Plastic tab on underside of wiper scratching pdms

I noticed a small plastic tab protruding from the underside of the wiper blade. Its indeed leaving a long scratch from across the middle of my pdms Is this intentional or some weird underhanded way Formlabs gets you to replace your vat faster?

I haven’t experience a problem with this, but at least one other person (@Nicolas_Rozet) has voiced their opinion about this issue.

You wanna look at the underside of your wiper arm and double check. As you can see from the pictures its clearly an issue. I’m not making it up. I have no clue why this tab is here in the first place. I clipped it down with some wire snips so it doesn’t continue to scratch the pdms as seen above.

It looks like the wiper surface needs to rotate 180 on the holder? take the wiper apart and flip the wiper.

@mlabird it came like this from the factory. Rotate vertically or horizontal? The wiper blade works as it should it just has this small plastic tab protruding down beyond the leading edge of the blade.

OK, after closer inspection of my wipers they have the same small tab protruding down below the level of the wiper. I have not noticed this before but have used many trays up and never noticed it to be a problem. One thing that I always do is pour a small amount of resin directly into the tank to cover the bottom of the tank when they are new. this does seem to limit the scratching on the PDMS layer from the wiper rubbing over a dry tray.
Mike A

Yeah double check that pdms from left to right and you will see the tab is scratching it. Why wouldn’t it. I’m still trying to rap my head around why its there or if it was just a defect in the original mold that never got remedied.

That nub is normal, but it’s meant to be trimmed flush as to keep it from damaging the PDMS. I’ve forwarded this to our manufacturing team so that we can look into what’s causing this. If this has damaged your tank, get in touch with our support team so that we can work towards a solution.

Edit: I made a mistake in my earlier reply. That nub is normal and it’s designed to help with resin distribution. The mark yours is leaving seems a bit more pronounced than usual, but we’ve run tests to verify that this doesn’t affect print quality. If you are running into print issues that seem to be caused by the nub, get in touch with our team so that we can troubleshoot.

I’d recommend against cutting this away as it could inadvertently sharpen the nub which would be more likely to cause issue.

Thanks @Frew I did last week and they are sending a vat and new liter of resin for some other issues Im experiencing. I snipped the tab off but think this is something that should be made aware of with end users and your manufacturing. Its a simple enough fix.

Yeah, thanks for letting us know. Reports like these are helpful in identifying issues in the field so that our teams can work towards solutions.

@tonberryhunter See edit

I trimmed it far enough up so its a good distance from the PDMS. I’m wondering how this would assist in resin distribution? I have new vats and resin coming in the mail either way. My prints started failing before I trimmed the nub. Another user told me the new LT Vat and wiper dont have this nub.

The nub elevates a portion of the wiper which improves distribution. So long as it’s trimmed above the bottom most portion of the wiper, there shouldn’t be much risk of scratching the tank.

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