Foreign material or FM can be loosely defined as something that’s not supposed to be present or part of the base material that’s being produced. The fact is that foreign material is always present in everything that is produced, no matter how much we wish that it wasn’t or how strictly we word our engineering drawings. It will be there so the key issue, twin issues actually, are how much is allowable and what exactly is the composition of the FM.
In the photo above its pretty clear that the allowable ppm of foreign material as well as the maximum size of the particulate has been exceeded. That’s what can happen when a couple of guys are tinkering with ink pump hoses that are under pressure. We know what the ‘foreign material’ is however. It is solvent safe water based black ink, approved for indirect food contact under FDA regs. Is it a health hazard? Not according to the MSDS sheet. Does it pose some disturbing cosmetic issues for those who might encounter these two yahoos? I would say the answer there is yes. So we have a known substance that is relatively inert, but just doesn’t look that great. Coincidentally, we had the same issue with some laser face stock from one of our suppliers. It opened up a large can of worms in regard to what it actually was, how much was allowable, and the perception of how it looked on a package.
In November of 2010 we began to see large (some half the size of a fingernail) spots on one of the paper laser sheets that’s qualified and validated at a number of our device customers for labeling terminally sterilized medical device packages. The paper industry has not been exempt from the go faster/make it cheaper pressures of the marketplace and we suspect that increased machine speed and less inspection might be the culprit. We discovered that the foreign material was calcium carbonate (which would actually make it parent material by definition) used in the paper making process. It’s a naturally occurring mineral and is commonly used, among other things, as a calcium supplement in diets and a key ingredient in antacids. Basically, people can eat it. Unfortunately, these specks had a rust colored hue, a color that looked very similar to dried blood. Our supplier had no interest in attempting to correct the issue since medical device usage is the proverbial flea on the elephants butt of total laser paper usage. We were sent a letter informing us that our vendor would no longer support our medical device application in early May of 2010. We informed our device customers and the gnashing of teeth and over thinking of the issue began in earnest.
The perfect solution would be not to have any at all. Unfortunately, a line on a drawing or print that says “There shall be no foreign material present on the printed side or adhesive side of the label” does not make the FM go away or even scares it a little bit. For example, neither you nor I want insect and rodent parts or mouse dung in our bread. Yet the FDA, those same guys that regulate our industry, have an allowable ppm for those very substances in flour. I worked in a bakery during part of college and one of my jobs before the inspectors came through was to thoroughly clean the dough mixer and vacuum up all flour bug tracks underneath it. At times it looked like Grand Central Station under there. So the real question becomes how much FM would be allowable?
Enter the venerable TAPPI chart. The most widely accepted particluate standards were developed in 2004 by Tyvek and film converters. Some of you may remember the 1073B Tyvek recall in 2001, when black FM from deteriorated brushes in the Tyvek production line in Richmond broke off and became embedded in the sheet. Many device manufacturers had standards before that and an ASTM group headed by some J&J folks attempted to come up with a standard but it never came to fruition. The current most commonly accepted working standard combines both embedded and loose FM with a maximum allowable size and maximum particulate count for smaller sizes. It addresses both parent material, components of the actual structure itself, whether it be Tyvek, film, or paper, and foreign material that is not part of the manufacturing process. If you sent him a nice email, Mr. Curtis Larsen of Spartan Design Group might send you a copy of some work that he did on FM on various substrates. Just don’t mention this years MSU basketball team. The other key part of FM evaluation is that the parts need to be examined at 18″ with the unaided human eye for two seconds. Poring over a label or lid for 20 seconds with a 6x magnifying loop is definitely not the accepted procedure.
The FM in the laser sheet face stock issue is still unresolved. Qualification and validation of the alternative cleaner, more bright white materials is crawling along at glacial speed at exactly 100% of our customers. However the main thing that dealing with the medical device industry has taught me is patience. One of my MedDev buddies, an engineer at a large device manufacturer, counseled me, “Olson, you gotta be patient. If the FDA regulated the auto industry your car would not have an electronic ignition and it wouldn’t even have points and a condenser. You’d have a magneto because magnetos are historically proven to be reliable”. It is the same with implementing the commonly accepted FM standards. 2004 to now is a mere blink in both geological and medical device time. I would encourage medical device companies to at least lurch forward toward adopting a practical and workable FM standard