Can’t wait for this 
More options for those DIY-gifts for friends/families like laser engraved wine/beer bottles
If you’re using a diode laser then it won’t be capable of etching glass, you’ll need CO2 laser for that. Another option that works very well for etching metal and glass is a diamond drag engraver. I’ve has one for a couple of years and don’t remember where I got it but there’s a pretty good deal on ebay. Only thing with these is they’re strictly for engraving lines and can’t do variable depth like you can with V-carving or milling but they’re very forgiving of Z-height changes in the material too.
thanks @Leo69. I’ve been contemplating getting those 40w CO2 ebay lasers from US sellers for a while. It seems like they were a bit improved compared to those coming directly from China. Would those work for etching glasses?
Yea, a 40w laser will etch glass.
thanks Barry. 40w CO2 laser then
Sorry that I’m dragging my ass on this a bit, been busy. If anyone would like me to post the software then let me know and I’ll just go ahead and do that while I’m finishing up testing and write-up for this project. There are plenty of fairly affordable rotary axis’ on E-bay so the software is the only thing needed if you buy off the shelf rotary. I did get a chance to do some testing with wood, better than expected since it’s a V-carve tool path which is sensitive to height changes. I didn’t “turn down” the stock before carving which indicates that the run out on the bearings and chuck/collet isn’t too bad. Definitely good enough for laser or drag knife work for sure.
Looking really good! Would there be a way to work on a tapered cylinder? Thinking of the butt of a pool cue. What about arbitrary shapes, such as on a turned table leg?
Hi,
Why do you need to wrap the gcode?
I would have thought you could just take the Y-stepper driver, and connect it to the rotary motor instead.
(with different steps, and maybe using the E axis instead, but in principle)
Thanks,
It’s early in the morning to think about it but your suggestion should work if you’re only doing laser work. A laser stays at a fixed Z axis height through the whole job so taking the circumference of the material and setting steps/mm should work ok. Anything involving the Z axis would be more complicated because the routing is generally done in multiple passes and the Circumference of the material changes with each pass. A constant steps/mm wouldn’t work in cases like that.
It’s early and I’m just a high school drop-out, maybe an engineer (Vicious, hint, hiny…) can chime in on this.
wrong post
I do not think the changing radius of the material is an issue.
But you would have to scale your design in the y-axis to fit a given radius of the wood.
-I think
If you imagine the outermost layer, unrolled, and laid flat… If you wanted that to be square, where 1mm in your drawing in x ended up being the same distance as 1mm of your drawing in y ended up being, then:
-
You’d have to compute your steps/mm based on the outside radius of the object spinning. It’s a simple calculation, pi * diameter gives you one entire rotation, so:
steps per rotation / (pi * diameter) -
If you want the deeper cuts to be aligned underneath the top layer*, then you don’t need to do anything else. The key (for me at least) is to think about how much the surface has to move to make a repeated cut. If the first pass is 5cm long, and that ends up rotating it 180degrees, then if the second pass was also 5cm (the drawing hasn’t changed) then the second cut would be 180 degrees as well. The cuts will end up being perpendicular to the surface. The distance the bit travels at the bottom of the cut will be smaller than the distance it travels at the top, and that’s a good thing.
-
If you don’t have the axis of rotation aligned with the x-axis, then the bit will enter the material at an angle, which is going to be bad for milling and will end up with strange results on multiple passes. It’s probably not as big of a deal with the laser, but with the laser, it will have a hard time staying focused everywhere. Just thought I’d point that out.
-
If you have a material that isn’t a constant radius, then the design will be stretched/pinched when the outside radius changes.
This is completely wrong if what you want is to project the image from a single viewpoint. i.e. If you want an image that looks square when you look at it straight on. You can imagine cutting a design that you want to look correct from straight on, but will be stretched when looking at it with the blob rotated. For that, you’d probably want to do something to “wrap” the design around the object, but it really wouldn’t even require a 4th axis, You would just have to adjust the z-axis and cut with the normal 3 axes. EstlCAM has a tutorial where they cut a design into the surface of a mouse. This would be more like that. Here that is:
- I can’t think of a better sentence to describe that. But I’m thinking the lower layers are just what you would have if you just cut a lot deeper the first time.
So then the g-code “wrapping” software isn’t really necessary at all right? It’s easy enough to set steps/mm with pre-processor gcode in Marlin. Wonder why no one does it this way if it’s that simple? I always figured the Z axis values had to be translated but after reading Jeff’s post , 3 times :), I’ve become enlightened. The wrapping software is a convenience, but not necessary if all that’s required is setting steps/mm for your stock diameter, connecting rotary stepper to X/Y axis, and maybe using a text editor to replace the X or Y moves with E moves in the gcode file. Oh well, the software to do this is done and I’ve already made the changes to “Marlinize” it so no turning back now… I do like the Estlcam wrapping on probed surface feature. The G-code ripper does that too but that only works with CNC controllers that support G38.2 probing codes, which I think will be added to future RC versions of Marlin.
jeffeb3,
Thanks for the thorough explanation !
My x-axis would be aligned with the rotational axis, and I would also be interested in having the layers radially aligned.
I would probably scale my design in the y-axis instead af changing the steps/mm ?
Have you published your designs anywhere ?
/thanks
FYI: I just uploaded my rotary to Thingiverse. I’ll be posting the software and a brief write-up soon in case anyone is interested.
Excellent, cheers,
I know how big a job it is, posting a documented design !
Thanks:) FYI: I just updated Thingiverse with a copy of the “Marlin-Friendly” version of G-Code Ripper. I was going to do a simple write-up but this is all pretty self-explanatory so I’ll wait and see.
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I know it has been a little while since anyone has posted on this subject but I would like to pose a question to the group. If you were to comment out this line in the firmware;
#define PREVENT_DANGEROUS_EXTRUDE
wouldn’t you then be able to use the extruder as the 4th axis and have a true 4 axis router or am I mistaken? The reason I ask is that my ultimate goal would be to have x,y,z and e axis available for use in say milling a model of a crank shaft.
Hi, awsome project - Silverback94 - the GCodeRipper mod by Leo - use in gcode E stepmotor - so i think the firmware can interpretate this code. I thing we can use REPETIER FIRMWARE too.
I’m wonder - Leo69 what soft you use to send code to firmware (CAM SOFT, something like LinuxCNC/ Mach3 - maybe freeware software) ? RepetierHost ? or you run from sdcard ? I think you use RAMPS/RUMBA board with arduino to stepper driver ?
I hope you write some of tutorial.
Second question is that GCode Ripper are in version 0.13 - you plan update ? or open source your modification ?
I know its been a while but I was curious if there have been any updates?