1mx1m hot plate?

Quote
dc42
the mass is 2700 * 1 * 1 * 0.05 = 135kg

I think you are wrong by one digit. The thickness is 0.005m = 5mm. But still the glass plate is the weak link in his configuration.

@rowrow
you confused electric resistance of copper vs. nichrome with thermal capacity.
-Olaf

Thanks Olaf. I made another mistake in the calculations too. I have added a correction to my original post. But the conclusion remains the same, i.e. 3kW would be enough.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

No, I am not. Again, its better to demonstrate a example in real life rather then explaining it so here you go:
As you can see nichrome wire heats up much faster because of its high resistance
[www.youtube.com]

Quote
rowow
As you can see nichrome wire heats up much faster because of its high resistance
[www.youtube.com]

Air has much higher resistance than nichrome. Oh wait, so if I detach the wires from the radiator I will have house heating almost for free!
That's how I'll get rich, after failing with perpetual motion.

Because of its high resistance then you will require a very high voltage, 1000 volts for every millimeter, then yes, its a virtually free house heating, You do realize a heater can be anything, even graphite, the stuff used in pencils are made into transistors, and many people use high powered transistors as a heating pad for their heat bed. So if your going to be a jackass and use ignorance at least use it when you have some clue in what your talking about.

Edited 1 time(s). Last edit at 10/11/2015 01:06PM by rowow.

My last post seems to never have appeared so I'll give it another try. I have researched and now seriously considering using a hot water recirculating system to heat the bed and enclosed chamber of a large delta I'm building. The bed itself is a 590mm dia. X 18mm thick three layer Lexan sandwich, where the middle layer is hollow to house plastic tubing for the circulating water. The system is essentially a zero pressure, closed loop tankless heater where the water flows through the bed and then into a small radiator where a fan blows heat into the chamber. The water then returns to the heater block for recycling back to the bed. I'm looking to maintain a 70c internal temperature common to Stratasys 3d printers, using a SSR, thermocouple, and PID control to regulate the programmed heat setting. I'm considering this because the bed is so large and its easy to plumb the system for even heat distribution. Secondary, the same system provides a means to distribute heat throughout the chamber through a common control. I'm interested to hear your views on the idea before I commit to it. Thanks...TP.

Stratasys uses that "oven" temperature for printing ABS. I have found that 45-50C is adequate to prevent delamination, and is a lot easier on the motors (X, Z, and extruder) which in my printer have to remain inside the build chamber. At 45-50C I don't need to bring in cooler room air to keep the hot-end cool. At 70C stratasys machines have to use hoses to supply and exhaust room air to cool the hot-end. That's a LOT of messing around and added mass on the extruder carriage. I don't know what kind of bed surface you're planning to print on, but AFAIK, 70C won't be high enough to get ABS to stick (unless you go for the unheated PIR foam). If you're going to do all this for printing PLA, 70C in the chamber will be too high, and PLA seems to print fine at room temp anyway.

Stratasys heats the chamber in at least one machine using a pair of 400W resistors powered by 117VAC, and a pair of small fans to circulate the air over the resistors.

My machine has 3-4 cuft build chamber volume and gets to 50C with top, bottom, and back made of PIR foam board and 1/8" polycarbonate on the other 3 sides without any additional heating other that that supplied by the 450 Watt bed heater, the extruder, and the motors. While you could use a recirculating warm water system to heat things, it seems unnecessarily complicated. Also, a closed system with heated water poses a risk of explosion and severe injury if the control system fails and the temperature gets high enough to boil the water. If you want to heat the chamber, a cheap electrical heater like the one I previously linked will easily do the job with lower cost, less messing around, higher reliability, and lower risk. You can bypass its own thermostat and use PID control via the printer controller board.

Water is quite massive and requires a lot of energy input to heat up. You'll have to use a very high powered heater or the time constant will be so long that PID control won't work very well. If you use a high powered heater, you increase the risk of boiling.

Edited 2 time(s). Last edit at 10/11/2015 03:08PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

This is something that I actually agree with Digital Dentist, water has a very high heat capacity, that's actually one of its special properties. So you would be putting far more heat in to get whatever amount of heat you need out.

