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Heated build chamber - Fridge?

Posted by hdp160 
Heated build chamber - Fridge?
September 18, 2013 04:52AM
Idea?

Use an old cube shaped deep freeze (refrigerator)* with a thermostatically controlled paint stripper heat gun** blowing air in at the bottom.

* Excellent thermal insulation. (Ideally with a front opening door (or a glass door***)- not a top loader)
** Thermostat mounted above the printer.
*** Point of sale drinks type fridge.
+ Excellent noise insulation
++ Web cam inside the fridge to see what’s going on from the "design studio" in the house maybe.

Aesthetically the beauty is in the eye of the beholder but in the workshop/garage no problem.


Comments?

Edited 1 time(s). Last edit at 09/18/2013 05:03AM by hdp160.
Re: Heated build chamber - Fridge?
September 18, 2013 06:00AM
This seems to be a good idea... however there is one concern and that is fridges are meant to function cold, so I am not sure how the materials inside a fridge or freezer will hold up to heat.

Along similar lines... I want to find out if it will be practical to 'gas proof' a fridge or similar in order to provide an inert atmosphere for metal printing.


3D Metal Printing and more - visit [www.metalbot.org] !
Re: Heated build chamber - Fridge?
September 18, 2013 07:24AM
I would guess that insulation works cold and hot.

I was thinking of stripping out the plastic lining, replacing with plywood and using the space where the compressor lives as filament storage and location for the heater.

Fridges are "air tight" that’s why mould grows inside an unused fridge, so the magnetic door seal would probably work for a positive (internal) pressure inert gas environment.

More Comments anyone?
Re: Heated build chamber - Fridge?
September 18, 2013 07:55AM
If the fridge is sealed, why bother heating outside air and forcing it in? Why not just place the heating element inside the fridge and heat/recirculate that air pocket? Much more efficient.

But even an old freezer/refrigerator would work. Store the filament on a bar in the freezer and feed it down into the fridge via a hole drilled between the chambers.


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: Heated build chamber - Fridge?
September 18, 2013 08:38AM
Totally agree in hindsight. (Hot air gun probably overkill)

This is an idea in the earliest of stages.

But maybe an internal radiant bar heater (with thermostat obviously) to speed up the warm-up of the compartment prior to printing especially on a cold day and if the unit were in an unheated garage Etc.

I like the idea of utilising the freezer box on a fridge freezer the way you described (for both storage and feed point.)

UPDATE..

Would also eliminate the smell (except when you open the door)

More comments anyone?

Edited 2 time(s). Last edit at 09/18/2013 09:06AM by hdp160.
Re: Heated build chamber - Fridge?
September 18, 2013 10:21AM
About the smell & fumes: How about a carbon filter with flaps that close when the printer is in use and open after a print to purge the air? That way, the chamber stays warm at least.
Re: Heated build chamber - Fridge?
September 18, 2013 11:20AM
Good idea.

The off-cut from the cooker hood carbon filter....... that bit is always thrown away anyway.

Would need a printable design for the carbon filter holder as well.
Re: Heated build chamber - Fridge?
September 19, 2013 06:25PM
Why not use an old oven instead of an old fridge?
Re: Heated build chamber - Fridge?
September 20, 2013 03:28AM
or just any oven, its a heated chamber already with temp control haha.
Re: Heated build chamber - Fridge?
September 20, 2013 06:41AM
Hahaha! That is the obvious solution!


3D Metal Printing and more - visit [www.metalbot.org] !
Re: Heated build chamber - Fridge?
September 22, 2013 09:24AM
Yes I guess your both right, and ovens are of course insulated as well.

Now all you have to do is find an old "CLEAN" oven free from fat and grease.

