Adding An Air Scribe to The DIY Table

[Pyrotech]

I recently picked up parts to start working on adding an air scribe to the table I built. Right now it's in the very early stages of being built.

Most all the parts I was able to pick up fairly cheap by keeping an eye on ebay.

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picked these up based on reading what others here have said about them

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test printing a mount for the air scribe.

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initial testing of the air slide

[adbuch]

So far - so good! I bought an similar air scribe (CP brand) on Ebay a few years ago, and built a mount to fit my Plasmacam table that works quite nicely. I most recently adapted it to my one of my AvidCNC router tables. Keep us posted on your project.

David

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[acourtjester]

I also built on for a table, as you can see with David's and mine was the same, no drive assembly for up/down movements. You really don't need one as if to strong the scribe will not work. One thing I will say it is very noisy to use, get you some ear muffs when you do use it.
I found the Easy Scribe type is much easier to use and cheaper too.
attached are some of the prototypes I tried.

newer scribe mount.JPG

pneumatic scribe assembly.JPG

[cuttinparts]

Nice builds guys! I had one of those at one point but the noise is horrendous and I found on larger scribe operations it would "coin" the material and make the part bow like it was being stretched. I use an EasySCriber now and all I hear is the cool robotic sound of my motors. Doesn't scribe deep like the pneumatic but works perfect for what I am marking.

[djreiswig]

I recently picked up parts to start working on adding an air scribe to the table I built. Right now it's in the very early stages of being built.

Most all the parts I was able to pick up fairly cheap by keeping an eye on ebay.

20240903_160712.jpg

20240903_160655.jpg

picked these up based on reading what others here have said about them

20240905_191838.jpg

20240905_191846.jpg

test printing a mount for the air scribe.

20240908_182225.jpg

initial testing of the air slide

Is that a precision regulator? That's what I ended up going to because I couldn't control the down pressure accurately. The precision ones leak a tiny bit of air all the time, but react very quickly to pressure spikes like uneven material will give you.
Not sure what machine you have, but I recommend setting it up differently that the two videos posted show. I didn't like the inaccurate delay that using the air cylinder to raise the scribe for rapids gave me. I set mine up so the cylinder fires at the start of the operation and stays on the whole time. Then I use the Z motor to raise and lower the scribe just as when cutting. This gives more predictable timing since the gantry won't move until the Z reaches its coordinates. It eliminated the deep dots at the start caused by the scribe slamming into the surface, and missed areas if the delay is set too short.

[Pyrotech]

it is.. I found 3 SMC IR2000-02BG Precision Regulators for a good price so I picked them up

the air slide is the SMC Air Slide Cylinder Table MXS20-100 20mm Bore 100mm Stroke

The scribe will be mounted to the Z axis, So lifting the Z like you mention will be an option

[adbuch]

Is that a precision regulator? That's what I ended up going to because I couldn't control the down pressure accurately. The precision ones leak a tiny bit of air all the time, but react very quickly to pressure spikes like uneven material will give you.
Not sure what machine you have, but I recommend setting it up differently that the two videos posted show. I didn't like the inaccurate delay that using the air cylinder to raise the scribe for rapids gave me. I set mine up so the cylinder fires at the start of the operation and stays on the whole time. Then I use the Z motor to raise and lower the scribe just as when cutting. This gives more predictable timing since the gantry won't move until the Z reaches its coordinates. It eliminated the deep dots at the start caused by the scribe slamming into the surface, and missed areas if the delay is set too short.

Djreiswig gives some great useful information here on his setup. If I were going to build one using the air cylinder method, I would most definitely try to use his setup. Both of my air scribes do make that "deep dot" at the start point. I have reduced the air pressure to the scribe and that has helped somewhat, but not eliminated the problem.

David

[djreiswig]

it is.. I found 3 SMC IR2000-02BG Precision Regulators for a good price so I picked them up

the air slide is the SMC Air Slide Cylinder Table MXS20-100 20mm Bore 100mm Stroke

The scribe will be mounted to the Z axis, So lifting the Z like you mention will be an option

I believe that's that same air slide I have. Another thing I did to mine was add a latch to the top of the air slide. If you look around, it's an option on those. I bought a second one , but it was a shorter stroke, so I robbed the latch. Basically it's a small pin that holds the slide up when the extend air is off so it stays put when you shut your air supply off. I did this because I tried to rip it off a couple of times when I jogged my table before I hooked the air supply up.
The precision regulators are awesome. I can rapidly lift up on my slide and the down pressure gauge barely twitches. Before it would raise the pressure significantly. I find a couple of psi was the difference between scribing perfectly and stopping and digging in.
You should only need a single solenoid valve. Just hook the slide and scribe together. They can both turn on at the same time. Then use the Z to lift. I put my extend pressure regulator on the end of my gantry so it's easy to adjust and close to the slide so it reacts quicker.
I don't use mine much, but it's handy. I also mounted a floating pen holder to my slide, so I can use my table as a plotter. That's another cool option you might want to add.

[Pyrotech]

made a little progress today

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Still have a decent amount of travel in the Z axis both up and down with the air slide extended

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Along with plenty of room for the torch with the slide retracted

Going to have to adjust the limit switch, just not comfortable with how close this is AND having to have the Z axis at the right "safe height" in order to gain an extra inch or so of travel. So I end up with a 48"x 50" cutting area instead of 50"x50" you can also see the crude zip tie slide lock

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[djreiswig]

Looks good so far.

[adbuch]

You are moving right along! Keep up the good work.
David

[Pyrotech]

I hooked everything up to air and did some "bench testing". I need to order a power supply to run the solenoids. and get everything wired into the control cabinet. I will also need to edit the post processor to add in the offsets for the scribe, and then start running some actual engraving tests.



but in the spirit of 90% done is the new 100% done (if you watch superfast matt on youtube then you know what I mean) i will probably run a small engraving test using the bench power supply and triggering it all manually

[SegoMan DeSigns]

Looking good and thanks for the reminder I need to get mine up and running.

[djreiswig]

Nice job. If you let me know what post you are using, I can try and help you set it up to have the Z motor raise & lower the scribe and have it stay on all the time.

[TJS]

So far - so good! I bought an similar air scribe (CP brand) on Ebay a few years ago, and built a mount to fit my Plasmacam table that works quite nicely. I most recently adapted it to my one of my AvidCNC router tables. Keep us posted on your project.

David

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David,
Nice mount. What is that horizontal spring for.
T.J.

[SegoMan DeSigns]

Nice job. If you let me know what post you are using, I can try and help you set it up to have the Z motor raise & lower the scribe and have it stay on all the time.

Do you use a 5/2 pneumatic solenoid valve for the up/down and a standard O/C solenoid valve to run the scribe? Adjust pressure as necessary with the regulators? That would only require 2 electrical signals to operate.

[djreiswig]

I think that's correct. I have them wired separately so I can trigger the slide without the scribe running so I can use a pen to draw. The pen holder is mounted beside the scribe.
When scribing,they are triggered together at the beginning of the operation and stay on until the scribing operation is done. The moves up for the rapids. I don't have to adjust for the slide delay. The x,y move automatically waits until the Z is down.
I initially had it set up to raise the slide between scribes, but wasn't happy with the inconsistent delay because of the low down pressure required to keep the scribe from digging. That's why I switched to moving the Z. It works pretty much like the torch when cutting.