Printing hollow cyclinders, angled or straight?

If you were printing cyclinders 20 mm long with a wall of 1.5 mm why might you angle them as opposed to printing the straight?


The surface of tilted parts are nicer. But you have to place and remove supports of the cylinders if you tilt them. I would place them vertical and straight on the platform

thanks bryan, why is the surface quality better tilted?

tilting it also spreads the laser over a larger area, meaning less wearing on pdms layer in resin tank.

Thanks Joe,
But why would "stair stepped " layers of the tilted part be smoother than “straight” layers directly on top of on another?

Concentrating exposure in one spot will degrade that spot on the pdms. A cylinder at that size you may be fine but if there is too much force required and you don’t have supports you will have some rippling on the surface. Remember the resin is still green (partially exposed) when just printed and as the layers peel, if you don’t have enough supports the part will have some buckling as it is printed.

A slight angle where you can run some supports up the side should help. A hollow cylinder is a difficult part to print because you need keep in consideration the printing as well as the cleanup aspect. Having internal supports could be a huge problem in cleanup depending on the criticality of the part.

Since your part isn’t all that tall you could try running it vertical but maybe toss some supports along the outside . Just a few to stabilize the print.

Thanks Ken, So are you saying tilting a part is to give you more lateral stability (by increasing its X,Y foot print) and that is what accounts for a better surface quality? that the surface quality increase is not due to the shifting of the layers in the X.Y direction as they build up in the Z?

If I printer a whole liter of resin with the cyclinders not tilted would the tray still last its advertised ammount? Lets say for example I printed a full cartaridge of resin worth of 2.5 mm walled cyclinders standing on end 20 mm tall, and of course moved them around to hit as much different area of the tray as possible. Is that going to really toast my tray way quicker than normal?

I still wonder about the whole support issue and cyclinders, especially after seeing the form labs article

on how they printed a whole platform of hollow pens standing on end and with no supports.

The surface finish acts a lot like a milling operation. Anything near vertical is going to be great. As you continue to get away from vertical there is little difference at first but things go south really fast after about 45 degrees.

You can use a bit of trig to figure this out but I try to keep things between vertical and 30 degrees from vertical if surface finish is critical.

Thanks, Fred
So all the tilting is done for support, or to reduce islands, and to protect the tank layer, not for surface quality?


Basically yes.

At most angles near vertical the quality is nearly the same.

Fred could you answer this for me.

If for example I wanted to have a 1mm diameter x 2.5 mm solid rod projecting out from the cyclinder wall, and the cyclinder was orientated vertical so that the rod would be horiontal, would that rod print ok, or is it to fragile to peel?

Being so short it will print at 100 microns.

Keep in mind that this little part will only be 10 layers thick and will show layers on the top and bottom sides. If you can print them both at 45 degrees this is the best finish compromise for both.

1mm diameter and 2.5mm long will be brittle in pretty much any material…

Thanks Fred, but why if it is part of the cyclinder that is printing at 25 microns how would that smaller rod attached to it print at 100 microns?

If you’re printing at 25 microns things may not be as accurate from what I’ve seen. It’s one of those print it and see type of things.

In my experience 50 microns is all you need unless it’s jewelry or very small parts.

Ok got it , But what I am really wondering about here are there horizontal type sections , that while not islands, because they are attached to the main form on their edge, start out as very thin layers with no mass behind them, how far can they extend before you need a support under them?

The short answer is try and see. Some prints will work even though they are outside the print guidelines.

I was going to post a link to the recommended limits for different shapes but the site is stuck in French for me.

@Frew The site is stuck in French For me in the US. Again.

Thanks for helping out in this thread! A few US users have gotten stuck in France and clearing your cookies should correct this for you. If not, can you post in this thread so that we can isolate the issue and get it corrected?

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.