Formlabs resin tray

I was just wondering why is there silicone in the formlabs resin trays? and why is it inside the tray rather than outside?

It keeps the cured resin from sticking.

The Silicone, or PDMS layer, enables each printed slice to peel away from the tray and remain adhered to the layer above it and the platform during the printing process. Not sure what you mean by on the outside of the tray?

sorry, I didn’t know what it was for so I was wondering why it had to be in the tray. Is there any way to replace the silicone rather than replacing the entire tray?

this question has been asked a few times already, I think I was first though:

the answer is yes - and you have a few options, the main two I’ve used are Sylgard 184, and Qsil 216 - you do have to be very careful both peeling out the old silicone and pouring in the new - any specks of dust in the base of the tray or in your new silicone will obviously affect all the prints from that tray.

I’ve read somewhere that the slygard wears out much faster than the formlabs PDMS. I’d still like to see a comparison of this.
I mean… If the slygard survives 3-7 prints in the B9C, it makes it quite a hassle and expensive as well to replace. I still have not clouded my original resin tanks that already have see 2 liter of resin mostly 50um layers.

@fantasy2 any chance you could tell us where you read this? I’ve replaced the silicone in dozens of resin vats myself and not noticed any difference in wear rate. The original post suggesting 3-7 prints was quoting a post on B9Creator forums and isn’t actually relevant to the FL machines.

I guess it’s possible there’s a difference in wear resistance - but given that sylgard and qsil are both platinum cure silicones, which is the more durable type - I would be quite surprised if there was any difference worthy of note.

Either somewhere here or on the B9C forum. It was in the same thread that discussed hardness of the slygard vs formlabs PDMS. If I find it again I’ll share it.

But in the silicone exchange do you have to configure the Z axis in F2?

not if you replace with same weight of silicone - it’s about 106g in the F2 tray - or you could weigh it yourself. It peels out easily as a single piece - I use a wooden skewer as an aid - running the point along the tray seams as I peel out old silicone.

Of course you also need a perfectly level surface for the tray while the new silicone cures as well.