[protrackcorp]

Has anyone converted their Navakon to a closed loop system ?

[SCzEngrgGroup]

Has anyone converted their Navakon to a closed loop system ?

You'd have to define what you really mean by "closed loop". Some would consider the servo-based machines to be "closed loop", since they have encoder feedback from the motors to the servo drives. If you mean adding linear scales with the position loop closed at the controller, then I'd wager the answer to your question is no, since Mach3 does not support that. I run a KFlop on my machine, with my own custom CNC controller app, and do hope at some point to add linear scales and dual-PID (velocity + position) to control it. However, that's more an educational exercise than a serious attempt the improve the machine. I get excellent accuracy and repeatability on my machine as it is, (I can crank out parts to +/-0.0005" all day long) and trying to improve it further is likely to be an exercise in futility, as I am already bumping up against the mechanical limitations of the machine, particularly in terms of rigidity.

Regards,
Ray L.

[engnerdan]

I am, I too am using the Dynomotion KFLOP motion controller and Kanolog boards. I have my servos configured for analog speed control with the encoders being fed back to the KFLOP/KANALOG to handle closing the loop and coordinating motion. I am still finishing the assembly/wiring of my machine so I do not have any history of how it will run.

[BTP]

as I am already bumping up against the mechanical limitations of the machine, particularly in terms of rigidity

I'm curious what you mean by that? I don't want to sound like a d**k but I'll I've seen you machine on it is mainly aluminum and plastic.

[SCzEngrgGroup]

I'm curious what you mean by that? I don't want to sound like a d**k but I'll I've seen you machine on it is mainly aluminum and plastic.

Sounds like you believe the myth that you can't run a machine at the limit of its capabilities unless you're cutting steel or other hard materials? That's simply not true. In fact, it would likely be harder to push it that hard with steel, without exceeding the proper operating parameters of the tool. What matters is how much work the machine is doing, which is limited by available spindle power. I often run my machine at close to the stall point of the spindle when cutting aluminum - that's as hard as it's ever going to work, no matter what I'm cutting. If there is a rigidity limit, you'll find it just as well with aluminum as you will with steel, unless you're limited by RPM rather than torque or power. And, BTW, I cut plenty of steel.

Regards,
Ray L.

[BTP]

I didn't intend for you to take as you did, but if your running your spindle at almost stalling, I would say that is a horsepower issue and not a rigidity issue. I think when anyone thinks in terms of rigidity, they are focused more on the machines iron and structural geometry and not how hard you can push it before you stall the spindle and/or an axis. Aluminum is a lot like cutting butter on most machines. If you really want to find where you machine is weak on rigidity, throw a piece of 17-4 in there and go to town. Or maybe some Invar. I'm sure the Torus could handle it, but by no means can you say cutting aluminum will challenge the same rigidity factors as going at a piece of much harder to machine material as the ones I've stated.

Take it as you will, but historically I have a good feeling how this is going to go.

[SCzEngrgGroup]

I didn't intend for you to take as you did, but if your running your spindle at almost stalling, I would say that is a horsepower issue and not a rigidity issue. I think when anyone thinks in terms of rigidity, they are focused more on the machines iron and structural geometry and not how hard you can push it before you stall the spindle and/or an axis. Aluminum is a lot like cutting butter on most machines. If you really want to find where you machine is weak on rigidity, throw a piece of 17-4 in there and go to town. Or maybe some Invar. I'm sure the Torus could handle it, but by no means can you say cutting aluminum will challenge the same rigidity factors as going at a piece of much harder to machine material as the ones I've stated.

Take it as you will, but historically I have a good feeling how this is going to go.

Nowhere did I suggest running near stalling the spindle was a rigidity issue. They are quite obviously two completely separate and unrelated things. But on the Torus Pro, when the spindle is running at it's limit, flex of the machine itself is also at the point of becoming an issue - the surface finish is beginning to degrade due to also running near the useful limit of rigidity. The harder you push the machine, the more it flexes. When the spindle is running near it's limit, you are also testing the machine rigidity to the maximum extent possible for that machine. On the Torus Pro, it just so happens that more spindle power would not give you much, if any improvement in useful throughput, because the rigidity would not allow you to really USE that extra power.

Regards,
Ray L.