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Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Modeling Of Selective Laser Sintering/ Selective Laser Melting, Xuan Wang, Connor West Jan 2017

Modeling Of Selective Laser Sintering/ Selective Laser Melting, Xuan Wang, Connor West

Industrial and Manufacturing Engineering

Selective laser sintering and selective laser melting are powder based additive manufacturing (AM) process that can rapidly manufacture parts with comparable mechanical properties to conventional manufacturing methods directly from digital files. However, the processing recipe development and design optimization of AM parts are often based on trial and error which erodes the benefit of AM. Modeling is a powerful tool to enable faster development cycle by significantly reducing the experimental efforts. In this paper we discussed the current status of selective laser sintering/melting modeling, in which the laser and powder interaction was studied to understand and predict the process ...


Mechanisms And Solutions To The Brittle Solder Joint In Electroless Ni Plating, Xuan Wang, C. Key Chung Aug 2016

Mechanisms And Solutions To The Brittle Solder Joint In Electroless Ni Plating, Xuan Wang, C. Key Chung

Industrial and Manufacturing Engineering

Brittle solder joints in Electroless Ni electroless Pd immersion Au (ENEPIG) surface finishes are one of the key reliability issues in electronics assembly. Previous characterization of the reflow process has indicated that interfacial voids formed after solder reflow are responsible for the decreases in solder joint strength. However, the mechanisms behind the formation of these voids in the ENEPIG process remain unclear. In this paper, the interaction between various aspects of the ENEPIG process and solder joint strength were investigated. Surface roughness, morphology, and nano-pitting at the interface between electroless Pd and Ni-P were characterized. The size and density of ...


Densification Of W-Ni-Fe Powders Using Laser Sintering, Xuan Wang, Matthew Wraith, Stephen Burke, Howard Rathbun, Kyle Devlugt Apr 2016

Densification Of W-Ni-Fe Powders Using Laser Sintering, Xuan Wang, Matthew Wraith, Stephen Burke, Howard Rathbun, Kyle Devlugt

Industrial and Manufacturing Engineering

In this paper, Laser Sintering (LS) of 90%W–7%Ni–3%Fe (wt.%) powders have been investigated, with the goal to understand the influence of final density by laser power, scanning speed, laser trace width, and the number of scanning passes. The results suggest that the laser power and scanning speed are the most important factors influencing density; the influence of trace width and number of scanning passes are not significant. With the increase of laser power and decrease of scanning speed, higher density can be achieved. The microstructure analysis indicated that the porosity changed from open porosity to ...


Warpage And Shape Distortion In Laser Metal Sintering, Xuan Wang May 2015

Warpage And Shape Distortion In Laser Metal Sintering, Xuan Wang

Industrial and Manufacturing Engineering

Selective Laser Sintering (SLS) is the primary method to fabricate metal and ceramic components in additive manufacturing. Due to the anisotropy of powder material, the sintering rate difference will inevitably causes shape change, distortion , and other defects of sintered parts. In this paper, a continuum model was developed to simulate the SLS process. The developed model has been successful to predict sintering kinetics. The impact of processing parameters, such as laser power, scanning speed, hatching distance, and particle size has been studied . The proposed method provides an innovative tool to optimize SLS process parameters.


A Control-Chart Based Method For Solder Joint Crack Detection, Jianbiao Pan Sep 2014

A Control-Chart Based Method For Solder Joint Crack Detection, Jianbiao Pan

Industrial and Manufacturing Engineering

Many researchers have used different failure criteria in published solder joint reliability studies. Since the reported timeto-failure would be different if different failure criteria were used, it would be difficult to compare the reported reliability life of solder joints from one study to another. The purpose of this study is to evaluate the effect of failure criteria on the reported thermal fatigue life and determine which failure criterion could detect failure sooner. First, the application of the control-chart-based method in a thermal cycling reliability study is described. The reported time-to-failure data were then compared based on four different failure criteria ...


