Support material almost solid filled into the printed piece

[rickmjohnston 0]

Hello all.

 

I have a rather small piece 30mm x 30mm x 10mm I am printing on my UM3 and have a question as tree supports never did what I am getting now with newer Cura s/w. The piece is of a bridge superstructure brace that basically is 2 beams with an 'x' cross brace between the beams there are several of these making up the total piece simply as a test piece to see how it prints. My issue is with support material almost solid filled into the printed piece throughout the cross bracing and there is so much I cannot break it free because it is so thick between the beams and cross bracing I continue to break the piece not the support material from the piece.

 

I've tried a lot of different support setting and cannot seem to get it to only do "trees" and not almost a complete solid fill. Attached is 1 picture that I managed to remove some of the fill before breaking the piece trying to press down with X-acto knife to cut it away.

 

TIA for any suggestions!!!

 

Cheers!

Rick...

 

[rickmjohnston 0]

Hello All.

Update I messed around with a few "hidden" settings in the configuration panel and managed to get the support as little trees that were easily removed from the printed piece.

 

Thanks.

Rick...

[Oliveros 11]

I was going to say, change your support density and distancing and that should do it.

 

Glad you got it sorted.

[rickmjohnston 0]

Well I am still having an issue with the amount of support after changing material from PLA to actual PVA support material. I left setting exactly as is and the amount of time to print with PLA support was approx. 7 hours. After changing to PVA material time went up to almost 20 hours! I wrote down setting and changed the default settings for density and distancing and still will not lower print time. I simply let it go as I wanted the print. After running all night the time increased from being finished at approx. 1:30 pm ET today to now estimating not finishing until 4 pm ET today? Makes no sense to me what is going on or why changing material would make such a drastic increase in printing time. NOTE: Setting for support placement is 'touching build plate' 

 

I also did a test reviewing after slicing between PLA and PVA with exact same settings. The PLA one shows support but not nearly what PVA shows which is completely solid. See attached pictures. As you can clearly see PLA doesn't even add support toe the highest side (right) of the model which seems odd it wouldn't add some. PVA is solid support everywhere and even on the right side has 3 round "feet" that stick way out from model (~10mm)? As well the PVA is also way outside where support is needed by about 5mm thickness. 

 

I've tried this with a smaller piece of this model and the PVA is almost tripling the amount of time due to the amount of support fill it is thinking is required. I also need to use PVA because there are some very thin pieces in this model and PLA when trying to cut the support away was snapping the piece even using an X-Acto knife trying to be careful in removing.

 

TIA for any other suggestions!

 

Cheers!

Rick... 

[Carla_Birch 116]

Click on the number 2 nozzle tab and you see that PVA prints much slower than you can print PLA at with PVA being around 35 mm/s and PLA being more 70 mm/s range.

 

You can print with PLA supports still and swap the floor and roof of the supports to PVA, but only do this if the supports are in places you can remove the PLA from.

 

On the number 1 nozzle tab set up your supports more like this in the image below (note the support density % is high so the PLA supports give the PVA a base to print on, but i have gradual support infill steps set to 2 so only the top 1mm of the support is 50%)

 

 

But in your case with how fine the model looks to be doing the above might not be the best because sometimes the PVA might not stick to the PLA supports right. But like i say the main factor to the time jump is the speed you print PVA and it's not something i would personally make faster because the higher risk of the supports failing.

 

Also on the amount of support PVA supports add's a 3mm support horizontal expansion, what basically means the supports are 3mm wider, also the support angle is 45 for PVA where PLA is 60

Edited July 12, 2020 by Carla_Birch

[rickmjohnston 0]

Thanks @Carla_Birch. Yes realize PVS and the BB0.4 nozzle extrudes much slower I was just pointing out it was a lot more and I was expecting maybe an hour or 2. The other issue is not just the time but the PVA is really thick and consumes the entire model with every nook and cranny filled with PVA support and that is increasing print time as well as wasting material where it is not needed. Seems to me PVA ignores all support settings while PVA respects those settings? PVA a solid support structure while PLA or other material I have tried just to see what would be extruded...what I mean is other than PVS material the supports are like "trees" while PVA is almost solid. I think this is where your statement adding 3mm horizontal expansion and I am not finding a way to change that setting?

 

I'll try experimenting with those settings but they seem to be default values in the configuration? And WOW! Support Density for you is 50%? I was told to lower that setting and I have it set to 5% and that doesnt appear to change anything.

 

Thanks again!

Rick...

[Carla_Birch 116]

With PVA you want a high % so you make a good roof to the support, but i have gradual support infill steps on, what means only the top 1mm of the support is 50% the rest is much lower more like 15%

[rickmjohnston 0]

Thanks good to know. Thanks @Carla_Birch

[rickmjohnston 0]

Here is what I am dealing with as the print finally finished.

 

As you can see in the attached pictures there is absolutely no need for a solid wall of support material as show. It has tree supports in the middle between the 2 pieces but on the outside of both pieces a solid wall of support material and there are cross 'X' bracing between the 2 columns and thus very minimal support should be required. As well I have it set to only print support touching the plate. So I cannot break the support I need to carefully cut it to hopefully separate the 2 wall of support from the pieces.

 

Any other thoughts why this is being printed in this manner?

 

EDIT:  Added a new picture after removing 1 piece. The trees are what I would expect and not the "wall" on the outside.

 

TIA!

Rick...

Edited July 23, 2020 by rickmjohnston
Added new picture