Embedded Components from Concept-To-Manufacturing
Copper Foil Elements Affecting Transmission Loss with High Speed Circuits
pH neutral Cleaning Agents - Market Expectation & Field Performance
Reducing Dust Deposition on Electronic Equipment
New Requirements for Sir Measurement
Effects of Mixing Solder Sphere Alloys with Bismuth-Based Pastes
The Development of a 0.3 mm Pitch CSP Assembly Process
Generalizations About Component Flatness at Elevated Temperature
Latest Industry News
iPhone 12 Production Could Be Delayed
Acer sees PC component shortages
Bio-Ink for 3-D Printing Inside the Body
Covid Seen Driving the Security Sector
U.S. Eases Restrictions on Private Remote-Sensing Satellites
EMS Manufacturing quote complexity drives OEMs to look behind EMS curtain
U.S. Manufacturing Rebounds to 14-Month High
IBM's New AI Tool Parses A Tidal Wave of Coronavirus Research

Solder Alloy Leads to Broken Glass

Solder Alloy Leads to Broken Glass
A manufacturer of defroster windows was breaking thousands of dollars of windows due to a soldering problem. What was causing a change in the solder alloy?
Mysteries of Science



Have you ever wonder how defroster windows work? Electrical current is applied to a heater pattern built right into the window. The electrical current heats up the strips that are typically configured as a set of thin dark lines made with metallic ceramic ink that has just the right resistance to heat up.

But how do you attach wires from the window to the vehicle's electrical system? The ink is made with enough metal powder to allow wire or metal connectors to be soldered to them.

One day the solder supplier got a call that something was wrong and they were breaking thousands of dollars' worth of windows every day. What could be going wrong?

Solder was applied to the connector tabs by dipping them into a molten solder bath and there wasn't much that could go wrong with that process.

Was there a change in the solder alloy? If the alloy changed, the assemblers might turn up the soldering iron settings or press harder when the solder doesn't melt within a few seconds.

But the soldering tools were not running hot and the solder alloy was right on target, so solder was not the culprit. But the auto manufacturer was sure that the solder was involved in some indirect way and here's why.

Every time the solder vendor went out to visit the plant, the yield went up dramatically and hardly any windows broke. But while the vendor was away, broken windows set new records.

Most everyone decided that it still had something to do with overheating of the glass, and maybe the workers were just extra careful when being watched.

So they tested a technique using conductive adhesive. The following week, samples were brought in and tests were started. The adhesive was more expensive than solder since it contained mostly silver power while the solder was made from tin and lead.

The vendor argued that the new process would cut labor costs and the higher materials cost was inconsequential. The vendor continued to make a case for this labor-saving breakthrough and pointed out that broker windows would drop to zero.

One of the workers, who was on break, was fascinated by the new technology since it looked like solder that soldered itself. So he asked questions until he had a good idea how it all worked.

He also recognized that he could be replaced since this process, if it worked, would need less than half as much labor as the old soldering iron method.

The following week, the yields went to 100% for the old soldering process. This wasn't a fluke because the same thing happened during the following week, and again on the 3rd week. So what's was going on?

Here's the rest of the story.

One engineer solved the mystery. The workers had a grievance that wasn't being handled too their liking, but it wasn't worth a strike. So they were cranking up the soldering irons and breaking windows. It may sound dumb, but this happened in the days when companies and workers acted like they hated each other.

But what fixed the problem? Once the line workers realized that conductive adhesive would fix the problem and probably get rid of a few workers, they decided to bring stop to their destructive tactics.


No comments have been submitted to date.

Submit A Comment

Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name

Your Company
Your E-mail

Your Country
Your Comments

Board Talk
Solder Paste Beyond The Shelf Life?
Issues With Fillets on Via Holes?
Can Tape Residue Contaminate a Clean Tank?
Suggested Stencil Wipe Frequency?
Reflow Oven Zone Separation Challenges
When To Use Adhesive To Bond SMT Components
How To Clean a Vintage Circuit Board Assembly?
PCBA Inspection Concerns
Ask the Experts
Lifted Lead on SOT Component
Allowable Bow and Twist on Round PC Fab
Mixed MSL Baking
Step Stencil Squeegee Angle
Solder Balling Splash After Reflow
Application Using No-Clean and Water Soluble Fluxes
IPC SOIC Defect Question
Mixed Process Solder Joint Appearance, Smooth or Grainy?