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perspex (acrylic) platform height

Posted: Fri Dec 20, 2013 12:17 pm
by mr6k
well it finally happened, my bed heater cable failed where it is most stressed as it bends.
So I thought an ideal time to try the perspex cold bed solution, bought a 4mm sheet and tried printing (ABS).
Sure enough ABS sticks well to the perspex, in fact a little too well. I normally set the platform two paper thickness below the extruder. at this setting the ABS bonds too well to the perspex, the job is difficult to remove and tends to leave bits of ABS stuck to its surface. After experiment I found that adding 0.3mm to the gap gives an ideal bond that grips the job but is almost as easy to remove as my old hot platform with kapton tape,

As an additional benefit perspex seems immune to MEK, therefore any ABS left on the perspex can be easily cleaned off without damaging the perspex surface. The only effect I have noticed with perspex is that there remain witness marks of where the print was, in the form of a subsurface micr crazing.

hope this is of interest.

now do i buy a new heater and lead, redesign the heater lead path and replace it ir just run a perspex cold platform?

cheers

Peter

Re: perspex (acrylic) platform height

Posted: Sat May 10, 2014 8:59 am
by R-A
Hi,

I'm rather curios, how did your perspex printing go after all these months?

Re: perspex (acrylic) platform height

Posted: Sat May 10, 2014 10:45 am
by mr6k
hi R-A,
I ran it for about 20 jobs of various sizes but then needed a heated platform for some other material. So I built a new wiring scheme to the platform. Used silicon flexible cable taken from the connector by the vertical axis, took it out of the back of the horizontal axis and around to the the on the outside. I poste description and images on here somewhere!!
Been running that ever since with no problem. Only time a non heated platform is useful is when printing ninjaflex, which seems to prefer a cold platform.

However I have no reason to doubt that the perspex would have lasted well as it did not seem to wear apart from initially leaving witness marks.

cheers

Peter