Reducing stringing without retraction?

[hotponyshoes]

I'm printing tpu (no retraction)
Slicer is Cura.

Say I'm printing a castle,
Bottom part prints fine but I get stringing between the 4 turrets.

If I wanted to print 4 models at the same time there is an option in cura to print 'one at a time' (or all at once)
Using the one-ar-a-time option would stop most of the stringing.

Is there a similar option for upstanding features on a single model,
Ie, so it would print the first floor of the castle, then print front left turret completely, lower back down to the top of the castle roof, print the front right turret and so on?

 

[sako243]

The one at a time model only works (probably) if there's enough space between them for the print head to clear.

I suspect on a smaller model you'd get the nozzle clashing on the turrets in your example. It might be technically possible but programming such a slicer would be a challenge as the slicer would need to know the exact dimensions of the head in 3d space to work out possible collisions.

 

[daedalusminos]

Using 'do not cross perimeters' will minimise stringing. But if you really want to print them one at a time you could slice the model in two parts and then add an offset to the Z in g-code and append to the end of the base g-code.

 

[Agroshield]

...it would print the first floor of the castle, then print front left turret completely, lower back down to the top of the castle roof, print the front right turret and so on?

With the 'print one at a time' option, I guess it starts from layer zero on each item. So the base layer of each item is on the heated bed.

If you tried that with your castle turrets that are up in the air, is there a risk the second one might have cooled down too much after the first has finished? And the fourth one even more so.

 

[ajlelectronics]

Stringing can show damp filament up.

 

[hotponyshoes]

The one at a time model only works (probably) if there's enough space between them for the print head to clear.

I suspect on a smaller model you'd get the nozzle clashing on the turrets in your example. It might be technically possible but programming such a slicer would be a challenge as the slicer would need to know the exact dimensions of the head in 3d space to work out possible collisions.

I'm sure there is somewhere in the slicer to input the head dimensions to avoid this when printing multiple things on the bed at the same time...

Using 'do not cross perimeters' will minimise stringing. But if you really want to print them one at a time you could slice the model in two parts and then add an offset to the Z in g-code and append to the end of the base g-code.

I'll have a look for that first option, the rest sounds a bit technical for me!

With the 'print one at a time' option, I guess it starts from layer zero on each item. So the base layer of each item is on the heated bed.

If you tried that with your castle turrets that are up in the air, is there a risk the second one might have cooled down too much after the first has finished? And the fourth one even more so.

I don't think so. I don't normally heat the bed with tpu. If I did, by the time it's printed a 10mm+ thick layer I can't see the heat getting through that? Never actually measured it, on something like a 10hr print I'd expect most of the model to be at ambient temperature but maybe it will stay at bed temp?

Stringing can show damp filament up.

It's not the filament that's damp. I can get it to print perfectly without any stringing but I'm not using those settings because I'm going for speed.
I just thought if I could print one upstanding part at a time I should loose 99% of the stringing and only add a tiny amount to the build time?

 

[MattF]

you could slice the model in two parts and then add an offset to the Z in g-code and append to the end of the base g-code.

I was thinking exactly the same.