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SMTnet Express, December 14, 2023, Subscribers: 25,234, Companies: 11,964, Users: 28,558

█ Electronics Manufacturing Technical Articles

How to Manage Material Outgassing in Reflow Oven

In a lead-free reflow process, temperatures are higher, and materials use outgasses more than in a leaded reflow process. The trends toward higher density populated boards and more pin-in-paste technology also increase solder paste use. More components and more solder paste result in more outgassing of chemistry during the reflow process. Some assemblies report condensation of vapors when the cold printed circuit board enters the oven. Little is known about the interaction between these condensed materials in terms of the interaction between these condensed materials and the reliability of the assembly. Apart from the question of reliability, a printed circuit board contaminated with a small film of residues after reflow soldering is not desirable.

Credit: Vitronics Soltec

Effects of Assebly Process Variables on Voiding at a Thermal Interface.

The present work offers a discussion and a first case study to identify and illustrate voiding mechanisms for a particular TIM between a heat spreader and the back of a flip chip. Pronounced differences were observed between stencil printing and dispensing in terms of initial void formation, apparently related to the specific properties of the material. Measurements of the effects of heat ramp rate and peak temperature showed the subsequent evolution and final void size distribution to be determined by the initial part of the cure profile up to the material gelling temperature.

Credit: Universal Instruments Corporation

THE EFFECT OF VACUUM REFLOW PROCESSING ON SOLDER JOINT VOIDING AND THERMAL FATIGUE RELIABILITY

A test program was developed to evaluate the effectiveness of vacuum reflow processing on solder joint voiding and subsequent thermal cycling performance. Area array package test vehicles were assembled using conventional reflow processing and a solder paste that generated substantial void content in the solder joints. Half of the population of test vehicles then were re-processed (reflowed) using vacuum reflow. Transmission x-ray inspection showed a significant reduction in solder voiding after vacuum processing. The solder attachment reliability of the conventional and vacuum reflowed test vehicles was characterized and compared using two different accelerated thermal cycling profiles. The thermal cycling results are discussed in terms of the general impact of voiding on solder thermal fatigue reliability, results from the open literature, and the evolving industry standards for solder voiding. Recommendations are made for further work based on other void reduction methods and additional reliability studies.

Credit: Heller Industries Inc.

Voids in Solder Joints

Presented at SMTA Boise Expo and Tech Forum, March 20, 2018

Credit: Intel Corporation

Controlling Voiding Mechanisms in the Reflow Soldering Process

While a significant level of voiding can be tolerated in solder joints where electrical conductivity is the main requirement, voiding at any level severely compromises thermal conductivity. For example, in LED lighting modules effective conduction of heat through the 1st level die attach to the substrate and then through the 2nd level attach to the heat sink is critical to performance so that voiding in the solder joints at both levels must be minimized. (...) In this paper, the authors will review the factors that influence the incidence of voids in small and large area solder joints that simulate, respectively, the 1st and 2nd level joints in LED modules and discuss mitigation strategies appropriate to each level. They will also report the results of a study on the effect on the incidence of voids of flux medium formulation and the optimization of the thermal profile to ensure that most of the volatiles are released early in the reflow process.

Credit: Nihon Superior Co., Ltd.

Effect Of Voids On Thermo-Mechanical Reliability of Solder Joints

Despite being a continuous subject of discussion, the existence of voids and their effect on solder joint reliability has always been controversial. In this work we revisit previous works on the various types of voids, their origins and their effect on thermo-mechanical properties of solder joints. We focus on macro voids, intermetallics micro voids, and shrinkage voids, which result from solder paste and alloy characteristics. We compare results from the literature to our own experimental data, and use fatigue-crack initiation and propagation theory to support our findings. Through a series of examples, we show that size and location of macro voids are not the primary factor affecting solder joint mechanical and thermal fatigue life. Indeed, we observe that when these voids area conforms to the IPC-A-610 (D or F) or IPC-7095A standards, macro voids do not have any significant effect on thermal cycling or drop shock performance.

