Print lines


#1

Hello,

So i’ve been struggling with these print lines lately. No matter which layer thickness i choose, those are always there.

The other night the the printer ran out of the resin, when i came in the morning i changed the cartridge and it continued to print. And it somehow printed the rest of the model smoother! still with lines, but much smoother!

How did this happen? How to get rid of these lines? please help.


#2

That big line in the middle is always there when switching cartridges. No problem. This i understand.


#3

The bigger line isn’t really because you changed the cartridge, it happens every time the part stays out of the resin for a while. If you are there when there is a need to change the cartridge and do it immediately, there will be no big line at that stage.

Similarly, when the cartridge is almost empty you can see that the printer is doing resin level sensing loops and refill operations much much more often. This leads to the part staying out of the resin for a longer time than usual at regular intervals and this shows in the layer lines.

If surface quality is critical for a part, I would advise to use a full cartridge or at least one for which the printer hasn’t been displaying the “low resin” warning for too long.

All of this is of course a workaround, Formlabs should solve this inconsistency issue on their side but that’s gonna be difficult with their resin dispensing mechanism, cartridge and sensors as they are on the printer.


#4

Did you print this part fully solid?

You can see some of the thin supports in the middle to be bent. I would say the peel forces are high and the print is a bit flexible(cause you’re printing in mid air with only the supports holding it) during the print causing it to move around a bit after every peel action, creating these line as a result.

I would definitely hollow it out.

Regarding the cartridge change line, if I remember correctly this is caused by temperature differences of the resin and the part. It’s been discussed on the forum before.


#5

Thank you for the reply. I understood why i am getting those lines. The sensing resin stage occurs almost every 10 layers… how to avoid that? my last hope is an Open Mode.


#6

@fantasy2 is absolutely right about the left part of the print being badly supported. This explains the extreme layer lines in that area.

For the other layer lines, I wouldn’t know for sure but to me a resin sensing loop every 10 layer seems like quite a bit than what I am getting with a cartridge that isn’t almost empty.

Have you tried with a new, full cartridge ? You should really get better results, no need for open mode,


#7

The sensing loop isn’t that surprising if this is a solid print. The printer tries to keep the level of resin very accurate and that base uses a lot of resin.

In my experience, printing large parts directly on the platform always gives you lines, no way around this!

I didn’t get an answer to my question: is this a solid piece? If so, hollowing it out can significantly increase surface quality.


#8

Thank you for the reply. Yes it is solid, and it must be solid. Will try an open mode and let you guys know the result.


#9

Hollow it, print it on an angle and fill it up later with cheap epoxy. It’s gonna save you money(resin, tank wear, print time) and improves surface quality. I’m afraid open mode is not going to be the solution.