A Control-Chart Based Method For Solder Joint Crack Detection - Conference Proceeding, Jianbiao Pan Mar 2014

A Control-Chart Based Method For Solder Joint Crack Detection - Conference Proceeding, Jianbiao Pan

Industrial and Manufacturing Engineering

Many researchers have used different failure criteria in the published solder joint reliability studies. Since the reported time-to-failure would be different if different failure criteria were used, it would be difficult to compare the reported reliability life of solder joints from one study to another. The purpose of this study is to evaluate the effect of failure criteria on the reported thermal fatigue life and find out which failure criterion can detect failure sooner. First, the application of the control-chart based method in a thermal cycling reliability study is described. The reported time-to-failure data were then compared based on four ...


Project Based Learning In Engineering Economics: Teaching Advanced Topics Using A Stock Price Prediction Model, Lizabeth Schlemer Jun 2013

Project Based Learning In Engineering Economics: Teaching Advanced Topics Using A Stock Price Prediction Model, Lizabeth Schlemer

Industrial and Manufacturing Engineering

A graduate level advanced engineering economics class taught at California Polytechnic State University, San Luis Obispo, includes a thorough review of time value of money, investment evaluation, inflation, risk and return, financing decisions, corporate investment strategies, risk analysis and decisions incorporating non-monetary considerations. Historically this course was taught using an advanced text where the topics were covered sequentially. A redesign of the course now includes the construction of a stock price prediction model for a company of the student’s choice. Through the model, the topics are covered and discussed in the context of the large model-building project. For instance ...


Work In Progress: Outreach Assessment: Measuring Engagement, Lizabeth Schlemer, John Oliver, Katherine Chen, Sophia Rodriguez Mata, Eric Kim Oct 2012

Work In Progress: Outreach Assessment: Measuring Engagement, Lizabeth Schlemer, John Oliver, Katherine Chen, Sophia Rodriguez Mata, Eric Kim

Industrial and Manufacturing Engineering

The Learn By Doing Lab (LBDL) at Cal Poly, San Luis Obispo is an on-campus laboratory where 5th through 8th grade students are taught by undergraduates who may be planning a careers in teaching. The two populations - elementary students and undergraduates - are equally important in the process. Since 2008, the lab has seen over 4000 elementary and junior high students and over 100 undergrads have participated. In most outreach assessment the number of individuals participating is an important metric, but this last Spring we experimented with a more in depth measure of effectiveness. As in any learning experience engagement in ...


Integrating Courses Through Project Based Learning, Lizabeth Schlemer, Sema E. Alptekin, Karen R. Bangs Apr 2012

Integrating Courses Through Project Based Learning, Lizabeth Schlemer, Sema E. Alptekin, Karen R. Bangs

Industrial and Manufacturing Engineering

Integrating three courses (one sophomore level, two senior level) through Project Based Learning (PBL) within the Industrial Engineering curriculum at the California Polytechnic State University, San Luis Obispo is presented. Three courses (IME 443 Facilities Planning and Design - senior level; IME 420 Simulation - senior level; and IME 223 Process Improvement Fundamentals - sophomore level) were linked by various mechanisms: Common industry projects, common students in two of the three courses; senior students having access to sophomores in their teams to carry out time consuming tasks such as time studies, and sophomores having access to seniors as team members, and as coaches ...


Effect Of Gold Content On The Microstructural Evolution Of Sac305 Solder Joints Under Isothermal Aging, Mike Powers, Jianbiao Pan, Julie Silk, Patrick Hyland Mar 2012

Effect Of Gold Content On The Microstructural Evolution Of Sac305 Solder Joints Under Isothermal Aging, Mike Powers, Jianbiao Pan, Julie Silk, Patrick Hyland

Industrial and Manufacturing Engineering

Au over Ni on Cu is a widely used printed circuit board (PCB) surface finish, under bump metallization (UBM), and component lead metallization. It is generally accepted that less than 3 wt.% Au in Sn-Pb solder joints inhibits formation of detrimental intermetallic compounds (IMC). However, the critical limit for Au content in Pb-free solder joints is not well established. Three surface-mount package platforms, one with a matte Sn surface finish and the others with Ni/Au finish, were soldered to Ni/Au-finished PCB using Sn-3.0Ag- 0.5Cu (SAC305) solder, in a realistic manufacturing setting. The assembled boards were divided ...


