scholarly journals Elimination of Smashed Ball Defect through Process and Design Improvement

2020 ◽  
pp. 39-43
Author(s):  
Jonathan C. Pulido ◽  
Rennier S. Rodriguez ◽  
Frederick Ray I. Gomez
Keyword(s):  
Design Improvement ◽  
Micro Holes ◽  
Micro Hole ◽  
The Wire ◽  
Bouncing Effect

This paper presents the modification and improvement done on the wire clamp and top plate (WCTP) design to eliminate the bouncing effect of the silicon die that leads to smashed ball reject during the formation of wire. The protrusion of the unit on the vacuum hole produced movement and slight vibration that affects the consistency of wirebonding. Through changing the standard vacuum hole to micro-holes provides underneath support to the unit and eliminates the overhanging or protrusion during the formation of wire. The implementation of the micro-hole design reduced the defect parts per million (dppm) occurrence to zero.

Improvement of thread turning process using micro-hole textured solid-lubricant embedded tools

2021 ◽  
pp. 095440542110199
Author(s):  
Salman Khani ◽  
Seyedhamidreza Shahabi Haghighi ◽  
Mohammad Reza Razfar ◽  
Masoud Farahnakian
Keyword(s):  
Surface Roughness ◽  
Mechanical Strength ◽  
Solid Lubricant ◽  
Operating Cost ◽  
Contact Length ◽  
Solid Lubrication ◽  
Turning Process ◽  
Micro Holes ◽  
Micro Hole ◽  
Cutting Inserts

In this paper, the thread turning of aluminum 7075-T6 alloy is studied using micro-hole textured solid-lubricant embedded carbide inserts. The primary focus of this work is to enhance the performance of the thread turning process for producing high quality threaded parts. To achieve this, micro-holes were generated by laser micro-machining on the rake face of tools and then, MoS2 and CNT (carbon nanotube) solid-lubricants were embedded into micro-holes. The effects of micro-holes and solid-lubrication on the performance of the thread turning process were examined using traditional tool ( T0), micro-hole textured tool ( T1), micro-hole textured MoS2 embedded tool ( T2), and micro-hole textured CNT embedded tool ( T3). In this study, cutting forces, chip-tool contact length, built-up edge (BUE), surface roughness, and operating cost were investigated. The influence of micro-hole generation on the mechanical strength of cutting inserts was evaluated using the finite element method. The results showed that the fabrication of the micro-holes on the rake surface of cutting inserts has no significant effect on the mechanical strength of the tools. The comparisons of our method with traditional tools demonstrated that the cutting performance improved in the threading process. Our results reveal that the main cutting force, radial thrust force, surface roughness, built-up edge, and chip-tool contact length reduced 37.1%, 40.9%, 37.9%, 58.3%, and 38.2%, respectively, as T3 tools are applied in this process. A cost analysis, based on estimated tooling costs, showed that the T3 tool can yield an 18% reduction in overall operating cost.

scholarly journals Geometry assessment of ultra-short pulsed laser drilled micro-holes

2020 ◽  
Author(s):  
Matthias Putzer ◽  
Norbert Ackerl ◽  
Konrad Wegener
Keyword(s):  
Pulsed Laser ◽  
Parameter Study ◽  
Cylindrical Shape ◽  
Multiple Reflections ◽  
Rayleigh Length ◽  
Drilling Method ◽  
Micro Holes ◽  
Micro Hole ◽  
The Impact ◽  
First Time

AbstractUltra-short pulsed laser ablation enables a defined generation of micro-holes. A parameter study on the ablation characteristics of copper clearly reveals a benefit for green wavelength with lower threshold fluence, simultaneously increasing the Rayleigh length. The use of a circular drilling method allows a defined manufacturing of micro boreholes and micro through-holes with 35 μm diameter of up to 165 μm and 300 μm length. Introducing high-resolution micro-computed X-ray tomography studying the micro-hole evolution and adjacent geometrical transformations reveals micrometer resolution and high usability. The conical geometry evolving up to an aspect ratio of 5:1 fits well to established models known for percussion drilling. However, increasing the number of pulses leads to non-conical geometry evolution, and this resulting geometry is studied for the first time. Henceforth, the exact geometrical evolution from conical to cylindrical shape upon laser drilling can be resolved revealing the impact of multiple reflections at the generated steep flanks.