And for the heating the air, I again would use nichrome wire. This is where my view shifts with Digital dentist.
The "cheap electrical heater" is actually not cheap and does not regulate temperature based on, well, temperature. It only has a high/low/medium function.
It would be cheaper to just use nichrome wire, or better yet, for 15$ (5$ more then digital dentist cheap heater), it would be better to make a PID temperature controller, which actually regulates the temperature based on what you give it. Which if you want to I can teach you how to make. Or search online/youtube on a how to. Very easy to make.

Thanks DD...good info; thanks for your input. Just for clarification, the Stratasys ABS printer I had occasion to use, doesn't heat the bed; just the chamber. The bed plates are sacrificial ABS, but they appear to last well in normal use. I have several options for the bed surface, the Lexan itself is the first choice, but others are available. PVC sheet as used for shower pans is one option that has been reported to work well. I'm also looking at a disc of the print bed material offered by Mutley3D on another thread. If/when I use PLA the chamber temp would be turned down and/or vented to whatever temp works best.

My motors are outside the insulated chamber except when I choose to use a direct drive extruder. I have one of the Berrystruders for that; and two of the Bondtech extruders for a dual Bowden setup. I am looking into a single fresh air line for the hot end where cool air is brought in from a side port, and then vented to the interior to mix with the heated air. I plan to use that regardless if I go with hot water or direct electric heat. I'm using a constant force cable reel to balance the weight of the motion system so I don't think the added mass of the small air hose will present a significant issue.

I erred saying a "closed loop" for the fluid, obviously a zero pressure system would need a vent line to prevent a blow up condition. The water tubing is rated to 30 psi but there's no need to pressurize the system. The fluid capacity of the current design is calculated to be about 2.5 liters total. A small, cheap 12v solar water heater pump pushing 2 to 3 gpm would easily keep the system flow paired to a 12v - 24v 600w or smaller screw in heating element. I think that small volume of glycol would very quickly heat to the desired temperature, and then need little added heat input to maintain a stabilized chamber temperature. I think a two zone temp control system would keep things in check; one for the fluid itself and one for the internal air temp. The plan is to run a separate power supply for the heat system where a run away condition would cut mains power to a dedicated 24v power supply. The 24v power supply for the printer would continue to run separately.

Honestly, I don't see the system being complicated at all; especially for a large bed and chamber volume such a mine. All the parts are pretty inexpensive and there's not much to it other than the controls, and those are pretty comparable to what's needed for an all electric system. I think power consumption will also be less considering heat retention in the fluid once chamber temp is reached. I hope this better describes my design....Thanks...TP.

Hi rowow...thanks for contributing to my idea. Let me say I'm not trying to be argumentative toward other points of view, I'm just responding as best as I can to why I like the idea of using hot water (fluid) for my application. Your point that the heat capacity of water is very high is well taken. Water or a combination of water/glycol as described, may well not be the best fluid for this application. Olive oil for example is a very inexpensive fluid, has less than 1/2 the heat capacity of water and almost three times the boiling point. I don't see applying heat efficiently as a problem given the different fluids available to me.

I previously used 16 ga. nichrome wire encased in PTFE tubing for an aluminum heat bead in another printer that worked well. I could do the same again here and place a coil of that in the bed instead of the water tubing; but that installation is actually more difficult, expensive, and harder to size correctly for this application. I already have all the temp control hardware, so adding the fluid components for this printer is actually very inexpensive. So far, I don't see good reason not to try it; but I'm still interested for other opinions that might change my mind. Thanks again rowow....TP

Out of curiosity why did you use PTFE tubing? If its for the bed why not kapton?

The bed was made from 8020 aluminum extrusions locked together for a 23 X 30 bed size. The attached picture shows how I looped the nichrome and PTFE tubing through the extrusions to make a closed circuit. The PTFE acted as an insulator for the nichrome. That bed uses 110v mains power, draws about 12amps and heats to 110c. Max temp on the PTFE is about 175c.

Oh I understand now. Thank you.

Quote
rowow
Hello, Currently I am making a 1000m+ cube 3d printer. I already have all the mechanics planned out (currently all of the material will ship in in the next few weeks which costed under 400$) but the only issue I cant wrap my head around is the heat bed. I want to print is abs and later homemade 3d printer filament/PETE/PET which warps as much as ABS,
*A head bed which can go 120C-150C
*Be very large 1m x 1m
*Be relatively cheap, under $100
Currently the only thing I can think of is nichrome wire, but does give alot of heat? I can get some 36awg wire 100ft for 5$, but is 36awg thick enough?
Thank you, this is my final struggle in my DIY 3d printing, once I get this dealt with I will start recording and building the printer.

