FAX TRANSMISSION
To:Tom Harada
Equipment Division #2
Kamigo Engine Plant

Re:

From: Bob Sanders
Date: Thursday, June 13, 1989

Follow Up Data Analysis (Fax 7)

Mr. Harada
You are right! This is not a simple skills problem as I mistakenly thought. I
looked at the data from TMM and Kamigo and realized that the typical callfor help from an assembly line is indeed to repair some type of sensor orswitch. However as we discussed the average time to make the repair inJapan is under 10 minutes for this type of problem versus over 20 minutes
here at TMM.
The data alone could not tell me the answer so I decided to follow “GenchiGenbutsu” as you suggested. I followed about 10 different relevant
maintenance calls to final assembly over the past 3 days for closer
investigation. Here is a short summary of what the typical repair process
looks like on average (Refer to attachment Comparison of Repair Sequence).
All the cases I observed were remarkably similar so I do not think I am
leaving anything significant out.
As you can see from the chart the difference is all explained by two areas ofaction A) the time it takes to diagnose the actual problem and B) the time ittakes to get a spare part. I anticipated your next question (Why does it takeso much longer?) and here is what I found on the two issues.
A. Why it takes longer to diagnose the problem.
There are three different factors that I found out
1. The electrical schematic drawings in the control panel do not matchthe actual circuits in the machine. Why? Upon installation various

circuits get added and changed and these are not reflected in the paper
drawings in the control panel.
2. The standard electrical symbols used in the schematics for items like alimit switch are different in Toyota versus the U.S. In total I foundover a dozen minor differences. Here is an example of just one.
Limit Switch Symbol
ToyotaU.S.

People are getting used to the new symbols but it is like having to readtwo languages on the drawings. This was a big problem initially andstill a considerable hindrance.

3. There are phrases either mistranslated or not translated at all in theschematic prints!
Mistranslation example:

What is written - Cylinder up end
What is meant - Cylinder advanced

Non-translated example:

ｼﾘﾝﾀﾞ後退端 - (Cylinder retracted)

The combination of these three items is very confusing to say the least
to the maintenance people doing the repair. I am surprised that therepairs are not even taking longer than they are.

B. Why is it taking so long to find the right spare parts?
Here again I can find three different reasons why it takes so long.
1. All parts are stored by a machine number that relates to an actual
location on the assembly line. There are 50 different sections to theassembly line and hence machine numbers. Spare part items likeswitches are common through out the line so we did not order themfor every section of the line on purpose to save money. But thismeans it is hard to find the common items as they are only stored insome machine number locations in the store but not others! This ismerely a problem of organization as common parts should not be
stored by machine number at all. This is 90% of the search problem I
am convinced and why it just looks like we are “missing” some spareparts.
2. However, I did check all the limit switch parts in the store for goodmeasure. There are over 17 types of basic limit switches used on theconveyor line between the U.S. and Japanese equipment! This seems
like too many but I have no basis for comparison. It take time to lookthrough the 17 types and takes additional minutes to find the right one
at times in the store room.
3. Some “wrong” limit switch spare parts are also in the store. I checked
the detail part specification by which we ordered the switch and theylook very close but have one digit missing or mistaken. For example:
LS-1734ZZTS-OP
LS-152522TS-ED

This is OK
This is no good. We don’t use thistype at all.

What I think happened is that when we faxed the spare parts list overso that TMM could order spare parts before launch some items got
fuzzy and hard to read. The latter example probably should be type
“ZZ” in the middle instead of “22” as this is a different style of switch
completely. The text was either written wrong into the purchase orderor mistaken when sent to the distributor in the U.S. for order.

I would like to discuss with you what to do during my last week here atTMM. I am happy to extend my trip if needed.

Regards,Bob Sanders