Finally got the $ to buy myself all the parts to build a cnc. A question for the cnc users / devs here, which is the best option for controller? I’ve got smoothieboard already, but I’ve seen much talk about grbl also.
I’m considering combining the cnc with the laser also (as k40 is starting to cause dramas due to its mechanical components) if that makes any difference to controller choice.
Thanks in advance fellow tinkerers.
I would never combine a Laser with a mill. They have complete different forces to handle.
A mill must handle changing forces from the milling cutter against the material and therefore will need much more rugged rails and a lead- or ball-screws for the movement.
A laser doesn’t have any forces against the part, just the drag of the rails (like 3d printers). Therefore belts work perfectly.
A Smoothieboard will work perfectly. If you want to do fast laser engraving, I would suggest to install grbl-LPC on it. For laser cutting or milling, stay on Smoothieware and probably use a GLCD panel with it.
Thanks @cprezzi . I’ll take that advice & build a separate setup for the laser instead. Gives me extra consideration when purchasing from openbuilds. So looks like I’ll run the CNC from the smoothieware & use grbl-LPC for the lasering.
@cprezzi I’ve been out for a while obviously, but what is the benefit of grbl-LPC over smoothie firmware? I’m running one of the early C3D boards with the firmeware-bin smoothie firmware. Is there a strong driver to move to a grbl platform?
the primary benefit of grbl-lpc is that it can handle raster engraving with less “stuttering” vs smoothieware firmware. I still need to see how much faster it is as grbl also voids the use of my GLCD.
Ahh, that kills it for me right there honestly. GLCD is my control panel now so loss of that makes the machine less usable for me. I guess I’ll stick with smoothie for now 
Thanks.
@cprezzi - if you already have a CNC, is there a reason you would not want to add a laser diode cutting module to it? It seems that extra rigidity and stronger than necessary motors would not be a negative?
The big reason that I would not run a laser on a mill is that it is difficult to make it safe. Enclosing and interlocking a set of covers on a mill is problematic.
I don’t see any reason why the rigidity of this mill is not a plus for a laser? This OX unit is belt driven.
I am running TinyG and Chilipepper on this unit (only because that is what is popular on these setups) and will later consider if I switch to LW + Smoothie.
I am still struggling to get to one tool chain, one controller and firmware and one software interface for both this OX and my K40.
I doubt its in the cards …:(.
Many people do add a laser diode to their large format CNC. I’m was thinking about it but decided not to due to safety. With only one set of eyes, I don’t want to take the remote chance that a reflected beam can damage them. I don’t have very good eyesight to begin with.
I still have my k40 c02 that is fully enclosed but recent received a blue laser diode from my brother. I may stick it on the k40 to test.
My brother did warn me since his coworker had permanent eye damage from a laser accident in the Lab at work. He gave me a pair of laser goggles and warned me that reflected beam can still get you from the sides of the glasses.
Interesting thoughts here. What I was planning with the laser was to use the CO2 tube from the K40, have it enclosed in a space to the side of the CNC so that the laser points directly at a mirror on the moving head (X axis) whilst the Y-axis moves the bed. Since I haaaaate (with a passion) aligning the 3 mirrors. This would make only 1 mirror necessary for the lasering.
I thought the issue that Claudio maybe was talking about could be due to running a lead screw setup would be slower movement than belt driven setup. No idea though.
@Yuusuf_Sallahuddin_Y I know the glowforge mounts the laser tube on the gantry, maybe other lasers do it too. Easier mirror alignment but then you have to deal with laser power cable/water tubing routing issues.
Unless you get a expensive high lead ballscrew/leadscrew, it would be much slower than a belt drive setup. I sometimes do 500mm/sec raster engravings on the k40. At that speed, the stepper motor turns about 750rpm. Much easier done with belt drive.
@Yuusuf_Sallahuddin_Y Nice idea. So you would have a static X gantry that has the laser tube at one side pointing along the gantry and the X slider just needs one mirror to reflect the beam downwards. The Y movement is then made by the table. This is not a compact machine, but it’s easyer to align one mirror and you should get more power (less mirror=less loss).
@cprezzi Yeah, that’s the idea I’ve been having. 1 mirror to align on the X slider. The thought was that a) closer to the same power level hitting that mirror b) less alignment nightmares. Indeed it would make for a much larger machine, but size is not really a concern when it comes to improved function. Even better would be a totally fixed mirror, moving bed on the X & Y, tube suspended vertically shooting straight through the lens (no mirrors involved).
Putting the laser vertical could be adventagous as the photons will gain energy falling that far. …
@donkjr Haha, whilst I understand that photons have mass, I’d imagine the amount of gravity effect on them would be minimal. Was that a serious comment & there’s something extra that would be coming into play?
@Yuusuf_Sallahuddin_Y nothing serious about my musings just couldn’t resist
Btw as you think about these ideas consider the challenge of running HV large distances and through moving drag chains 
@donkjr I wasn’t planning on having the tube moving at all. Having it permanently stationary & have the bed moving. Then it can all be encased (for safety) & minimise the hassle with mirrors.
