Wraped and uneven print where two filaments meet

[SebastianBur 0]

Hello,

I have a big problem. I have been struggling with it for few months and can't find the answer.

I work with Ultimaker 3. When printing one material, everything is OK, however when I print model from extrunder 1 and support from extruder 2, the printed models gets wrapped and ugly but only in the area where two materials meet.

What can be causing this issue. I tried leveling and calibrations etc.

Feeder one prints PLA, feeder two prints PVA (water disolvable).

I appreciate your help.

[Legendary_zotar 0]

Well, I'm not a 100% positive what the exact issue is, cause I'm having a similar issue, but 1 way that might fix it is making the print speed less this will give it more time to place and turn on the fan so it will harden and will more likely stick to each other, but if you mean that the support won't print on top of the first filament, it could be because the filament is heated and it wont stick to it, in that case i do not know what to do.

[kmanstudios 1,120]

Pictures would be helpful. I, for one, cannot even fathom the description as I have not seen anything like this.

[SebastianBur 0]

Here are some photos.

The support gets printed but the part looks very bad where the support is.

[kmanstudios 1,120]

What are you using for your support material?

If you are using the same material, it will not be smooth as, I believe and have seen on my experiments, it does not create a smooth interface between support and model. If it did, you would not get it apart. All prints I have done using the same materials have had a bit of roughness because of the gaps and attachments between support and model.

If you are using PVA in conjunction with another material, you should get a decent interface. The only time this has not proven true is when I scrimp a bit on the amount of support and it, itself, is not smooth (pillowing, too large a gap/not enough density) and I usually put that in a place that is not seen or needing to be smooth. An example of that would be the inside of a casing that is not needing that level of detail.

[tomnagel 126]

The surface of the PLA which rests on the PVA should be almost as good as the top surface. So yes, there is something wrong.

From your pictures I cannot see what. Is the PVA printed in the right place? Compare it halfway with what you see in layerview.

Layer by layer PLA and PVA should be against each other where the slope is

Edited August 22, 2017 by Guest

[Legendary_zotar 0]

I've had a similar problem, and these 2 things fixed it:

1- Slowing down the speed of the print.

2- Enable Support Roof, This makes a floor ontop of the support which allows the main material to print ontop of the support material easier, give it a try and let us know how that goes

[gr5 2,265]

Did you do the X/Y calibration step?  That calibrates the distances between the heads.  If you are off by quite a bit (e.g. .5mm) then there could be a gap between pva and pla but like Tom says it should be touching.  If you still have a problem after above suggestions (they all sounds good - slow down, enable roof, calibrate x,y) then take a photo of a layer while it's printing.  Like Tom says it should be touching.