Mount and Reservoir Discussion

[rylangrayston]

Awesome. 40 degrees of deflection is great. With those angles, 10' of height (e.g. a ceiling mount) gives you 7.2' square of surface below the top of your build area, so this seems like it's already operating at a good scale for doing very large prints.

How long does the laser need to cure each layer? Say, if you are targeting 1 micron layers or so. This is important for understanding how much acceleration of the dripping actually makes sense to attempt. Does the software compensate (or need to compensate) for longer cure times at the larger outside angles ?

Oh, what is the interface for the 2-way digital communication? Is it going to be possible to signal a drip command and/or other parameters? Would be sweet to digitally control the dripping. I have also been thinking about using a used automotive fuel injector; they typically have open/close times in the neighborhood of 2ms, so an injector would provide excellent digitally controllable variable drip size and frequency, though it would also require a pump.

Thanks again for the great work on this printer project. I can't wait to get my hands on one.

The software dose no yet do exposure compensation for the laser spot becoming elongated at higher deflections, but this is planed.
Since the laser spot isnt round It draws like a calligraphy pen ( its a very suttle effect) but that hasnt been accounted for in exposure ether.

how long would it take to cure a 7.2 ft long layer (say were printing a 7.2 foot long wall) from a celing mount....
The peachy printer software dosent use accelaration yet, instead we just go the speed at which we can turn a sharp corner and still have it look sharp.
Which is about 1 second per 40 degrees of deflection. But by the time we ship acceleration will very likely be working so the printer will be much faster than it is now.
ok so we know that we can go about 7.2 ft per second in this masive setup what is that in mm per second
7.2 * 12 * 25.4 = 2194 mm per second is the speed the laser spot would be travleing.
To expose the resin at that speed we will need lots more laser power.
typicaly in a small printer we go at 100 mm/s so now we need 22 times the laser power of a standard setup ( 2194 / 100)
I cant quote exactly how many mw a standard printer emits just yet.

now here i need to be careful I dont want anyone to think that a normal peachy printer emits an extremely powerful laser beam, that can burn the flesh on your arm...
We have put various measures in place limit the laser power to safer levels, so that you only need laser saftly glasses, and or a good enclosure around your printer, to be safe.
We also dont want the diodes to burn out so we are shipping diodes that are over rated for the job, technically they could handle emitting 50 mw with no aperture and a heat sink.
Which would be very dangerous to the eye! For liability reasons im sure its a bad idea for me to explain how to make the laser more powerful but I trust the community of expert hackers here has all the skills necessary to thwart our safety measures and get a printer to emit more laser power.
So I will just end with a warning, Lasers can be really dangerous, make sure your taking the necessary precautions, alwase where laser safety glasses, not just normal safely glasses and build a completely enclosed printer, so that when others walk in to the room unexpectedly, they are safe too.


As for a hack to tell the peachy that you have just Put water in the printer.. There will be lots of ways to do this but here is one I did just yesterday it works like this :

paristaltic pump shaft > IR inturpt sensor > arduino( with debounce script) ----voltage divider----> peachy printer circuit ----USB---> peachy printer software

Peachy circuit is 3.3 volt hence the voltage divider between it and the arduino and the 10k resistor between the peachy circuit and ground makes me feel safe if i happen to create a ground loop between it and the arduino. So when pin 13 goes high the peachy gets 2.5 volts, which is over the 1.8 volt on threshold for its 3 volt circuit.

IMG_3793.jpg


and here is the debounce code for the arduino:

int ledPin = 13;
int sensorPin = 8;
int debounceTime = 1000 / 20 ;

void setup() {                
  pinMode(ledPin, OUTPUT); 
  
}

void loop() 
{
  
  if (digitalRead(sensorPin) == HIGH )
  {
  
    digitalWrite(ledPin, HIGH);   
    delay(debounceTime);
    
  }
   
  
  
  else if( digitalRead(sensorPin) == LOW ) 
  {
    
    digitalWrite(ledPin, LOW);
    delay(debounceTime);
  }
  
}

I love the injector + pump Idea , I dont know how injectors will like salt water but i know there are some injectors that put water into diesel engines ( making steam that makes extra power from the heat in the engine)
I hope you will post all about some it day.