Just let me know where to find one. winking smiley
Re: Heated build chamber - Fridge?
September 22, 2013 07:31PM
I would say that heat insulation of fridge is much better than that of oven. Fridge is designed for continuous 24/7 operation, so it makes sense to provide better insulation, and it doesn't have to withstand high temperatures. Also ovens have quite high thermal capacity. I think that best material to build heated chamber are polystyrene foam tiles, like the one used for thermal insulation of buildings. They are light, easy to cut and should contain some fire retardant. I believe that its essentially the same material as used in fridge insulation.
Re: Heated build chamber - Fridge?
September 22, 2013 08:56PM
yup, polystyrene works really well to insulate. Additionally, a layer of aluminium foil on the inside will deflect IR radiation. That's why I chose those retrofit radiator insulation mats for my heat insulated chamber. The mats however are rather thin (3mm or so), maybe adding the thicker polystyrene tiles used in wall insulation will improve the retaining capacity even more...
Re: Heated build chamber - Fridge?
September 23, 2013 07:21AM
Good points.

Just to be clear I think the the creamy coloured building insulation panels like Kingspan, Celotex Etc. are made of polyisocyanurate foam not polystyrene (which can be inflamable if not treated and also has a very low melting point.)

So would go for Polyisocyanurate.
Re: Heated build chamber - Fridge?
September 23, 2013 12:48PM
Is there a particular reason you want to heat the build chamber? I made a "chamber" to surround my machine with some 4mm poly tubing. It eliminates drafts and temp changes from the room its in, and with the heated bed and extruder on, it definitely traps in a good amount of heat - worked wonders for filaments that warp.

I mean, it sounds like you're going for function over form, so why not make it cheap and easy on yourself?

You can get poly tubing for a few bucks. Print a few "arms" that connect to the top of your printer that you can drape the tubing over, and voila - cheap temp controlled chamber.
Re: Heated build chamber - Fridge?
September 23, 2013 01:28PM
To reduce warping, get the machine off your desk, reduce odor, etc.

Chambers may be expensive to produce in the short-run, but if they're thermally efficient they can be very inexpensive to operate in the long-run.

I've tried the turkey bag method before with mixed results. It's why I built a heated chamber. That and you're radiating/wasting all that energy. Better to leverage that trapped heat and keep your running costs low so you can buy more filament.


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: Heated build chamber - Fridge?
September 23, 2013 01:48PM
Eh, I agree with what you say in principle, but I haven't found much lost in efficiency. I saw a pretty nice increase in bed heating speed with the sheeting, and I definitely noticed a big decrease in operating current. While printing, my bed is rarely running above 30%, and my hot end - unless I'm printing nylon at 260-265C, is rarely above 50% - so how much am I going to gain in efficiency with a nice heated chamber?

Certainly not enough to justify spending a few hundred bucks on a nice heated chamber.

And buying some dampers will do more for machine noise than a chamber - unless you're using thick acrylic or some other medium that will absorb a lot of sound. It will also likely improve print quality for most. Not a ton, but depending on your setup it could.

[astrosyn.com]


As for the smell, well, you got me there, but I really like the smell of ABS when it's printing. smiling smiley
Re: Heated build chamber - Fridge?
September 23, 2013 03:13PM
There is no reason a fridge wouldn't work. Your hotbed would be more than enough to heat it up. Your problem may actually become too much heat or uneven heating from top to bottom. Another problem would be keeping your steppers cool enough and making sure that all your printer parts can handle a higher temperature environment.
Re: Heated build chamber - Fridge?
September 23, 2013 03:23PM
A few hundred bucks? I spent about $100 on a chamber that fits two machine and holds temp at 45C.


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: Heated build chamber - Fridge?
September 25, 2013 03:48AM
have you ever seen those grey foam pads that you can put in your work space, they have them at lowes for cheap, I just used them to make an awesome lightweight build chamber for my corexy machine, each panel was the perfect size for my bot, just cut off the puzzle bits. i think you can even just hot glue them together, or just use zip ties. then line each panel with aluminum foil and bind it with foil tape, works perfectly, just needs a heating element, I was thinking about just a bunch of led strips, they actually generate quite a bit of heat.
Re: Heated build chamber - Fridge?
September 25, 2013 11:19AM
That sounds like an effective and cheap alternative to using a fridge or oven as a heated build chamber.

