Scratch on Glass Bed

I am a teacher and working with high school students. This week we have opened up our TAZ 5 and started printing. We have already started to make some small scratches in the glass heated table. I do not see specific advice about managing this. I really appreciate your hard earned insights.

Well the good news is the glass is covered with a sheet of PEI, so its probably not damaged… which really is good because the borosilicate glass is difficult to find.

So it sounds like you gouged the PEI… probably with the clamshell knife they supply. A gouge can be sanded out, but make sure to sand the entire surface and not just a single spot. Otherwise you’ll leave a low spot in the PEI. A fine grit is recommended.

To prevent this in the future, use a tool like a spatula style cheese slicer (filing down the slicer is recommended) or a artist paint knife. Or this rounded paint knife with a larger surface. The keys to these tools is the slight angle that offsets the handle from the spatula blade, which allows the blade to slip under the object by pushing the tool. Once under the print, work around the object. Resist the urge to pry upwards, this will put stress on the PEI and it will eventually release from the glass… bubbling. As you work your way around the object, it should pop off the bed at some point.

Its also recommended to remove parts at bed temps lower than 60C to help the adhesive. 50C is good for most materials. See Lulzbot recommendations for part removal temp.

Mitigating the aggressive adhesion can be as simple as raising the nozzle by .1-.2mm through the Z-offset setting in your slicer. Typically that’s for ABS. But the method really depends on the material you’re printing. For PET and Ninjaflex, a layer of glue stick will lessen the adhesion to the PEI.

The PEI in the end is a better print surface overall. Its durable and does away with blue tape, kapton, ABS slurry, hair spray… that can get messy or become a hassle, IMO.

More reading:
https://www.lulzbot.com/learn/tutorials/pei-print-surface-troubleshooting


Post pics of the bed and tell us what filament type… the forum community can probably chime in with more advice.

Hope this helps.

For sanding you’ll want superfine 1000/1500 grit.