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twicx
So by the sounds of it, I'm going to need something between the Rumba, the power supply and the heater(s). This makes it tricky.
The first problem is the mounting points. Because of the design of how the bed is mounted to the z axis gantry, the mounting points for anything is going to be a tricky issue. My printer (Felix 1.5 Rev.E) uses 3 mounting points for the Heated bed. One is in the centre of the heated bed, and the other two are in the corners. However, if I move to a larger print bed, for example, 300mm x 300mm, Those two corner mounting points move up along the edge by about 1/3. So the centre mounting point would be the same, but the two other corner ones would still be on the edges, but about 40-60mm from the corner. Looking at the PCB option, I think I made an error in thinking that the holes in the middle of them are another mounting point. I think they're for the thermistor.
The next problem is the power supply. I've already gotten a new ATX power supply that puts out 58A at 12V, so I would like to try to stick with that one, rather than go to 24V.
This brings me back to the whole heater issue. By the sounds of it, I need something to manage the power (it's going to be >10A) in or around the Rumba/Heater/Powersupply. What would be my cheapest/best/easiest solution for that?
As for the heaters, I still like the convenience of the PCB one in that I can keep the weight of the heat bed down. It looks like I can drill outside of the white boundary line where the traces are, but then I still have the problem of that 3rd mounting point in the centre of the board, which I'm not so sure how to tackle. I'm still very reluctant to use the silicone ones, and I'd favor the kapton foil option over those, as they're cheaper, adhesive, and maybe 4 x foil heaters might be an option.
Edit:
[www.alibaba.com]
This is the kind of printbed I have in mind. The ideal (albeit optimistic) setup would be that, use the center hole as the 3rd mount point, drill two new mount points up from the corners (you can also see the white border), and then figure out how to manage the power supply bit. Is this possible?
Try looking at a Solid State Relay these can be driven by your Rumba board easily and still switch the high current dc that you need They are available in various Current rating's
Doug