grbl firmware

[johnrpm]

soldered board

I have opted for grbl running on a uno for my dlp printer, with blue ice stepper drives and a protoneer shield, this makes for a small controller that can fit in a small corner somewhere, the only seller I could find for the grbl shield was from new zealand, only took 6 days to arrive in the UK.

As the PC must be connected to send images to the projector, no point having sd card support, or temperature stuff with ramps type boards,

Links to grbl stuff

The firmware
https://github.com/grbl/grbl

A controller to control your axis, good for setting thigs up ready for Creationworkshop
http://zapmaker.org/projects/grbl-controller-3-0/

Blue ice stepper drives, but stepstick, pololu also good
http://blog.think3dprint3d.com/2013/08/ ... sting.html

A library to flash grbl to arduino
http://blog.protoneer.co.nz/grbl-arduino-library/

A shield for the arduino to make things tidy, but not absolutly needed
http://blog.protoneer.co.nz/tag/grbl/

These are my choices, and may not be the best options, but got to start somewhere, I will post on progress and any problems.

[PacManFan]

It looks like the grbl firmware and board controller you have will be a good fit for the hardware requirements of a SLA printer. I have a hard time recommending a full RAMPs board to people when all they really need is an Arduino and two stepper motor controllers with some limit switches.

[johnrpm]

The shield is not essential, but makes it neater, to keep costs down, direct connections could be made, grbl is the basis of a lot of firmware versions available, without temperature, extruder stuff.
I think that temperature of resin may be an important factor, viscosity goes up when cold, and maybe cure time, and temperature control may be needed one day for the vat, if so I may use a separate heater control, my shed is cold this time of year.

[johnrpm]

Today I connected the board to the motors and fine tuned the settings, by sending $$ over serial, it lists settings,
for example X steps/mm is $0=100, would make the number of steps for X axis 100.
$1 is Y, $2 is Z, and so on, no need to resend with arduino ide.
the blue ice stepper drivers do not get warm, but I have not set the amps above half way, I had intended having a small fan, but it looks like it is not needed.
I have a PC power supply with the green wire tied to ground to enable it, will put a switch on eventually, when the panel is added along with some LED's, nice to have some LED's here and there to make things interesting.
The tilt and slide is working well, limit switches have been added but not wired yet, next is a base plate for the whole thing, with a sub plate for the projector to be able to slide it forward and backwards to align and focus the single element lens.

[PacManFan]

Cool! Keep us informed as to your progress. I'd like to know how it works for you.

[johnrpm]

I have had my 3d printer powered by grbl doing dry runs, that is to say, no resin.
the settings take some time to fine tune for smooth operation, one is $7 enable,
normally after a move the motor power is removed, this is ok for leadscrews but
my worm and wheel vat was loosing position, so I set $7=255, which leaves motors
powered on, they only get slightly warm so no problem, the current adjuster can be
lowered if things get to hot.
still need to configure endstops for homing, and I think I now understand the invert mask,
so will invert the z motor direction.

[sitzme]

Good to hear. I looked for the grbl shield on eBay but no luck right now. If I can find one I'll fiddle with it on another project.

It sounds like the firmware might be a bit more of a job to set up than some of the popular RepRap firmware though.

[seasicksinbad]

Here's a good guide for setting up GRBL on an Arduino Uno, it is pretty straightforward and took me no more than 5 minutes to do:
I wanted to use a shield also but decided to order an EasyDriver, which looks pretty easy to set-up as well. While I waited for it, I set up a standard Stepper Driver I had laying around.
The greatest difficulty was configuring CW to work with my configuration, turns out some of my settings were wrong and now it is working like a charm on preliminary tests at least.

[vonhellsing]

[PomeroyB]

Welcome to the forum!

The first thing I would suggest is not using a limit switch at all, for two reasons:
1) The limit switch behavior in Grbl is a little bit weird, and will some times lock up all motion when it shouldn't.
2) It's extremely easy to manually home the DropLit. Push the build plate all the way down until it is touching the vat, and that's it! As long as you've removed "G28" from your starting Gcode, this should work perfectly.

If you are determined to use a switch, I can at least point you in the right direction. You're first configuration is definitely correct. The second one may work, but it's a bit unorthodox. You also might try switching to NO and ground -- it could be that your firmware settings just has that logic reversed.

Good luck, and let us know if you solve the problem!