Heated bed issues.
Posted: Sat Nov 23, 2013 1:32 pm
Ok, I saw a post about someone who made a 1/4" aluminum bed cover, and i have spent 2 hours searching and googling and I cannot find it again.
>>>> Did I dream that or can someone point me to the post with the 1/4" bed plate build?
(NOT the 1/8" plate.
BTW, the forum thinks it unreasonable to search for 1/4 says "1 and 4 are too common"
NOT helpful in a build forum to treat fractions as 2 numbers.)
My onyx bed has the usual hotter in the middle problem, which I must solve to make large prints.
I'm leaning toward aluminum plate. My standard setup is 50 C on printable edge then center is 100 C.
Questions:
I also see aluminum foil as recommendation. How much benefit does that have?
Calibration:
The issue is that changing temp changes the surface curve. Edges HAVE to be cooler,
so hotter center must expand, and that must go somewhere. So the curve changes
depending on the bed temperature, so the calibration for ABS cant possibly work for PLA,
at least not over the whole print surface. I would expect the software to handle this,
such as giving it a "hot" and "cold" calibration, and making an interpolated Z axis adjustment
based on both the Z zero measurement and the Radius correction. In other words,
for a given bed temperature, it should be straight forward to calculate the correct
calibrations between the hot and cold settings.
I may fix the software myself, but this is such a large change, I'd like to know
my effort may be incorporated into the main product. Any way to submit bug fixes?
As it is now, if you have a big print, you had best recalibrate of you make any significant temperature changes.
Problem solved(not)
Hint, as a workaround, I set my first layer thickness to about double, instead of 0.35 I used 0.6
so while the surface calibration may be .3 mm off, a .6mm first layer will at least do SOMETHING
if it is too high or too low. I was getting parts of the bed with nothing printed because the head
was touching the glass. 0.6 is larger than recommended for 0.5 head, but its just to get the thing stuck down,
and has the added effect of "leveling" the virtual print surface slightly. This allowed me to print
a 138mm by 1mm circle. which came out decent. I will post the gcode if anyone wants it. Slicr3r can
generate bad code printing that big.
What Temp?
I have recommendations for ABS from 70C bed temp to 110C bed temp? What is the right answer?
>>>> Did I dream that or can someone point me to the post with the 1/4" bed plate build?
(NOT the 1/8" plate.
BTW, the forum thinks it unreasonable to search for 1/4 says "1 and 4 are too common"
NOT helpful in a build forum to treat fractions as 2 numbers.)
My onyx bed has the usual hotter in the middle problem, which I must solve to make large prints.
I'm leaning toward aluminum plate. My standard setup is 50 C on printable edge then center is 100 C.
Questions:
I also see aluminum foil as recommendation. How much benefit does that have?
Calibration:
The issue is that changing temp changes the surface curve. Edges HAVE to be cooler,
so hotter center must expand, and that must go somewhere. So the curve changes
depending on the bed temperature, so the calibration for ABS cant possibly work for PLA,
at least not over the whole print surface. I would expect the software to handle this,
such as giving it a "hot" and "cold" calibration, and making an interpolated Z axis adjustment
based on both the Z zero measurement and the Radius correction. In other words,
for a given bed temperature, it should be straight forward to calculate the correct
calibrations between the hot and cold settings.
I may fix the software myself, but this is such a large change, I'd like to know
my effort may be incorporated into the main product. Any way to submit bug fixes?
As it is now, if you have a big print, you had best recalibrate of you make any significant temperature changes.
Problem solved(not)
Hint, as a workaround, I set my first layer thickness to about double, instead of 0.35 I used 0.6
so while the surface calibration may be .3 mm off, a .6mm first layer will at least do SOMETHING
if it is too high or too low. I was getting parts of the bed with nothing printed because the head
was touching the glass. 0.6 is larger than recommended for 0.5 head, but its just to get the thing stuck down,
and has the added effect of "leveling" the virtual print surface slightly. This allowed me to print
a 138mm by 1mm circle. which came out decent. I will post the gcode if anyone wants it. Slicr3r can
generate bad code printing that big.
What Temp?
I have recommendations for ABS from 70C bed temp to 110C bed temp? What is the right answer?