Credit: Alpha Assembly Solutions

Operation of a Vacuum Reflow Oven with Void Reduction Data

Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness.

Credit: BTU International

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█ Printed Circuit Board Assembly & PCB Design Forum

Lead trimming -- Looking for information on lead trimming after wave solder. Does anyone do this through automated equipment? I know ideally parts would be cut to length before insertion and not trimmed after wave solder but sometimes that is cost prohibitive. When necessary we have always hand trimmed with the proper type of pneumatic clippers but we have needed to increase our throughput substantially. To do so we purchased an automated pcb lead trimmer (KA-B6) which would be perfect if it didn't leave flagged leads. If the leads are flagged and we need to go over the boards by hand then the lead trimmer process is pointless. Open to process/different equipment suggestions. Thank you.

Handling/storing SMT leftover parts - cut strips -- Looking for ideas/conversation on how people handle short strips or leftover SMT parts in inventory

We do a lot of high mix low volume jobs we often have strips or even parts in bags which we need to keep and inventory. Presently the non reels are coiled or kept in esd bags - but the bags are different sizes because our people like to keep the original labels from DK for instance once there is a future question to realize about the part.

This is only the start of a conversation. I wish I could print labels 1/2" square and the. We could use small bins for instance for loose parts.

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█ SMT, PCB Electronics Assembly Manufacturing Industry News

Altus Adds Innovative New Vapor Phase Soldering System from ASSCON Altus Group has further enhanced its product portfolio with the addition of the ASSCON VP810 Vapor Phase Soldering System, the latest innovation in vapor phase technology launched at this year's Productronica trade fair in Munich.... Altus Group
SMTA Women's Leadership Program Announces First Quarter Webinar Schedule for 2024 The SMTA announced speakers for the next three Wine Down Wednesday webinars taking place in 2024. These virtual meetups are open to everyone and free to attend, organized by the SMTA Women's Leadership Program the first Wednesday of each month.... Surface Mount Technology Association (SMTA)
Materials Costs Continue to Improve but Labor Costs Remain a Pain Point for Electronics Manufacturers IPC Releases November Global Sentiment of the Electronics Supply Chain Report... Association Connecting Electronics Industries (IPC)

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█ SMT / PCB Products & Services

NEW SMT / PCB EQUIPMENT & SERVICES - For Sale

SELECTIVE SOLDERING

Pillarhouse Jade Handex

Pillarhouse USA

INSPECTION

MIRTEC GENESYS-PIN - 3D AOI for PIN inspection

MIRTEC Corp

PCB SOFTWARE

ProntoTEST-FIXTURE - ATE Programming

Unisoft

PCB ASSEMBLY

PCB Fab & Assembly

Imagineering

PCB REFLOW OVEN

NEW! Mark 7 Series -
Reflow Oven

Heller

PCB DISPENSING

MAX II High Precision Dispensers

GPD Global

Printing

Full-auto SMT Stencil Printer I.C.T-P4034

I.C.T

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█ SMT / PCB Assembly Equipment Auctions

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█ Electronic Equipment Market

MARKET - Used Electronic Assembly Machines For Sale

Board Cleaners

Aqueous Technologies Trident XLD

Baja Bid

P&P / FEEDERS

Panasonic NPM-W2

SMTUnion - Panasonic NPM-W2 Chipshooter

SMTUnion

Gen'l Purpose T&M

Zeiss LSM-880 Laser Scanning Microscope

World Equipment Source, LLC

Adhesive Dispensers

Musashi FAD2500

KD Electronics Ltd.

