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Box (case, outer insulation) for Prusa?

Posted by Fizpok 
Box (case, outer insulation) for Prusa?
December 03, 2016 02:53AM
I got tired with printed parts deformation, so I am looking for a way to include my Prusa i2 into a box, to reduce parts bending / increase their sticking to the table.
Could someone suggest some schematics for it? Like plywood, or something?
What should be a temperature inside?
Any additional things I need to know on the subject?

Thanks.

By the way: 110 C works fine with ABS heated bed. As I found, using infrared thermometer, the problem is in temperature reading. As soon as you print something on top of a thermistor (one in the middle of a heated bed), it becomes "insulated", and its temperature decreases slower, then the temperature of, any "open" part of the bed. As the result, we have a hot mid-table, and cold (down to 85C in my case) "open" areas. And the borderline between "open" and "covered" areas is cold, too.
This, as I understand, is the reason for parts unsticking and bending, but how to fix it?
First thing that comes to mind is a box (one I am asking about), the second is using multiple heaters and multiple thermistors, but...
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 05:20AM
The cheapest, and surprisingly good, solution is to just put a Mylar foil over the printer. It usually has a silver and a gold colored side, put the silver side on the inside. Since these foils are often sold as emergency blankets you can get them pretty cheap.
If you want to create a more permanent solution, anything that isolates is a good idea. Wood is better than acylic, but it does not look as nice. I once made a cover from double sided, hollow, thin PC plates you get for small greenhouses. It does not look as bad as wood and insulates very good.


[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 05:35AM
I have several shapes of MDF to cover the unused parts of the bed after ABL is done. This helps to keep temperature drop low.
This is an easy fix on a nonmoving delta bed, but for a Prusa it's a bit more tinkering...
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 07:38AM
You can have the whole project done in 15 minutes. Get a sheet of 1" PIR foam at Home Depot for $15, and a roll of duct tape. 1" PIR foam has foil/paper on both sides, is quite rigid, so self supporting, and is fire resistant (unlike the pink or blue foam) as well as being a great insulator. Cut the foam with a razor knife. Connect the pieces with the tape. Use the tape as a hinge for the door.

If that's not "rep-rappy" enough for you, print the connectors and hinges: [www.thingiverse.com]

It is best to move the electronics out of the box.

I don't know what your printer's bed is made of, but 1/4" cast aluminum tooling plate on 3 leveling screws with a layer of PEI or kapton tape (not glass) solves all PLA/ABS/TPU first layer adhesion problems. Don't trust your IR thermometer. It is easily fooled by reflections, and only reads accurately when pointed at an object of the same emissivity as the one it was calibrated (yeah, sure youbetcha) with.


Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 07:43AM
What temperature of a bed should I set if I use the Mylar foil?
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 07:45AM
Do you mean using aluminum instead of glass?
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 08:14AM
Quote
Fizpok
What temperature of a bed should I set if I use the Mylar foil?
Whatever the filament you want to print requires. The foil is only for insulation.


[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
Re: Box (case, outer insulation) for Prusa?
December 03, 2016 08:35AM
Glass is not thermally conductive and is prone to developing hot/cool spots.

Here's a thermal image of a Taz printer with the heater directly stuck to the glass, notice the temperature variation:



Here's the same heater mounted on a 1/4" cast aluminum plate with a layer of PET tape:



Some people use a thin piece of aluminum with a piece of glass on top and manage to get it to work. You can cook a steak in a microwave oven, too. That doesn't make it the best or even a good option.


Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
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