Why not use the Mach3 CALIBRATION to get it spot on.

@Kobus, I just learned about that 10 minutes ago :). I will check it first thing tomorrow morning. Thank you.

Cold Air Gun Success
 

Today I finally had a chance to hook up the Cool Air Gun I bought a while back. I have to say I am pleasantly surprise, more like blown away, how well it works. Although the manual says that it likes to work at 100PSI @ 15 SCFM I was able to run it without a problem at 85 PSI @ 5 SCFM and it cooled perfectly in my opinion. I started by cutting 1/4" acrylic with a 1/8" bit @ 18K RPM without the plastic even melting. The different with and without the cool gun was very noticeable. As as second test I cut 1/8" thick Aluminum with a 1/4" carbide bit and again the bit didn't even begin to get hot. I didn't have the right hose or fittings or filter connected to the system which I will connect tomorrow so I think it can only get better from here. I will also measure how cold the air comes out of the gun but it felt as cold as air coming out of window air conditioner.

Bellow is a quick picture of the air gun, I will take some better shots when the hose is connected properly.

Lastly, the problem with my circles not looking like circles was a combination of "loose" parts:

1) One of the Z-Rail Rollers was not making good contact with the Z-Slide. Barely noticeable but was causing problem.
2) One of the rollers in the Y Axis was dirty with what looked like a piece of dried paint from the rails. It was a nice chunk so I know it was also affecting it.
3) The little lock screw on the Y Axis stepper was a little too long and was touching part of the laser put part(wall) once per revolution.

Thank you to everybody that pointed me to the Mach3 Axis Tunning function. I think this is the best thing since sliced bread :).. After about 15 minutes I had the machine 100% tuned.

OK Miguel

A success. You get the first cold air gun on a Mechmate award (that I know of anyway).
At 18k acrylic is generally melting big time unless the feed rate is really quick.
I do like 12k max for acrylic, polycarbonate and alloy using cheap carbide 2 flute cutters.

Very interested in any information you can pass on about RPM, feed rate and depth of pass with your cold gun and aluminium.

Regards
Ross

Another good day. For some reason I had my Y motor fail on me today but since I had a spare one I was up and running within 30 minutes.

I finally been able to get all the fittings correctly for the Cold Gun and I have to say that it works great. Even with my 5HP compressor it works great. The little smoke you see in the video is from the spill board. Every 5 to 6 minutes there is a little rock of ice that comes out of the gun, it just shows how cold it gets. I will post some pictures of the final cut piece later today.

I had to turn off the video to pause the cut job and remove the middle piece before it could break the bit.

https://www.youtube.com/watch?v=2s0wB9r8O1Q

Some Pictures
 

Here are some pictures of the final plate and installation.

That looks very very good actually..

What was the plate for???

Kim; Thanks. The plate is to mount a Pneumatic cylinder to a Vacuum Forming machine I am building.

Cool.

How long was the actual cutting time for the entire plate?

21 Minutes. The plate is 10x10 with 12 3/8" Holes, 2.75" Middle Square and outer Edges.

That's not bad at all... a bit slower than lasercutting, but still, for DIY then it's actually rather fast when milling...

whats you spindle power? its the first time i see mm cutting iron. iam not crazy thats iron right?

so now get a bending machine and MM can replicate itself.

@Fernando. Yes, it is iron/steel (Hierro). I have a 3HP air cooled chinese spindle.

Miguel,

What size and kind of bit did you use?

Now this is very interesting. :)

wow.. iam amazed.. i was looking the idea of a 1hp spindle.. not any more.
soft materials.. aluminum and not ferrous, now steel. the working posibilities are too wide.
please give us more specs about the cutting.
speed mm/min , spindle speed, i see you using reductions.
bit specs.
you cooling using cool air. liquid can be use but you need a container to not ruin the spoiler mdf base.

Gracias Miguel

@Nils; For that video I was using a Onsrud 57-281. It's 1/4" Double Fluted Carbide Bit. Picked it up on ebay for $7

Cutting Edge Diameter: .250"
Cutting Edge Length: .875"
Shank Diameter: .250"
Overall Tool Length: 2.500"
Tool Material: Solid Carbide
Number of Cutting Edges: 2
Helix: Downcut Righthand Rotation

@Fernando;

When cutting the steel here were my settings

Spindle Speed: 9000rpm (200Hz on the VFD)
Belt Reduction: 3.33:1
Speed: 10% of my 'Normal Speed(450ipm)' or 45ipm for this cut(I incorrectly stated this yesterday)
Acceleration: 25in/sec
Downward Rate: 0.05
Cool Air Gun: Exair Cold Gun 5215

Iincredible that you can use the onsrud 57-281 for steel.

It's normally for wood...

Was it dull after the completion of one plate??

@Kim; I know it's probably crazy but I didn't even pay attention to the "Wood" specification part of it. The bit is carbide so I figured it should work. I have read in the forums that when asking for a bit most distributors/resellers wont know the material type so I figured it was worth a shot. The bit is not dull at all. I checked the machine first thing this morning after cutting that plate and the bit still as sharp as when I first bought it. It still razor sharp!.. Which I was impressed..

wow, .05" (1.27mm) depth at 45ipm (1143mm/sec) that is aggressive! did you observe what is thr highest spindle current drawn?

You really need to be careful not to plunge your bit too fast or it will chew up your spindle bearings. They are expensive to replace. I found out the expensive way...

Ken C

u might want to revise the feedrate a bit. It's 45 inches a minute, not 450 inches a minute. :)

And the plunge rate is 0.05@ not the cut depth.. I counted 14-16 runs to go through 1/4" of material. So it's not that aggresive at all...

My bad. :o
45in/min... = 19.05mm/second.
That is actually slower then what I did, 25mm/sec.
The difference is I use HSS end mill bits at 2000rpm. with ample of kerosene applied with a small brush.
& I hate cleaning up the steel chips...

Got them all thinking Miguel
 

Me too :)

Ross

Thanks....
 

just finished this whole thread in one sitting.....things are getting clearer !

Miguel,

Would you please give me some details on the compressor you are using with your cold air gun?

HP and tank size.

Thanks

the 3 minute video
 

Miguel,
Thank you for shearing. The 3 minute or so video has been a huge sorce of inspiration and motivation for me. I have had the plans for 10 years (when they were free lol) I have had them printed out on 11X17 paper for at least 2 so I am starting on the Y car soon (I have a quote for some of the laser cut parts) The balance of the "laser cut parts" I am going to cut on a friend's cnc plasma.

Thanks again
archie

Hey Archie, glad to see you posting about your build. I'm anxious to see how your "laser cut parts" experience goes.

I am more intrigued with the cutting and milling of the rails.

archie

With all respect to yall, com-on guys, since Miguel has kinda disappear (MIA) for about 6yrs, I'd wouldn't expect "much" a reply :p

NILS.....Look here : Exair prod