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It's just too cold!

Posted by KillerDave 
It's just too cold!
November 21, 2015 06:42AM
Hi Friends!

Just spent a good many hours designing a part and went to my printer to set it of printing but it's just too cold to print....

My workshop is un-heated and right now the temp is showing 3*C! Brrr!!!... I don't mind it but my printer is a big girl and doesn't like the cold!

So... My options are.....

1, Heat my workshop.... It's a very big room and wold cost the earth to heat plus take forever!
2, Move the printer into the house... I do not want to move it as it'll need to be fully adjusted again! I do NOT like this option....
3, Build a heated cabinet to put it in..... probably the easiest option....

Has anyone done this?

Any ideas would help me out lots......

David.
Re: It's just too cold!
November 21, 2015 06:55AM
You can just a reptile heating mat under the printer and cover the entire setup with a big garbage bag.
Should keep the inside of the bag well over the 20° range.
An incandescent light buld inside the bag might work too but it has the risk of creating to much heat if something comes into contact with the hot glass.
These reptile mats create a max of about 45°C, so if you go that road select one that is big enough or use two.

Edited 1 time(s). Last edit at 11/21/2015 06:59AM by Downunder35m.
Re: It's just too cold!
November 21, 2015 07:00AM
I did think of a reptile mat but also a cabinet round the whole thing...???
Re: It's just too cold!
November 21, 2015 08:35AM
I had the same thoughts and never finnished my cabinet idea.
Wanted it simple and easy to remove as my printer often requires access from more than one side.
My last thought was to use polysterene sheets as used for house insulation.
A bootom sheet with cutouts for the side walls and the same for the top.
One or two sides with a little plastic window glued in.
But so far and if it is getting too cold the garbage bag worked a treat so I always had an excuse not to make a box around the printer LOL
Re: It's just too cold!
November 21, 2015 09:00AM
If you use foam insulation it's worth picking one with good fire resistance. Some of that polystyrene stuff burns like crazy with horrible fumes. I was pretty impressed by this test on PIR foam: [www.youtube.com]

I couldn't find a directly equivalent test, but this is pretty scary: [www.youtube.com]
Re: It's just too cold!
November 21, 2015 09:16AM
Ok, I'm working on it!
I have an unused baby table and it has a top area of 760 X 495.
My Prusa i3 actually fits in the short side but I will build the "box" as big as I can on that platform and mount the printer that way... Maybe???

Anyway, I'm working on the design now so when I have something, I'll post it up....

Thanks for the help....
And of course, keep this going as the more ideas the better... thumbs upsmiling smiley
Re: It's just too cold!
November 21, 2015 09:24AM
A while back I built this enclosure for my printer. Something similar might work for your situation. I would avoid polystyrene foam as it produces toxic fumes when it burns. PIR costs slightly less ($15.25 vs $15.87 per sheet Insulation at Home Depot) but is fire resistant. In fact, you can even print on the stuff without a bed heater. If you don't need to move the printer around, you don't need to print the parts to hold the box together, just use duct tape.

If your controller has an unused thermistor input (for a second extruder, for example), you can use it to regulate the temperature inside the enclosure. Then all you need is a source of heat. Pick up one of these and bypass its own thermostat- all you want is the fan and heating element. Get an SSR to switch power to the heater on and off under control of your printer's controller board. Place a thermistor in the enclosure to measure the air temperature. If you want to print ABS you want the enclosure to be at about 45C. Use bang-bang or turn on PID control for the enclosure heater and run an autotune cycle and Bob's yer uncle.

It might be best to keep the electronics outside the enclosure if you're going to run it as warm as 45C, but if it gets too cold outside, that isn't ideal for the electronics either.


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: It's just too cold!
November 21, 2015 11:09AM
I wouldn't want a fan in there though???
I did think of that though....
Re: It's just too cold!
November 21, 2015 11:13AM
Maybe if I design the box with a false floor and a filter to diffuse any drafts and a vet at the top???
Re: It's just too cold!
November 21, 2015 11:15AM
As long as it isn't blasting right against the print it should be OK. You can always add a cardboard/PIR baffle or two to slow/redirect the air motion. You probably have a fan on the hot-end that stirs up the air right around the print and it's OK with that...

Edited 1 time(s). Last edit at 11/21/2015 11:15AM by the_digital_dentist.


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: It's just too cold!
November 21, 2015 05:59PM
It is too cold to print, I can't get anything to stick, and when I turned on my printer it was showing mintemp error as it was below 5 deg C, I had to warm up the heat bed with my hands before I could reset it and turn on the heater.

