The Peachy Printer Suggestion Thread

[DoulosDS]

As you know, several of the Peachy Printer guys frequent this unofficial forum. I thought it would be a good idea to create this thread to take suggestions for the Peachy Printer. Perhaps your idea would be something that would help put Peachy Printer over the top, and make it just that much better.

Let's hear your ideas!

I lucked into a 55-gallon drum of clear UV cured resin, but I suspect it has a higher viscosity than Peachy Juice, though I may be able to thin it. (Does anybody know the viscosity of Peachy Juice (in centistokes or Zahn cup) or the maximum viscosity resin that Peachy is designed for?)

Regardless, it should be possible to install a solenoid valve in the Peachy drip tube, and set the drip rate near the maximum rate. Whatever the software determines the slice thickness to be, when the drip count is reached, the computer could raise a flag on a USB port and pause for a programmed interval before scanning the slice with the laser. The output signal would close the solenoid valve and stop the drip during the pause interval. This would allow time for the resin to flow over the previously-exposed layer and any bubbles to pop or voids to fill.

After the slice is scanned by the laser, the flag would drop to open the solenoid valve and the process would repeat. Even for normal low-viscosity resin, this modification might allow faster printing or better quality prints. Anybody know how to make this hack happen? What programming tools do I need to modify the Windows version of the Peachy programs?

Anybody want a sample of the resin to experiment with? It is Quakercoat 021-UV Clear. It can be thinned with Sartomer 5102 monomer (not sure where to get that yet).
Thanks, DonS

[DoulosDS]

".... Whatever the software determines the slice thickness to be, when the drip count is reached, the computer could raise a flag on a USB port and pause for a programmed interval before scanning the slice with the laser. The output signal would close the solenoid valve and stop the drip during the pause interval. This would allow time for the resin to flow over the previously-exposed layer and any bubbles to pop or voids to fill...."

From another suggestion: the flag signal could also trigger dunking a displacer in the print tank to raise the resin level momentarily and ensure the previously printed slice is evenly covered with fresh liquid resin. The displacer would have a tapered base to minimize waves and a time delay would be programmed for resin to flow off the displacer and any disturbance of the resin to settle before the next slice is printed. A micro controller (R-Pi?) and stepper motor would lower and raise the displacer, with a sensor to maintain the approximate depth of displacement as the resin rises in the tank, and keep the tip of the displacer just under the surface to prevent drips during the print. The displacer would begin to lower when the flag indicates the laser has completed scanning the current slice, while the drip system is running. When the solenoid stops the drip, the displacer would be raised as quickly as can be done without undue disturbance of the resin.

[DoulosDS]

There are so many good ideas on these forums! As I read, I keep getting more inspirations...

OK, the displacer would work fine, but an even better method uses a positive displacement pump, driven by a stepper motor. (I'm assuming the drip system is far more precise than the pump, but the pump is sufficiently precise for pumping repeated volumes.) At the end of the slice print, the flag signal opens the solenoid valve and the drip system begins adding brine to raise the resin to the level of the next slice. Meanwhile the pump is also adding brine by a precise number of revolutions. When the drip count is complete, the excess brine has caused the resin to cover all the previously exposed slice. The pump is then run in reverse by the same number of revolutions, returning the resin level to the height of the next slice. A short pause would allow any movement of the resin to cease before the next slice is scanned.

However, if the stepper-driven pump is sufficiently precise for positioning the resin from slice to slice, the pump can replace the dripper system. It would raise the resin enough to cover all the previous slice, using X revolutions; then lower it to the level of the next slice, using -X+slice revolutions. I think this could speed up the printing process significantly.