Power Consumption

[mike_biddell]

I note, in threads for hot extrusion printers, that people have noticed large increases in their power consumption. Simply because of 250-500 watts of heating per hour. Peachy scores again..... probably 5 watts max? Unless someone has accurate power consumption figures?

[harpo99999]

based upon the 20mW laser power, the largest power consuption would be in the audio interfacing board (guess <1w?? no idea actually) so possibly able to be powered from a usb port(5v @ 200ma) of the computer or a small power brick. and the reason for the low power needs in relation to the MELT plastic 3d printers(that have 40w PER extruder(165+ pla, 235+abs, other plastics possibly approaching 300c) and typically 100w for the hotbed(large area lower temp 110-120c) just to keep the plastic sticking to the bed) is the photon-activated curing of the liquid resin

[Slatye]

USB power (especially on USB3.0 where you can get 900mA) could well be possible, although technically you're meant to ask the PC before drawing that much power.

The other advantage of the low power, of course, is that you don't end up heating up whatever space the Peachy operates in. It's annoying to have an air conditioner running just to get rid of the heat dumped by a conventional FDM printer.

[mike_biddell]

USB power (especially on USB3.0 where you can get 900mA) could well be possible, although technically you're meant to ask the PC before drawing that much power.

The other advantage of the low power, of course, is that you don't end up heating up whatever space the Peachy operates in. It's annoying to have an air conditioner running just to get rid of the heat dumped by a conventional FDM printer.

There is no doubt, the very low power consumption of the Peachy is a major selling point, especially if you intend to use it for small scale manufacturing. Does anyone know how the resin cost per unit volume compares with extruded plastic per unit volume???

[prototrout]

Does anyone know how the resin cost per unit volume compares with extruded plastic per unit volume???

I can make a guess (with a lot of poor assumptions). MakerJuice's most expensive resin currently sells for $45/L, so I'll assume PeachyJuice will sell for the same amount. After a quick search, it looks like PLA costs around $30/kg, which ends up being (at 1.25 L/kg) around $37/L.

So the resin will be a somewhat more expensive than PLA, but not by a ton.

Making some rather larger assumptions (and using some numbers from this page), using up 1L of PLA would take about 1kWh of electricity. 1 kWh will only cost a few cents, so the savings in power consumption isn't nearly enough to make up for the higher materials cost.

Of course, the price of resin could end up being lower (or higher), and if the Peachy (and SLA printers in general) get popular enough that will help drive down the price. But we have no way of knowing when or even if that will happen.

Bonus: at a price difference of $7/L, assuming a price of $500 for a printer kit (I think that's about what they go for), you'd have to print around 57L worth of stuff before the PLA printer becomes cheaper (with a break-even point of around $2200).

[Slatye]

It's a difficult question because the production techniques are so different.

With a conventional (FDM/extrusion) 3D printer you generally fill the interior of the part with a low-density mesh pattern. This increases strength and allows the top of the part to be supported - otherwise even something like a cube couldn't be printed because it'd be impossible to print the top.

With something like the Peachy, a standard cube will be completely solid. Even if your model is hollow, there's no way to get the spare resin out of it - so it'll be full of liquid resin that will solidify over time. As a result, it uses far more material than an FDM-printed cube. On other other hand, if you leave a tiny hole in the cube then you can print it completely hollow and drain the excess resin afterwards. No need for internal structure to support the top. This would use far less material than an FDM-printed equivalent.

For many things, like sculptures, this is perfect. You just leave the bottom completely open because it's never going to be seen, and that allows excess resin to drain once it's done. No need for internal structure, since the printer can do overhangs unsupported and a sculpture doesn't need to be really strong. For machine parts it's probably largely irrelevant, because you'd want them to be solid anyway (and the Peachy won't have the delamination issues that FDM printers have). Where it will matter is stuff like toys, where you want a part that's pretty solid but not too heavy and not too expensive to make. In this case it's just a matter of deciding how you optimise the part. Maybe you make the walls thicker and skip internal structure. Maybe you use the Wiggle resin so the whole thing is nice and flexible. Neither option is available on FDM.

