General Centroid processing speed & accuracy question

[suntravel]

The motion controller is running with Linux.

Uwe

[cnckeith]

That is awesome.
To explain myself a bit: I do wooden form work, which led to me milling it out of aluminium and sometimes steels as well, as we were making smaller and smaller parts with higher accuracy needs. There are, unfortunately, tighter corners as well, so I often have to finish the surface with a 1/8" or smaller ball end mill. High quality tooling with shrunk fit tool holders, no backlash (pre-tensioned) ballscrews, negligible runout, rigid workpiece fixture.
We always run into the same problem: Feeds/speeds/stepover/roughing toolpaths and Fusion specs like smoothing and so on are right on, machine is geometrically pretty darn good, but in the end I always get some type of "pitting" on the surface. That results in some painful manual finishing work to be done and accuracy suffers from that as well.

When we looked at a new machine they offer software options for exactly this phenomenon. They include a picture of a surface like mine, and another one pretty much perfect picture of a surface with the option turned on. I mean with standard smoothing, cutting down the code, your accuracy will obviously suffer but they advertise as if with such control software options that is negligable as it appears to work different. There is also not a lot of info how it actually works - just faster processing speeds, refresh rate, some advanced maths behind it, servo tuning, some whatever, I don't know.

I don't know anything behind the mathematical or electronical challenges behind a CNC control, but would love to know whether or not this could be a feature with Centroid controls in the future. I would definitely pay for it as an upgrade if it is not ridiculously expensive.

if you want to run fast and as smooth as possible, use the Centroid Hickory CNC controller.
more info here. https://shopcentroidcnc.com/hickory-cnc-controller/

While Acorn and AcornSix perform better than their competitors, there is only so much you can do with the step and direction axis motor drive interface.

Our g code smoothing technology enhances a well designed and configured machine tool even further and works with any of our CNC control platforms. more info here. https://www.centroidcnc.com/centroid_di ... manual.pdf

machine design can not be overlooked, a great cnc control will not perform well on a bad machine design. rigidity, axis motor gearing as well as axis motor sizing (torque/rpm etc) are very important.

Thank you for your answer.
We will definitely try out the Hickory control. First of all, this community is just great, your support is great. The products seem to be well made with lots of thought behind it, in the USA, and still affordable.
If we were to buy a new machine with a Fanuc control, it throws us in a sterile environment, with sales persons which are still very knowledgable, but hesitant to give out details (rightfully so, it's probably a very competitive market) and there is no real community behind it like it is with Centroid; we have to take them at their word. They are though, with all respect, still on a different level - but that comes with different cost as well. I am eager to see how the Hickory will perform. We would probably use Yaskawa servos with Bus connections. The machine is very rigid, Japanese made cast iron with oversized linear guides and ballscrews. For finishing ops there is no to us measurable deflection. Ballbar tests are (according to a befriended service guy) great. We've even sent out shrink fit tool holders to be balanced and measured out for run-out. Shop is not in a highly fluctuating temperature climate. No floor vibrations accumulated from other machines sitting aside of it.

We looked at Brother Speedios which seem to be amazing. Completely different mechanics/general machine layout though. But it would be perfect for surfacing as well. They showed us mold parts, and they looked absolutely flawless - with a cycle time I couldn't really believe. From what I've been told by others they are basically a Linux CNC control, with lots of Brother's engineering on top of it. Even though they are drill/tap machines, everyone I've asked about them is absolutely loving them, doesn't matter if they are machining castings, doing smaller mold work, higher accuracy work, large quantity work. Is centroid not also Linux based?

The Centroid CNC12 software runs on a Windows 10/11 PC but the Motion control (and PLC function) is performed by our hardware.

The Centroid CNC control is a hybrid PC based control.

The Windows PC is being used for the user interface, while the critical high speed machine tool motion and function is being handled by the Centroid Hickory on-board Motion Control processor and the on-board PLC. This arrangement is the best of both worlds, a PC for a non-proprietary, wide compatibility, reliable, affordable, serviceable computer without the problems of a fully PC based CNC control as any issues related to the PC CPU or a momentary Windows glitch will not affect the CNC machine tool operation as both the PLC and Motion control is performed on directly on our hardware by our integrated firmware (which even auto updates with each new Centroid CNC software release, so no drivers to mess with or other complicated procedures).