On Jun 20, 2012, at 1:40 AM, Viesturs Lācis wrote: > I do not know if this several passes approach would work for wood. > This certainly is the first time I hear about this way, regarding > laser cutting.
I help fund the Lasersaur project and gained access to the forms ($30). After the alpha stage it will all be open sourced. Someone has a 600W laser working that they are going to offer as a kit. They claim it can cut 1/4" steel! 8) Anyways; I posted a question asking about wood thickness and here is a response: >> Wood cut thickness isn't about tube power, it's about species, >> construction and wood flammability. >> >> To cut wood, you dump energy into it. Enough to burn it locally and >> make some disappear as fumes, not enough to heat the surrounding bulk >> up to make the whole thing catch fire. With an adequately large laser >> you can of course cut this wood, however you presumably want a fairly >> neat cut, not just a firelighter. >> >> In most cases, a laser machine will find a maximum single-pass wood >> cutting thickness and this will depend on the wood type, the air >> assist, the travel speed and power settings, and the wood type. >> Balancing power vs cut speed, pulsing too, can improve this single >> pass depth, but simply turning the power up to 11 won't - that will >> just char it and probably ignite it. So anything "thick" is multi-pass >> work. Fortunately that's just a trivial setting to change. As lasers >> aren't mills, the mechanical repeatability is good enough that this >> just isn't a problem. >> >> You can also choose your timber carefully. "Laser plywood" is chosen >> so that it's well-behaved for cutting. Some materials are just a pig. >> >> IMHE, servomotors (compared to steppers) cut thick, flammable, wood >> faster than huge tube power does. Go round repeatedly, but do it fast. >> Power allows you to cut the same depth faster (your limit is energy / >> length, i.e. heat dumped into the bulk wood) so powerful tubes can >> start to help their, but you also need a real cutbeast to work it. >> >> You also have a cut depth and focus issue. This is (IMHE) where >> Epilogs are good, as their beam expander optics give a deeper depth of >> useful focus. Progressive auto-focussing between passes can help too. >> >> There's also a weird effect (mostly in narrow drilling, not cutting) >> where smoke density diffraction causes beam steering, defocussing and >> corkscrew holes! (try thick rubber). Air assist solves this, if >> there's enough slot kerf to get deep airflow. >> >> 3/4" can be done, but it's a trial for a machine builder and operator >> to set it up right. Cut speed in birch ply is at least twice what it >> is in MDF. Cheers, Jeshua Lacock Founder/Engineer 3DTOPO Incorporated <http://3DTOPO.com> Phone: 208.462.4171 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
