I cannot figure out where to ask this, has more to do with the laser than lightburn, I use inches not mm it’s what I grew up on and honestly I s few up mm every time I try to change, I am trying to find out in inches what is the max speed of my laser when I set the speed/power in lightburn, I’ve been only using 100 as the fastest and if that’s the max speed then ok but I think it should go faster. I sent a request to the manufacturer and they sent a document that u do not understand but I’m sure someone here does.
This sets the maximum rate each axis can move. Whenever Grbl plans a move, it checks whether or not the move causes any one of these individual axes to exceed their max rate. If so, it’ll slow down the motion to ensure none of the axes exceed their max rate limits. This means that each axis has its own independent speed, which is extremely useful for limiting the typically slower Z-axis.
The simplest way to determine these values is to test each axis one at a time by slowly increasing max rate settings and moving it. For example, to test the X-axis, send Grbl something like G0 X50 with enough travel distance so that the axis accelerates to its max speed. You’ll know you’ve hit the max rate threshold when your steppers stall. It’ll make a bit of noise, but shouldn’t hurt your motors. Enter a setting a 10-20% below this value, so you can account for wear, friction, and the mass of your workpiece/tool. Then, repeat for your other axes.
NOTE: This max rate setting also sets the G0 seek rates.
That shows the manufacturer rates the machine’s maximum sustained travel speed at 20000 mm/min, which converts to 787 inches/min.
I say “maximum sustained” because it takes time & distance to both accelerate and decelerate the machine parts whether to reverse direction or make a turn. Just like a car that “can” do 200mph will “never” get to that speed except in strictly controlled circumstances. So, smaller motions never get close the maximum speed.
In my experience, max rates for most diode machines are useless even not taking accel into account. My machine is rated at 48,000 mm/min and I have yet to find anything that can be done at speeds above about 10,000. Maybe lightly marking thermal paper? Lol…
That said, you can set Lightburn to report in imperial/fractional units. See here
The RepRap calculator will give the distance required to reach a given speed at whatever acceleration the machine uses:
Except for surprisingly long straight lines, the machine will never reach the absurd speeds found in the seller’s description.
The maximum acceleration and speed settings interact, because a very high acceleration on a long vector can require more torque than the motor can supply and cause a stall, while a bunch of short vectors work just fine because the speed never gets high enough to matter.
Fun fact: manufacturers often claim the maximum speed along the diagonal of a square, because Pythagoras tells us the laser head will travel at √2 = 1.4 times the speed along either axis. That obviously justifies a claim of 700 mm/s for a machine with axes limited to 500 mm/s.
