Page 19 - MetalForming June 2015

offering knowledge that failures will be minimized or elimi- nated.
Actual stamping tri-
als involve much more
than just filling the application system
with a new lubricant
and running parts. Do
not gauge success
upon a proposed lubricant making or
not making the part. Determine and moni-
tor preliminary met-
rics prior to the test,
and during the new- lubricant test. Parts
made with the current lubricant must be gathered, marked and
set aside for later comparison.
What is the die-maintenance sched- ule for the chosen tool that will run the test lubricant? Has it recently been serviced, or is it near the end of its nor- mal production run? This factor alone can determine the success or failure of a lubricant trial. The volume and frequency of lubricant application must be known prior to the test, so that dur- ing the lubricant trial, if the volume can be reduced, or the frequency extended, cost savings can be ascer- tained. Just as importantly, know if the volume must be increased or the fre- quency reduced, as this results in addi- tional cost, and possibly additional residue or other issues in cleaning and welding.
With a lubricant trial underway, compare the actual parts produced via the previous lubricant to the new-lubri- cant parts coming off of the press. Is there a visible difference between the parts? Have burrs appeared or disap- peared? Are the formed areas more or less shiny? Have cracks developed or now become unnoticeable?
The successful stamping of parts represents just the first step in a pos- itive lubricant trial. Parts must be moved to subsequent operations and monitored. During welding, is there
washed prior to welding, to a cleaner synthetic lubricant where parts can go directly to welding without washing, an entire process step has been removed and cost pulled out of the part. If the synthetic-lubri- cant purchase price is less, then it is a home run, but if it costs more per gallon, factor the costs of the washing step into total cost.
Lubricant Cost Goes Beyond Purchase Price
Know the difference between price and cost. A cheap, inex- pensive lubricant at first may seem the way to go, but addi- tional processes or steps may be required to use it. Actual run- ning ratios tell a better story.
There is the purchase price per gallon, and then there is the actual-use cost per gallon.
Be ready to do a bit more work than just spraying a new lubricant on a die to see if it will make the part. Do your homework. Due diligence, and data gathered, will help in making an edu- cated and informed decision that improves your operations, reduces overall costs and produces quality parts for your customers. MF
Commonly used in lubricant trials, the twist compression test uses a rotating tool-steel cylinder and a material coupon, along with a hydraulic force, to measure friction and provide a lubricant compari- son. Pressures and speeds can be adjusted to mimic the stamping process.
less or more smoke? Are the welds equally as strong or weaker? Do the parts clean easier, or are they more difficult to clean, requiring more time or a higher wash temperature? Is the residue acceptable after 24 hr. com- pared to the previous lubricant?
While the purchase price of the lubricants is one factor to compare, the entire process flow truly determines overall lubricant costs. If switching from a soluble oil where parts must be
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