*EDIT* I also forgot to add that the heat plate will be stationary, so you can go for the heaviest solution possible, I dont care, just as long as it's cheap and works.

Hi rowrow

Have you tried silicone heated bed? Please have a look at the pics attached: etched foil silicone pad, 8000 watts of power, made in china, 450 USD shipping included. The dimensions written on the white board in the second picture are the size of the printing platform (1332 x 1326 mm). I don't know if 450 is cheap enough for you, but when I asked Durex for a quote, their number was in the four digit bracket. Hope this helps.

Edited 2 time(s). Last edit at 11/10/2015 10:42PM by val c..

Ive already researched into these, and as you see yourself 500$ is way too much for me.

Hi guys,

I agree with most of what have been said above by experienced reprappers.
Let's be honnest, you can't buy a 1000x1000mm flat within 100µ surface.
Your budget just does not match your expectations. It sounds like a newbie lost cause.

There's no other way than to be the luckiest man on earth to find the build plate and heating in the garbage.
You want a very strong and thick surface to don't bend too much under its own weight at these dimensions.
Mabe a 15mm aluminium plate won't bend. Its weight will be about 60kg.
Aluminium from the garbage cost at last $4/kg. Calculate by yourself.
Keep in mind you will have at last to lift that weight.

To heat the bed, the less expensive would be to get owen's heating resistances from the garbage.
It won't be perfectly even, but it should work at the requested temperatures.
But even if it works under AC power, you will need wires and a regulator with relays.

If you want a low cost machine of this size, you should be very ingenious and find usefull things from trash.
If you're lucky enough you will find corrugated aluminum sheets or so.

To me inexpensive printers are obviously smaller ones.

++JM

I already have an aluminum sheet of 1m, so if I need to I could use PLA... And for the heating part, I already solved it, I should just close this thread as only inexperienced people as you come by and make me laugh.
And aluminum IS NOT STRONG. Its slightly flat, and very difficult to keep strait because of how it bends, even 15mm.. Your funny, you really are. Only material that can meet my standards is glass. Cheap (under 100-150$, cheapest one I found was 60$) and extremely flat.
And may you lead me to one person other then bonmotwang who has some basic experience in anything that is related to mechanical or electrical design? Digitaldentist who has been on this topic the longest has repeatedly failed in basic calculations and other tips(If you check his posts)

Please keep us updated on your progress. I am particularly interested in the performance of your bed/heater and look forward to seeing video of your machine printing. Thanks!

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Will do, I am currently clearing up my old shop to make space, mostly for the fact that when I was purchasing the linear rails the price between 1000mm and 1500mm was only 2$ (openbuilds linear rails) so I just went with the 1500mm...

Quote
the_digital_dentist
Please keep us updated on your progress. I am particularly interested in the performance of your bed/heater and look forward to seeing video of your machine printing. Thanks!

Way to be the bigger man DD....I for one appreciate all that you contribute to the forum. Thanks again.

Have you thought about using the heating element out of an electric oven.
You could try the oven element and the controller from the oven
to switch the 220V element and control it's temperature.

I don't have any experience with a 1m square bed.
but a flat has been very important on my meager 300mm square bed

Parts not sticking --- then getting knocked off.

Many brims, multi layer, if there is a bit of a dip in the build surface, no adhesion, no print.

Glass, etched glass, kapton tape, blue painters tape whatever
just follows the dips in the base plate.

Pissing all over those that are trying to help --- won't get you much help.
Your so good --- do it yourself --- we will watch the Noble prize ceremony for you

I thought about that at first, but for 1m there would be too many hot/cold spots. To solve that I would need some sort of heat balancer, like a liquid. But that's getting way too complicated and expensive.

Hi,

Quote
rowow
I should just close this thread as only inexperienced people as you come by and make me laugh.

