1 Topic by elmoret

  • elmoret
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  • Registered: 2012-10-11
  • Posts: 6,048

Topic: Heating Build Volume

So I've been battling warping. I'm trying to print a part that is 5.5"x5.5"x5.5", and seeing some warping. Things are much better since going from an 80C bed to a 100C bed, and enclosing the 3 sides, but I'm running into a problem. The ambient temperature is about 38C inside the build volume now, and the steppers are rated at 50C ambient maximum.

http://gelikor.ru/docs/1.8%20Nema%2014% … 0Motor.pdf

So... if I get much warmer, I'll cook the steppers.  I'd like to run the build platform around 60C, to reduce warping. As it is right now, the middle of the part is running about 35C, and I see some warping before the print finishes.

I'm thinking... what about low-power peltiers? Based on the formula here:

http://reprap.org/wiki/Sanguinololu

and the voltage specs on SD's website for adjusting the drivers, they're pushing about 1.2A per motor. (which is funny since the x-axis is rated at 1.0A/phase...cool, solidoodle) roll Similar story on the Y-axis. Motor rated at 1.33A, SD running it at 1.3A.

Anyway, I'm thinking these babies could benefit from some active cooling. However, I want the build volume to be above the rating for the motors. So, perhaps I can use small pelters...

The motors draw about 4W each, regardless of motion (stepper motors are constant power devices, unless the driver is smart enough to reduce current. I do not think this is the case).

Therefore, a little baby peltier would work just fine. Like this:

http://www.ebay.com/itm/New-30mm-TES1-1 … 19d1040564

I could run it at 4V, which would require roughly 1.5A each, and push 4 watts of heat with a deltaT of 40degC. If I kept the motors at 40degC, then my peltier hotside would be 80degC. I'd have 5w of heat from the stepper, 6w of heat from the peltier, and 20degc difference between peltier hotside and ambient. Then, I just need a heatsink capable of ~2C/W or better.


This guy needs roughly 10 CFM to get under 1.5C/W:
http://www.luxeonstar.com/54mm-Square-A … 54-20b.htm

12CFM @32dB
http://www.mouser.com/ProductDetail/Bi- … WvYiVyM%3d


So it looks like you could do it, for about $15 per axis plus power supply (12v, 2A). You'd be adding 18W of heat to the build volume, which could probably push air temps up around 50degC. (which actually gives more buffer room to the above calcs than if build volume was the target 60C.


Thoughts? You'd be adding about 70 grams, but the motors themselves are 220 grams, plus carriage inertia. I don't see a need to put a cooler on the extruder motor, as it already has a HSF and runs well under the currents that the XYZ axes see.

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2 Reply by Kvirre

  • Kvirre
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  • From: Malmö, Sweden
  • Registered: 2012-10-05
  • Posts: 81

Re: Heating Build Volume

elmoret wrote:

So I've been battling warping. I'm trying to print a part that is 5.5"x5.5"x5.5", and seeing some warping. Things are much better since going from an 80C bed to a 100C bed, and enclosing the 3 sides, but I'm running into a problem. The ambient temperature is about 38C inside the build volume now, and the steppers are rated at 50C ambient maximum.

http://gelikor.ru/docs/1.8%20Nema%2014% … 0Motor.pdf

So... if I get much warmer, I'll cook the steppers.  I'd like to run the build platform around 60C, to reduce warping. As it is right now, the middle of the part is running about 35C, and I see some warping before the print finishes.

I'm thinking... what about low-power peltiers? Based on the formula here:

http://reprap.org/wiki/Sanguinololu

and the voltage specs on SD's website for adjusting the drivers, they're pushing about 1.2A per motor. (which is funny since the x-axis is rated at 1.0A/phase...cool, solidoodle) roll Similar story on the Y-axis. Motor rated at 1.33A, SD running it at 1.3A.

Anyway, I'm thinking these babies could benefit from some active cooling. However, I want the build volume to be above the rating for the motors. So, perhaps I can use small pelters...

The motors draw about 4W each, regardless of motion (stepper motors are constant power devices, unless the driver is smart enough to reduce current. I do not think this is the case).

Therefore, a little baby peltier would work just fine. Like this:

http://www.ebay.com/itm/New-30mm-TES1-1 … 19d1040564

I could run it at 4V, which would require roughly 1.5A each, and push 4 watts of heat with a deltaT of 40degC. If I kept the motors at 40degC, then my peltier hotside would be 80degC. I'd have 5w of heat from the stepper, 6w of heat from the peltier, and 20degc difference between peltier hotside and ambient. Then, I just need a heatsink capable of ~2C/W or better.


