Re: laser cnc

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Bob McKnight"
<bobmcknight@c...> wrote:

> Rick
>
> Thanks a whole bunch. Went to my Browser and typed
> Laser Cutting. What a fantastic start. We have been
> wanting to turn a pen plotter into a cutter for vinyl. Have
> only looked at knife tech
> nology. This may be better, most
> of the problems of the knife disappear with the laser. Of
> course, some others show up. And then they mentioned
> the Laser Printers. That might be a source of parts, only
> I doubt if the laser is powerful enough to cut the vinyl film.
> Speed is not a concern. Another site had all kinds of Algebra
> formulas for determining the power and speed necessary.
> Didn't get to the Synrad site, but saw several good comments
> about it.
>
> bob mcknight

I don't think my cnc mill/laser can even go fast enough to NOT cut
vinyl, and I can move at 120+ IPM. I assume you are talking thin
stuff, like signs are made out of.

My next step is to build a flying lens system, since there are no
forces on the laser beam. It is really overkill to be using my cnc
mill to move the laser and workpiece. Much better to move a mirror
(s) and the lens and have the laser fixed. I may go ahead and build
a smallish gantry for this (maybe 24" by 24") and then later build a
bigger unit. The trick is to make something that can accelerate
really fast, and that means low mass. I haven't decided on the
actuator yet, but I am thinking low-stretch timing belts and
brushless servo motors. I have been getting brushless motors on ebay
for dirt cheap...if only I could find the right type of driver. I
want to be able to use encoder velocity control with EMC and a PCI
card by Abdul. Most of the driver amps use tach velocity control, or
current control. Well, let me rephrase..I know where to buy the
brushless drivers new, but I want something cheap! :-)

Rick