How to do a Ramp Test on your CO2 Laser - The Easy way

[@ginamaybee5280]

Fire Up Chips!!! (born and raised in Shepherd!) Can't wait to try this out this week...

[@jinnajim]

Thanks, i finally understood how to do the ramp test with your video.

[@EdmondsWoodshop]

Glad it helped!

[@petraromankova3757]

Thank you, you saved my sanity!!! Best video ever, you explained the most important things

[@jg2850]

once again, great job!

[@vortech306]

Great video, thanks for this. Another method for getting an accurate final measurement is slide a drill bit between the nozzle tip and the workpiece, or on my case, using my 1/4 drive socket set then using my calipers to get the O.D measurement

[@francoispotgieter7567]

That’s actually a super great idea! Thanks!

[@blewprent]

Can you do a video where you swap out the focal length lenses? For a person who wants to go from 1.5 to 4? Also, if you have a machine with autofocus, is a ramp test necessary?

[@jbrondos]

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.

[@diannetrigg7853]

Thank you

[@EdmondsWoodshop]

Absolutely

[@narvin2012]

Thank you for this video. Good work. Ciao

[@ksnax]

A wood wedge marked and subsequently detented would work for this as a single piece to test and calibrate.

[@EdmondsWoodshop]

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!

[@agunjal]

Perfect..thank you

[@EdmondsWoodshop]

Thanks for checking it out

[@1-Nice-Guy]

Nice video! If you have an autofocus CO2 laser, does this make the autofocus obsolete?

[@EdmondsWoodshop]

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

[@1-Nice-Guy]

@@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.

[@Baldwij7]

Thanks for the video! If you are cutting material, I had always heard you should be aiming for the center of the material. So if your focal point for engraving is 18mm and you are cutting 3mm material, you should be focused at 16.5mm from the top of the material so you are 18mm away from the center of the 3mm thick piece. Is this correct?

[@mpkogli]

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

[@jrdnhrrm7]

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.

[@DS-ng2kj]

Great video. Thank you!

[@jmcexx]

I know this is a little old, but what about turning the bed height knob until the nozzle touches the wood? Counting the number of turns you made should give you a pretty accurate measure of the distance. Just my $0.02

[@EdmondsWoodshop]

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!

[@Mye_DIY]

super helpful. thank you for sharing! I need to know what measuring tool you used at the end. lol I need one!

[@jasonpotts6490]

Does the type of tape matter? Is painters masking tape okay?

[@EdmondsWoodshop]

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

[@jarodmorris611]

Use a set length of board with a known height of block and know the angle. Then if you move the piece, you can't still calculate the height using simple trig.

[@nicknolan8254]

Great video, thanks. Why do you have the other gauge numbers if you only use 18mm?

[@squidskunk]

you mention a facebook group..? no link to the group..?

[@EdmondsWoodshop]

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

[@babbittfamily]

Ok - now how do I update my autofocus setting?

[@EdmondsWoodshop]

Under edit>machine settings>focus distance you can change your focal distance parameters

[@bobby3tim3s]

I was thinking you could actually use the depth gauge at the other end of the caliper. The depth end of the gauge is a fairly fine point and would come pretty close to accurate.

[@jasonm1974]

I thought each laser comes with a focal length gauge. Are those usually off or does the material change the focal length?

[@EdmondsWoodshop]

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!

[@gscraftyshop3910]

My machine has auto focus do I still need to do this?

[@EdmondsWoodshop]

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.

[@Team90j97]

When you find your focal point, do you use that measurement for all engraving? How do you find out what lens you have? I am using the 60w Omtech.

[@EdmondsWoodshop]

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.

[@Team90j97]

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

[@EdmondsWoodshop]

@@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.

[@BLSportsPhotography]

Do I have to do this is I have autofocus? And how do I raid and lower bed? I have same panel as you.

[@EdmondsWoodshop]

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

[@psychoslingers8732]

Is it this same method if you have autofocus? Or do I need to use a different method?

[@spiritburners]

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.

[@cheryll6232]

I am a bit confused maybe u can help. I also have a 2" lens and my ramp test came out just like yours, at .7". But I have a gcc laser also and it has a 2" focal lens and it is supposed to be set at 2" and that has been perfect for me foe 14 years. Why would the 2" focal lens on this machine be .7 and not 2"

[@EdmondsWoodshop]

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

[@paybossman]

Trying to find the focal gauge file. Has it been removed?

[@EdmondsWoodshop]

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

[@chasityhendley4274]

What does it mean if when we push them simultaneously they don’t fire? It will do a dot but not continue to go

[@kombolasha]

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.

[@scotthamel7928]

I have the red and black 60w. What size lens comes installed? 1.5"?

[@EdmondsWoodshop]

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.

[@ImaginationDesign]

In another vid about ramp testing, the person used hex keys to measure - or at least get a ball park.

[@EdmondsWoodshop]

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