However, wouldn't it be very inefficient to use LED strips to heat the chamber? LEDs are fairly efficient at producing light so even though they do product some heat, most of the energy they consume is converted into light energy which would be useless for your application. An alternative would be to use a Prusa PCB bed or a silicone rubber heat bed sandwiched between two aluminium plates with fans blowing over them to circulate the heat within the chamber. The advantage of this is that you could use an adjunct electronics board to easily control the chamber temperature.

My 2 cents smiling smiley

Eric
Re: Heated build chamber - Fridge?
September 25, 2013 03:31PM
this is true, but interestingly, I was using a bunch of strip lights on this sheet of steel, they got hot enough to warp the entire sheet, with a deflection in the middle of nearly 2 inches, and it was so hot the adhesive started peeling off of the led strips, the reason is because the strips have resistance too, and the resistors create heat as well, if you run the strip of leds from end to end, instead of in parallel you basically have a large heating element, also the light heats up stuff too.
Re: Heated build chamber - Fridge?
September 25, 2013 04:05PM
Wow, that is very interesting.

The LEDs are wired with resistors in the LED strips so it's understandable that the heat produced by those resistors would contribute to the warping of the steel sheet. I image that this LED strip would draw a lot of power. How do you plan on controlling the power supplied to this LED strip?

Eric
Re: Heated build chamber - Fridge?
September 25, 2013 04:18PM
If you were to use conventional incandescent bulbs to produce the heat/light you would be able to pop a web cam in there and see from a far what's happening. ( at least when they are on?).

I'm want the printer in the garage away from the house, and I don't want to go outside in the winter to check Etc.
Re: Heated build chamber - Fridge?
September 25, 2013 09:59PM
actually after looking, it seems like that little space heater is 1400 Watts, I think that may be the way to go, its only 20 bucks on amazon prime. I have a little camera for recording the printer, perhaps it will get more use now that ive made the chamber, just ordered the space heater, im going to modify it so it can be controlled by the electronics, the thermostat part at least, and then just have a thermo couple attached to a thin aluminum plate in the build chamber somewhere.

Edited 1 time(s). Last edit at 09/25/2013 10:08PM by aduy.
Re: Heated build chamber - Fridge?
September 28, 2013 10:48AM
Wow 1400W that's a beefy heater!

I think the one in my cooker oven in the kitchen is about that size.

That may turn out as a forge not a printer if the thermostat / couple were to go rogue.
Re: Heated build chamber - Fridge?
September 28, 2013 12:41PM
hdp160 is right. If I can get my makeshift chamber to 40C using just a 200W heat bed that is not even always on, imagine what would happen if your temp sensor for your 1400W heater stopped working eye popping smiley Your chamber would probably top 100C and you would find puddles of molten ABS parts around your printer!

Eric
Re: Heated build chamber - Fridge?
September 28, 2013 05:10PM
Strip heaters are perfect for this. You can get them as low as ~75W. I'd think something in the 250-500W range with a temp controller should be about right. Something like this:

http://www.ebay.com/itm/Vulcan-OSF1517-1550B-Heater-strip-240-volt-/161069188022?pt=LH_DefaultDomain_0&hash=item258078c3b6
Re: Heated build chamber - Fridge?
September 28, 2013 07:12PM
its got a 100 year warranty, and tons of reviews on amazon, im not concerned about it staying on, btw abs starts to melt at 100c, meaning it gets soft, seeing as it will be sucking in air from the outside, room temp, the temp output will be constant. also it has a built in thermal shutoff.
Re: Heated build chamber - Fridge?
September 28, 2013 08:18PM
Ok, that sounds quite reliable and safe.

BTW, I was exaggerating about finding puddles of melted ABS parts winking smiley While ABS won't turn to liquid at 100C, if you pass it's glass transition temp (about 105C) it will get soft and will be much more susceptible to deformation due to printer movements. I wouldn't go above 80C just to be safe. Besides, if you can get the chamber temp up to 80C you definitely won't have any problems with ABS warping!

Eric
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