I agree, I have a limited experience. I'm not a graduated machinist.
I started building my first CNC 10'x5' aluminium machine in 2009, it runs at about 1.5 foot per seconds and weights over 700lbs.
And I'm a reprapper for only two years. You saw through me. Thanks for your modesty and kindness.
I'm looking forward to seeing how smart your machine will be.

++JM

IMO you cannot build a large 3D printer on a budget. The only way I know of getting a sufficiently flat bed of that size is to use an aluminium tool plate. To heat it, I would ask these people [www.aliexpress.com] to quote for a silicone heater slightly less than 1m square. They did a custom heater for my delta printer at a very good price, so I would expect it to cost a lot less than the $450 that has been mentioned.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

A large griddle

[www.ebay.co.uk]

After a print session you could do pancakes and bacon for the whole neighborhood.

But at 3Kw you may have to notify power supplier to put a couple more reactors on line?

Perhaps a steel tooling plate with many small tubes constructed in it.
A large boiler could pump in superheated steam --- the exit steam could be router to heat your house.

Perhaps a visit to the GE 3D printing development facility.
[www.ge.com].

Maybe they will let you comb thru the "surplus" area

Thats bullshit. I have already got all the material (I just need to find a place to put it together) for around 450$, which includes dual extruder, proximity sensor leveling, lcd, stepper motor cooling, and much more.

its super great and all but 300$ D; With some more research I managed to find a 200$ one, and I bet if I search on craigslist or something I can go for 50$-100$. But thank you! If my nichrome idea fails this should work,

I'm going to post here, only because this topic will be found and read by others, and they deserve good information.

I am however very very disappointed in the tone of this thread, it's almost a shame to post in it. The members that have given the most of their time here are some of the most respected and experienced. Their advice has been very good. Guys, you have my highest regard, thank you. You have a lot of patience.

What does it take to heat a bed of 1m size?: this has already been discussed, I will just add some insights from my own experience:

There was a heated bed referenced earlier in this thread on Grassrootsengineering.
For reference that one has a 403x403 build area, sightly thinner material for the bed than mine, and a 480 watt heater. (BTW, he estimates it would take $3000 to $5000 to build that printer, and you can get his plans for $99 - it does cost something for engineering.)

Also for reference, my printer is a Delta with an unusually shaped build plate, the longest dimension across being 431mm. It's roughly similar in size as the above, a bit smaller, but thicker.
It is made of cast aluminum tooling plate - 9.51mm thick (I got the plate as a rem for $40, about 1/2 price), and I use a sheet of mirror glass on top as a print surface.
Due to the unusual shape of the bed, used twelve - 50w power resistors. In parallel these have 8.33 ohms. With my custom 64.5v DC power supply, at 7.74A, this puts out 500W of heat. I didn't want to use mains power there, and I do use a hardware thermostat too for safety, but that's just me... being safe.

- Un-insulated it used to take about 40-45 minutes to reach 109C, using 500 watts, with an enclosed and insulated build chamber.
- After I fully insulated around the bottom of the build plate it now takes 25 minutes. The uninsulated plate referenced on Grassrootsengineering is perhaps slightly larger, I estimate will take that somewhere near 30 minutes to come up to temp, give or take 5 minutes. Someone could ask him to be sure, but I'm estimating here.

Requirements for a build plate?
A build plate needs to be extremely flat over the entire surface in order for the first layer to stick properly, and the print must also be even enough for the following layers to be smooth.
In my experience a difference of .1mm is too much variation, I shoot for .02mm. Your tolerance will vary somewhat depending on the first layer thickness used, and if a raft is used. You must define your tolerance, and engineer to make that happen.

Cast aluminum tooling plate is nearly flat enough.
- For thicknesses over .5 inch it has a tolerance (converted to metric) of 0.416mm per meter, and will weigh 78lbs or 35.38 kg for .5 inch, and will deflect several mm just under it's own weight, since it can not be securely constrained at the outside edges.
- The tolerance is worse for less than .5 inch thickness for cast tooling plate: 1.25 mm per meter tolerance, and will deflect more.
- So clearly a machine of this size machine must be firmly mounted (not on rollers, on carpet, etc), with an adjustable mount for the build plate so it can be trued up.

Regular aluminum plate is not recommended. Why?
- The flatness tolerance starts out worse (over 2.5mm per meter), and the internal stresses cause it to warp when heated and cooled. This does not happen with cast tooling plate.

How thick does the plate need to be? An engineer could specify more exactly, and there is a much better thread here where support methods are discussed. I think near .5 inch, and will need to be supported in the middle, and the supports need to be adjustable to true the plate.

Mirror glass is flat enough, but as stated is a very poor heat conductor, and would need to be thicker than usual for that large dimension, making it even worse. I'm not sure mirror glass is obtainable in the thickness required. Regular glass is not required to be as flat, and others have seen here that it isn't always flat enough.
Because of the poor heat conduction, there would need to be some form of heat spreader, or put more heaters close together. If you use a regular aluminum plate as the heat spreader then it has to be flat and not warp - hence a cast plate, or multiple smaller heat spreaders bonded to the glass. This could make it more of a challenge to support the glass in a perfectly flat/adjustable way, and would cause it to expand unevenly. I haven't seen it done, but there's always a first time. It would be a shame if something dropped on it and it cracked tho, and I would expect it could crack if some of the heaters failed or were not used.

How much More for 1 meter square?
The referenced build area was 162,409 square mm, a one meter square bed is 6.15 times as large.
However I estimate the build plate also needs to be between 50 and 100% thicker in order to stay flat at that size, and this extra thermal mass has to be taken in to consideration for the preheat time - as stated you are heating a mass, not air, or just a wire.

In the thread below they estimated they needed a 2500 watt custom silicone heater for their 45 lb, 1 meter build plate (preheat time not tested, that printer is still not finished as of this date).

Just based on the increase in area: 480 watts x 6.15 = 3130 watts.
I estimate it would actually take close to an hour+ to reach over 100C as the bed must be thicker unless more power is used (more thermal mass, more convection and radiant losses). I can tell you, that's a painfully long time. Insulation placed on the top could speed this up some. It must definitely be insulated below.

That's also an awfully lot of power use, and a lot heat being generated. The heat from the printer will need to be exhausted outdoors, unless you plan on heating the room with it (not recommended - ABS fumes = toxic). That's a change from the usual, the build chamber will need to be cooled, not heated.

As has been stated you also need to account for the deflection of the frame, gantry, etc. for the weight and forces to be applied.
This was best discussed in this thread: 1 Meter Bot Project.
They didn't use cast plate there for their build plate, and didn't support it properly, so I think they will have problems - if they ever finish it.

To others that are considering building a very very large printer, my humble advice:
- Make sure the products you are going to make with your monster are worth the 10x to 30x investment in time and materials that a printer of this magnitude will take over a smaller sized printer.
- Read about all the other large printer builds
- Learn all you can, read the entire site in fact. The more you learn, and experiment, the more you will find you still don't know. It can be very humbling, but illuminating to find out you were wrong.
- Take the good Dr's advice.
- Then build at least one normal sized printer from scratch. Then you can use that printer to make parts for the bigger one, and will have gained invaluable experience (anyone want to buy a really nicely tricked out, used Rumba... just kidding.).

No one here has successfully created a printer of 1 M size that will print its whole volume, yet, despite some considerable effort. There have been a couple pictured with some large prints, but not near their entire volume.

We're pulling for anyone that wants to try, someone's going to do it.

We'd sure like to know how it turns out for you.

P.S.
I think the good Dr is right, for a printer this size - a bed of the special (but not expensive) foam is more practical. That's one of the reasons the really big printer manufacturers use it. He's found an easily sourced alternative, and gone to the trouble of testing it. You've done him and others a great disservice, and should apologize.

P.P.S.
Please post some photos of your other 3D printers, that will help us know where you're coming from.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

Quote
rowow
Will do, I am currently clearing up my old shop to make space, mostly for the fact that when
I was purchasing the linear rails the price between 1000mm and 1500mm
was only 2$ (openbuilds linear rails) so I just went with the 1500mm...

Can you post a link for 1500mm linear rails for $2

What material / size will support the linear rails to prevent defection while printing?
What type of carriage will you be using, what type of bearings?
What will keep the 8mm leadscrew from whipping around?

How about details of the rest of the printer mehcanisms, core XY, belts or cable?

Oh im sorry, I meant $2 difference, not in whole, and I already posted where it was from, open builds, here is the link I guess if your lazy doing a google search...
[openbuildspartstore.com]
and its gt2 belts,