Repeat Laser Image in the Same Spot


New to this and trying to laser multiple items with the same image, so have placed the blank in the same location but image seems to laser in slightly different location. might only be 1mm or 2 different but makes it difficult to produce multiple items such a coasters the same as the image moves. am I doing something wrong or is it a normal problem.

Do you always ‘Home’ before the next cut ? I found that if I didn’t, the next cut could be slightly off.
To avoid this I added $H to the ‘Start Gcode’ tab in Lightburn (device settings then Gcode). I haven’t had a problem since.
Hope this helps

In machine settings set $1 = 255 that will keep motors powered between jobs and hold position.

I’m somewhat new to LightBurn and lasers, is there any downside to keeping the steppers always enabled? I’m on this and other forums trying to learn as much as I can about LightBurn and my OLM2P (like homing after each run and $H), which is why I’m asking.

Yes there is a downside to keeping the motors constantly engaged they get hot, but its quite simple after a batch of the same work to use $slp command and disengage them until rehoming is needed for the next job, I always keep my motors engaged unless i know the machine is going to be sat idle for more more than 30 mins. You can also get some heatsinks from E-bay for nema 17 motors with the stick on heat pads to attach, they help , but stepper motors getting hot is pretty normal, and even hotter than can able to touch should not concern, so just use one of the Macro buttons in Lightburn so its an easy click to sleep the motors only takes a click then.
To be honest with Ortur using acrylic gantries, I would imagine that over time with use the heat from the steppers would distort the acrylic any way, and may even come loose with heating and cooling, just need to keep an eye on that. and seriously consider some heatsinks for the back plate of the motors.
You should not need to Re-Home the laser after every run, only after putting it into a $SLP state. Due to periods of setting up causing long periods of inactivity, say 30 mins plus.
it does sound like loosing position is down to the free movement and any tensions from cables etc, put it this way it’s a lot less hassle to leave the motors engaged than to have to start again due to position loss.
I would defiantly set $1= 255 just for ease of use and repeatability, as homing should be done at a relatively slow speed for accuracy, with the debounce homing fast and slow settings.
But do not be too concerned about Motor heat, the motors running hot is normal.

Here is a link with some concerns people have had with heat issue , should put your mind to rest.

Hope this helps,

Paul, thank you for that very informative answer. I have an OLM2 Pro so it’s an all metal gantry (just one of the reasons I opted for the Pro version).
Thanks again,

Sorry but i disagree, stepper motors too hot means an error in setting the vref for that motor, i have my 3D printer working for 3 days and his motors are at about 35-40° (celsius).
When motors are too hot they can lose some step ruining the job, so be careful with the vref you set.

Its you prerogative to disagree, and yes i defiantly know how to set Vref, and heat is not all down to that setting, many factors speed how much of the motors torque is being used.
But if your so sure your right, Il will inform all industries with CNC machine centres to contact the manufactures, and ask them to re configure as they defiantly run at over 120+ C with heat guards around the motors!
Perhaps people use all the Torque a motor is designed for. and not a small percentage of it., and can lower the vref to a point where the motor provides enough for the application it is used in.
And 3d printers, rarely hit the speeds of laser engravers, in use.
My 3d printer uses the same motors as my laser, and about 20% of the vref setting, they do not get hot either, but neither does is run at anywhere near the speed of the laser, or have two steppers on the X axis and a Cbeam with a diode laser to halt when changing direction without missing steps. slowing from 16000mm/min to 16000mm/min in opposite direction without missing a step. and of course during the travel slowing to burn and re accelerate, in white space.
For example my Z axis motor on My laser needs to use very little of its available power, just enough to move the unit to correct height and hold it, always near cold to touch, using about 25% of its total vref max setting, but that is al it needs to hold position.

Did you read the article attached, in previous post ?

Sorry, was not my intention ti disagree with a master like you…
Glad your machine are all ok
Have fun.

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I am no master, but have been employed as an engineer in high volume production all my life, never stop learning, but the golden rule of protecting plant investment, is always down to longevity of plant life against, service and maximum rate of use, we tend to run most CNC plant at a max of 80% of its capability, more so on 24/7 production capabilities usually means higher maintenance intervals and service cost, it would be awesome if we could afford to plant at <50% of its production capability. But yes you are totally correct in pointing out that steppers on most 3D printers do not get hot. even industrial printers be they SLA or SLS based need to be very stable, and over engineered with regard to movement and control systems. mainly down to time and the cost of risking lost production time, that would be incredibly damaging to production schedules/ profit :slight_smile: