Difficulties with prime tower/ooze shield failures

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mertzga
Posts: 1
Joined: Fri May 06, 2016 9:19 am

Difficulties with prime tower/ooze shield failures

Post by mertzga » Mon Jun 06, 2016 12:16 pm

I recently started working with a v2 dual extruder using Innova-1800 and eSun natural PVA. My hope is to use pva in 2nd(front) extruder as support for my models. I am using one or both the prime tower or the ooze shield when extruders switch. I am growing frustrated that I have not had one of the features successfully build beyond the very early layers of the model. The issue with both is they come free from the bed. The prime tower specifically has an issue because the first layer is PVA and it rarely extrudes material immediately creating partial layer and leaving little or nothing for next layer to build on. excess material begins to build up on hot end getting wiped off by edge of model. I run the Innova at 240c and the PVA I have tried at 210, 200, and 190, the bed I am running at 70c. I am using glue stick. My thought is what would code look like so wipe tower starts with the model material? Possibly, enter sequence in start/end sequence gcode tab. I am no expert with code but I need to try something it stinks to wipe out my models because the features fail.

-On a separate note is anyone using Scaffold support material from E3D? Successful settings for temps, etc. It hasn't run well yet for me mainly adhesion to the bed and to the Innova-1800.

Sebastian
Posts: 514
Joined: Sun Sep 13, 2015 5:54 am

Re: Difficulties with prime tower/ooze shield failures

Post by Sebastian » Mon Jun 06, 2016 12:24 pm

Maybe you want to use a nozzle prime procedure like I do. Instead of using a skirt to prime the nozzle, I extrude ~3mm of filament at the coordinates 0,0,0.3mm. After that, the nozzle lifts to z=20 and continues to a single prime loop that's fully printed now. You might try to get this into your start code..

killacycle
Posts: 38
Joined: Mon Apr 04, 2016 2:14 pm

Re: Difficulties with prime tower/ooze shield failures

Post by killacycle » Mon Jun 06, 2016 4:48 pm

Most definitely use a brim on the wipe tower. We often tape down the brim on the wipe tower when it gets a few cm tall to keep it from falling over.

Haven had much luck with an ooze shield. <meh> The wipe tower is generally all we use.

Bill D.

kcchen_00
Posts: 1718
Joined: Thu Feb 19, 2015 12:42 am

Re: Difficulties with prime tower/ooze shield failures

Post by kcchen_00 » Mon Jun 06, 2016 10:05 pm

Check the print setting recommendations for the PVA on LB's product page (expand the Parts & Specifications section for extrusion temp range and bed treatment):
https://www.lulzbot.com/store/filament/natural-pva
Check the Inova-1800 product page also while you're at it. :)

You're at the high side of the extrusion temp for PVA. The recommendation is to print PVA on blue painters tape, this may work for the Inova-1800 though they recommend glue stick... which by the way is PVA. So if you're printing the PVA on the glue stick coating... that may be the problem.

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