CPE+ print very high shrinkage and stuck to glass bed

[alfonsvh 14]

Hi all,

 

Hoping to get some feedback on a problem I'm having.

I designed a part with several holes to print in CPE+

 

The dimensions are quite important, so I used Ultimaker CPE+ in Engineering mode to have the best chance of accurate dimensions.

 

I used Magigoo on the build plate.

 

After the print had finished, it was left on the buildplate for a couple of days. When trying to remove it, I put it under a stream of cool water to dissolve the Magigoo. While doing this, suddenly the build plate shattered.

 

Any ideas on what may have caused this? 

 

And the other problem: the dimensions of the part itself were not correct. The larger holes were drawn as 12 mm diameter, but the diameter on the print was only 11.5 mm. 

Smaller holes drawn as 4.2 mm were just shy of 3.5 mm in the actual object. 

 

I know that there might be some shrinkage, but a shrink of 4 % and 20 % respectively seems a bit extreme, no? Especially since the Ultimaker Material profiles should be tuned?

 

Any suggestions? 

 

[PizzaTijd 17]

How much magigoo did you apply to the glass plate?

I have found that if I don't apply a thick enough layer with CPE+, that the adhesion to the glass plate will still be so aggressive that it'll pull the glass right off either while cooling down (warping) or when removing the print manually. You have to make sure that when it shrinks or is removed, it pulls on the glue instead of the glass.
I personally use a different brand glue stick, but I imagine that they're all just about the same.

 

And in regards to the shrinking; I have found CPE+ to just be a generally tough material to print consistently with. Keep large tolerances, and maybe use walls thick enough to facilitate manual reworking later if necessary.

[alfonsvh 14]

Thanks. I applied what I think is quite a thick layer 😄

 

I think I'll end up trying a different material: I can't afford the time to do several iterations of a 1 day+ print just to get the parts correctly dimensioned. 

 

[PizzaTijd 17]

2 hours ago, alfonsvh said:

Thanks. I applied what I think is quite a thick layer 😄

 

I think I'll end up trying a different material: I can't afford the time to do several iterations of a 1 day+ print just to get the parts correctly dimensioned. 

 

Yeah I would consider CPE+ to be a very situation-specific material, personally. For general use and easier prints you might want to take a look at PLA instead (provided it fits within your use case). It is by far the easiest material to print with, IMO.

[alfonsvh 14]

Yeah I'm well aware. However in this case we need good chemical resistance and temperature resistance up to at least 70 °C (and preferably higher); hence the choice.