Form 3 raft over-adhesion to build platform problem


#1

To preface things, I am a near-daily user of multiple Form 2 printers for a few years.

I just got my first Form 3 and am having a problem with extreme raft adhesion to the build platform. I have tried clipping it, chiseling it, soaked it in IPA, and still, the rafts are stuck on the platform.

I have had stuck prints with my Form 2 printers in the past but NOTHING like this, I fear it has completely ruined the platform. What suggestions do people have for getting these rafts to stick less to the build platform? I prefer the full rafts as they have identifiers for my prints which help. Do I have to switch to no rafts to change my Z compression? If so, what Z compression values have you found that worked best?

Any help is appreciated. Thank you!


#2

The printer’s initial Z compression may need to be adjusted. I am not having any problems with my Form3.

However, I use an “insulation knife” to get my prints off the build platform. It’s a 12" long thin, hardened steel knife intended for cutting rolls of fiberglass insulation. But because it’s a thin/stiff steel blade, it gets under the edges of prints much better than the Formlabs tool. And once the edge of the blade is under the edge of a print, twisting the blade gently works the print loose without requiring you to really lean on the knife.

I need to be really extra careful of course, because the knife could easily remove a finger or two. But I’ve been using this as my preferred removal tool for a few years now with no mishaps so it can be done safely… (famous last words).


#3

Thank you for the suggestion, I am looking into these now. I have always used the FormLabs tools to get prints off my Form 2, so having to use something else is new to me. It sounds problematic though if we need to use dangerous tools just to get the prints off the build platform. They really need to work on this.

Stay safe my friend!


#4

Consider sending a ticket to Support asking for a way to adjust adhesion (equivalent to the “Z-Offset Fine Tuning” in the Form 2). I have the same complaint of direct-on-base prints that are just way too hard to get off my 3L platform and they logged it in their feature request queue, but unless more people ask for it I doubt it’ll see the light of day.


#5

Hi there. I’m afraid I don’t have an answer for you but we’ve just experienced this exact same phenomenon on our first print with the Form 3B. It’s hard to find any results in a search as most complaints are a lack of adhesion rather than stuck-so-well-it-breaks-when-you-pry-it-off.


#6

I have found on both the F2 and F3 that prying the parts off is a pain. I use the supplied scraper and hit the rafts hard, breaking the bond between the platform and raft.

With the F2, I was always careful to keep the supports as intact as possible. The internal stresses would warp the parts I make pretty consistently. This is far less of an issue with the F3, and many times I will remove the supports before the final cure.


#7

I use a #17 narrow chisel blade made by X-Acto with the tapered (chisel) edge contacting the platform. The Formlabs-provided chisel is too thick for my applications. I only print parts with mini rafts.

Rarely do parts stick resulting in damage. I also keep the tip diameter of the supports at 0.10 mm whenever possible. If the raft breaks, it releases from the part to prevent damage. Occasionally, I’ll wipe the entire platform, including sides, with 99% IPA and let air dry in the printer before the next build. So far, so good.


#8

And I use a 12" insulation knife for the same reason. I prefer it over my Xactos because it’s a much stronger/stiffer tool. Though it is quite a bit more dangerous, you have to be quadruply careful. But once the edge of the blade gets under the lip of the print, twisting the blade is often enough to pry the print loose. If it’s not, the prying is enough to lift some of the base up, allowing the knife blade to get further in and I pry again. I rarely if ever leave material behind on the build platform, even with prints that almost needed a jackhammer to pry off… Once or twice, though, I have to admit, I’ve sent the part flying across the room when I popped it off. Luckily, the resin fluoresces under UV, so if you’re quick with a black light you can find and wipe up all the spots the part hit as it bounced off the walls and other fixtures.


#9

I wanted to update this with some info I have received from FormLabs. I figured the community might be interested in hearing some possible solutions to this that I had received from the company.

After speaking with FormLabs a bit here are a few recommendations they gave me to remedy the issue:

> If you are still having difficulty removing this part from the build platform, here are a few tips that might help:
> Warm the build platform with a hairdryer or heat gun.
> Freeze the build platform.
> Position the flat face of the flush cutters against the build platform, with the blades on either side of a corner of the part. Squeeze the handle to force the blades between the part and the build platform.
> Spray a small amount of solvent around the edges of parts.
> It looks like _____ has also ordered a replacement build platform, hopefully, this will help solve the issue. Once you receive it, one thing you can try is to buff the new build platform with fine grit sandpaper if you have it. This can help with parts over adhering to the build platform sometimes.

I opted to just sand my new build platform as freezing/heating it after every print didn’t sound like a good solution in a production environment. The “flush cutters” worked some on the first platform but did fail to remove several spots as well.

The bottom line is sanding the platform worked wonders! The prints came off much easier, similar to what I am used to from years with the Form 2.

I used 320 grit wet/dry sandpaper, but it is almost too smooth and would probably use 240 for a perfect balance if I had to do it again. My process used some water and a very light touch to gently treat the surface of my new build platform (referred to as BP from here). I measured the height of the new BP in several spots before sanding and found that it was on average 35mm thick (as low as 34.98 and up to 35.02, so a tolerance of .02mm). After some very gentle sanding, I measured again and found I had reduced it by approx. 0.1 to 0.2mm.

The surface of my new BP was quite smooth, and I think the 240 grit would have been the sweet spot. But the prints came right off and I was very pleased with the results. This was a great solution to my issue and I would recommend this to anyone having a problem with over-adhesion of their rafts to a BP.

Thank you all for your suggestions and feedback,I greatly appreciate it!


#10

@JourneyDental thanks for passing that on. I knew sanding could be used to fix poor adhesion, didn’t know it could help with over-adhesion as well.

Did sanding reduce the amount of aluminum dust that comes off the new BP? I’ve noticed my 3L platform in particular has a fair bit of particulate coming off it - especially after it sits for a while with Rigid resin on it. When I clean it with alcohol I get silvery discoloration on every wipe, and a large print I did (with a surface covering 60%+ of the BP) actually had what looks like veins of aluminum dust embedded in streaks in the first several layers.


#11

@rkagerer very interesting, I have not had an issue with aluminum dust particulate in my resin or prints. I did not have that problem before sanding but double-checked and none was present after sanding either. I did wash my platform several times after sanding with IPA just to be sure.

I wonder if that might be a problem with the 3L build platform? I’ve not experienced that with any of my BPs for the Form2/3.


#12

I too have had this issue.
The scrapers supplied with the Form3 are too blunt and rounded.
My solution was to go get my very, very sharp wood chisel 1" wide.
I don’t “chisel” in the traditional sense like I would with wood, BUT, I merely use the so-very-sharp edge to get under the raft only so slightly and use the bevel of the chisel to pry.
This has worked very successfully where I am lifting a very little bit at a time.
I have to go around the raft and usually by about the 3rd or 4th pry the raft pops.
I avoid trying to run the chisel fully under in one or 2 pushes. This only scratches the surface of the build plate and makes my push go wildly off in a wrong direction which is a dangerous activity with my sharp wood chisel.
(you may be tempted to use the very sharp 1" chisel to chop horizontally through the supports - trust me, this is not worth it. Just made a mess of it and the raft was still holding my part.) So try the pry with a super sharp chisel.