The Morphology Evolution And Voiding Of Solder Joints On Qfn Central Pads With A Ni/Au Finish, Julie Silk, Jianbiao Pan, Mike Powers Feb 2012

The Morphology Evolution And Voiding Of Solder Joints On Qfn Central Pads With A Ni/Au Finish, Julie Silk, Jianbiao Pan, Mike Powers

Industrial and Manufacturing Engineering

In this paper, we report on a comprehensive study regarding the morphology evolution and voiding of SnAgCu solder joints on the central pad of two different packages – QFN and an Agilent package called TOPS – on PCBs with a Ni/Au surface finish. Samples were isothermally aged at the equivalent of 0, 2, 7 and 14 years service life. Representative solder joints were cross-sectioned and analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) in order to investigate the evolution of the solder joint morphology as a function of Au content and isothermal aging. IMC thickness was measured ...


A Study Of Solder Joint Failure Criteria, Jianbiao Pan, Julie Silk Oct 2011

A Study Of Solder Joint Failure Criteria, Jianbiao Pan, Julie Silk

Industrial and Manufacturing Engineering

One of the challenges in an experimental study of solder joint reliability is to determine when cracks occur in a solder joint or when a solder joint fails. Cracks in a real solder joint are difficult to identify using an X-Ray system. Cross-sectioning and scanning electron microscopy (SEM) is a destructive method. A common non-destructive test method is to monitor resistance increase in a solder joint or a daisy-chain. However, no scientific research has been done in establishing the relationship between the crack area of an interconnection and the change in resistance of the interconnection. This paper proposes a method ...


Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, J. Silk, M. Powers, P. Hyland Oct 2011

Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, J. Silk, M. Powers, P. Hyland

Industrial and Manufacturing Engineering

Electroplated Ni/Au over Cu is a popular metallization for printed circuit board finish as well as for component leads, especially wire-bondable high-frequency packages, where the gold thickness requirement for wire bonding is high. The general understanding is that less than 3 wt% of Au is acceptable in SnPb solder joints. However, little is known about the effect of Au content on the reliability of SnAgCu solder joints. The purpose of this paper is to determine the acceptable level of Au in SAC305 solder joints. Three different package platforms with different Au thicknesses were assembled on boards with two different ...


Evolving A Summer Engineering Camp Through Assessment, Katherine Chen, Lizabeth Schlemer, Heather Scott Smith, Teana Fredeen Jun 2011

Evolving A Summer Engineering Camp Through Assessment, Katherine Chen, Lizabeth Schlemer, Heather Scott Smith, Teana Fredeen

Industrial and Manufacturing Engineering

EPIC (Engineering Possibilities in College) is a one-week summer program for high school students (entering 9th-12th grades) to learn about engineering and experience hands-on labs in a university atmosphere. It's an opportunity for students to explore the different types of engineering available at many universities. The aim of EPIC is to expand the College of Engineering mission to K-12 students: "To educate students for careers of service, leadership and distinction in engineering or other fields by using a participatory, learn by doing, ‘hands-on’ approach".


The Inside-Out Classroom: A Win-Win Strategy For Teaching With Technology, Daniel J. Waldorf, Lizabeth Schlemer Jun 2011

The Inside-Out Classroom: A Win-Win Strategy For Teaching With Technology, Daniel J. Waldorf, Lizabeth Schlemer

Industrial and Manufacturing Engineering

As costs of higher education soar and many universities face uncertain funding models, institutional pressures have increased to improve instructor efficiency. At the same time, U.S. industry leaders and leading educators have called for improvements in engineering education based on more interactive, hands-on student learning experiences. Although many efforts have been made to take advantage of technology to either improve student learning or to maintain student learning while increasing instructor efficiency, few approaches have been shown to improve both learning and efficiency. A teaching method is proposed to improve student learning and increase student satisfaction while also addressing the ...


