It seemed so simple.  We knew about the importance of keeping the mirrors and lens clean and had been diligently cleaning them all at least weekly.  So when the quality started deteriorating, I was sure that there had to be some other problem going on.

We had just finished cutting several sheets of acrylic for a couple of sign jobs and I decided to create some additional business cards.   We were using Leatherette sheets for the business cards, and I had run these before so all of the settings were saved and ready to go.  Being bold, I created a large group of cards covering most of the sheet.  However, when I ran the job, the engraving close to the left or the right side of the sheet was accurate, but the engraving toward the middle was very poor.    I thought maybe it was the sheet of Leatherette (sure, I know, it's easy to blame the raw material!).   So I went back to cutting some more acrylic, but now the same issues arose - the cuts toward the edges were clean and complete in one pass where the cuts toward the middle began taking 3 or even 4 passes.  

So now that I knew it wasn't the raw materials' fault, it appeared that something must be wrong with the laser.  Was the calibration suddenly off?  Something more dire?  So I submitted a tech support request directly with Epilog.   

They responded almost immediately and requested that I send them pictures of the mirrors and lens.   At first I thought "I just cleaned those a day or so ago...it CAN'T be the mirrors or lens".   I also (mistakenly) thought that if the mirrors were dirty, wouldn't the engraving be poor over all areas of the sheet?  But I shut down the machine and pulled the main mirror and lens to take their picture and show that they were just fine...

That is when I realized just how wrong I was.  Both the main mirror and lens were filthy with the dust and dirt from the extensive acrylic cutting we had been doing, even though they had both been cleaned a few days earlier.   The pictures below show the before and after cleaning.   After they were cleaned, "magically" the engraving and cutting went back to working just fine!   

Lens Before and After

Mirror Before and After

Lesson Learned:  Always check the mirrors and lens and make sure that they stay clean.   We've learned to especially check them after large glassware orders or heavy cutting (acrylic or wood).