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Ryan8696

Soluble Filament not sticking to bed

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Hi everyone,

 

Firstly I want to say thanks to the community to help me fix a variety of problems I've been having with my UM3 recently. I've finally been able to print my PLA successfully - but I'm still having issues with my PVA layer - it just doesn't want to stick to the bed!! 

 

I've tried slowing down the print speed, running the manual and auto bed calibration again - but nothing seems to help!

 

I've attached a photo of the first layer...

 

20180826_111039.jpg

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What kind of printer is it?  I think the pva extruding nozzle is too far from the bed.  You need to calibrate the difference between nozzle height better.  For example if this is an S5 then try heating the nozzle and cleaning it.  If there is a tiny bit of filament on the tip of the nozzle during auto leveling it will throw off the measurement.

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It's a UM3. I have cleaned both nozzles thoroughly before doing the auto-levelling but it still doesn't want to work....

Should i just do a manual level and not worry about the auto level?

I was hesitant to do that as I was told auto levelling was much more accurate - however this doesn't seem to be the case!

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Is that the standard Ultimaker glass plate? It looks different but it could be the light situation.

I see something like tiny white sparkles on that build plate. Could there be some kind of contamination?

Do you have any possibility to check if the surface of that build plate is even? Unevenness should be below 0.2mm.

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Hello again - I've just finished the manual level and there is an improvement - however the filament still gets tangled and starts dragging accross the bed - i feel like i'm almost there but there's something else that i need to do - any ideas?

 

I have the printed heat for the PVA on 225 (I tried 215 and it was worse - 235 just sizzled a lot)

I've also tried lowering the print speed to 30 with no luck.

 

New photo below.

 

@Dim3nsioneer I'm printing on BuildTak - i've also tried the glass but I have the same problem.

I've triple checked the bed and i'ts level (the PLA print perfectly)

20180826_184855.jpg

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4 hours ago, Ryan8696 said:

it's only sizzling when i print it at 235 - when i print it at 225 it's ok.

Plus i keep it in a dry box when not in use. 

Oh!  This is good.  This is the problem.  Even though it doesn't audibly sizzle at 225 it's still a problem.

 

Is your dry box just a box with desiccant?  You have to recharge the desiccant often.

 

Put the PVA on a heated bed with a towel over it at 55C (it gets soft at 65C) for 2 hours.  That should get the outer portion at least so it should work well for many hours.  If it gets bad again try drying overnight the next time.

 

For PVA I bought large 25g boxes of desiccant that changes color when it needs to be recharged.

 

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5 hours ago, Ryan8696 said:

Hello again - I've just finished the manual level and there is an improvement

It's okay to turn the 3 screws an equal amount (CCW from below) about 1/4 turn at a time to get it to stick better *while* printing the bottom layer.

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Thanks @gr5

 

In response to your 1st post - the dry box i have actually has a heat function - i'll try running it at 55c for 2 hours to see if that helps (along with getting a desiccant bag).

 

In terms of your 2nd point - if i adjust the screws during the PVA layer - wont that affect the bed hight of the PLA layers? (which are currently printing ok)

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6 hours ago, Ryan8696 said:

In response to your 1st post - the dry box i have actually has a heat function - i'll try running it at 55c for 2 hours to see if that helps (along with getting a desiccant bag).

Yes, good idea 🙂

I always put the PVA on my heated bed at 55°C for half an hour before I start printing.

If it's been more than a day or two, I put it on there for at least 2 hours.

 

Edited by pbackx

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1 hour ago, AndersK said:

Sorry for hijacking but will this regeneration method be good for nylon too?

I don't print with Nylon, but I would guess it works similarly. I just put the role in a cardboard box on the heated bed.

 

A proper dry box like @Ryan8696 would be even better, because you can keep printing while the filament is drying.

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Thx, Ill try that on Nylon then. Have a roll that makes me hungry while printing, sounds like frying bacon. 

 

Idea of a modification project, build an enclosure around the rolls back on the UM3 and lead in heat from the chamber to keep em dry while printing.

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5 minutes ago, AndersK said:

Thx, Ill try that on Nylon then. Have a roll that makes me hungry while printing, sounds like frying bacon. 

 

Idea of a modification project, build an enclosure around the rolls back on the UM3 and lead in heat from the chamber to keep em dry while printing.

I am very interested in how this works. Please keep us posted :)

 

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11 hours ago, Ryan8696 said:

In terms of your 2nd point - if i adjust the screws during the PVA layer - wont that affect the bed hight of the PLA layers? (which are currently printing ok)

@Ryan8696 - Yes but the bottom layer is typically .27mm by default and squishing by an additional. 0.1mm isn't going to change things too much on the left core.  Look this is mostly an experiment to see if the problem is:

1) too much moisture

2) not enough squish

3) oil/wax/grease on the bed

4) Something else?  Bed is cold?

 

When I see your photo I instantly think "not enough squish".  I've seen it hundreds of times.  It's happened to me many times.  Personally I only do manual leveling.  When you do the last step of manual leveling on the UM3 you need to set the second core height to be the EXACT same distance from the bed as when you do the left core.  You want to use the calibration card and you want to feel the same amount of friction.  Once that is done and calibration is done, then it's okay to mess with the 3 screws (in equal amounts) to get the bottom layer good for either core.  It will be good for the other core as well since you got the two heads exactly the same in manual calibration.

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Oh - and another quick experiment is to push up on the bed gently when the PVA isn't sticking.  See if that helps.  Personally I just reach for the 3 screws and turn them the same amount.  The first 5 times I did that I had to think "um want nozzle to go down - oops no I want the bed to go up -- so loosen. - so counter clockwise from below - okay do it".  After hundreds of prints I don't have to think anymore -- I just do it.

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Funny you should say that - I tried that before and had a panicked trying to remember mid-print how many times I turned each screw and which direction was up or down! I gave up because I assumed that adjusting the height for the PVA would stuff up the PLA.

I'll try the manual calibration again and try to get the card resistance exactly the same for both nozzles.

If that doesn't work ill give the screws another shot.

 

On another note - can I ask if you print straight onto the glass? I've been using a Buildtak sheet so that I could avoid having to use any glue etc. The great thing is is that the PLA sticks 100% of the time without curling etc. but it's a bit more of a pain to get the print off.

 

If you do print straight onto the glass - do you need to use glue etc?

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