Quantifying Lubricant Thickness Accurately

Guest Blog: Mike Justice
President, UPA Technology

Forming good parts is a demanding and difficult task, mainly because of the many variables that can interrupt the process. Stamping problems can be due to several areas including problems with dies, substrates, press issues as well as incorrect amounts of lubricant. Quickly evaluating and eliminating the possible causes of stamping problems speeds up correction at the press where downtime often is measured by minutes/month.

Quantifying lubricant thickness quickly and accurately can determine or eliminate whether lubricant issues are the cause of forming issues. But, measuring lubricant thickness has not been easy and has been the cause of much discussion and dissension.  

Stampers, processors and mills are routinely tasked with accurately measuring oil-films ranging between 7-120 Milligrams per square foot (mg/ft2) in order to meet specification for making good parts.  As a thickness instead of a weight, this equates to only 2 - 40 millionths of an inch! Making things even more challenging is that measurements have to be made instantly, portably, on a number of different substrates, and the inspection equipment must be easy to operate with virtually no training. In reality, this is but one of the many difficult challenges facing the stamping industry, metals mills and coil processors.    
 
Lubricant thickness has been determined for many years from weighing a sample, cleaning off the lubricant and then re-weighing (weigh/strip /weigh). The average thickness of lubricant can then be calculated from those numbers. Mills and automotive plants have used this method because of the availability of extremely accurate scales/balances, but the weigh/strip/weigh method is not without issues. The weight difference between coated and uncoated samples can be less than .008 grams. Adding all of the uncertainties resulting from imperfect sample size, scale error, uneven lube distribution and improper handling normally reduces the accuracy to below acceptable limits. Plus, the weigh/strip/weigh method is destructive, slow and untraceable to any national standard.

Fortunately, advancements in electronics technology are occurring rapidly and many promising new technologies have been introduced. This is good news and just in time for measuring at the tightened lubricant-thickness specification requirements that have increasingly become difficult to confirm and control.

New measurement devices are primarily using infra-red, beta backscatter or ultra-violet principles for oil-film measurement. Each of these new technologies have their strengths and weaknesses, so choosing the best one will depend on any number of factors, depending on the specific conditions.  Choosing the wrong method can be an expensive mistake, so doing some homework beforehand is worth the effort. Gone are the days when companies can say “I will use this method—because my customer uses it.”  Having both companies using an incorrect method

doesn’t help anyone, so the best choice of instrumentation should be based on facts and careful evaluation.

Hear more from Mike at PMA's Metal Stamping Technology and Tool & Die Conference, December 6-7, 2016 in Chicago, IL.

Comments

Post a Comment

Popular posts from this blog

PMA and MetalForming Magazine Conference on ERP Software

Image
ERP software is changing the way companies do business.  ERP, enterprise-resource-planning, programs compile all of a company's data and processes into one system, an effort that saves time and money. Interested in learning more about how your business could benefit from ERP software?  Check out the PMA and MetalForming Magazine event on the technology in a few months in Cincinnati.  Read more in the press release below. PMA and MetalForming Magazine to Hold Conference on the Latest Developments in ERP Software     CLEVELAND, OH—July 23, 2013—The Precision Metalforming Association’s (PMA) flagship publication, MetalForming magazine, announces The Manufacturing ERP Experience, a conference that will provide information on the industry’s leading enterprise-resource-planning (ERP) software systems for small to midsized manufacturing companies.  The event is scheduled for October 8-9, 2013, in Cincinnati, Ohio. Modern ERP systems have changed how companies do business.
Read more

Annual Automotive Conference Moved to Virtual Format For 2020

Image
Due to the ongoing COVID-19 pandemic, PMA is announcing today that the in-person 2020 Automotive Parts Suppliers Conference , originally scheduled to take place September 1-2 in Detroit, MI has been moved to a virtual only event on the same dates. This was not an easy decision, but, ultimately, the health and safety of our attendees, exhibitors, sponsors, speakers and staff is our highest priority.  While we look forward to a time when we can be together again face-to-face, the PMA team has been working hard behind the scenes to transition this event and deliver tremendous automotive content and information that our industry needs. Registration for the virtual event is open, and you can view the updated agenda here and list of speakers here .  We look forward to seeing you virtually in September. 
Read more

New Steel Tariffs on Brazil and Argentina?

President Trump announced via tweet on Monday that he was imposing tariffs on steel and aluminum imports from Brazil and Argentina due to both governments devaluating their currencies. These two countries previously had reached a deal with the Trump administration to avoid Section 232 steel and aluminum tariffs by agreeing to quotas. Both Argentina and Brazil were exempted from the 232 steel and aluminum tariffs in May 2018. The tariffs can’t be “restored” because the two countries were not subject to tariffs in the first place. The exemptions for both countries required Presidential Proclamations, and to change the quotas to tariffs would require new proclamations as tariffs can’t be re-imposed by a tweet. At this writing, we are still awaiting these proclamations. If the President does move forward with these tariffs, it would likely lead to an immediate legal challenge. A current U.S. Court of International Trade case (Transpacific Steel v U.S.) is focused on this exact issue of
Read more