Experimental Investigation Into Sequential Micro Machining (SMM) for Micro Hole Drilling on SS–304

2019 ◽  
Vol 9 (4) ◽  
pp. 1-16
Author(s):  
Raju Mahadeorao Tayade ◽  
Biswanath Doloi ◽  
Biplab Ranjan Sarkar ◽  
Bijoy Bhattacharyya
Keyword(s):  
Xrd Analysis ◽  
304 Stainless Steel ◽  
Hole Drilling ◽  
Machining Parameters ◽  
Micro Machining ◽  
Machining Processes ◽  
Taper Angle ◽  
Micro Holes ◽  
Micro Hole ◽  
Ss 304

Sequential micro machining (SMM) is a strategy of machining applied for micro-part manufacturing. Due to the finding of new sequential machining combinations, the authors have presented a novel combination of micro-ECDM (µECDM) drilling and micro-ECM (µECM) finishing for producing micro-holes in SS-304 stainless steel. An experimental setup was developed indigenously to conduct both machining processes at one station. The sequential processes were employed with desirable machining parameters, during their individual execution. The most desirable parameter like machining voltage, for hole drilling by µECDM was decided by studying hole taper angle, radial overcut, etc. The µECDM generates a recast layer, to overcome the adverse effects of µECDM, with the µECM finishing applied subsequently. The experimental results of SMM indicate a reduction in hole taper angle, improved circularity, and better surface quality. The change of phase of material due to sequencing of µECDM and µECM processes was analyzed by an XRD analysis of SS-304.

Numerical Investigation on the Effect of Abrasive Property for Abrasive Flow Machining

2014 ◽  
Vol 574 ◽  
pp. 406-410
Author(s):  
Li Feng Yang ◽  
Chun Yan Dong ◽  
Wei Na Liu
Keyword(s):  
Material Removal ◽  
Volume Fraction ◽  
Metal Removal ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Particle Volume ◽  
Micro Holes ◽  
Micro Hole ◽  
Abrasive Property

Numerical investigations of the abrasive influence on material removal efficiency of the micro-hole for AFM process is conducted in this paper. A three-dimensional model is constructed for this process. The abrasive with various particles volume fraction and different micro-holes with various diameters are selected in this study. The simulation results show that the lower particle volume fraction may be in favour of the metal removal uniformity, but the processing time will be too long if too low fraction is selected.

Experimental Study of Titanium Alloy Micro-Holes by EDM Fuzzy Control System

2011 ◽  
Vol 188 ◽  
pp. 195-198
Author(s):  
Yu Kui Wang ◽  
X.S. Geng ◽  
Zhen Long Wang ◽  
D.B. Shan
Keyword(s):  
Titanium Alloy ◽  
Control System ◽  
Fuzzy Control ◽  
Pulse Interval ◽  
Control Parameters ◽  
Fuzzy Control System ◽  
System A ◽  
Suitable Parameter ◽  
Micro Holes ◽  
Micro Hole

Aiming at machining deep micro-holes in titanium alloy, an experimental approach for EDM adopted a fuzzy control system was introduced. The fuzzy control system based on statistics of discharge states, that pulse interval and jumping height as control parameters, was self-developed. The suitable parameter for the deep micro-hole EDM process can be handily adjusted and modified in visual MATLAB fuzzy editor. A lot of experiments for titanium alloy micro-hole machining were performed on the EDM machine tool adopting the fuzzy control system. A titanium alloy deep micro-hole with 80μm in diameter and 15 in the ratio of depth-diameter is obtained. The process and results of experiments show that the process stability and efficiency be improved; due to the fuzzy control system and its suitable control parameters are applied.

Micro-Hole Machined by Electrochemical Discharge Machining (ECDM) with High Speed Rotating Cathode

2011 ◽  
Vol 295-297 ◽  
pp. 1794-1799 ◽  
Author(s):  
Shao Fu Huang ◽  
Di Zhu ◽  
Yong Bin Zeng ◽  
Wei Wang ◽  
Yong Liu
Keyword(s):  
High Speed ◽  
Electrochemical Machining ◽  
304 Stainless Steel ◽  
Machining Accuracy ◽  
Micro Machining ◽  
Rotating Speed ◽  
Electrochemical Discharge Machining ◽  
Electrochemical Discharge ◽  
Micro Holes ◽  
Micro Hole

Electrochemical discharge machining (ECDM), based on electrochemical machining (ECM) and electrodischarge machining (EDM), is an unconventional micro-machining technology. In this paper, with the use of water, the process of micro hole on ANSI 304 stainless steel machined by micro-ECDM with high speed rotating cathode is studied. The effects of machining conditions such as the cathode rotating speed and cathode diameter on the surface quality and accuracy of the shape are investigated. The results indicate that a relatively higher electrode rotating speed can improve the machining accuracy of the micro-holes and reduce the electrodes wear.

