It’s not actually possible for the software to access the rotary settings in the Trocen controller. They don’t provide a way to do it, which is why LaserCad doesn’t do it either, so unfortunately my hands are tied. You have to change the rotary settings through the controller panel interface. I’ve requested this from them, and they’ve been unwilling to change it. If they provide a way to do it in the future, LightBurn will add it.
Earlier versions of LaserCad had a rotary settings function. Not sure how long ago it was dropped.
My method is, measure the diameter of the job, multiply that number by my pre calculated number, and enter this into the Y axis pulse value.
Someone as clever as yourself could make a rotary control panel like you already have for Ruida, that takes the steps per rev and job diameter (that you already have) and send the calculated value to the relevant axis step setting. (Y in my case) Trocen does not need to know anything else.
I may be missing something (quite possible) but that does not sound too difficult.
That’s effectively what’s done for some machines, but the problem then is that the system has no way to properly respect travel speeds. What might be a valid linear speed for the Y axis when not connected to a rotary could exceed the limits of a rotary, or the opposite could be true and the controller could limit the rotational rate, thinking that the axis was traveling too fast - it affects how the controller ramps power, takes corners, and so on.
So, yes it can be done, and it’s probably fine for scanned graphics, but vector marking would be a crap shoot as to whether it would behave well or not.
What is wrong with setting up the rotary from the Trocen front panel? It’s dead simple to do and only has to be done once. Then you just enable/disable the rotary as needed. No more futzing with your Y-axis settings.
“So, yes it can be done, and it’s probably fine for scanned graphics, but vector marking would be a crap shoot as to whether it would behave well or not.”
Not sure it would be the issue you might think.
When you think about a typical Y axis velocity and acceleration, and compare that with
a rotary which is typically somewhere about 2:1 to 6:1 ratio belt drive. With insignificant inertia compared to a Y axis gantry.
Anyway mine behaves perfectly well.
As a side issue. Is there some trick to accessing manufactures parameters in Lightburn?
If you tell the machine to vector engrave a circle, at a constant speed of 50mm/sec, the horizontal axis will move exactly at the speed you command, when moving perfectly horizontally. As it transitions to vertical, however, the controller has no idea whatsoever what the “surface speed” of the object is, only how fast it thinks it’s supposed to limit the Y axis when running a linear move across the bed. If I was using a chuck rotary with 3:1 gearing, as an example, one full stepper rotation would move the surface of a 100mm object by 104.7mm. By contrast, one full rotation of my stepper motor for the Y axis moves the head about 30mm.
So a vector pass, running at 50mm/sec, would be moving over the surface at ~150mm/sec instead of 50, resulting in inconsistent power output, and all the accel & speed limit parameters would be incorrect. So, as I said, probably fine for raster work, kind of hit or miss for vector marking.
The step value for Y is altered according to job diameter, so that 50mm of Y axis movement now becomes 50mm of rotary axis movement of the material under the laser head.
A commanded speed of 50mm/sec remains 50mm/sec. Because a commanded move of 50mm in Y is now 50mm of movement on the surface of the job. The step distance has been altered
To quote what I said in earlier post;
Someone as clever as yourself could make a rotary control panel like you already have for Ruida, that takes the steps per rev and job diameter (that you already have) and send the calculated value to the relevant axis step setting. (Y in my case) Trocen does not need to know anything else.
I may be missing something (quite possible) but that does not sound too difficult.
Ohh, you’re talking about altering the stepping distance for the Y axis, not just scaling the job in Y. That was the critical bit I missed.
Yes, that would work - I’d have to be very careful to record / restore the original step value or it would cause lots of trouble, but I’ll consider this though - Older Ruida controllers basically need to have the same thing done, so I need to write something close to this anyway.
Thanks Oz. I am on the other side of the world so time differences make flowing conversations difficult.
Have used my home built laser for eight years with LaserCad/CorelDraw, but have now donated it to the local Mens Shed.
This is the reason I am only now using Lightburn. Recommended it to the members as an easier to learn and use program. So I am trying to learn it as well as teach members how to use it and the laser.
