The Study on Evaluation of Hybrid Drilling Command under Deep Hole Drilling

2012 ◽  
Vol 579 ◽  
pp. 219-226
Author(s):  
Jen Ching Huang ◽  
Wei Piao Wu
Keyword(s):  
Tool Life ◽  
High Speed ◽  
Small Hole ◽  
Hole Drilling ◽  
Deep Hole ◽  
Cnc Machine ◽  
Drilling Depth ◽  
Deep Hole Drilling ◽  
Peck Drilling ◽  
Custom Macro

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.

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
Keyword(s):  
Tool Life ◽  
High Speed ◽  
Small Diameter ◽  
High Speed Steel ◽  
Minimum Quantity Lubrication ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Flute Surface ◽  
Twist Drills

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.

Iterative Learning Method for Drilling Depth Optimization in Peck Deep-Hole Drilling

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Ce Han ◽  
Ming Luo ◽  
Dinghua Zhang ◽  
Baohai Wu
Keyword(s):  
Iterative Learning ◽  
Hole Drilling ◽  
Machining Efficiency ◽  
Learning Method ◽  
Deep Hole ◽  
Drilling Depth ◽  
Deep Hole Drilling ◽  
Modified Newton’S Method ◽  
Peck Drilling ◽  
Chip Removal

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%.

A Study on the Characteristics of Micro Deep Hole Machining Processes

2007 ◽  
Vol 364-366 ◽  
pp. 566-571
Author(s):  
Tae Il Seo ◽  
Dong Woo Kim ◽  
Myeong Woo Cho ◽  
Eung Sug Lee
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Hole Drilling ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Micro Drilling ◽  
Hole Machining

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.

Determining the Tool Life of a Cemented Carbide Drill Using Optimized Process, Delivery System, and Drill Design Parameters in Deep Hole Drilling Using Environment Friendly Machining Method

2010 ◽  
Author(s):  
Muhammad I. Hussain ◽  
A. Filipovic ◽  
J. Dasch ◽  
D. Simon
Keyword(s):  
Tool Life ◽  
Metal Removal ◽  
Cemented Carbide ◽  
Design Parameters ◽  
Innovative Technology ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
High Production ◽  
Cemented Carbide Drills

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.

scholarly journals Investigation of Chip Deformation and Breaking with a Staggered Teeth BTA Tool in Deep Hole Drilling

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 46
Author(s):  
Xu-Bo Li ◽  
Jian-Ming Zheng ◽  
Yan Li ◽  
Ling-Fei Kong ◽  
Wei-Chao Shi ◽  
...  
Keyword(s):  
Chip Thickness ◽  
Contact Length ◽  
Hole Drilling ◽  
Drilling Process ◽  
Rake Face ◽  
Deep Hole ◽  
Drilling Depth ◽  
Deep Hole Drilling ◽  
Chip Breaker ◽  
Chip Breaking

The problem of chip breaking and evacuation is the key point of staggered teeth boring and trepanning association (BTA) drilling. The factors that influence chip breaking with staggered teeth BTA deep hole drilling are analyzed by using the chip bending deformation mechanism for chip formation and flow through the rake face and chip breaker. This study investigated the distribution and variation of chip deformation and breaking along drilling conditions, with respect to drilling radius, drilling process parameters, tool wear, and chip breaker geometric parameters. The results show that the tool-chip contact length is about 1.65 times the chip thickness in staggered teeth BTA drilling. The cutting radius of the teeth has a considerable influence on the chip thickness. Compared with the drilling speed, the feed has a greater impact on chip deformation and breaking, and the chip thickness and strain increase with increased feed. Increased drilling depth and tooth wear aggravates the friction state between the chip and the rake face, augments chip thickness and tool-chip contact length, and increases the chip’s strain increment. As the width of chip breaker decreases and the height increases, the chip strain increases and the breaking conditions are improved.

Deep hole drilling of AISI 1045 via high-speed steel twist drills: evaluation of tool wear and hole quality

2017 ◽  
Vol 93 (1-4) ◽  
pp. 1115-1125 ◽  
Author(s):  
Sarmad Ali Khan ◽  
Aamer Nazir ◽  
Mohammad Pervez Mughal ◽  
Muhammad Qaiser Saleem ◽  
Amjad Hussain ◽  
...  
Keyword(s):  
Tool Wear ◽  
High Speed ◽  
High Speed Steel ◽  
Hole Drilling ◽  
Deep Hole ◽  
Hole Quality ◽  
Deep Hole Drilling ◽  
Aisi 1045 ◽  
Twist Drills

Modified DLC-Coated Guide Pads for BTA Deep Hole Drilling Tools

2010 ◽  
Vol 438 ◽  
pp. 195-202 ◽  
Author(s):  
Dirk Biermann ◽  
Nadine Kessler ◽  
Thorsten Upmeier ◽  
Thomas Stucky
Keyword(s):  
Surface Quality ◽  
Borehole Wall ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Forming Process ◽  
Workpiece Material ◽  
Drilling Depth ◽  
Deep Hole Drilling ◽  
Drilling Tools

The BTA (Boring and Trepanning Association) deep hole drilling process is commonly used to machine boreholes with a large drilling depth-to-diameter ratio (l/D) and outstanding workpiece quality. The asymmetric tool design leads to a nonzero radial component of the cutting force and the passive force, which are conducted to the borehole wall by so-called guide pads. These guide pads smooth the borehole wall by a forming process and improve the surface quality. Processes, that machine materials with a high adhesion tendency, such as high alloy stainless steel, suffer from poor surface quality in the borehole and the adhesion from the workpiece material on the guide pads. In this paper modified Diamond-Like-Carbon (DLC) coated guide pads for BTA deep hole drilling tools are investigated. The scope of the experiments was the reduction of the adhesion by reducing the friction coefficient of the guide pads, as well as the improvement of the quality of the borehole wall.

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