[theclive]

I have been looking for lasers, i have found a few however i now have a problem. I am looking to engrave something with varying thickness. Will autofocus be able to compensate? The second problem is. The thing I want to engrave are about 1 to 2 inches thick. I dont believe most lasers will go up high enough...what do i do? =(

Finally. How much power do i need to engrave anodized aluminum?? How about to cut 1/2 acrylic?

[9lrac9]

9lrac9... You were doing fine on the first request of the laser, but the engrave of al, and cut 1/2 ac, now you talking some big money, not going to be just a hobby machine. Contract the work out and save for big machine.

[theclive]

well its not exactly engraving...more like laser marking, burning away a little bit of the anodizing, nothing deep or even a noticeable reduction in material.

[9lrac9]

Now you say...You can buy the toy machine. it will work ok. Except the cutting of the 1/2 plastic. You will need the larger machine.

9lrac9 ie more power scotty...

[theclive]

cool stuff...the cutting of the plastic i can contract out as its just a set design. Thanks =D

[Neil Pritchett]

Hi, Just stumbled across the thread.
1/2" (12.7mm) can be cut with a 50w sealed glass co2 laser.
We do it on a Redsail RS5070 (M700) machine. This has a work area of 700x500mm (27.5"x19.7") also, the 'C' version of the machine has an adjustable table which allows up th 260mm (over 10") material depth! This is actually designed for a rotary attachment and works well on static items as well.
Have a look at out web site for spec's. http://www.ctrlasers.co.uk
Best regards. Neil (for CTRfuture Ltd).

[theclive]

does your machine have an autofocus feature? This is very important as some of the things i need laser engraved vary in thickness and a non-autofocus machine would be baaaad

[Neil Pritchett]

The Redsail machines do not have auto focus. However, i think there is confusion of the phrase.
To the best of our knowledge, there is no machine on the market that has what you are looking for. A better name for it would be 'follow-focus'.
Auto focus, as it stands, only replaces the initial focus procedure at the start of a job. This takes just a few seconds to do manually; not a great saving considering the additional cost!
To have a continuous focusing system would need an incredibly fast servo system when you consider that the head is scanning at meters per second.
For example: Running at 6m per sec. and tracking a 10mm rise and fall variation in 100mm of travel. This would require a servo system to 1/ read the variation. 2/ calculate the rate of change. 3/ Drive the servo, all in 0.8ms per 1mm of change. Also the acceleration would need to be incredible.
I'm sure someone out there can calculate the G forces!
Back to the Redsail machines: We did some tests on variations in focus depth.
We found that a variation of 4mm caused virtually no deterioration in image quality of a jpg file on slate. This may depend on the particular image; we did this trial for a customer some months age with their file.
I hope this information helps. Neil (for CTRfuture Ltd)

[theclive]

318.87 g's to be exact.

Thanks for the info though that was extremely helpful (especially about the test run)