Design Projects With Out-Of-Town Companies, Lizabeth Schlemer Jun 2011

Design Projects With Out-Of-Town Companies, Lizabeth Schlemer

Industrial and Manufacturing Engineering

The capstone design class in the industrial engineering department at California Polytechnic State University, San Luis Obispo (Cal Poly) includes projects with companies. The projects are large ambiguous facilities design problems that allow students to incorporate many aspects of the IE curriculum. For the past 15 years students have been participating in these projects with local companies. Over the past several years, companies from out of town (200 miles to the north in Mountain View or 200 miles to the south in Oxnard) have participated. These out of town companies have presented certain logistical issues, but they have proven to ...


Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, Julie Silk, Mike Powers, Patrick Hyland Apr 2011

Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, Julie Silk, Mike Powers, Patrick Hyland

Industrial and Manufacturing Engineering

Electroplated Ni/Au over Cu is a popular metallization for PCB finish as well as for component leads, especially wire-bondable high frequency packages, where the gold thickness requirement for wirebonding is high. The general understanding is that less than 3 wt% of Au is acceptable in SnPb solder joints. However, little is known about the effect of Au content on the reliability of SnAgCu solder joints. The purpose of this study is to determine the acceptable level of Au in SAC305 solder joints. Three different package platforms with different Au thicknesses were assembled on boards with two different Au thicknesses ...


Testing The Test: Validity And Reliability Of Senior Exit Exam, Lizabeth Schlemer, Daniel Waldorf Jun 2010

Testing The Test: Validity And Reliability Of Senior Exit Exam, Lizabeth Schlemer, Daniel Waldorf

Industrial and Manufacturing Engineering

A senior exit exam is considered an excellent direct measure of student learning for ABET assessment, but the usefulness of the information gathered is related to the validity and reliability of the test itself. The Industrial and Manufacturing Engineering Department at California Polytechnic State University, San Luis Obispo has used a content exam for several years. This paper will discuss test development, administration, and the role it plays in the assessment process. In addition, the test is evaluated using the standard psychometric techniques of reliability and validity. The results of the evaluation are used to refine the test. The importance ...


Assessing Curriculum Improvement Through Senior Projects, Jianbiao Pan, Albert Liddicoat, James G. Harris, Linda Shepherd Jun 2010

Assessing Curriculum Improvement Through Senior Projects, Jianbiao Pan, Albert Liddicoat, James G. Harris, Linda Shepherd

Industrial and Manufacturing Engineering

Senior project and/or capstone design courses are intended to provide a culminating design experience for students and to demonstrate their understanding of engineering knowledge and their ability to apply that knowledge to practical problems. It is expected that the quality and attributes of students’ senior design projects can be used as a good measure of determining how well the curriculum prepares students to engage in engineering design as well as a measure of faculty teaching and student learning. This paper reports the results of a study designed to assess whether the new computer engineering curriculum implemented at Cal Poly ...


Development And Assessment Of A Pcb Layout And Manufacturong Laboratory Module In Introductory Electric Circuits For Ee And Non-Ee Majors, Albert Liddicoat, Jianbiao Pan, James G. Harris, Gary Perks, Linda Shepherd Jun 2010

Development And Assessment Of A Pcb Layout And Manufacturong Laboratory Module In Introductory Electric Circuits For Ee And Non-Ee Majors, Albert Liddicoat, Jianbiao Pan, James G. Harris, Gary Perks, Linda Shepherd

Industrial and Manufacturing Engineering

In standard introductory electric circuits laboratories for electrical engineering (EE) majors and non-EE majors, prototype boards are typically used to construct and test electric circuits. Students typically do not learn how to design and manufacture Printed Circuit Boards (PCB) that are commonly used in more sophisticated design projects and other engineering applications. This paper will present the development and assessment of a PCB layout and manufacturing laboratory module that has been used in introductory electric circuits laboratories for EE and non-EE majors. The feasibility of integrating the new PCB layout and manufacturing module into the electric circuit course will be ...


