Ironing in Cura is great, but...

[jaywalk 1]

So I tested the ironing function some and it's really useful. Especially with colorfabb woodfill filament (or others with wood fibers I guess) which gets a really nice top surface!

However: I tried just activating ironing on a model today and an effect I've seen earlier became a real problem. The model has three flat surfaces on different levels. After ironing a layer and moving on to print upwards the next maybe 20 seconds the filament goes really dark and weak - I'm guessing the nozzle is way too hot but I haven't checked during print to verify this. It could also be that since so little is extruded during ironing the filament in the nozzle has been liquid for a long time and started to deteriorate?

So I got the idea (first looked if it already existed but couldn't find it): A pause after ironing, to a specific temperature or for a certain time (like maybe 30 seconds). This should fix this issue. This print easily cracked in half which was a bit of a shame, it looked so good!

EDIT: Printing on a Ultimaker 2 Go, neglected to mention this.

Edited November 12, 2017 by Guest

[DidierKlein 729]

I didn't try it with woodfill but i know woodfill doesnt like to stay in a hot nozzle for some time so maybe this is your problem?

[Dim3nsioneer 557]

On an UM3 one could solve the issue of temperature sensitive filament degrading during ironing by using the other nozzle for ironing. This would make an extruder selection necessary. Question is how many temperature sensitive filaments are there where people want to use ironing with?

[SandervG 1,521]

I didn't try it with woodfill but i know woodfill doesnt like to stay in a hot nozzle for some time so maybe this is your problem?

 

I was also thinking this. Your problem manifests with woodfill I suppose? During ironing you only extrude something like 10%, so the remaining woodfill stays in your nozzle too long and burns (a little). I remember there was also a plugin for Cura changed temperature from high to lower and this would result in darker rings in your print for a more wooden look. Keeping it in your nozzle longer will probably only make it more brittle.

[neotko 1,417]

Try to increase the ironing/neosanding to at least 20% MORE of the real print speed. Cura dev team left it at 20mm/s and that indeed allows the filament to drip and more importantly it overheats the print area making overhangs and weak parts suffer. Unhidde all options and speed it up. Read my post about why/how it works and then you can get the whole picture. Google neosanding ultimaker

Edited November 13, 2017 by Guest

[jaywalk 1]

I didn't try it with woodfill but i know woodfill doesnt like to stay in a hot nozzle for some time so maybe this is your problem?

 

Yeah, I got the most interesting results and problems with woodfill. I'm figuring it degrades in the hot hotend and when I start printing again I have a problem. I'll keep tinkering. There are probably improvements to be made!

[jaywalk 1]

Try to increase the ironing/neosanding to at least 20% MORE of the real print speed. Cura dev team left it at 20mm/s and that indeed allows the filament to drip and more importantly it overheats the print area making overhangs and weak parts suffer. Unhidde all options and speed it up. Read my post about why/how it works and then you can get the whole picture. Google neosanding ultimaker

 

Thanks for the tip! I'll test it. I've found the hidden options but didn't figure out which would help my situation.

I think the slow speed helps in burning and creating nice patterns in the surface but maybe a fast run will do similar. Only one way to find out!

Prints with large surface following the ironing already come out well as they get enough fresh material to fuse and the burnt woodfill ends up as infill.