Dynamic characteristics of a drill in the drilling process

2003 ◽  
Vol 217 (2) ◽  
pp. 161-167 ◽  
Author(s):  
B W Huang
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Thrust Force ◽  
Time Dependent ◽  
Drilling Process ◽  
Improve Quality ◽  
Vibration Model ◽  
High Speed Drilling ◽  
Spinning Speed ◽  
Twisted Beam

The dynamic characteristics of high-speed drilling were investigated in this study. To improve quality and produce a higher production rate, the dynamic characteristics of the drilling process need to be studied. A pre-twisted beam is used to simulate the drill. The moving Winkler-type elastic foundation is used to approximate the drilling process. A time-dependent vibration model for drilling is presented. The spinning speed, pre-twisted angle and thrust force effects of the drill are considered. The numerical analysis indicates that the natural frequency is suddenly reduced as the drill moves into a workpiece.

The Drilling Vibration Behavior of a Twisted Microdrill

2004 ◽  
Vol 126 (4) ◽  
pp. 719-726 ◽  
Author(s):  
Bo-Wun Huang
Keyword(s):  
Dynamic Characteristics ◽  
Printed Circuit Boards ◽  
Thrust Force ◽  
Time Dependent ◽  
Drilling Process ◽  
Improve Quality ◽  
Circuit Boards ◽  
Rotating Speed ◽  
Printed Circuit ◽  
Vibration Model

The dynamic characteristics of a microdrill in the drilling process were investigated in this study. The trend toward higher density printed circuit boards requires smaller holes, down to 0.3 mm in diameter, to be drilled through the board layers. To improve quality, produce a higher production rate, and avoid drill breakage, the dynamic characteristics of the microdrilling process must be studied. A stepped pretwisted beam is used to simulate the microdrill. A moving Winkler-Type elastic foundation is used to approximate the drilling process. A time-dependent vibration model for drilling is presented. The rotating speed, pretwisted angle, and thrust force effects of the microdrill are considered. The numerical analysis indicates that the natural frequency is reduced suddenly as the microdrill moves into a workpiece.

Dynamic Instability in a High Speed Drilling Process

2005 ◽  
Author(s):  
Bo-Wun Huang ◽  
Jao-Hwa Kuang
Keyword(s):  
High Speed ◽  
Multiple Scales ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Work Piece ◽  
Drilling Process ◽  
Drilling Depth ◽  
High Speed Drilling ◽  
Spinning Speed ◽  
The Galerkin Method

The variation of dynamic instability in a high speed drilling process was investigated in this article. A pre-twisted beam is used to simulate the drill. The time dependent thrust force and drilling depth are considered in the equation of motion. A moving Winkler-Type elastic foundation assumption is employed to the drill tip to approximate the time varying boundary conditions in the drilling process. The Galerkin method is used to formulate the characteristic equation in a discrete form. The variation of instability regions of the drill system is solved and analyzed by employing the multiple scales perturbation method. Numerical results indicate that unstable regions are enlarged and shifted toward a lower frequency suddenly at the moment when the drill attaches the work piece. The effects of spinning speed, pre-twisted angle and thrust force of the drill on the variation of the dynamic instability in a high speed drilling process are also studied.

The Parametric Resonance Instability in a Drilling Process

2007 ◽  
Vol 74 (5) ◽  
pp. 958-964 ◽  
Author(s):  
Bo-Wun Huang ◽  
Jao-Hwa Kuang
Keyword(s):  
High Speed ◽  
Multiple Scales ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Work Piece ◽  
Drilling Process ◽  
Drilling Depth ◽  
High Speed Drilling ◽  
Instability Regions ◽  
Multiple Scales Perturbation Method

This study investigates dynamic instability in a high-speed drilling process. A pretwisted beam is used to simulate the drill. The time-dependent nature of the thrust force and the drilling depth is considered in the equation of motion of the drill. A moving Winkler-type elastic foundation assumption is applied to the drill tip to approximate the time-varying boundary conditions in the drilling process. Galerkin’s method is used to formulate the characteristic equation in a discrete form. The variation of the instability regions of the drill system is solved and analyzed by employing the multiple-scales perturbation method. The numerical results indicate that the unstable regions suddenly enlarge and shift toward a lower frequency when the drill first contacts the work piece. The effects of the rotational speed, pretwisted angle, and thrust force of the drill on the variation of the dynamic instability in high-speed drilling are also studied and are found to be highly influential.

Model of vibration in drilling into fibre-reinforced composite materials

2009 ◽  
Vol 223 (9) ◽  
pp. 1107-1114
Author(s):  
B W Huang
Keyword(s):  
Composite Materials ◽  
Vibration Amplitude ◽  
Time Dependent ◽  
Process Time ◽  
Drilling Process ◽  
Improve Product Quality ◽  
Analysis Model ◽  
Inhomogeneous Materials ◽  
Reinforced Composite ◽  
Twisted Beam

A model of the dynamic drill characteristics while drilling through fibre-reinforced composite materials (FRCMs) is investigated in this study. Anisotropic and inhomogeneous materials such as FRCMs, which are used to improve product quality, make it possible to improve production rate and avoid drill breakage. Such materials were used to study the dynamic characteristics of the drilling process. A theoretical analysis model for drilling composite materials is proposed. A pre-twisted beam is used to simulate the drill. A moving Winkler-type elastic foundation is used to approximate the drilling process time-dependent boundary. Numerical analysis indicates that the vibration amplitude changes significantly as the drill moves through composite material.

