times the diameter into carbon steel AISI 1045 using minimum quantity lubrication. The performance of small twist drills is determined, first, by their deep-hole drilling capability, i.e., in how far the cutting forces can be kept at a noncritical level by maintaining the chip disposal, and, second, by their tool life. This work shows that both the deep-hole drilling capability and tool life of small drills are strongly dependent on their geometry, in particular the size of the chip flutes, and the flute surface topography.

2017 ◽  
Vol 93 (1-4) ◽  
pp. 1115-1125 ◽  
Author(s):  
Sarmad Ali Khan ◽  
Aamer Nazir ◽  
Mohammad Pervez Mughal ◽  
Muhammad Qaiser Saleem ◽  
Amjad Hussain ◽  
...  

2012 ◽  
Vol 579 ◽  
pp. 219-226
Author(s):  
Jen Ching Huang ◽  
Wei Piao Wu

The hybrid drilling command was proposed in this study. The hybrid drilling command is established by combined the merit of G73 (high speed peck drilling cycle) and G83 (small hole peck drilling cycle) using custom macro command. The concept of hybrid drilling command is to divide the total drilling depth into several distances and its distance is shortened gradually. The drilling chip is breaking with the G73 in the distance between each one and banishing from the hole with the G83 after drilling a distance each time. The evaluation on the merit of hybrid drilling command was carried out by deep hole drilling test on CNC machine center. After experiments, the hybrid drilling command can reduce wearing, extending the tool life of the driller and shorten processes time.


2012 ◽  
Vol 433-440 ◽  
pp. 552-557 ◽  
Author(s):  
Gerhard Petuelli ◽  
Christoph Nentwig

In this paper results of manufacturing tests are described done in order to evaluate the performances of twist drills of diameter d = 1.2 mm and 1.4 mm respectively, if boring into stainless steel X90CrMoV18 (1.4112). Deep-hole drilling was realized thus, that the depth of the bore hole was greater than 10 times the diameter of the twist drill (L/d >10). In order to reduce the impact on the environment caused by the coolant, it was found that minimum quantity lubrication (MQL) can be applied. Hence, the ecology of the mass production of perforated discs for the food processing industry can be improved. The performance of the several small diameter twist drills was determined and evaluated by, firstly, their deep-hole drilling capability, e.g. assessed by the variation or even increase of cutting forces with increasing depth and travel, whether the forces exceed a critical level due to poor chip extraction. In addition, the suitability to use or rather implement the different small diameter twist drills for high-speed cutting (HSC) and finally the individual tool service life for each investigated twist drill. This research project has shown that the accomplishable performance and operating time are strongly dependent on tool cutting material and the tool geometry, especially the size of the chip flutes of a twist drill, as well as the individual coating of the cutting tools.


Author(s):  
Andreas Baumann ◽  
Ekrem Oezkaya ◽  
Dirk Schnabel ◽  
Dirk Biermann ◽  
Peter Eberhard

2007 ◽  
Vol 364-366 ◽  
pp. 566-571
Author(s):  
Tae Il Seo ◽  
Dong Woo Kim ◽  
Myeong Woo Cho ◽  
Eung Sug Lee

Recently, the trends of industrial products move towards more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is required to perform more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multilayered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. The industries of precision production require smaller holes, high aspect ratio and high speed working for micro deep hole drilling. However the undesirable characteristics of micro drilling is the small signal to noise ratios, wandering motion of drill, high aspect ratio and the increase of cutting force as cutting depth increases. In order to optimize cutting conditions, an experimental study on the characteristics of micro deep hole machining processes using a tool dynamometer was carried out. And additionally, microscope with built-in an inspection monitor showed the relationship between burr in workpieces and chip form of micro drill machining.


Author(s):  
Muhammad I. Hussain ◽  
A. Filipovic ◽  
J. Dasch ◽  
D. Simon

Near dry machining or Minimum Quantity Lubrication (MQL) methodology appears to be a valid solution to meet environmental challenges of metal removal processes. However, in order to implement environmentally friendly machining into high production manufacturing environments, it is imperative to invent a robust solution for a wide variety of machined features. In previous work by the authors, capabilities of the MQL process, calibrated for machining extremely deep holes with length to diameter (L/D) ratio of up to 15, were proven. An optimal machining solution was developed using the Box and Behnken experimental design approach, and it was demonstrated that cemented carbide drills with proper cutting geometry and MQL settings can be used for deep hole drilling of aluminum. This work, focused on developing a production ready application, proved that MQL technology is also robust enough to achieve adequate tool life for high volume manufacturing requirements. It actually exhibited that such approach may even exceed tool life requirements currently enforced for conventional processes using gun drills or G-drills. In addition, machining time was significantly reduced with this innovative technology achieving productivity approximately 7 times higher than in traditional drilling operations. Considering these achievements, MQL has been demonstrated to be the drilling technology of future that will help reducing capital investments into production machinery and minimize landfill discharges of high production manufacturing facilities.


1992 ◽  
Vol 114 (4) ◽  
pp. 459-464 ◽  
Author(s):  
W. E. Henderer

Tool-life tests are reported which show the relationship between the alloy composition of high-speed steel twist drills and performance. Tool-life is shown to depend primarily on the composition of the matrix consisting of tempered martensite and precipitated secondary carbides. The longest tool-life was obtained from alloys with high vanadium content and low tungsten or molybdenum content. This observation is consistent with the dispersion characteristics of vanadium carbide which precipitate during tempering.


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