Hello, I have not purchased a Form2 printer yet, but am close to making a decision. If my model is a flat piece with no overhangs (think of something that could be easily created on a 3 axis mill from one side), can I successfully print directly to the platform without angling the model, and with no supports? For my uses, this would save a lot on print time and materials.
Yes, you can print directly onto the build platform, without any supports.
\There are a couple of things you need to consider though. The first few layers a re pretty compressed, and depending on your current set up (the print platform height), the height dimensional accuracy will be affected.
I found that based on my settings, I had to add .8mm to the bottom of the model to make up for that compression. You can print a small item of know height (at least 60-70 layers (6-7mm), then measure the thickness. Whatever your measurement is, that is the amount of over compression that you need to account for.
Another thing to consider is ease of removal off the platform. The raft/base that preform creates has an outward draft/bevel that makes it easy to put a spatula under an pop the model off. You will probably not have that, so I came up with 2 possible options. Use a very sharp blade to remove the model without damage, or build a small “bump” into your model, with the outward bevel (similar to the bumps that Preform automatically builds into the support base. This way, you can put the spatula under it, pop it of, then you can cut or sand off the bump.
I have printed washers directly to the build plate successfully . My 1.5 OD x 1.0 ID x .125 thick washer came out approximately .100 inch thick. I did put a beveled edge on the OD to help removal. I could design a correction factor if that was necessary but it wasn’t. I did notice that first few layers on the ID had a slight flare in wards, like mold flash.
Another consideration is stair stepping in the Z direction. If your models have a lot of curvature the stepping will be most pronounced building flat. It is much better than on an FDM machine but it will still be there.
I haven’t tried with the Form2 yet but with the Form 1+ the first 5mm or so of the print is not only over compressed it’s over cured. The over cure causes dimensional changes in X and Y as well. This can be a problem if you’re printing mold/casting cavities flat on the platform.
I’ve been printing with the supports even with prints that could be printed on the base. This allows you to rotate the part in a way that gets the best surface finish in certain areas (place important areas vertical). This costs print time but will give the best results.