rocket_scientist Wrote:
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> Nophead,
> I noticed from your blog page (still haven't
> figured out how to add a comment there) that you
> are having trouble with too much heat being
> retained. Try adding insulation under the heated
> bead to reduce heat loss in that direction. Even
> cotton batting will help, as the flash point of
> cotton is over 220C.
I have wool insulation under the bed of HydraRaptor. The reason I don't use it on Mendel is it takes too long to cool the bed down after the build. The top surface is insulated by the PET tape and the objects built on it so I blow air across the bottom with a powerful fan to cool it. It still takes about 10 minutes to go from 110C to 50C. Ideally it would be nice to get back to room temp as the objects are easier to get off then but it wastes too much time.
>
> This looks to be a major improvement, so I
> suspect you will want to make it permanent. Try
> moving the electronics boards and power supply to
> the outside back of the enclosure. That way, they
> will not suffer from the heat, and they generate
> no ill fumes.
Yes the long term plan is a machine that uses the box as the frame and has the electronics on the outside.
To cool the extruder stepper motor,
> it sounds like you are currently using enclosure
> (warm) air to cool it. Try adding one more hole to
> the side of the enclosure and put the fan there,
> with a flex tube to carry the cool air to the
> stepper motor on the extruder. That should help
> keep it cool enough to allow a much higher
> internal temperature, and more uniform ABS
> printing.
I recently had to replace the extruder bracket and all of the x-carriage because the temperature just above the bed is enough to degrade the ABS so after a few months printing it starts to crumble and fall apart. To maintain temperatures high enough to completely eliminate ABS warping the parts can't be made from ABS. I am planning to put a heat shield under the carriage just to make it withstand the current temperature.
To stop warping completely you need to heat to the point where the plastic is just turning soft, so you can't use the same plastic to make the machine.
An ABS machine could have a chamber hot enough for PLA.
A PLA machine can only have a heated bed, not a chamber, and the bed can only get hot enough for building PLA. The temperature required for the ABS bed (140C on the first layer) would melt a PLA carriage and extruder without a heat shield and some cooling.
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www.hydraraptor.blogspot.com]
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