Improving Solder Paste Printing


Reading time ( words)

In my recent conversation with process engineers at an EMS company here in the Philippines, they said one of the critical processes that determine yield in their line is the solder paste printing process. According to them, one of the key reasons for this is the incorrect printer set-up, which results in issues such as insufficient solder or solder bridging. Of the three elements involved in the process—stencil, solder paste, and printer—the stencil is considered one of the major factors affecting the transfer efficiency, accuracy, and consistency, of solder pastes into the pads, especially with the continuing trend towards miniaturization.

Indeed, in our latest survey on solder paste printing, a majority of the respondents highlighted stencils as one of their key challenges. They mentioned the quality of the stencils; getting the right stencils—their stencils are done by a third party; aperture design; and stencil wear, among others, as issues around this part of the process. This is made more challenging because of the finer pitch and spacing in PCB designs. Specific problems in this regard include complete filling of apertures, paste release, and the large range of component types and sizes and the solder paste thickness requirement on the same design.

Other main issues include the accuracy and repeatability of the equipment, and the characteristics of the solder pastes being used.

Which brings me to our topic for this month’s issue of SMT Magazine. Many studies over the years have found that up to 70% of PCB assembly defects come from the solder paste printing operation. In this issue, we look at the critical issues in the solder paste printing process, and how assemblers can address these challenges to help improve their yield and quality.

To read the full version of this article, which appeared in the December 2017 issue of SMT Magazine, click here.

Share


Suggested Items

What SMT Component Shortages Mean for Design and Manufacturing Engineers

09/13/2018 | Russell Poppe, JJS Manufacturing
Much has been written about the increasing shortages of electronic components such as MLCCs, chip resistors and other semiconductor devices. And the manufacturing industry is now seeing price increases and greatly extended lead times. It seems the situation is likely to get rapidly worse rather than better. What can we do? Read on.

RTW NEPCON South China: Mycronic Discusses Industry 4.0

09/12/2018 | Real Time With... NEPCON South China
At the recent NEPCON South China 2018 event in Shenzhen, Clemens Jargon, VP for Global Dispensing and Asia at Mycronic, discusses I-Connect007's Edy Yu the challenges that customers face on their journey towards Industry 4.0, and how Mycronic is addressing these issues. From jet printing to solder paste inspection, to pick-and-place, Jargon talks about their total solutions that aim to help customers take their production to the next level.

Whitepaper: Electronics Cleanliness Testing

09/11/2018 | Jason Fullerton, Alpha Assembly Solutions
This paper investigates and compares the performance of no-clean liquid wave soldering fluxes using a commercially available localized extraction and cleanliness testing system, and surface insulation resistance (SIR) testing. Find out which test is suitable for your processes.



Copyright © 2018 I-Connect007. All rights reserved.