Reasons for printer FEP Failures

[The Fatadder]

I am having issues with the FEP on my printer,  I am getting marks white marks on the FEP as per below (this was the last time it happened earlier in the year). This time the marks on the FEP are more pronounced.   I use red resin (the marks are clear), soaking in IPA and trying to scrape off with the scraper it wouldnt shift (it feels more like the FEP has stretched).   Any thoughts as to what is going wrong?

I am going to switch the FEP to a spare, but I would really like to try and get an idea as to what is going wrong in order that I can stop wasting money on new FEPs... 

 

When printing after this has happened, I end up with print errors for example last night I printed the SSA and the supports didnt print for the middle square inch corisponding with the worst of the damage.

 

[stevel]

34 minutes ago, The Fatadder said:

I am having issues with the FEP on my printer,  I am getting marks white marks on the FEP as per below (this was the last time it happened earlier in the year). This time the marks on the FEP are more pronounced.   I use red resin (the marks are clear), soaking in IPA and trying to scrape off with the scraper it wouldnt shift (it feels more like the FEP has stretched).   Any thoughts as to what is going wrong?

I am going to switch the FEP to a spare, but I would really like to try and get an idea as to what is going wrong in order that I can stop wasting money on new FEPs... 

 

When printing after this has happened, I end up with print errors for example last night I printed the SSA and the supports didnt print for the middle square inch corisponding with the worst of the damage.

 

When you run your finger over the surface can you feel a raised surface. I had something very similar, was able to free it by pressing from the underside of the FEP, after exposure in the UV chamber, for a minute.

[The Fatadder]

It’s a little hard to tell wearing a glove, but i think so.   I am doing one last print tonight that I desperately need (arranging the small items for my class 66 around the edges of the build plate where there are no issues). 
I wish I’d saved the last old fep to test I with…

I assume it needs to be absolutely spotless first to avoid issues, (and to separate the feb from the tank when curing)

[monkeysarefun]

Are you using an implement to remove stuck items from the FEP or to wipe out the resin?

[The Fatadder]

11 minutes ago, monkeysarefun said:

Are you using an implement to remove stuck items from the FEP or to wipe out the resin?

I’ve never had any issue with stuff getting stuck on the fep.  At least I don’t think I have.  I tried scraping it with the scraper that came with the machine.  

[stevel]

Try adding a little resin to the Vat, just enough to cover the surface, and then expose it for 30 or more seconds.

this will give you a solid that can be removed, with a light pressure too the underside of the FEP.

there are some videos on YT showing this.