21st Birthday Present

[Frank Corker]

This is a 21st Birthday Present I have done for a friend. Three quarter inch (20mm) clear acrylic 9" long 3 and three quarter" at widest point. Inlaid with 2mm thick gold/black Rowmark. One pass cut, smoothed and flame polished to finish.

[Craig Hogarth]

very cool.

How did you come up with the idea?

[Alan Case]

Really neat. Is the picture engraved on the surface or is it in the acrylic.
Regards Alan

[Steve McKee]

Frank, that is awesome. I'll bet your friend will really appreciate it.

Steve

[Frank Corker]

The guy is a top accoustic guitarist, so it wasn't too much of a brainer to choose this for the subject, making the guitar was a damned sight harder. Strangely enough, the black/gold insert took nearly 4 hours to draw out alone. Over the black areas it had to be gold, over the gold areas, black. Getting the order right was a nightmare. The photo is engraved onto the front of the acrylic and not 'inside'

[Mitchell Andrus]

Very nice!!!

3/4"! must've taken a while at a really sloooww speed.?

[Joe Pelonio]

Very nice!!!

3/4"! must've taken a while at a really sloooww speed.?
That's my question too, Frank, I have to run on speed 1 to cut 3/8" with 45 watts, I'd never think of trying 3/4", and you said one pass!

[Frank Corker]

Yup, one pass. 1 speed, with air assist 100 power 5000 frequency.
Joe, 3/8ths I can do at 4

[Michael Kowalczyk]

Awesome work Frank.

I have a 60 watt and have done 1/2" (12MM) acrylic in one pass but it is still painfully sssssssslllllllooooooooowwwwww. On a Trotec it was around 100% power and .15 V (speed) I think. It may have been slower. It was a long time ago.

So inquiring minds (laserers) want to know.

[Von Bickley]

Frank,

Great gift for your friend...:)

[Joe Pelonio]

Yup, one pass. 1 speed, with air assist 100 power 5000 frequency.
Joe, 3/8ths I can do at 4
I'm guessing that you lucked out and have well over 45 watts then. The manual limits the 45 watt to 3/8", the 3/4" thickness is not mentioned until you get to the 75 watt. Do you have the 2" focal length lense?

[Frank Corker]

Joe, it's the bog standard one that comes with the machine. Listening to what is being said, it looks like I have been lucky. It would be nice if it were really smooth when it finished but unfortunately it still has the wave lines, but it does cut right the way through

[Brian Robison]

Super job Frank!
I only have 25 watts and I cut 1/8 and 1/4 a lot.
I've found lately that if I cut at 10% speed 100% power
on the 1/8 it works better using on 1000 hertz. I was using 5000 like you.
Any one else have similar results?

[Frank Corker]

Do you know, I don't think I have ever tried it at a lower frequency. i'll give that a go and I'll post next time the machine is running. It is interesting though

[Dean Carpenter]

Michael,

Your Trotec 60w should handle 3/4" in one pass because the likely output power should be in excess of >80w but at 3/4" thickness the extraction and air assist play super important roles.

Use the small bore nosecone with 4 bar air pressure (external air, not the onboard pump as that is only really good to keep the lens clean)

beyond 5mm thickness use the 2.5" lens and really for 3/4" you should use a 4" lens (your machine's max). Ideally at such a thickness you should use a 5" lens but this is not available for the benchtop format laser.

Regarding pulse rate: more pulses generally = smoother edge for acrylic. 5kHz is the best rate of pulse. Low pulses will give a jaggy edge and more than 5kHz with cause the effect of the beam being 'less powerfull'.

At greater thickness focus about 1mm into the material and using a lead-in and lead-out toolpath of at leat 3mm to every vector is a major advantage because the beam 'bends' as it cuts through the material. Slowing down the motion system will cancel this out.

regards

Dean

[Michael Kowalczyk]

Hey Dean,
I assume you have a Trotec? What do you have?

Thanks for the tech info. I will try the 5k on the next run and see how it goes.

I have not used an external source of air for the air assist. What would 4 bar be for a lay person? Could something like a silent giant aquarium pump work???

I have been wanting to get a longer focus lens for a while but just have not committed. From what I have heard the longer the lens the wide the laser kerf but a longer focal length. I guess the easy way to explain it would be that it elongates the narrow point in the middle of the hour glass focus area.(377)

Thanks,

[Larry Bratton]

Frank:
One word! Beauuuuuutifullll!!!! :)

[Bill Cunningham]

Nice looking Geetar there Frank.. Actually, it's better than nice.. The first thing I said (to my self. :D )was "Wow..Cool"

For Michael.. A 'bar' is 1 atm, or 14.7 psig.. 4 Bar = 60 psig (58.8 close enuff)

[Dean Carpenter]

Hi Michael,

I am very familiar with all of the Trotec models because not only have I sold (hundreds of) them for the last 7 years but I have also contributed to the R&D/design for most of the current models. I'm out there all the time in Austria, I was there only week before last, so if you ever get stuck with your Trotec let me know.

Re the lens: actually, shorter length lenses work against you the thicker the material gets.

Re air assist: bypass the on-board pump (just pop off the blue hose that connects to the pump outlet) and hook-up to an external air compressor. An aquarium pump won't have the pressure or rate of flow sufficient enough for the job. Really, you need much higher pressure (bar). IMPORTANT The compressor MUST deliver oil/moisture free air and it is ideal if it has a reservoir tank + a method of regulation. You will find this a massive benefit.

For really good tips about how much air pressure to use cutting materials with a CO2 laser go to the Synrad web site, the apps section

best regards

Dean

[Michael Kowalczyk]

Bill and Dean,

Thanks for the info.

[Scott Shepherd]

Just cut some 1/2" with no problems on our 45W. Customer was standing there watching and he was going crazy. He actually shook my hand when it finished cutting like I had just done something worthy of a handshake :) I think he was hopped up on caffine or something :)