Using Sports Coaching Techniques To Enhance Project Based Learning Instruction, Lizabeth Schlemer, Faith Mimnaugh Mar 2010

Using Sports Coaching Techniques To Enhance Project Based Learning Instruction, Lizabeth Schlemer, Faith Mimnaugh

Industrial and Manufacturing Engineering

As instructors attempt to apply project based learning as a preferred pedagogy for many aspects of engineering education, countless questions are raised. For instance, how do instructors assess individual performance in a team based environment? How do instructors prepare students for the culminating presentation or report? How do instructors develop the students individually? After reviewing literature on both project based learning and exceptional coaching, we have found that much can be learned from John Wooden, Phil Jackson and other coaches. This paper will organize some of the best practices in sports coaching and draw parallels that will enhance student learning ...


Drop Impact Reliability Of Edge-Bonded Lead-Free Chip Scale Packages, Andrew Farris, Jianbiao Pan, Albert Liddicoat, Michael Krist, Nicholas Vickers, Brian J. Toleno, Dan Maslyk, Dongkai Shangguan, Jasbir Bath, Dennis Willie, David A. Geiger Jul 2009

Drop Impact Reliability Of Edge-Bonded Lead-Free Chip Scale Packages, Andrew Farris, Jianbiao Pan, Albert Liddicoat, Michael Krist, Nicholas Vickers, Brian J. Toleno, Dan Maslyk, Dongkai Shangguan, Jasbir Bath, Dennis Willie, David A. Geiger

Industrial and Manufacturing Engineering

This paper presents the drop test reliability results for edge-bonded 0.5 mm pitch lead-free chip scale packages (CSPs) on a standard JEDEC drop reliability test board. The test boards were subjected to drop tests at several impact pulses, including a peak acceleration of 900 Gs with a pulse duration of 0.7 ms, a peak acceleration of 1500 Gs with a pulse duration of 0.5 ms, and a peak acceleration of 2900 Gs with a pulse duration of 0.3 ms. A high-speed dynamic resistance measurement system was used to monitor the failure of the solder joints. Two ...


Teaming Multi-Level Classes On Industry Projects, Lizabeth Schlemer, Jose Macedo Mar 2009

Teaming Multi-Level Classes On Industry Projects, Lizabeth Schlemer, Jose Macedo

Industrial and Manufacturing Engineering

For the past few years we experimented with teaming students from a sophomore-level class and a senior-level class to work on industry projects. The classes are “work design” and “facilities design.” Projects are selected to require the application of knowledge from both disciplines. In addition, the projects are selected from small local companies. The intent of this paper is to describe the benefits and difficulties associated with this methodology. While specific classes in this experience are typical of an industrial engineering curriculum, the lessons learned and benefits could translate to other disciplines.


Optimization Of Engineering Tolerance Design Using Revised Loss Functions, Jeh-Nan Pan, Jianbiao Pan Feb 2009

Optimization Of Engineering Tolerance Design Using Revised Loss Functions, Jeh-Nan Pan, Jianbiao Pan

Industrial and Manufacturing Engineering

Engineering tolerance design plays an important role in modern manufacturing. Both symmetric and asymmetric tolerances are common in many manufacturing processes. Recently, various revised loss functions have been proposed for overcoming the drawbacks of Taguchi's loss function. In this article, Kapur's economic tolerance design model is modified and the economic specification limits for both symmetric and asymmetric losses are established. Three different loss functions are compared in the optimal symmetric and asymmetric tolerance design: a revised Taguchi quadratic loss function, an inverted normal loss function and a revised inverted normal loss function. The relationships among the three loss ...


Finding And Optimising The Key Factors For The Multiple-Response Manufacturing Process, Jeh-Nan Pan, Jianbiao Pan, Chun-Yi Lee Jan 2009

Finding And Optimising The Key Factors For The Multiple-Response Manufacturing Process, Jeh-Nan Pan, Jianbiao Pan, Chun-Yi Lee

Industrial and Manufacturing Engineering

With the advent of modern technology, manufacturing processes became so sophisticated that a single quality characteristic cannot reflect the true product quality. Thus, it is essential to perform the key factor analysis for the manufacturing process with multiple-input (factors) and multiple-output (responses). In this paper, an integrated approach of using the desirability function in conjunction with the Mahalanobis-Taguchi-Gram Schmit (MTGS) system is proposed in order to find and optimise the key factors for a multiple-response manufacturing process. The aim of using the MTGS method is to standardise and orthogonalise the multiple responses so that the Mahalanobis distance for each run ...


