Gee that’s not mean to sound racey. I am wondering after reading post after post and brochure after brochure, just how fast and deep can a laser cut? specifically looking at the 45watt mini epilog and the rep says that it can zip through wood up to 1/4″ without a problem but it sounds like (from what I’ve read anyway) that 1/4″ is slow if not even possible with most setups. I don’t mind a bit longer time if it works–but not the difference between a couple minutes and an hour with a charred edge. So, if I get the 45 watt laser, just how does 1/4″ or even 3/8″ work? Thanks.
I’ve got a 30 watt and i must run the 1/4 inch acrylic at .3 inches per minute. So about .5 inch per minute @ 45 watt. One aspect of acrylic you might like to know about is the cut is in the shape of a “V”. The top of the sheet of acrylic has a wider opening than the bottom side.
Wood is a bit different because it builds up a carbon layer. With my laser i can cut 1/4 at the slowest setting, but no matter how many passes or how slow i go, i can’t cut much thicker. The edge the laser leaves on wood is a burnt black. Using a shield gas might help, but I’m not looking to cut wood. Also bark and knots can cut much slower so it not uncommon to not have a complete cut.
If you’re looking to work with wood, a CNC router might make more sense. It’s basically the same thing as a laser engraver but uses a spinning bit rather than a laser.
Do I read this right that you’re cutting at 1/3 of an inch per minute? I have a 75 watt Epilog legend and am cutting 1/4 ” oak at about 40 inches a minute. Have cut as thick as 9/16 oak at very slow rate that gets the wood very hot. Anything with much detail at this slow a rate tends to burn up.
Yes, it’s that pathetic, but I didn’t buy it to cut. It might also depend on the wood I’ve tried which is mostly been plywood. Its fine for etching and making sand blasting resists. To get a 75 watt would have nearly doubled the price. So since for most things it’s only a matter of time. When it makes sense to buy a second machine, I’m hoping to get the big one then. My focus is to put photographs onto granite and glass. Small $45-$150 keepsakes.
This past year has really warped my plans. I got a computer contract which put to shame what little I would have made engraving this year, so rather than engraving, I’ve been earning good and throwing the surplus into infrastructure. I’m hoping this year to find someone to hire to work the business, since i really hate to see it all sitting idle.
My background is R&D at large printing companies, but large companies aren’t much fun to work for anymore. On the other hand, its been a lot of fun being a contactor for a large company. Its almost been like being on vacation, but hopefully this year I’ll press forward. At the top of my list is to contract to have a web site built which will allow preview of a design it yourself interface. So users could upload a photo, crop a photo, add text, move text and see a preview so the user can just click to order rather than needing to “ask for pricing” or “call to order”
How deep/thick is not really a function of power (It is actually but…) its a function of the focal point of the lens The focusing lens makes the beam converge and diverge almost like an hourglass shape and the power is concentrated into the “waist” of the hourglass. At a certain point above and below the “waist”, the power density is too low to cut most anything. The shorter the hourglass (short focal point lenses) the thinner you can cut. Obviously more power will allow you to use more of the hourglass above and below the waist, however the way the laser works at these points is not ideal. The laser beam should actually vaporise the material leaving adjacent material unaffected (i.e. a small heat affected zone either side of the cut), using the wider portion of the beam will tend to create massive heat affected zones and thus damage (or char) the material. In these wider zones, the laser does not work as intended and really just burns or melts. As you go to longer lenses that have more stretched hourglass characteristics, the problem is the waist gets thicker (called the spot size) and the amount of power concentrated in that waist is spread over a larger area, which in itself gives a wider cut. 25 watts concentrated on a pinhead can cut better then 100 watts concentrated into a match head.
Wood is a bad material to cut, it requires huge power to get clean edges and a lot depends on what you cut, some high resin woods will require tons more power to cut than dry tinder like ones. Acrylic is another case altogether as the material acts like a wave guide, IE it tends NOT to diverge the beam too much, thus one can cut thickish acrylic with straightish sides. Speed of cut is also a variable that is not that straight forward as the laser does not fire continuously, it actually pulses (PPI= Pulses per inch (of travel)). Cutting with a laser is much like drilling a series of overlapping holes in an item and breaking it out. so pulses per inch when cutting make a huge difference, if for example one pulses at 10 PPI then you get a perforation, if one pulses at 50000 ppi you get a series of “holes” so close together that the material does have a significant heat affected zone and gets damaged. Most lasers will set the optimum PPI for you, but some materials respond and cut better with different values.