Will it Print? Models that take up the entire build platform?

[tmarquis]

Hello, I have a mold part that I need to print. And because I want to maximize the number of parts I’m getting out of the mold I’m making the mold as big as the maximum printable area on the build platform. This makes me really nervous as I’ve never actually printed anything this large. Will it work? The model needs to be oriented parallel to the build platform as I can’t have any supports on the inside areas of the mold. Also, would you recommend printing directly on the build platform? (i understand that the first few layers might be compressed) I’m just not sure supports are needed given the flat surface? What are the advantages/disadvantages in this case?

Also, there are a good amount of cup warnings but I’ve been able to print successfully other variations of this model so I’m going to hope for the best for this one.

Mostly concerned with the size and to support or not to support.
The model will be printed in one of the tough resins on a Form 3.
Thanks so much!

[tmarquis]

So after some experimenting and placing supports by hand where needed I was able to get a preform green light to print. I’m still worried as this is my first print on a new Form 3. I have experience with a Form 2 but I have never printed across the entire build platform. Should I stop worrying and just hit the button?

[rybu]

The only criticism I have with that lay-out is the initial surface area might be a tad large. If you get a print failure, I would suggest putting it on a tiny angle. Like maybe just a 1-degree angle, to lower the surface area when the printer gets to your primary print object – i.e. past the supports.

If you have an early failure that would be my guess for the cause.

I have printed objects that take the entire build platform before. They have an increased risk of failure, but they seem to often work. IMO just hit the print button and see what happens. If you get a failure, try again with a slight angle.

[Randy_Cohen]

The back side of the print is going to look pretty rough. Printed flat to the build plate like that maximizes the peeling force applied to the model, which maximizes how hard the support touch points are getting tugged each peel, which maximizes the deformation around the touch points. It would print better if you angled it I think. You could reduce the “painted area” of each layer significantly if this was tilted at 45º along one axis.

[rkagerer]

I agree, for something like this I’d go direct-on-base or more much angled (even 25º would probably do if it’s a concern).

[tmarquis]

Really great suggestions. Thanks, everyone! I went ahead and tilted the part up a bit. Here are some shots. I only tilted it a few degrees so midway through it goes into a pull across the entire build plate. But i guess that’s ok because there is a solid foundation of layers below? I will let you know how it turns out!

[Randy_Cohen]

You want to tilt it more, so there’s less “painted area” in the middle layers. something closer to 30 or 40 degrees, not the ~10 or so you tilted it. This little tilt helps a little, but not nearly as much as if it was really tilted.

If you come to the Form from a FDM printer, you want to print stuff “flat” on the build plate. You have to unlearn that habit. The SLA printing process generally works best when the object is not even close to square to the build plate.

[tmarquis]

Well, it failed. What do you think contributed most to the failure? Not enough angle? To big a model (printing right to the edge of the build platform). Or a combination of both? You can see how it pulled away from the supports at the corners. And the bottom of the model. (where the supports attach) is pretty wavy and distorted. The top of the model (resin tank side) is perfect. How do I get the support side to be perfectly flat? Print on the build platform? I’m worried it will crack when I remove it.

Thoughts, Suggestions? Thanks in advance!
Tom

[tmarquis]

Yep the print failed. All kids of distortion happening on the support side. Going to try 35 or 45 degrees this time. Thanks!

[tmarquis]

Here is my new build. I had to put supports on the mold interior which sucks but the Form 3 seems to leave less of a mark.

[leonhart88]

Your initial print isn’t that much of a failure tbh.

From my experience printing this flat would probably work, but you would likely need to increase the support density on the first layer otherwise you’ll get a lot of distortion.

The support side will always be rougher in surface finish. If you printed flat, at least the top would be good and you could lap the bottom manually.

I would not print this directly on the build plate unless you solve the cupping issue. Cupping on this part is likely to break your tank.

[tmarquis]

Sorry, I forgot to post a pic of the supports tearing away. It may not be evident in the photos but there is some serious waves on the surface and the corners are deformed where the supports lifted away.

I have had great results printing flat. I’ve been forced to do that in the past because it’s the only way I can avoid having support blemishes on the crucial faces of the parts. These parts were much smaller though. If this current print fails then I may cut this model in half to make it smaller.

[leonhart88]

This is why you need to greatly increase the density of supports on the underside if you’re going to print it this way.

Printing flat is great but unless you add some vent holes in your CAD file, this will likely fail pretty badly because of the cupping. If your part can live with small vent holes running on the bottom surface then you can add those in and print flat.

You could also attempt to print it on it’s tall side with internal supports disabled. It might come out fine given how large your features are.

[tmarquis]

Success guys thanks for all the help!

[leonhart88]

Looks great! How did you end up printing it?

[tmarquis]

At a 45 degree angle worked. Had to add supports inside the mold surface but easily sandable.