Some PVA problems..

[rscudder 0]

Hi there, 

(first time posting, my company and myself are very new to 3D printing)

Machine: S7 with material station; AA 0.4mm core, BB 0.4mm core, OEM build plate 

 

Having some issues with PVA supports: using Ultimaker PVA that is stored in Ultimaker material station, I have a probe that monitors humidity and it averages 15-20% RH

 

PVA prints a brim very nicely but when printing on or around primary material (PLA and ABS so far) it will not stick to the material, ends up stringing and blobbing up, tried enabling prime tower between changeover layers, ended up making a blob mess around/inside tower

 

BB print core looks to be clean under a scope and no blockages (pre-print purge is fine)

 

Using the Cura Ultimaker default settings for the material (see screenshots)

 

Currently baking the filament @ 65°C for 8 hours to see if any difference

 

Any thoughts? Was unable to capture any photos of the actual print failures unfortunately but can include next time I attempt to run the part that keeps failing

 

 

[gr5 2,224]

Can you post the model?  If that's allowed then please post the project file: in cura do "file" "save project" and post that file here.  That will include all your settings including profile settings, printer profile, material profiles, model, position of model, etc.

 

I haven't printed ABS with PVA.  I really hate ABS and recommend you avoid it as it's harder to print, weaker (especially along layer lines), and stinks (last issue not a problem for you with your air filter).  But with PLA there is a crucial thing you should know:

 

Printing PLA on top of PVA works great.  Printing PVA on top of PLA barely works at all.

 

This is the reason for the support layer expansion setting which tries to get PVA a path all the way to the print bed but this is very model dependent so I want to see your model please.

 

Also please post a picture - I know you said you didn't get a picture but next time please get one.  From a picture I can learn 100s of things instantly.

[rscudder 0]

7 minutes ago, gr5 said:

Can you post the model?  If that's allowed then please post the project file: in cura do "file" "save project" and post that file here.  That will include all your settings including profile settings, printer profile, material profiles, model, position of model, etc.

 

I haven't printed ABS with PVA.  I really hate ABS and recommend you avoid it as it's harder to print, weaker (especially along layer lines), and stinks (last issue not a problem for you with your air filter).  But with PLA there is a crucial thing you should know:

 

Printing PLA on top of PVA works great.  Printing PVA on top of PLA barely works at all.

 

This is the reason for the support layer expansion setting which tries to get PVA a path all the way to the print bed but this is very model dependent so I want to see your model please.

 

Also please post a picture - I know you said you didn't get a picture but next time please get one.  From a picture I can learn 100s of things instantly.

Here is file, thank you for quick reply 

switch housing (PLA+PVA).3mf

[gr5 2,224]

This part doesn't need any support.  Turn it off.  You have lots of "bridging".  I can't describe bridging in words so do a google image search for "3d printing bridging".  I just did and those pictures help.  Longer bridging is difficult like in those photos but your bridges are only a few mm which is trivial to print.

 

But for other parts...

 

I can see that PVA in those narrow channels will be a bit difficult because they are PVA on top of PLA which is what I mentioned in bold in my previous post.  I don't have a good solution for that if your part didn't have nice easy bridging.  Basically you want a horizontal path outside of your part where the PVA can connect to some existing PVA support that connects down to the build plate.  Otherwise it just slides around and makes a mess.

 

You may want to also try enabling PVA support but print the part sideways.  That will make those side clips stronger and less likely to break due to "grain".  ABS will have massive "grain" issues - which is a good reason to stick with PLA if possible.  Of course sometimes you are dealing with temperatures too high and need ABS or Nylon or PETG or well any other material, LOL.D

[rscudder 0]

4 minutes ago, gr5 said:

This part doesn't need any support.  Turn it off.  You have lots of "bridging".  I can't describe bridging in words so do a google image search for "3d printing bridging".  I just did and those pictures help.  Longer bridging is difficult like in those photos but your bridges are only a few mm which is trivial to print.

 

But for other parts...

 

I can see that PVA in those narrow channels will be a bit difficult because they are PVA on top of PLA which is what I mentioned in bold in my previous post.  I don't have a good solution for that if your part didn't have nice easy bridging.  Basically you want a horizontal path outside of your part where the PVA can connect to some existing PVA support that connects down to the build plate.  Otherwise it just slides around and makes a mess.

 

You may want to also try enabling PVA support but print the part sideways.  That will make those side clips stronger and less likely to break due to "grain".  ABS will have massive "grain" issues - which is a good reason to stick with PLA if possible.  Of course sometimes you are dealing with temperatures too high and need ABS or Nylon or PETG or well any other material, LOL.D

I also have breakaway support but I see what you mean by bridging, hmmm very fascinating, will try your recommendations and report back