Hi everyone, I’m a new Form 2 owner. The world of SLA is completely foreign to me, and I have only done FDM for the past several years.
One thing I am having an immense problem with at the moment is removing the raft. Some of the time, I have to press so hard and then eventually break through (uncontrollably) and end up destroying the part or also neighboring parts. It’s really hard to get the included spatula under the removal tabs. I don’t see a way to change raft removal tab parameters, but it would be really nice if they changed them so there’s a better lead in for the spatula. Maybe an additional slight angle before it meets the build platform, or a radiused interface?
Nice video, @gdmccormack we also use the fine needle point tweezers as well to just get under the base and tilt it up to pop the part off the build plate
I use an Exacto knife with a chisel blade and it works really well, just be careful that you control your pressure because once it loosens if you are applying a lot of force it will go and fly off somewhere and you might damage the part.
I use a different scraper than FL provides in the finishing kit. It is thicker material and smaller contact edge. When my parts are large enough to have the removal tabs I can simply wedge one point under the hood and twist, otherwise I match the angle of the scraper and apply pressure until I can see the base release from the build plate, repeat on other edges until you can get the scraper under the part or it comes free.
Try a couple of methods and find what works for you. Chances are your best method will still require some force so always be mindful of where your hands are and where your tool will end up if your removal force suddenly translates into movement. I have split my tool hand open on the sharp edge of the build plate when a stubborn part finally released, that’s a one time mistake for sure. 0.o
I have written extensively on this in the past but will boil it down briefly.
We use a heavy scraper with a beveled edge but the tool is less important than build platform preparation.
After EACH print:
1 - Clean the aluminum with IPA and paper towels.
2 - Using a maroon scuff pad soaked with IPA, thoroughly scuff the aluminum surface.
3 - Repeat step 1.
4 - Using 150 abrasive paper, sand aluminum surface in a circular pattern. Make sure your final surface is very “silver” in color with no gray or black streaks.
5 - Repeat step 1 until your paper towel remains white (any aluminum dust will leave it gray).
6 - Make sure that no aluminum dust is left on the sides of the platform (the black plastic parts). If you do not do this the dust will contaminate the resin in your resin tray and you will have “metal flake” resin. I found this out the hard way…though it did not seem to hurt the prints…It can’t be good.
Do this after each print and you should have no trouble at all removing prints. They stick as they should during the print and pop off easily when you are ready to remove them from the platform.
At the moment, I just wash the surface with IPA and clean with paper towels, then do it again but use one of those lint-free wipes that came with the machine. I’ll keep your other surface prep tips in mind! The only thing I worry about is over time, causing an uneven surface due to uneven application of pressure.
I understand that concern but so far after prepping our build platforms as described (for dozens, if not hundreds, of prints) we have had no issues. I fold the abrasive sheet into about 4 or 5 folds thus you have some thickness and support so it is not just the unevenness of finger pressure, abrasive to aluminum, but you are presenting somewhat of a stiff backed abrasive pad to the aluminum. One could use a sanding block if they so desired, personally I don’t think that precaution is necessary. Very little metal is removed in this process.
If you have ever tried “sanding down” a piece of metal with a goal of removing even only a couple thousandths of an inch (measuring with a caliper as you go), you will realize how slowly metal is removed via abrasive sheet in that 150 grit range. I have done this in the past on various projects I worked on. If you care to experiment with a scrap piece of aluminum and some 150 paper, I think you would find it rather eye opening just how much “sanding” one must do to remove a measurable amount of material over a surface as large as the build platform. Granted if you were using 40 or 60 grit paper on aluminum the results would be different but 150 is not very aggressive using only hand sanding.
I have thought about your concerns before too and I feel that the only areas of the aluminum plate that might suffer from this process are the very edges of the plate and how often does a print go to the very edge of the plate ? For our prints, that answer is ,never.
small height differences shouldn’t be a big deal–the build platform doesn’t have a leveling calibration which means that it could be slightly not level with the bottom of the resin tray, that’s partly why the first layers have such long print times, because they increase the exposure to make sure that if it’s thicker than the layer setting that it will still cure fully and stick to the platform.
I do think it’s probably far overdoing it to sand the platform smooth after each print, in fact on the Form1+ I got better adhesion after the platform was scuffed up a bit from using the knife for part removal. And it’s really not difficult to pop off the prints and then wipe it clean afterwards.
Another vote for an X-acto knife with a chisel blade. I use the wider (#18?) blade in a #2 medium weight handle. It works wonderfully on small bases, and works well on larger bases.