Concept: h.ORD

[mxk]

I think the preferred firmware is Marlin, followed by Sprinter. Most slicers hardly ever do a Z movement at the same time as an X or Y, the only occasion I recall seeing that is in the hop function to prevent dragging very small warm surfaces along when moving between them, and the cool functions and support for fans built into modern slicers have largely made that obsolete.

I would have to print or talk a buddy into laser cutting some idler plates, and I wouldn't be able to test it in the near future (too many other in-progress projects, plus a full time job), but if you publish some adapted firmware I could probably re-jig one of my ORD bots to try this out.

[canadianavenger]

Thanks.. I took a look at marlin, and it looks to be pretty well organized. Most, if not all the changes should be confined to the interrupt routines in stepper.cpp. In this case combined movements should also be pretty straight forward, as all the steppers are evaluated and pulsed at the same time. (that was not the case for the code I looked at earlier). I'll try delving into it over the next week or so.

[canadianavenger]

I think I have a better solution for the "gravity" problem, than my initial plan of having parking pegs. I'm going to borrow a solution used for over century on double-hung windows, and garage doors. Basically use a pulley and counter-weight [or possibly spring]. I then have the option of balancing it, or making it so the counter-weight always causes the gantry to rise to the top home position.

[TLHarrell]

Interesting. I wouldn't use a spring though as spring tension is not linear. Isn't this needlessly adding complexity though? Still, a fun exercise in "what if".

[canadianavenger]

it is very much a "what if" exercise. I like to do them, as quite often something interesting comes out of it... so while the design itself may not be practical, some element of it somewhere may be useful in something else, or even the original design. As for the tension if using a spring, it doesn't really matter if it is not linear, as long as it does not exceed the holding torque of the motors. Having said that, I was leaning toward just a weight and not a spring.

[bdring]

You could use a geared stepper motor. I have seen ones like the MakerGear extruder stepper go for less than $20 some places. A 1:3 - 1:5 ratio would add enough detent torque to hold it in place.

You have have acceleration and top speed issues on the X, but you could still probably do 200-300mm/sec.

[Enraged]

what about changing the overall layout to be a horizontal H-bot (driving X and Y) and have the build plate move only in Z? It wouldn't look exactly like the ORDbot, but you could use all the same components. Add a bowden extruder, and you might be able to have a machine that's even faster.

[canadianavenger]

You could use a geared stepper motor. I have seen ones like the MakerGear extruder stepper go for less than $20 some places. A 1:3 - 1:5 ratio would add enough detent torque to hold it in place.

That would be an option, however I'd be concerned with the introduction of backlash. It's fine for an extruder, as the direction of travel is pretty much constantly in one direction. Constant reversals will start to introduce error.

what about changing the overall layout to be a horizontal H-bot (driving X and Y) and have the build plate move only in Z? It wouldn't look exactly like the ORDbot, but you could use all the same components. Add a bowden extruder, and you might be able to have a machine that's even faster.

Certainly a horizontal configuration would be more ideal, but the challenge/fun of this exercise is implementing it in the current ORD Bot configuration as closely as possible. It introduces some unique challenges that I'm enjoying trying to solve.

[bdring]

We disassembled a MakerGear extruder stepper at PS1 last night. It had surprisingly little backlash. Also, the load is always the same way, so the backlash tends to not be an issue. You do need to be careful though because there are some junk geared steppers out there.

[fma]

Just to say that repetier firmware has such geometry support...