The Peachy Printer Suggestion Thread

[erikk]

If “rocking platform” is in action, every next layer (half layer) before gets under bright laser light can move a bit and submerge in to resin to get fine layer of fresh resin over the previously “bombarded” laser path. Than will return in “0” (horizontal) position just before making another laser layer/path.

I like the general idea, but maybe there's a simpler way to do the same thing.

It seems all you need to do is raise the resin level, relative to the printed object.
Your idea requires moving a large amount of water (at the end of the print), and probably wouldn't scale well to large print containers

A mechanism could drop and then lift the printed object by a fixed amount any time the laser is shut off
Or something could get pushed into the water to displace a volume to get the resin higher temporarily.

I talked to Rylan about these and he likes all of them as options for users to modify and test, but it likely won't be an option for the $100 printer.
So anyone who is doing a beta, test out one of these on your own when you get it and let him know how it goes.

[Slatye]

The big problem I see with that is that you'll create waves in the resin. Since the Peachy just hardens the top layer, this would create waves in the print too. To fix it you'd have to rock the bed a little bit, then wait 30+ seconds for the waves to die down before doing it again. With a 30-second delay per layer, printing is going to take ages.

If you can get a pump in there, that opens up a whole lot of options. For example, rather than dripping water onto the job, you could pump one layer's worth of resin through a spray nozzle. That would create a fine layer of resin coating everything, and then the laser can selectively harden whatever bits are required. No need to worry about waves either, although ensuring that the resin doesn't just hang around in the air could be an issue.

The most important thing for any modifications is going to be getting some I/O pins available. Can't control a pump or servos or autofocus or anything else without extra I/O pins. I remain hopeful that converting the Blender plugin to just output raw serial data to an STM32F4-Discovery will be straightforward; then that can handle all the timing-sensitive I/O tasks.

[DoulosDS]

I like the bobbing displacer idea best. A negative buoyancy mass located in a corner or at the side of the build tank could be supported by a linkage to an eccentric on a small motor shaft. The eccentric offset would be very small, and the motor would make one revolution at the end of each print layer, then be still during the next print layer. Is there access to the control signals on the peachy board which signal the end of a print layer, or is there a flag in the software? Keeping the rotation speed slow enough to prevent waves might be a challenge, if using a simple dc motor (like the vibrator motor from a cell phone). Maybe it could be controlled with a digital circuit using PWM (pulse width modulation). If the weight were sufficient to return the eccentric to the bottom when power is off, no feedback for motor position would be required. The motor controller would drive it to approximately 270 degrees, and gravity would complete the rev. DDS