Effect of Periodic Drilling Force on Instability in a Drilling Process

2005 ◽  
Vol 219 (8) ◽  
pp. 733-742 ◽  
Author(s):  
B W Huang ◽  
H K Kung ◽  
A W L Yao
Keyword(s):  
Numerical Analysis ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Drilling Process ◽  
Twist Drill ◽  
Unstable Condition ◽  
Drilling Force ◽  
Cutting Geometry ◽  
Drilling Quality ◽  
Spinning Speed

The periodic drilling force effect on the dynamic instability of a drill in a drilling process was investigated. This investigation involves the cutting geometry drilling force from the two active parts of a twist drill subjected to small fluctuations during the drilling process. Theoretically, at some drilling force, this small drilling force fluctuation may lead the system into a dynamically unstable condition. Most hole location errors, reaming, and drill fractures occur in this unstable drilling process phase. The dynamic instability in a drilling process is an important issue in increasing the drilling quality and production rate. In this article, a pretwisted beam with a moving Winkler-type elastic foundation is used to simulate the drill and drilling process. Numerical analysis indicates that the unstable regions are enlarged and shifted to a lower frequency suddenly as the drill bites into a workpiece. It is also observed that the thrust force, spinning speed, and pretwisted angle effects drastically change the dynamic instability of drilling.

Experimental Research on Microburrs of High Speed Drilling of PCB Using Microdrill

2012 ◽  
Vol 497 ◽  
pp. 215-219 ◽  
Author(s):  
Xiao Hu Zheng ◽  
Zhi Qiang Liu ◽  
Cheng Yong Wang ◽  
Qing Long An ◽  
Ming Chen
Keyword(s):  
High Speed ◽  
Copper Foil ◽  
Great Influence ◽  
Burr Formation ◽  
Drilling Process ◽  
Fiber Plastic ◽  
High Speed Drilling ◽  
Micro Hole ◽  
Three Stages ◽  
Exit Burr

Microburrs have great influence on printed circuit board’s quality. PCB is composed of glass fiber plastic reinforcement material and copper foil. The PCB microburrs are generated in copper foil drilling process. These burrs are generated by copper extrusion and accumulation around the micro-hole. Enter burr and exit burr is quite different. Enter burrs are lower than exit burrs. The burr formation experienced three stages: First, Copper foil extrudes with the feed of microdrill; Second, Most of the Materials are cut off by drill tip and the rest of material; At last, rollover burrs appear when drill enters or exits uncut chip rolls.

Drilling Force in High Speed Drilling Carbon Fibre Reinforced Plastics (CFRP) Using Half Core Drill

2010 ◽  
Vol 102-104 ◽  
pp. 729-732 ◽  
Author(s):  
Dong Liu ◽  
Hong Hai Xu ◽  
Chao Ying Zhang ◽  
Hong Juan Yan
Keyword(s):  
High Speed ◽  
Thrust Force ◽  
Air Cooling ◽  
Carbide Tool ◽  
Drilling Force ◽  
Drilling Tool ◽  
Reinforced Plastics ◽  
Drilling Tools ◽  
High Speed Drilling ◽  
Carbon Fibre Reinforced Plastics

The Composites are difficult machining materials which widely used in aerospace industry due to their excellent mechanical properties. Tool wear and delamination are considered the major concern in manufacture the parts and assembly. The thrust force and torque affect the tool life and delamination mostly. This paper investigated the drilling force and torque of carbon fibred composite with carbide drilling tools and half core drilling tool. The experiments were carried out under air cooling cutting conditions and the drilling force using carbide tool and half core tool were compared and the experimental results indicated that the drilling forces using half core drill were smaller than that of using carbide tool.

Effect of Diamond Coating on Drilling Force and Temperature during High Speed Micro Drilling of Bone

2016 ◽  
Vol 1136 ◽  
pp. 239-244
Author(s):  
Zi Han Zhao ◽  
Liang Wen ◽  
Jin Bang Song ◽  
De Dong Yu ◽  
Ming Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Drilling Process ◽  
Diamond Coating ◽  
Bone Drilling ◽  
Drilling Force ◽  
Drilling Temperature ◽  
High Speed Drilling ◽  
Development Direction ◽  
Micro Drilling ◽  
Huge Impact

Bone drilling commonly exists in clinical practice and the heat and force generated by the drilling process has a huge impact on the surgery effect and the recovery of patients. High speed drilling, proved to have less injury and be more efficient when compared to the traditional low speed drilling, is considered to be the development direction of bone drilling-related surgeries. In order to make a further study of the controlling of the heat and force during the bone drilling process, the experiment designed to examine the influence of the diamond coating has been conducted and the result indicates that the diamond coating generally has little influence on the drilling force, however, it can increase the drilling temperature to a certain extent which indicates that the diamond coating is not suitable to apply to bone drills under the conditions of the conducted experiments. The result of this research could be of some help to the development of new kinds of medical drills.

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