Ray's Articles
Visit this page each month to see the latest columns written by Ray Prasad.
Problems and Promises of BTCs: Bottom Termination Components
What are bottom termination components (BTCs)? You may not know the term BTC, but expect to hear about them,...
Tin- Copper Alloys for Lead-free Reflow?
Some suppliers are promoting their patented Sn-Cu (tin-copper, melting point 228C) lead free alloys with trace amounts of magic...
Selection Criteria for SMT Placement Equipment
The pick-and-place machine is the most important piece of manufacturing equipment on an SMT line. Typically, surface mount pick...
Selective Laser Soldering: DfM Rules
All soldering processes have specific design for manufacturing (DfM) requirements. For example, via-in-pad is not desired in reflow to...
SMT - Unresolved Issues in Lead-free Through-hole Soldering and Surface Finishes
Since we have been in SMT for more than two decades in high-volume productionSince we have been in SMT for...
SMT- DFM in a Lead-free World: Part 1
Our industry has adapted to and thrived on numerous changes in 25 years — from thru-hole to surface mount; wave...
SMT- Vapor Phase Soldering: The Comeback Kid
Vapor phase soldering (VPS), also known as condensation soldering, has gone through changes in popularity. It was the process of...
SMT - Lead-free Reflow Profile Development : Part 2
As discussed in my February column, to accommodate constraints imposed by large components with high thermal mass requiring higher peaktemperature...
SMT - Lead-free Reflow Profile Development: Part 1
With tin/lead there has been total industry unanimity about the composition of solder to be used — eutectic solder with...
SMT BGA Ball Drop in Pb Free: A concern in Lead Free Assemblies: Part 1
No matter where you stand on the wisdom of lead free directive by the European Union and their numerous followers...
Three Steps to Improve SMT Yield
Most companies attempt to achieve higher yield in SMT products through trial and error at considerable expense and frustration. Even...
SMT - BGA Ball Drop - A Concern in Lead-free Assemblies
No matter where you stand on the wisdom of the EU’s leadfree directive, and the numerous followers across the globe...
SMT- How clean is clean? Well, make up something.
There is no other requirement as confusing and muddled in our industry as the definition of cleanliness of an electronics...
Part 2: How Clean Is Clean? - SMT Assembly Part 2
As I stated in my December 2004 column, the definition of cleanliness of an electronics assembly board may be one...
Key Considerations in Selective Soldering for SMT
If you happen to be in the market for selective soldering systems, there are lots of choices. However, before settling...
SMT - End of an Era: Moore’s Law
Two cores are better than one. Why? Intel says so. It has to do with hitting the brick wall in...
SMT - Outsourcing to India
I visit India every year for personal reasons, but tend to teach a class or two while I am there....
BGA Voids and Their Sources in SMT Assemblies
Ball grid array (BGA) is widely used because of its inherent advantage in producing overall lower defects. However, one defect...
Tools and Techniques for Developing SMT Solder Profile
The solder profile, also known as thermal profile, is a key variable in the manufacturing process that significantly impacts product...
One Solder Profile for All SMT Boards -SMT Article
The solder profile, also known as thermal profile, is a key variable in the manufacturing process that significantly impacts product...
SMT - AOI, Test and Repair: Waste of Money?
Any money spent on inspection, test and repair is wasted money. It adds only to cost and, hence, adversely impacts...
BGA Repair in SMT Assemblies
All surface mount components, including BGA, require uniform heating of components and boards and a mechanism for accurate component placement....
Repair and Rework Requirements for SMT Assemblies
In my last two columns, (August and September 2001), I discussed the broader issues of surface mount repair as they...
SMT- Mass Rework? Automated? You must be Kidding!
Mass rework? Automated? Why would anyone need to do mass rework? Are they totally new to SMT? Haven’t companies figured...
Despite all effort put into design, process and material control, there always will be some assemblies that fail to meet...
SMT - Mass Rework? Automated? You must be Kidding!
Mass rework? Automated? Why would anyone need to do mass rework? Are they totally new to SMT? Haven’t companies figured...
SMT Optoelectronics or Optronics — Promises and Problems
The optoelectronics field is so new that no one can even agree on what to call it. Most people refer...
SMT Packaging Moore’s Law and You
Gordon Moore, whose name is synonymous with integrated circuit (IC) technology, retired from the Intel board this May. Dr. Moore...
Voids in BGAs in SMT Assemblies - SMT Article
Ball grid array (BGA) is no longer considered a technology of tomorrow but a technology used today. If you are...
SMT- AOI System Alternatives
Quality control is key to effective competition in the international market. Specific tools such as statistical quality control (SQC), inspection,...
SMT- Placing an AOI System in the SMT Line
There are various inspection and test methods used in the industry. The visual inspection method is the most common and...
Building SMT Assemblies with Missing Components to Improve Quality and Delivery
From the title of this column, you might find it strange that someone with a reasonable understanding of the SMT...
Selective Automated Laser Assembly of SMT Assemblies
Let me first take this rare, rather once in a lifetime, opportunity to wish all of you, the readers of...
SMT Solder Paste Printing for SMT Part 1
Part 1 of a 2-part series.In surface mount assembly reflow soldering, solder paste is used for the connection between surface...
SMT Solder Paste Printing For SMT Fine-pitch and Through-hole Components Part 2
Part 2 of a 2-part series.In last month’s column (“Solder Paste Printing,” September 2000 SMT, p. 28-33), I discussed the...
SMT - Role of Packaging in Moore's Law
I was having a leisurely morning reading my Saturday New York Times not hoping to find any thing that important....
Registration is Open for SMT Course
Ray Prasad will be teaching his flagship SMT course: