Tank3d printer build

[Boyan Silyavski]

Doddy, many thanks!

Your figures are broadly correct, but there's a bunch of information missing from the cable spec - max current rating (you can guess at 0.8A given the 25W/M - but that's likely derated given the intended installation buried in a concrete scree) - to be honest, I'd just try it and see. Yes, you'll get a bit over 500W heating which should give a respectable amount of heat energy for the 1kg block of ali that you're using.

My research on similar setups shows that in real life 500W non insulated bed this size will heat very fast, and insulated will heat probably under a minute, so no worry as you say.

Temperature control you've mentioned, and a thermal fuse (you mention) a necessity in this system; zero-crossing SSR also a good idea as well as a current protection device (fuse). All good stuff, but very little in the data on the cable to give support to your design simply because you're using it for a different purpose. Try it and see - my thoughts are that it should be workable.

Good info for the zero crossing SSR, i did not know what that means. Learned something. So are the cheap Chinese SSR relays zero crossing? I have used them for my kiln but they just work, i did not have an idea that they are different types.

My only reservations are: No indication of the thermal expansion of the cable - if you bed this too tightly in the ali block you could sheer the cable strands - I'd look to a loose fit and infill with thermal paste when you look to productionise.

I chose the carbon fiber cable exactly for that reason that the carbon fibre itself is very stable and does not expand or shrink. At least that is what they brag about it. But will look into further info about the whole cable.

Experiment, is the name of the game - you've nothing to lose (provided you keep a fire-extinguisher to hand :) ) In case the cable fails catastrophically I'd certainly use a test bed well away from anything flammable and be able to isolate the supply easily. Once you have your thermal control in place then test worst-case performance with it shoved in a cardboard box crammed full of thermal insulation (cloth sheets) to make sure that the control system still works.

I will do exactly that.

The one area I'd be concerned about with this cable is making the ends off correctly - looks like you are supplied with copper ferrules to crimp - that to me is the area that you're likely to see failure if not done properly.

I briefly looked into that and saw how people connect carbon fibre tape into clothes. More or less they use some kind of silver glue. So i am thinking i have to buy some ferules and test, if needed fit inside some extra silver compound for better conductivity. One thing is clear that everything should ve additionally fixed mechanically to the bed, meaning pressed between plates or sth, and from bed only 3 kevlar teflon double shielded thermo resistat wires will protrude.

I'm not sure I'd agree that this is a cheap solution, though - in the UK I can source heated beds off ebay for £6 each (214mm x 214mm) and these will be being etched in their hundreds or thousands in china with the precision from decades of investment in PCB manufacture. Only 120W, but two in parallel for the 400mm bed and you're not a million miles from your solution.

I will explain why i like this solution below. Mind me that the actual bed in the drawing is 440x220mm, so it will take 2x MK2 heated beds 12/24VDC on top of it bolted, which 1 of these is 7 euro.

1.The overall design of the machine.
-The printer must be rigid, fast and able to Scale Up. From that the result will be precision, nice prints and easy to build a second one, which probably most of the people will do, once they have one and are serious into printing.

I meditated long on the various possible designs and chose this one due to the simplicity to build and later adjust, compared to all of the other designs. Some of them are so ridiculous honestly, that even i can not imagine what hassle will be to straighten it to some acceptable precision. If i that build a 3m machine to some standard, can not be sure how to put together precisely a 50cm machine, then imagine what the result will be for a person that has no idea at all.

When you start scaling the machine up, the so called Core designs start to loose in moving weight compared to this one, though i dont know why the guys are so confused and praise them so much.

Thats another story but suffice to say that from what i see scaling the machine up, if i do the custom bed then the bed weight will keep in line with a Core XY design moving mass weight very simple. 20x20 beam is 0.45kg per meter even a 1000x1000mm bed could be done from same 6mm precision aluminum cast sheet and a simple beam bolted from below if it starts deflecting from heat. At the same time Core XY will have very serious lengths belts which will start back slashing/ from stretch/ on high accelerations, or motors have to be moved, which is additional mass...


And anyway all other design suffer from the problem called twisting the machine out of precision when prying out a printed object from bed Or separate glass bed that is insulator, ... and so on.

2. The lack of additional under bed carriage that is connected to the bearing blocks on which the bed lies, or whatever they call it. If that thing is made from plastic it bends, if its from aluminum it is heavy. In fact the aim here is to go without it.

3. Eliminate adjusting the bed once its adjusted when building the machine.

This practice is absolutely ridiculous to me. From day one i saw a 3d printer. Imagine having to do that on your mill or router every time you start a job

4. Ability to bolt it and to make bolt holes from bellow where i like. You can not drill PCB heated bed. That will additionally provide support to bed against bending from temperature, though from reports 6mm bed is alright.

5. If you glue additional silicone plate which is the only viable solution for big beds for now, first you can not drill it-means additional plate from below, second as i said its heavy, expensive and not any safer or cheaper.

6. I found a nice 230V heated PCB project which also seems stack-able but it will suffer from need of additional glass on top, hence weight, low reliability, loss of precision surface etc.

7. I think an additional sheet of thicker PEI on top of the aluminum bed will allow things to be removable and exchangeable, without f"""g the precision of bed and machine. Glass i dont like for 2 reasons- first its an insulator, second i dont like one shiny surface and all else different. Anyways i learned to print 100% with rafts.

I am not in a hurry, i prefer the quality result.


Here bellow is the latest update on the design. At the end when all is clear, printer will look very simple and clean. Bed will be thermo insulated from bellow. Electronics and motors will be below. Heat flow will be up , so all is ok. After long search at the end i found some people sharing that when bed temp 100C in enclosure temp is around 45C, which is ok for the plastic parts and the motors, so i dont believe they will need additional cooling.

Meanwhile i looked most of the extruders and hotends. The way i see it- E3d6 plus E3d Titan extruder or i have to make sth similar, which i dont have the time to investigate. One company, great products. No super duper over complicated extruders that cost 200$. These days i printed 24h and many different things, and i found that the weakest place in the 3d printer is the extruder itself and the measurement of the heat in the block- hence the thermistor type, position and especially way of attaching it.


All else could be Chinese or mediocre and will work more or less, but not feeding reliably the filament and not knowing reliably the temperature of the heating block= bad prints, unreliable prints, messing with adjustments that is not needed to mess with if these 2 are working right.

And these 2 could make you crazy if they are not perfect.