My rotary guide (found here) seemed to be well received, so I’m going to move onto the laser. This guide will be a bit shorter, as it’s not too involved, but is mostly to help increase repeatability, accuracy, and quality of your laser projects.
Likely any machinist will say a repeatable, accurate origin is a key component in quality production. You gotta know exactly where you start to know where you’re gonna end right? I know the snapmaker method is just eyeball it, be it with a mark and lining up the laser, or just wingin’ it. However; I find results are a lot more satisfying if you can do it mathematically. Especially doing things like greyscale picture burns in wood or other material, you can figure up your border, center it properly, or anywhere you want without fiddling with “where” the center actually is.
To start, in this section we’ll be determining the true machine zero on your snapmaker. I don’t know how different the machines are in production, or if my settings will match yours, but I’ll go through what I did to find mine and provide files of the tools I printed to make it easier.
1: Repeatable laser bed placement.
1a: The easiest I find is when placing the laser grid table, leave the screws a half turn loose so you can jiggle the plates around. Place your fingers firmly in the center of the very left plate and firmly push directly outward, no forward/back, with your free hand, tighten the screws. With the plate next to it, same thing, pressing it against the first place, the front should be lined up on its own, tighten the two center screws. Repeat mirrored for the right side and fully tighten the screws.
1b: This method ensures the grid table is in the same place every time you switch it in, since the holes have a bit of leeway if you just toss them on, there’s no guarantee they’re in the same spot.
2: You will need a square piece of paper or cardboard, something you can quickly burn a dot into. Place it flush with the front and left so it matches the corner and secure it.
II: Finding True Origin Or X0,Y0
1: I find it easier to just “start” an engrave from the file menu, set the thickness, and let the laser come down to the proper height, then back out so I don’t have to mess with Z.
2: Go into the control app, jog X/Y to MACHINE 0,0 NOT WORK 0,0. (from here on, assume numbers written as 0,0 to be X,Y coords). It should be the numbers on the left side. Set origin for X/Y, then move to 10,10. Turn on the laser for a second to burn a small hole.
3: Measure the distance from the edge with a good set of calipers to the CENTER of the dot to the best of your abilities from the left (X), and front (Y).
3a: Remember, we set X,Y to 10,10, so take your measurements and subtract 10, this will be your machine 0,0. Write down your results somewhere, it’s essential when setting up your engraves.
3b: My results were 8,25, so my machine origin is -2,15.
III: Setting Up And Testing Your Origin
1: You will now need to print spacers or guides (or just measure it and fixate) matching the sizes you recorded in the previous section. I found what works best for me is the laser bed clips by mrwolfe: Laser bed clip for Snapmaker 2.0 by mrwolfe - Thingiverse
1a: They’re already 15mm (not including the hold down front), so just making them flush on the front ensures my item is 15 on Y, placing it on 0. Note this is because my Y was 15.
2: If you have a negative number, like my X is -2, place the item you want to engrave flush on the side of the plate. You will have to compensate the negative mm in either the placement, or work origin before you print (which will be easier for newcomers)
3: You can test your origin by repeating section II, except move the paper by the amount you found before.
3a: For my -2,15, I place the paper 15mm from the front, and flush on the left.
3b: After jogging to 0,0, since my X value is -2, I compensate by moving X those 2mm. My machine coords are now 2,0. Which should be directly over the corner of the paper.
3c: Set work origin, move work origin to 10,10, turn on laser to make new dot. If lined up correctly, your dot should measure 10mm from both directions.
IV: Using Your Newfound Knowledge In Real World Applications
1: Begin your laser projects as you normally would. However, we’ll be using a lower left origin. (I still use Luban 3 since 4 never generates a thumbnail for me)
2: To place what you wish to burn directly center in what you want to laser, place the objects on the laser bed as we did the paper.
2a: Measure the size, divide by two, and place that in X/Y in Luban. Your model will move to the upper right quadrant.
3: Add your offsets from before, keep in mind, positive numbers are physically moved on the bed, negative numbers are compensated in either work origin, or Luban.
3a: For my -2,15, since I have 15mm spacers, I use those on the bed, and treat Y as 0, no modifications necessary.
3b: For X, I’ll simply add 2 to whatever my half material X measurement is. i.e. to center on 100mmX100mm stock, I’d put 52,50 in Luban.
3c: HOWEVER, it may be easier to do this movement on the snapmaker itself when setting work origin, this will be covered later.
V: Start The Fire Maker
1: Load your project into workspace and send it to the snapmaker.
2: Start the file and set your work origin according to how you prepped your file.
2a: If you compensated negative values (see my -2 above) in Luban, simply jog to MACHINE 0,0 and set work origin. You’re ready to go.
2b: If you centered (or moved wherever you wanted) without taking the compensation into account, compensate it here. i.e. mine would be MACHINE 2,0, set work origin and go.
3: If you’re using Luban to control the machine, use the terminal to set your 0,0 instead.
3a: In the terminal use G53 G0 X0 Y0 F3000 to move X/Y to machine 0, then use the control menu on the right to reset X/Y work origin.
3b: If you’re using the machine compensation method, modify the movement command to match, i.e. G53 G0 X2 Y0 F3000
VI: Wrap Up And Other Information
If your measurements seem to match mine, I’ve uploaded models for easily placing objects and they can be found here: PrusaPrinters
You can use this and resize it to match the sizes you’ve gotten on your machine if you need to. For non-square objects, such as circles, just keep in mind to have your furthest points aligned as above. For a circle, the front center should be at your Y distance, and the left center should be flush with the edge of the bed. Using the method I’ve laid out above, it makes it so much easier aligning things like a clock face, especially when the center hole is already drilled and you can’t realistically line up a dot with a marked center (unless you cover the hole with tape, center, and remove before lasering, but why?).
This method also makes it easier to scale objects for a certain border or margin, perfectly center, or granularly move it around exactly where you want. It’s also very handy if you want to do multiples of the same. Since you can repeat the setup quickly and efficiently. If you have any specific questions, feel free to ask and I’ll try to answer to the best of my ability.