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Witnessed in the field - A crowd developed around the
machine at the end of a long service call, everyone
wanting to hear first hand the elusive results of a long
standing and expensive service call.
How could a loose wire fifteen feet up on a
tool clamp switch damage an expensive thread hobbing tool
insert once every 4 to 8 hours?
The final service results found the thread hobbing operation
on the machining center created a sustained heavy vibration,
this vibration intermittently caused a
switch signal up on the tool changer to open, which was
erroneously interpreted by the ladder sequence to command a
quick jump in the spindle rpm, which would chip off a tooth of the
expensive hobbing tool. The same unexpected jump in
spindle rpm also created a sharp vibration that
would shake the machine harder and re-seat the loose switch wire for another 4
to 8 hours.
I have spent twenty years solving tough service
problems at thousands of the best machine shops in
North America. On the job, we apply a set of
standard techniques to solve complex service
problems. In my book I review these techniques.
Use these basic guidelines to evaluate the results of your
visiting service people; before signing-off on their next
service report.
Good luck, everyone deserves top
service for machine tools.
Dan Nelson
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