AOI INSPECTION

Viscom S3088 Ultra Chrome 3D AOI

Lewis & Clark Viscom S3088 AOI

Lewis & Clark

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MARKET - Used PCB Assembly Equipment Wanted To Buy

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KD Electronics Agilent 3070

World Equipment Source Assembleon MG-1R

World Equipment Source, LLC

PCB TEST

Agilent 3070

Lewis & Clark Agilent 3070

Lewis & Clark

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█ Electronics Manufacturing & Assembly Events Calendar

EVENTS

Pan Pacific Strategic Electronics Symposium | January 29 to February 1, 2024

SMTA

█ Electronics Manufacturing Training Courses & PCB Assembly Training

FIND TRAINING FOR:

IPC Certification

Soldering & Rework

PCB Design

Electronics Assembly

Electronics Inspection

Online Training

TRAINING - PCB Inspection Electronics Manufacturing Training Courses

IPC-A-640 Interactive PCB Inspection Lab (CIT or CIS Option)

Multiple dates and locations. Check the link for details

EPTAC Corporation

TRAINING - PCB Rework and Hand Soldering Training Courses

Customizable Basic Hand Soldering

Multiple dates and locations. Check the link for details

Blackfox Training Institute, LLC

Advanced Surface Mount Micro Hand Soldering

Illinois, Schaumburg

Dec. 14 to Dec. 15, 2023

EPTAC Corporation

TRAINING - Online Electronics Manufacturing and Assembly Training Courses

Reflow Soldering 101 Training Course

Surface Mount Technology Association (SMTA)

IPC/WHMA-A-620 Expert (CSE) Certification Training Course

EPTAC Corporation

IPC Certified Electronics Program Manager (CEPM) Training and Certification Program

Association Connecting Electronics Industries (IPC)

Component Placement 101 Training Course

Surface Mount Technology Association (SMTA)

ESD Control for Electronics Assembly

Association Connecting Electronics Industries (IPC)

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█ Electronics Manufacturing & PCB Assembly Career Center

Job Needs & Wants

JOBS

YOUR job openings

Overseas SMT Engineer

All over the world, Alabama, USA

I.C.T ( Dongguan Intercontinental Technology Co., Ltd. )

SMT Engineer, Marketing Representative, Sales Representative, Business Assistant

All over the world, California, USA

I.C.T ( Dongguan Intercontinental Technology Co., Ltd. )

AOI Engineer

Hai Phong, Vietnam

Dongguan RuiHengHuaTai Electronic Co., Ltd

SMT Process Technician III

Racine, Wisconsin, USA

Cree Lighting

Experienced SAKI AOI programmer

All US, USA

AirDataIOT,LLC

Engineering Project Manager

Strongsville, Ohio, USA

Spartronics

Senior Quality Engineer

Williamsport, Pennsylvania, USA

Spartronics

Senior Systems Engineer

Strongsville, Ohio, USA

Spartronics

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Brooksville, Florida, USA

Spartronics

Buyer/Planner

Williamsport, Pennsylvania, USA

Spartronics

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Williamsport, Pennsylvania, USA

Spartronics

Automotive service Technician

Golden, CO, USA

Engage2excel

Program Manager

Williamsport, Pennsylvania, USA

Spartronics

RESUMES

YOUR resume

POSITION: SMT Technician/ Engineer/ Management

JOB CATEGORY: Engineering Maintenance Management Production Technical Support

CURRENT LOCATION: Raymond, WA, USA

WILLING TO RELOCATE?: Not willing to relocate.

SUMMARY OF QUALIFICATIONS: Expert knowledge of circuit board manufacturing for the through-hole and Surface Mount Technology industry, international and national field work to manufacturers. Provided high value technical assistance and formal training to industry standards. Specialized in staff and department development.

YOUR next job ... YOUR next employee ...

█ PCB Design & Assembly Industry Associations

Surface Mount Technology Association (SMTA)

SMTA is a non-profit international association of companies and individuals (totalling 4,000) involved in all aspects of advanced electronics assembly, surface mount and related technologies.

Membership Info | SMTA Certification | Bookstore | Upcoming Events

Association Connecting Electronics Industries (IPC)

IPC is a US-based trade association dedicated to the competitive excellence and financial success of its nearly 2,600 member companies which represent all facets of the electronic interconnection industry, including design, printed wiring board manufacturing and electronics assembly.

Membership Info | Training & Certification | Online Store | Upcoming Events

Editor - Dave "davef" Fish (submit your technical articles)

SMTnet.com, 98 Elm Street, Portland, Maine 04101 USA, Tel.207-780-0887.

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