[masterada]

It's a difficult question because the production techniques are so different.
With something like the Peachy, a standard cube will be completely solid. Even if your model is hollow, there's no way to get the spare resin out of it - so it'll be full of liquid resin that will solidify over time. As a result, it uses far more material than an FDM-printed cube. On other other hand, if you leave a tiny hole in the cube then you can print it completely hollow and drain the excess resin afterwards. No need for internal structure to support the top. This would use far less material than an FDM-printed equivalent.

Wouldnt the liquid resin float to the top of the water as you print the sides of the cube? In this case, the cube would be filled with salt water instead of liquid resin. (Or a mixture of the two).

[harpo99999]

only if there is an opening in the bottom of the cube to allow the water to enter, if no opening then the resin is the only thing inside the cube

[Slatye]

Wouldnt the liquid resin float to the top of the water as you print the sides of the cube? In this case, the cube would be filled with salt water instead of liquid resin. (Or a mixture of the two).

I don't think so. Say you've got 1mm of resin on top of the water. Obviously for the first 1mm of the cube there can't be any water inside it; the water layer starts below the bottom of the cube. For the next layer (ie 1.01mm or so) the water is above the bottom of the cube, but it can't get into the cube because the walls of the cube prevent it. The only thing that can get into the cube is the resin, which goes right up to just over the top of the partly-completed cube. This continues all the way up; the cube sides are always just under the top of the resin layer, and above the top of the water layer. Therefore the water can never get in.

One thing to be careful of here is that you might need quite a lot of resin, even if you're not using the laser to solidify all of it. A 100x100x100mm cube will require a litre of resin even if you only actually use the laser to solidify the sides - the entire interior will be full of resin too. If you wanted a solid cube than that's no big deal - obviously a 1L solid cube is going to require 1L of resin.

What if you wanted it to be hollow with 1mm wall thickness (total volume of the finished cube 0.06L)? If you print it with a hole at the bottom it'll still require a full 1L of resin, because the hole will be covered by the build platform. Once it's finished you can take it off and drain the spare 0.94L of resin from it, but if you don't have at least 1L of resin to begin with then the job will never finish. Same applies to a hole at the top - you can get the spare resin back but you have to load the printer up with 1L of resin first. If, however, you have a hole very low on one side then the water will be able to flow into the cube during the build. Now you can get away with only having 0.06L of resin (or, more realistically, about 0.1L so there's a bit to spare) for the print job.

[rylangrayston]

I don't think so. Say you've got 1mm of resin on top of the water. Obviously for the first 1mm of the cube there can't be any water inside it; the water layer starts below the bottom of the cube. For the next layer (ie 1.01mm or so) the water is above the bottom of the cube, but it can't get into the cube because the walls of the cube prevent it. The only thing that can get into the cube is the resin, which goes right up to just over the top of the partly-completed cube. This continues all the way up; the cube sides are always just under the top of the resin layer, and above the top of the water layer. Therefore the water can never get in.

One thing to be careful of here is that you might need quite a lot of resin, even if you're not using the laser to solidify all of it. A 100x100x100mm cube will require a litre of resin even if you only actually use the laser to solidify the sides - the entire interior will be full of resin too. If you wanted a solid cube than that's no big deal - obviously a 1L solid cube is going to require 1L of resin.

What if you wanted it to be hollow with 1mm wall thickness (total volume of the finished cube 0.06L)? If you print it with a hole at the bottom it'll still require a full 1L of resin, because the hole will be covered by the build platform. Once it's finished you can take it off and drain the spare 0.94L of resin from it, but if you don't have at least 1L of resin to begin with then the job will never finish. Same applies to a hole at the top - you can get the spare resin back but you have to load the printer up with 1L of resin first. If, however, you have a hole very low on one side then the water will be able to flow into the cube during the build. Now you can get away with only having 0.06L of resin (or, more realistically, about 0.1L so there's a bit to spare) for the print job.

This is completly correct, Great Thinking everyone!