Hi Neil Am 07.12.2010 19:00, schrieb Neil Baylis: > What's the best strategy for controlling a laser? > > My machine uses 2 axes to move the laser optic to the right position. I've > got this much working satisfactorily. Now I need to control the laser power. > I was planning to use a 3rd axis for this, let's call it Z. > > My plan was to use the sign of the Z position to control the laser-enable > signal, and the magnitude of the Z position to control the laser power. But > maybe this is a stupid idea... I don't know.
maybe you shold use the spindle controls for this, e.g. use S for laser power and M3/M4/M5 for switching. This way you could use normal cam to program your machine. > For example, let's say I wanted to cut/burn a dashed line. It would be > preferable if the optic could keep moving at a constant speed, and the beam > would just turn on and off at the appropriate positions. Would I be able to > do that if the beam was controlled by the Z axis position? If you have to program a dashed line, this would mean having two program lines for one dash and one space. This is with both solutions Z / M3 I would try to create a canned cycle wich handles off/on of the laser. you could also vary dash length with an aditional parameter to it. > > This thing moves pretty fast.. maybe 25 to 30 inches per second, and I'm not > sure if I'll be able to turn the beam on and off with enough precision. > > Later, I'll need to compensate for the linear velocity of the optic, so that > it burns with less power when it is moving slowly. This will require > computing the real-time velocity vector in x-y space and using that to > control the laser power. if you use spindle controls for this, you could create whatever control mechanism you want in hal using spindle speed pins:pid for simplest, but also laser power to feed rate or vice versa via the feed override pin maybe it asking the EDM people may help to as controlling a laser may be nearly as complicated as controlling an electrical discharge. > > Neil --------------------------------------- Dr.-Ing. Ulf Dambacher [email protected] --------------------------------------- ------------------------------------------------------------------------------ What happens now with your Lotus Notes apps - do you make another costly upgrade, or settle for being marooned without product support? Time to move off Lotus Notes and onto the cloud with Force.com, apps are easier to build, use, and manage than apps on traditional platforms. Sign up for the Lotus Notes Migration Kit to learn more. http://p.sf.net/sfu/salesforce-d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
