UMS5 Extruder 2 - too close/touching buildplate (third party spring steel on magnet on UM glass), strips PVA printing 1st layer

[camiwtnb 0]

Hello!

 

As stated in the title, my company's UMS5 extruder 2 is printing the 1st layer much too close to the build plate even after active bed leveling. Extruder 1 prints fine, but once it switches to extruder 2, the build plate comes so close that little to no material is allowed to extrude, which in turn strips the filament so that the flow sensor has to stop the print on the 2nd layer. 

 

I am currently using a 3rd party build plate: Uncoated Spring steel (Printed Solid) on top of a magnet base (Printed Solid) adhered on top of the original Ultimaker Glass build plate. I understand that adding additional thickness to the stock buildplate is most likely what is causing this issue, however because I am printing CPE/CPE+ with PVA supports (extruders 1 and 2 respectively), the high build plate temp required to print CPE causes the PVA to over-adhere to the glass buildplate alone. I've already chipped both sides of the included glass plate trying to remove the stubborn PVA, which is why I went ahead and adhered the Printed Solid magnet to it and then ordered a replacement glass plate as back-up. (Bed Weld and the classic freezer-trick don't help.)

 

Is there a way to adjust the settings in Cura or on the printer itself so that this 2nd extruder prints the 1st layer with the correct layer height?

 

My current set-up is as follows:

Extruder 1: 

     - UM CPE

     -  AA 0.4

Extruder 2:

     -  UM PVA

     - BB 0.4

Build Plate:

     - Layer 1 | Uncoated Spring Steel (Flexplate Solution - Printed Solid) 

     - Layer 2 | Magnetic Base (Flexplate Solution - Printed Solid) 

     - Layer 3 | Glass Build Plate (Ultimaker, factory)

[gr5 1,933]

You can't disable active leveling in the S5 so I can't tell you that you are doing the leveling wrong 🙂

 

I just don't have this problem.  Keep the nozzles clean.  Make sure the silicone doesn't hit the bed when it's leveling.  Watch the beginning of the procedure - that's when it compares left and right nozzle - the first two touches.

 

Clean the tips of both nozzles while hot - although that shouldn't be much of an issue normally as it heats the nozzles before leveling.  But still try cleaning them.  Also clean that little spot on the bed where both nozzles touch down.  I use a putty knife.

 

It just works for me.  It's one of the few things that is really consistent and works well.

 

Oh and check the seating of both cores.  Sometimes the core is too far forward when it goes down and doesn't slide completely into the metal "fork" that positions both cores.  Sometimes a core slides down a little farther after printing.  You can make the right core go up with the lifting switch manually and then down and then push the nozzle towards the back of the machine (not much force - no more than 1/kg or 1lb - 4 sticks of butter kind of force).  If the core goes down some more then that would explain your issue and you can fix that with a tiny bit of high temp grease.

 

I doubt that's the issue.  I don't know what the issue is.

 

Maybe replace the silicone dam?  If you don't have a spare, try printing without the silicone dam one time to see what happens.  It's important to have though for a few reasons.  One is if the print fails and it's not there it's possible to have a head flood.  The other is airflow control to keep the part cool and the nozzle hot.  But that's not as critical as you might think.