Glass Damage

[xman 0]

Hello, I have been printing CPE+ on my Ultimaker 3 and this is what it did to the glass.

Heat bed temp 110 degrees. The print has removed a fine layer from the glass surface.

Any ideas on why. As soon as it cooled the print just popped off. No scraping.

[phantom 17]

Sure it's not residue from the filament and tried scraping it off ?  Pieces can come of the glass when you have print thats stuck and u use force, but those fine lines don't look like damaged glass too me and I had some damage on my glass bed after extensive use but still running the original, maybe yours is faulty.

Must admit I haven't printed CPE though.

[mastory 44]

Happens when you have very strong adhesion.  Happens to me on window glass with hairspray, PLA or ABS.  Usually can be avoided by waiting for the print to cool and pop off.  Not uncommon or entirely avoidable.  This is why I print on cheap replaceable window glass ~ $4/ea cut to dimensions I specify.  Have several so always a clean spare ready to go.

[geert_2 557]

I have also had it once when printing PET and using glue. I didn't use force to remove the model. And I heard a weird cracking sound while it was cooling, so I guess the glass chipped while cooling, even before I touched it.

 

For PLA I only use my "salt method" for bonding (=wipe the glass with a tissue moistened with salt water, nothing else). This never causes issues, but it only works for PLA. For other materials where bonding is required, I guess you will occasionally have this problem.

 

Mainly for this reason, I think a ceramic build plate might be beneficial? Or try a different type of glass?

 

[fergazz 60]

as someone above said... are you sure that a thin layer glass comes off? This top view is unconclusive but if this happened it's a really bad issue. 

Maybe you got the bad UM3 batch glass, if yes, check for a replacement with your reseller or directly with Ultimaker. 

 

As @geert_2 mensioned, if you want to make a moddification take a look for ceramic type glass. I use a Nextrema glass from Schott which is super

flat, the thermal deformation is close to zero and holds a radical thermal shock.

Schott sells tempered glasses, borosilicate glasses and ceramic glasses and they divulge for me these comparison numbers:

 

 

Edit: the above link goes to the first page of the topic, the data is in page 3 or below:

 

Comparision of coefficient of expansion:

Tempered: 6.0x10^-6

Borosilicate: 3,3x10^-6

Neoceram: 0.6x10^-6 (close to zero)

 

Thermal shock:

Tempered: 270°C

Borosilicate: 360°C

Neoceram: 760°C

Edited March 26, 2018 by fergazz