Thanks Doug that makes sense but I have 360mm arms and 300mm calipers, so what I wondered is whether there is a trick to measure something that is longer than the calipers? I could use the metal rod that protrudes from the caliper, but how to measure to high accuracy like this I don't know.
Just clap a block to the edge of your desk, butt the rod up against it, mark the end, then repeat for each rod, see if all your lines are in the exact same place
I would be so excited if you found a way to make this work. Right now SLA is taking off and the field of printers is so small mostly because of the difficulty of driving a galvo/the fact that arduino boards can't do it at proper resolution. All the solutions are proprietary and expensive. If you can get a duet and a duet branded DAC on the market that could drive a galvo they would sell like hotcakes.
Came here to post this exact suggestion.
Could be HUGE for the duet, as Arduino lacks the tech to drive a galvo currently and a lot of people are looking to drive galvos in 3dp
Haha thank you! 70lpm was just an example of one of the more powerful units. I certainly don't need that much through a berd air…it'd probably blow my effector up to my home switches! I would consider that unit for hotend cooling though, if I make a super heated chamber.
What's the best way to integrate this to my system I wonder. Can pumps be pwm? Is it possible to do some sorcery like hot to a power supply and negative to the duet and get pwm? Or get an ssr and hook it up like a bed?
Hi Mr. 42 & Co.,
I'm considering a "berd air" cooling setup. I planned on using 110v and a solid state relay like my bed to control the pump. Now though, I'm stumbling on 12v DC air pumps with some impressive specs! Unfortunately my electrical knowledge ends somewhere around operating a light switch. The pump feature specs like this:
OUTPUT: 70LPM /Min POWER: 35W VOLTAGE: DC 12V PRESSURE: 0.10MPa
If I hook this thing up directly to a duet wifi does it ( a ) blow cool air across my prints surface or (b) explode
Thanks!
Stefan
Note that the extruder doesn't have to be directly fixed to the carriage…. the fourth tower could reach out over the print area. If if it was just an upside down L that held the extruder fixed downward over the center of the bed and just high enough to be out of the way of any printer moves you could have a fairly short Bowden with no mass on real carriages. The firmware capability is the tricky part. I haven't bothered thinking through exactly how I'm going to work out the mechanics until I have a way of moving a fourth axis pretty in tune with the effector. My other idea is a long worm-gear looking thing that spans across the top of the printer and suspends the extruder, as it rotates the string/wire/whatever you're suspending with follows the path around the gear (at a constant steps/mm) effectively reeling the extruder up the print goes.
That is the point – this intended for a large delta, like mine. My carriages -- under normal conditions park at the top -- engage breaks (servos driven by an arduino) and printer powers down, if the breaks don't engage, the effector will fall down. If assuming normal conditions, we are assuming perfect knowledge in all cases -- I can't always assume that. If I have a hall effect sensor -- -- and I have 1 small tube and a large tube -- and a universal joint at the effector -- I can track small tube going in and out and know if I have to move the extruder axis up or down -- if you can bake that into the firmware - -great, but I plan on implementing it as a standalone feature -- like the piezo board. It will use the sensor to keep the rigid arm between the effector and the extruder carriage at a predefined distance -- it's actually fairly simple, your output of the hall effect sensor must be 512 -- you have a magnet at one end of the tube, and as the value decreases, that means the distance between the extruder and the effector is decreasing, so you move away -- which is up...as the value is increasing, which means the distance is increasing also, so you move the effector down
My delta is 1m tall with a 350mm bed, and my carriages don't fall when I turn my printer off.
In other words, rods+ (radius of ballstud * 2)
If you purchased them from Haydn/ultibots etc, the number on the rod will be correct. The actual measurement is from the pivot point of both ends, which is the distance between the center of each ball-stud.