Modeling Aspect Ratio of a Micro EDM Hole

2010 ◽  
Vol 126-128 ◽  
pp. 829-834
Author(s):  
G. Yin ◽  
Z. Yu ◽  
C. An ◽  
J. Li
Keyword(s):  
Aspect Ratio ◽  
Electrical Discharge Machining ◽  
Micro Edm ◽  
Metallic Materials ◽  
Micro Electrical Discharge Machining ◽  
Proposed Model ◽  
Micro Holes ◽  
Micro Hole ◽  
The Difference ◽  
Discharge Gap

Micro electrical discharge machining (EDM) has the ability to drill micro holes with high accuracy in metallic materials. The aspect ratio of a micro hole generated by micro EDM is usually higher than those by other processes such as etching, mechanical drilling, and laser. However, it was found that the drilling speed of micro EDM slows down and even stops when the aspect ratio reaches a certain value. To understand this phenomenon, a theoretical model is proposed based on the fluid mechanics and surface tension. Experiments under different machining conditions are carried to verify this model. Experimental results agree with the theoretical values, which indicate the validity of the proposed model. The difference between the theoretical values and the real values might be caused by the debris and the temperature in the discharge gap, which are ignored in the model.

scholarly journals Elimination of Non-stick on Leads Defect through Re-designed WCTP

2021 ◽  
pp. 22-26
Author(s):  
Richard G. Mariano ◽  
Alyssa Grace S. Gablan ◽  
Frederick Ray I. Gomez
Keyword(s):  
Positive Bias ◽  
Defect Reduction ◽  
The Reformation ◽  
Hollow Part ◽  
The Wire ◽  
Bouncing Effect ◽  
High Rejection

This paper presents the reformation and fabrication resolved on the wire clamp and top plate (WCTP) design to eliminate the presence of lead finger bouncing resulting to high rejection of non-stick on leads (NSOL). Problem experienced was that the hollow or half-etched portion of the leadframe at the top and bottom units caused its bouncing effect. With the aim to improve localized massive NSOL defect, WCTP has been modified to provide positive bias to support its hollow part or the half-etched part of the leadframe at the top and bottom of the units. The re-designed WCTP was fabricated, extending its clamping with enhanced vacuum on top and bottom rows. The implementation of the improved WCTP design reduced the defect with 88 % improvement with the defect reduction during the lot runs.

Optimizing the Electrical Discharge Drilling Process for High Aspect Micro Hole Drilling in Die Steel

2017 ◽  
pp. 120-141 ◽  
Author(s):  
Kamal Kumar
Keyword(s):  
Turbine Blades ◽  
High Strength ◽  
Hole Drilling ◽  
Drilling Process ◽  
Die Steel ◽  
Cooling Channels ◽  
Micro Holes ◽  
Grey Relational Grade ◽  
Micro Hole ◽  
Grey Relational

Electric discharge drilling (EDD) is a thermo erosion process used to produce holes in high strength materials for various applications such as fuel injector, medical devices, turbine blades cooling channels etc. In this chapter, high aspect micro holes are drilled in die steel (of thickness 15 mm) using tubular electrodes of diameter 500µm. Using Taguchi' design of experiment method, four process parameters namely electrode material, discharge current (Ip), pulse on time (Ton) and pulse-off time (Toff) are investigated and optimized for two performance characteristics namely drilling rate (DR) and electrode wear rate (EWR). DR and EWR are opposite in nature, i.e. DR is higher the better type of characteristics while EWR is lower the better type of characteristics. Using Grey relational analysis (GRA) along with Taguchi method, both the characteristics are optimized simultaneously. Through GRA, grey relational grade has been computed as a performance index for predicting the optimal parameters setting for multi machining characteristics.

Anodic Dissolution Behaviour of Passive Layer During Hybrid Electrochemical Micromachining of Ti6Al4V in NaNO3 Solution

2021 ◽  
Author(s):  
Mukesh Tak ◽  
Rakesh Mote
Keyword(s):  
Hybrid Approach ◽  
Passive Layer ◽  
Electrochemical Micromachining ◽  
Abrasive Tool ◽  
Specific Strength ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Hole ◽  
Micro Tool ◽  
Bio Compatibility

Abstract Titanium and its alloys are considered as difficult to cut material classes, and their processing through the traditional machining methods is a painful task. These materials have an outstanding combination of properties like high specific strength, excellent corrosive resistance, and exceptional bio-compatibility; therefore, they have broad fields of application like aerospace, MEMS, bio-medical, etc. Electrochemical micromachining (ECMM) is a very vital process for the production of micro-domain features in difficult-to-machine materials. The machining issue with ECMM for titanium and their alloys is the passive layer formation, which hinders the dissolution and causes stray removal. To overcome these issues, a hybrid ECMM approach has been proposed by using a diamond abrasive tool combined with ECMM. The present study focuses on the detailed characterization of the passive layer formed using the hybrid approach. Through the use abrasive tool, the abrasive grits scoop the passive layer by the mechanical grinding action, formed in micro-drilling on the Ti6Al4V alloy to expose a new surface for further dissolution. The micro-holes were produced incorporating the abrasive tool and then compared by the holes created using a cylindrical tool (tool without abrasive). The taper and the stray dissolution of the micro-holes were also compared, produced at different applied potentials. The minimum average entry overcut and exit overcut of the hole were obtained as 29 µm and 3 µm, respectively, also a micro-hole with the lowest taper of 2.7°, achieved by the use of the abrasive micro tool.

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