Effects Of Reflow Profile And Thermal Conditioning On Intermetallic Compound Thickness For Snagcu Soldered Joints, Jianbiao Pan, Tzu-Chien Chou, Jasbir Bath, Dennis Willie, Brian J. Toleno Jan 2009

Effects Of Reflow Profile And Thermal Conditioning On Intermetallic Compound Thickness For Snagcu Soldered Joints, Jianbiao Pan, Tzu-Chien Chou, Jasbir Bath, Dennis Willie, Brian J. Toleno

Industrial and Manufacturing Engineering

Purpose – The purpose of this paper is to investigate the effects of reflow time, reflow peak temperature, thermal shock and thermal aging on the intermetallic compound (IMC) thickness for Sn3.0Ag0.5Cu (SAC305) soldered joints.
Design/methodology/approach – A four-factor factorial design with three replications is selected in the experiment. The input variables are the peak temperature, the duration of time above solder liquidus temperature (TAL), solder alloy and thermal shock. The peak temperature has three levels, 12, 22 and 32°C above solder liquidus temperatures (or 230, 240 and 250°C for SAC305 and 195, 205, and 215°C ...


The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham Jan 2009

The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham

Industrial and Manufacturing Engineering

This paper presents a systematic study on the effect of 120 KHz ultrasonic frequency on the bondability and reliability of fine pitch gold wire bonding to pads over an organic substrate with gold metallizations. The study was carried out on a thermosonic ball bonder that is allowed to easily switch between ultrasonic frequencies of 60 KHz and 120 KHz by changing the ultrasonic transducer and the ultrasonic generator. Bonding parameters were optimized through the design of experimental methodology for four different cases: 25.4 mm wire at 60 kHz, 25.4 mm wire at 120 kHz, 17.8 mm wire ...


Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers Nov 2008

Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers

Industrial and Manufacturing Engineering

Mobile and handheld electronic devices are prone to being dropped. This drop event may result in failure of solder joints inside these devices. The need for RoHS compliant boards coupled with the demand for reliable electronics has resulted in the development of the JEDEC Standard JESD22-B111 to standardize the method of drop testing surface mount electronic components. However, there has been little study on the effects of additional mass on the board and rigidity of the board on drop test reliability. This paper examines the drop impact dynamic responses of the JEDEC JESD22-B111 board. Of interest are the effects of ...


The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham Nov 2008

The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham

Industrial and Manufacturing Engineering

This paper presents a systematic study on the effect of 120KHz ultrasonic frequency on the bondability and reliability of fine pitch gold wire bonding. The study was carried out on a thermosonic ball bonder that is allowed to easily switch between ultrasonic frequency of 60KHz and 120 KHz by changing the ultrasonic transducer and the ultrasonic generator. Bonding parameters were optimized through design of experiment methodology for four different cases: 25.4 μm wire at 60 kHz, 25.4 μm wire at 120 kHz, 17.8 μm wire at 60 kHz, and 17.8 μm wire at 120 kHz. The ...


Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan Nov 2008

Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan

Industrial and Manufacturing Engineering

This paper presents the failure analysis results of board level drop tests. In this study, the test vehicle was designed according to the requirements of the Joint Electron Device Engineering Council (JEDEC) drop test board. The test vehicle was assembled with 15 chip scale packages (CSPs) each having 228 daisy-chained 0.5 mm pitch solder joints using Sn-3.0 wt% Ag-0.5 wt% Cu (SAC305) lead free solder. Assemblies were drop tested using three different peak accelerations of 900 G, 1500 G, 2900 G, with 0.7 ms, 0.5 ms, and 0.3 ms pulse durations, respectively. Scanning electron ...