Glad it helped!

That’s actually a super great idea! Thanks!

Thanks for checking it out

Absolutely

There's a few different ways I've seen a ramp test done. This is just quickest for me. I'm all about learning different techniques. Post a video!

I'm interested in this, too. I can adjust the Z-axis on my laser bed to adjust the distance between the laser nozzle and the workspace . . . but what about the distance between the "3rd" mirror and the lens? My laser tube has an adjustment screw to shorten or lengthen the nozzle. Are the 1.5 inch, the 2 inch, and the 4 inch lenses measuring the distance between the mirror and the lens or between the lens and the workspace? ALSO, can you describe what each laser length is used for? For example, one distance might be better for acrylic, but another different for wood -- or different between cutting and engraving. Thanks! Great video.

100%. My way definitely isn’t the only way. If you have something that works for you or for the masses, then I’m happy you shared. Community is what it’s all about!

This makes logical sense to me, but I'm also curious what the pros have to say!

Not a pro myself, but I wager it depends if you're engraving or cutting. The ideal for cutting might be midway through the material, while the ideal for surface engraving might be to focus at the surface.

Each laser does come with a focal gauge HOWEVER, many of these lasers don't come properly calibrated from the factory (i.e. alignment, proper focal length, etc). It's best to check at minimum. You may be surprised that you're of by a mm or two. Material doesn't change focal length unless you're trying to do something specific "out of focus". So if your focus is 18mm, there are times you may want to be out of focus due to different engraving or cutting abilities. Good Question!

Depends on your laser and how they setup their settings. If you have an OMTech laser you need to calibrate your autofocus meaning that you have to find out the focal distance first through a ramp test and then input that number into your settings. After that, you can use your autofocus

@@EdmondsWoodshop excellent...thank you very much for that info. I narrowed down my first CO2 purchase to OMTech, but because I'm not in a super rush...I'll wait for the next Polar to be released. This is purely for fun, so I really don't want a large laser.

Yep exactly. So if you're measuring, say 18mm, you'll make sure that the tip of your nozzle is 18mm from your workpiece every time. A ramp test can help you identify what focal length lens you have. Remember focal length is measured from the LENS (inside the laser nozzle) to the workpiece. However, we are only worried about the distance from the tip of the laser nozzle to the workpiece. Usually 4 to 5 mm distance is a 38.1mm (1.5 inch) focal length lens. A 18 or 19mm distance is a 50.8mm (2.0 inch) focal length lens. Hope that makes sense.

@@EdmondsWoodshop Thank you! Mine is 18mm so I assume that is common with the 60w Omtech.

@@Team90j97 I manage an OMTech users group with 11k members. In the group I've seen 60w ship with 1.5 inch focal length lenses where their focal distance is 4 to 5 mm so I wouldn't exactly say its common. That's why its important to do a ramp test. The distance will really tell you what kind of focal length lens you have. My focal length is also 18mm so I have a 50.8mm (2.0 inc) focal length lens.

Yeah, some lasers when they say “pulse” they really mean just a pulse; it won’t keep going. In that case you’ll have to make a line with a decently dark power setting and send it through to the Laser.

No autofocus on mine, but if you press the z/u button it’ll take you to the menu where you’ll be on the Z move feature. From there press the directional key left or right and you motorized bed will move

This is how I explain it to people: Focal length is the distance from the lens to the workpiece. Focal distance is the space between the tip of your laser nozzle and your workpiece. Every laser has a lens that has a focal LENGTH, but we can’t reference our measuring gauge from the lens since it’s mounted in the laser head assembly so we have to reference from the tip of the laser nozzle. If you were to measure where the lens was mounted to the tip of the laser nozzle and add that to the focal distance it would equal the focal length

Thanks for catching that! Added to the description box but I'll also paste below. I help manage over 11,000 members. facebook.com/groups/1364016877267714/?ref=share_group_link

with autofocus you need firstly to determine the height of your bed, the placement of the autofocus pen or hall sensor and then you have to calibrate it all, use a cloudray autofocus pen, attach it to the lens tube, so its just below the nozzle , your focal length determines the height above the bed where perfect focus is obtained, normally 50.8 mm from the bottom of the lens. the bed must come up to that point on the pen , make sure autofocus on your controller is switched on, then use the Z offset control to make sure that when you home and the bed comes up that it puts whatever is on the bed at the correct level from the nozzle, it will touch the autofocus pen and then stop. that is perfect focus. you need to look at the gcode for your controller as all the switches and settings are built in already , All you need to do is keep adjusting the Z offset to the perfect point. You might need to adjust the autofocus pan a little to get it in the right ball park takes only a few minutes to do and you dont not need to be a cnc geek to do it. just beef up on gcode for your controller and it will pop out, the bounce back is what you have to get right as that pulls the bed back after it comes up... Then home and it will do all 3 axis at once, well mine does. Just remember autofocus will only focus once, it does not allow for the fact that your wood or items has different levels. it focus's once, after that its basically an end stop depending on your controller. I have yet to see one that can control the height of the object if it changes, the amount of procesisng power would be huge to do that.

Are you in our facebook group? Here's the file location facebook.com/groups/1364016877267714/permalink/1391837407818994

Nope. Type of tape doesn’t matter. You just need something to see a pulse mark from your laser

Yes absolutely. Your autofocus will need to be calibrated to account for its current position and height. It won’t know where it’s at until you tell it.

I've seen both 1.5 inch and 2.0 inch. Generally of you're getting a 3 to 5mm measurement on your ramp test then you probably have a 1.5 inch focal length lense where if you are measuring 17 to 19mm you probably have a 2.0 inch focal length lens.

Might have been BeardedBuildco. He’s my partner in the OMTech official group