How long has the PVA been open? How was it stored? It can have issues with too much dryness as well as too much humidity. Have you dried this same roll more than once?
Is your silicone nozzle cover installed and intact?
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5 hours ago, DCranstoun said:Just out of curiosity, is the PVA spool you are printing with relatively new?
And do you know the relative humidity of the area around the printer? We bought sensors for our work here at our shop, and keep one in the material station empty slot that we have to ensure it is drying properly.
This spool of PVA is about a month old, there is little left on the spool, enough for a few more prints. We have another spool on order. The rest of this spool has been very reliable.
In addition, the hygrometer in our lab reads 62% humidity, so we have been printing and storing everything at this level.
1 hour ago, fbrc8-erin said:How long has the PVA been open? How was it stored? It can have issues with too much dryness as well as too much humidity. Have you dried this same roll more than once?
Is your silicone nozzle cover installed and intact?
This spool of PVA has been open for about a month, there is little left on the spool, enough for a few more prints. We have another spool on order. The rest of this spool has been very reliable.
The hygrometer in our lab reads 62% humidity, so we have been printing and storing everything at this level. The spool has been dried in the filament dryer before each print, approximately 10 times.
That's pretty high humidity. Even trying to bake it before printing, it may be too far gone. Can you tie the PVA in a knot without it breaking?
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I have a love and hate relationship with PVA
For shorter prints, when super dry, it can work really well. But on our 7 machines here, we notice it likes to burn and coat the nozzle.
One change I have made recently is just to use PVA or Breakway ONLY as the support interface. Speeds up the print time and we get the best of the ease of removal. PVA has some pluses over Breakaway, which can sometimes be hard to remove from finer details.
On 5/6/2024 at 11:34 AM, fbrc8-erin said:That's pretty high humidity. Even trying to bake it before printing, it may be too far gone. Can you tie the PVA in a knot without it breaking?
Nope. I think that spool is done for. A new one just arrived, ill give that one a shot
On 5/3/2024 at 12:38 AM, TheMainMan said:On an Ultimaker S3, I am printing a 24 hour print with PLA and PVA. I dry the PVA with the filament dryer before beginning the print. It will print well for a few hours, then the flow sensor stops the print.
I open the feeder box, clean it out, ensure the tightness aligns with the center line on the side of the feeder (and once tried printing with it set tighter, no luck), and remove the PVA filament.
I then use the hot/cold pull method to clean out the BB print core. Then I reload the PVA, and restart the print.
Once again, the PVA will print fine for a few hours, then ceases to flow out through the nozzle.
I turn the flow sensor off and sure enough, after a few hours, the PVA still ceases to extrude out of the nozzle. It seems the flow sensor is functioning correctly.
I test both feeders with PLA and an AA print core, and all goes well. I know the problem does not lie with the feeders, nor the flow sensor. Either the PVA is bad (though I do dry it and do not print or store filament in a humid environment), or the print core is bad because it stops extruding out after a few hours even after cleaning.
I feel I have tried everything. Before investing in a new BB print core, how can I resolve this issue? @Dustin, I know you are a PVA pro.
I tried a different brand of PVA, it would not come out of the nozzle at all.
So I loaded a brand new, mint condition BB print core. And loaded a brand new, mint condition spool of PVA from a supplier that has served us well in the past. Sure enough, the PVA will print fine for a few hours, then ceases to flow out through the nozzle, stopping the print. What else can I possibly do to get PVA working again after three weeks of troubleshooting?
I have attached the project file if that helps. @Dustin
If its printing well as a new spool.. and after a few hours its having issues.
The issue is moisture.
PVA is super hygroscopic.
Sounds like the humidity level in the area where the printer is located is too high (at least for this case)
Have you ruled out issues with your front fan? Are there any filament hairs stuck in there?
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12 minutes ago, fbrc8-erin said:Have you ruled out issues with your front fan? Are there any filament hairs stuck in there?
+1 to what Erin said. Check the front fan. I’ve gone through a few over the years. Sometimes the filament strands get tangled in there. I’ve also had fan blades break off and burn up the motor. Be sure to clean that core. The Filament Cleaning sticks (polycarbonate) do a great job getting the gunk out.
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DCranstoun 0
Just out of curiosity, is the PVA spool you are printing with relatively new?
And do you know the relative humidity of the area around the printer? We bought sensors for our work here at our shop, and keep one in the material station empty slot that we have to ensure it is drying properly.
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