[tinwhiskers] Has Toyoda transitioned to lead free manufacturing?

  • From: "Bob Landman" <rlandman@xxxxxxxxxxxxxxxxx>
  • To: <tinwhiskers@xxxxxxxxxxxxx>, "'\(Leadfree Electronics Assembly Forum\)'" <Leadfree@xxxxxxx>
  • Date: Wed, 3 Mar 2010 12:05:43 -0500

The question has been asked - is there evidence that Toyota has gone lead-free? 
I found this discussion on SMTNET that discusses the topic
(we aren't the only ones debating this subject)


Toyota developed their own lead free alloy

Quote" Several engineers are readying the Toyota recall press daily to see 
whether Toyota - an early adapter of lead-free solder - is the first casualty." 

Quote "January 2001, we inaugurated our own company-wide lead free project, 
starting activities and efforts to eliminate lead thoroughly" unquote

Transforming Compliance into a Competitive Strategy


Here's the details on their solder:

"A highly reliable Sn-Ag-Bi-In-Cu lead-free solder alloy was developed by 
improving the melting property, the wettability and the mechanical property of 
the Sn-Ag solder alloy which has a high thermal fatigue resistance due to the 
addition of bismuth, indium and copper. The optimum alloy composition for the 
Sn matrix is 2.5-3.0mass%Ag, 3.0mass%Bi, 1.0mass%In and 0.2-0.5mass%Cu. The 
additional elemental bismuth contributed to the control of the solidus and 
liquidus temperatures and the improvement of the wettability and tensile 
strength. Indium contributed to the control of the solidus and liquidus 
temperatures and the improvement of wettability. Copper contributed to the 
improvement of the ductility which is degraded by the addition of bismuth. In 
comparison with the Sn-3.5Ag eutectic solder, this new lead-free solder alloy 
has a 19.DEG.C. lower solidus temperature, 6-7.DEG.C. lower liquidus 
temperature, 4% higher spreading factor and 200% higher tensile strength. Its 
elongation is equal to and above Sn-3.5Ag at 125.DEG.C. though it is half as 
long as that of Sn-3.5Ag at 25.DEG.C.. It was confirmed that this new lead-free 
solder joint has a high thermal fatigue resistance and the same electrochemical 
reliability in comparison with the conventional Sn-37Pb solder joint. (author 

I found the following report on their corporate website which is not clear 
about the percentage of products which are lead free.  Of course, the 
components we all buy, are mostly lead-free tin plated.

"Under the European Union's end-of-life vehicle (ELV) directive*, the use of 
lead, mercury, cadmium and hexavalent
chromium will be banned from all vehicles sold in Europe starting from July 
2003. In response to the ELV directive, Toyota
Industries' Product Technology Subcommittee has established objectives aimed at 
reducing the company's reliance on
substances of concern in all of its business activities including its 
non-vehicle related businesses.
During FY 2002, Toyota Industries made changes to the design of parts that 
previously contained lead, cadmium or
hexavalent chromium and switched to using alternative chemical substances. 
Toyota Industries also asked its suppliers to
submit data regarding the inclusion and quantity of banned substances in 
materials and parts supplied to the company,
and also requested that its suppliers submit plans for eventually phasing out 
the use of banned substances. In addition,
Toyota Industries revised its in-house guidelines for substances of concern to 
reflect the policy of banning certain
designated chemical substances."

"Lead-Free Circuit Boards

Lead contained in solder used in circuit boards has been
noted for polluting the environment when it is not properly
disposed of. Consequently, Toyota Industries is trying to
switch to lead-free solder in its circuit boards for its industrial
machinery, automobiles and textile machinery products.
When designing circuit boards with lead-free solder,
Toyota Industries had to overcome various issues such as the
high melting point of lead-free solder, which made it difficult
to control soldering temperatures while ensuring that parts
could stand the heat. However, Toyota Industries was
successful in overcoming these issues and in January 2003
began producing lead-free circuit boards for use in the
displays for one of its electric reach truck models."


Bob Landman
H&L Instruments, LLC

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