This guy needs roughly 10 CFM to get under 1.5C/W:
http://www.luxeonstar.com/54mm-Square-A … 54-20b.htm

12CFM @32dB
http://www.mouser.com/ProductDetail/Bi- … WvYiVyM%3d


So it looks like you could do it, for about $15 per axis plus power supply (12v, 2A). You'd be adding 18W of heat to the build volume, which could probably push air temps up around 50degC. (which actually gives more buffer room to the above calcs than if build volume was the target 60C.


Thoughts? You'd be adding about 70 grams, but the motors themselves are 220 grams, plus carriage inertia. I don't see a need to put a cooler on the extruder motor, as it already has a HSF and runs well under the currents that the XYZ axes see.

This could be the reason why my X-axis stepper is so hot (really hot)?
http://www.soliforum.com/topic/423/hot-xaxis-motor/

Kvirre's Website

3 Reply by solijohn

  • solijohn
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  • Registered: 2012-08-07
  • Posts: 1,465

Re: Heating Build Volume

Kvirre wrote:
elmoret wrote:

So I've been battling warping. I'm trying to print a part that is 5.5"x5.5"x5.5", and seeing some warping. Things are much better since going from an 80C bed to a 100C bed, and enclosing the 3 sides, but I'm running into a problem. The ambient temperature is about 38C inside the build volume now, and the steppers are rated at 50C ambient maximum.

http://gelikor.ru/docs/1.8%20Nema%2014% … 0Motor.pdf

So... if I get much warmer, I'll cook the steppers.  I'd like to run the build platform around 60C, to reduce warping. As it is right now, the middle of the part is running about 35C, and I see some warping before the print finishes.

I'm thinking... what about low-power peltiers? Based on the formula here:

http://reprap.org/wiki/Sanguinololu

and the voltage specs on SD's website for adjusting the drivers, they're pushing about 1.2A per motor. (which is funny since the x-axis is rated at 1.0A/phase...cool, solidoodle) roll Similar story on the Y-axis. Motor rated at 1.33A, SD running it at 1.3A.

Anyway, I'm thinking these babies could benefit from some active cooling. However, I want the build volume to be above the rating for the motors. So, perhaps I can use small pelters...

The motors draw about 4W each, regardless of motion (stepper motors are constant power devices, unless the driver is smart enough to reduce current. I do not think this is the case).

Therefore, a little baby peltier would work just fine. Like this:

http://www.ebay.com/itm/New-30mm-TES1-1 … 19d1040564

I could run it at 4V, which would require roughly 1.5A each, and push 4 watts of heat with a deltaT of 40degC. If I kept the motors at 40degC, then my peltier hotside would be 80degC. I'd have 5w of heat from the stepper, 6w of heat from the peltier, and 20degc difference between peltier hotside and ambient. Then, I just need a heatsink capable of ~2C/W or better.


This guy needs roughly 10 CFM to get under 1.5C/W:
http://www.luxeonstar.com/54mm-Square-A … 54-20b.htm

12CFM @32dB
http://www.mouser.com/ProductDetail/Bi- … WvYiVyM%3d


So it looks like you could do it, for about $15 per axis plus power supply (12v, 2A). You'd be adding 18W of heat to the build volume, which could probably push air temps up around 50degC. (which actually gives more buffer room to the above calcs than if build volume was the target 60C.


Thoughts? You'd be adding about 70 grams, but the motors themselves are 220 grams, plus carriage inertia. I don't see a need to put a cooler on the extruder motor, as it already has a HSF and runs well under the currents that the XYZ axes see.

This could be the reason why my X-axis stepper is so hot (really hot)?
http://www.soliforum.com/topic/423/hot-xaxis-motor/

We appreciate the analysis. As was noted in previous discussions, the Solidoodle motors seem to operate quite well at these temperatures/voltages.  In past incarnations of the machine we attempted to use the motors at the recommended voltage, and had inadequate results. Since they appear to work perfectly well at the higher temperature, we allowed the change.

Former Solidoodle employee, no longer associated with the company.

4 Reply by elmoret

  • elmoret
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  • Registered: 2012-10-11
  • Posts: 6,048

Re: Heating Build Volume

What do you mean by "inadequate results"? Skipped steps?

Exceeding the manufacturer specified maximum is not an acceptable solution just because it works for a few months. Using properly sized motors is a better solution.

If SD feels the need to overdrive the motors they could at least put fans and heatsinks on them.

SD: what is your nominal design current on each axis?

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