Oh well. Heated enclosure for me too I think.
Re: It's just too cold!
November 21, 2015 06:14PM
How do you reset it?
I warmed it with my hand to about 15 degrees but when I power cycled it, it still said "min temp error"
Re: It's just too cold!
November 22, 2015 05:25AM
Also could just get a portable floor heater, and point it at the printer.
Re: It's just too cold!
November 23, 2015 04:10AM
Quote
KillerDave
How do you reset it?
I warmed it with my hand to about 15 degrees but when I power cycled it, it still said "min temp error"

How did you set the min temp?
In Marlin its in °C:

// The minimal temperature defines the temperature below which the heater will not be enabled It is used
// to check that the wiring to the thermistor is not broken.
// Otherwise this would lead to the heater being powered on all the time.
#define HEATER_0_MINTEMP 5
//#define HEATER_1_MINTEMP 5
//#define HEATER_2_MINTEMP 5
#define BED_MINTEMP 5

On my replikeo duet0.6 I found 1k pullup resistors, which got me in trouble with temps below 15°C. RRF_DC42 firmware has no parameter to set min_temp.
I use body heat and a fire lighter to raise temp then reset the controller.
-Olaf
Re: It's just too cold!
November 23, 2015 07:46AM
Quote
o_lampe
On my replikeo duet0.6 I found 1k pullup resistors, which got me in trouble with temps below 15°C. RRF_DC42 firmware has no parameter to set min_temp.
I use body heat and a fire lighter to raise temp then reset the controller.
-Olaf

The problem is not the lack of a mintemp parameter in RRF, it's that with 1K thermistor series resistors the ADC can't tell the difference between cold temperatures and a disconnected thermistor. That's why RepRapPro and T3P3 changed to fitting 4.7K series resistors over a year ago. Replikeo doesn't appear to have picked up this change.

If it's still a problem for you after adjusting the M305 H parameter, then the best solution is to replace the 1K resistors on your Duet by 4.7K.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: It's just too cold!
November 26, 2015 05:27PM
Built a heated enclosure photos enclosed, just a bit of preliminary testing going on now. Decided on a 3 sided MDF box with lots of insulation foil, the left side of the enclosure is just foil bubble wrap so I didn't have to worry about catching any cables and to allow my PSU cables to enter at the back. For heating have cannibalized a 400w 1 bar electric heater which is insulated from the MDF by fibreglass exhaust wrap material. The heater is currently controlled from an external controller, but planning to use E2 thermistor and an SSR for it at some point. The heater mains voltage is connected in parallel with the printer PSU, for safety the smoke detector board I posted elsewhere is now inside the enclosure, so hopefully any smoke issues and the heater gets shut off along with the whole printer (its currently set to just above the max sensitivity and no false triggers from normal printing yet). The heater and LED light can be disconnected to allow me to lift the whole thing off the printer for access, its just the hole for the filament to enter which spoils this quick access plan. Planning a fan to keep the electronics cool and a fume vent on the top. Running heater set to 45 Deg C. But for now I am printing again smiling smiley
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Re: It's just too cold!
November 26, 2015 06:37PM
That's very cool! No, wait, I mean it looks very warm.

I'd be just a little bit worried about a radiant heat element in there, it may tend to produce hot spots on anything that gets close. I'd guess that a small oil filled convection element would be a better choice, although a quick search on ebay completely failed to find anything suitable sad smiley
Re: It's just too cold!
November 27, 2015 03:42AM
Quote

The heater is currently controlled from an external controller, but planning to use E2 thermistor and an SSR for it at some point.

I'm not sure you could control the SSR, when you have a min_temp error on the two other thermistors?!
-Olaf
Re: It's just too cold!
November 27, 2015 04:03AM
Quote
JamesK
That's very cool! No, wait, I mean it looks very warm.

I'd be just a little bit worried about a radiant heat element in there, it may tend to produce hot spots on anything that gets close. I'd guess that a small oil filled convection element would be a better choice, although a quick search on ebay completely failed to find anything suitable sad smiley

Yeah well this is what I'm testing now, the only thing actually near and facing the heater is the top of the frame, which does get warm but not too hot that I can't touch it, the heater element cycles on and off and once the heatbed and extruder are hot it doesn't cycle on that much. Plus I've made the enclosure fairly tall so that the heater is a way above anything more delicate.

I'd like to cut an aperture for a small fan to blow cold air on my ramps board, and have a fume vent coming out of the top of the box and out of my workshop, so my hope would be that this might circulate air gently around equalising the temperatures inside the box a little.

Quote
o_lampe
Quote

The heater is currently controlled from an external controller, but planning to use E2 thermistor and an SSR for it at some point.

I'm not sure you could control the SSR, when you have a min_temp error on the two other thermistors?!
-Olaf

I agree but the mintemp default is 5 Deg C which can be reached by just warming the heat bed and extruder with my hands at the start of a printing run, or perhaps a hair dryer to just raise the temperature above 5 deg C then I can power on the heaters.

My main concern was that heat rising from the heater element would scorch or burn the MDF box but 8mm of fibreglass insulation between it and the box, and there is nothing more than a little warmth above the heater. So far so good.

Since the heater is at the top and back of the enclosure, if I home Y before heating the bed then the bed heats very quickly without my usual piece of insulation I put over it to speed up heating, and then have to remember to pull out before printing begins, so this is an improvement.

My x,y and z motors do not run hot in this environment the extruder motor is a little warm but not too hot to touch after printing for 2 hours, it is nearer to the heater and conceivably working harder than the other motors anyway.

Edited 1 time(s). Last edit at 11/27/2015 04:13AM by DjDemonD.
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