HBC Temperature

I have built an open RepRap Prusa I3 on wooden frame. I print ABS straight on glass. The printer works fine except when printing large flat objects where I have warping issues. The printer has a heated bed and I can handle the warping with glue stick and if needed ABS glue. However these do not help when I try to print something with overhang. I tried to print a sphere with a hole for an LED in it. I added support heavily so basically the bottom half of the sphere had support below. Even with this support the surface of the ball started to warp upwards during printing. I guess it did so because there was not much plastic below it (every layer was wider than the one below) so nothing kept it warm and it was cooling too fast. I cannot see any other solution to tackle this problem than adding a heated chamber around the printer. The question is what would be the ideal temperature in the box and what would be a practically high enough temperature? I guess the ideal would be the same as the heated bed temperature. However having such high temperature probably would cause some other problems like heating the motors up too much etc.

Stratasys prints ABS in heated enclosures at 70C. I have found that 45-50C is sufficient to print even relatively large object without warp/delamination.
At 50C the motors are usually OK, but in my printer, I kept the Y axis motor outside the print chamber because it runs pretty hot in a room temp environment and I didn't want it heating up more.

Both ABS, the one on the right was printed without a warm enclosure, the one on the left printed in an enclosure at 45C.

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

Is the heating bed enough to get the HBC temperature to 45-50C or do you use some other heater in addition? If you use additional heater, do you use some controller for keeping the temperature on that level?

During warm weather months, I find the bed heater is sufficient to heat the print chamber, but during cold weather it's border-line inadequate. I will be adding a supplemental heater to my machine some time in the near future.

You can help things by building a thermal enclosure using foam insulation board to prevent heat loss. If you do that and check the temperature inside the box and it isn't high enough, add a heater. I recommend PIR foam because it is fire-proof, readily available, and cheap ($15 for a 4' x 8' x 1" sheet at Home Depot)

Low cost heaters can be pulled from things like old coffee makers, hair dryers, etc., usually available at garage sales and second-hand shops for almost-free. You can add a thermostatic controller for about $15 or use an unused thermistor input and extruder output on your printer's controller board to regulate the temperature.

I added a heater to this solidoodle printer by building up a plywood base (I hate to use plywood for this sort of thing because it is going to warp and delaminate eventually, but it was all I had available), and adding a 400W heater from a Stratasys printer and a 220V fan wired in parallel with the heater. There's a $15 thermostatic controller that reads and regulates the temperature. The whole thing runs on 117VAC, so the fan turns very slowly and quietly without generating a huge amount of air movement inside the enclosure. The fan pulls air into the base which then passes up over the heater and back into the chamber. It heats to 50C faster than the bed heats up to print temperature. There is a piece of 1" thick PIR foam covering the bottom of the base to prevent heating up the table that the printer sits on.



This project isn't finished yet- I have to add a new top cover to the printer with a mount for the filament spool so it feeds straight down into the enclosure.

Edited 1 time(s). Last edit at 03/11/2016 12:51PM by the_digital_dentist.

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

Thanks for the very detailed and useful answer!