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Well, Mach3 just went off again and ruined another $50 body blank. It just out of nowhere put in an offset in the Y axis. I stopped the machine and rechecked zero and it was right on.

Is there a direct replacement program I can use without any hardware changes?

Thinking about it some more, it only showed up when it got hot, around 110 degrees. Is it possible it's in the PC itself?

Try running the program in air and see if the bug occurs in the same place. I've had similar things happen where it seems like Mach 3 skipped a G0 move for no reason what so ever. It would do so consistently, I could start the program a few lines before the G0 and it would always just skip it and pretend that everything was ok. If I remember correctly, the DRO was even updating.

I went back to my CAM software and made some tiny little change, just so the program would be ever so slightly different and it stopped skipping the G0 and worked fine. Not that that helps you now but it's something you can try until you purge Mach 3 from your life.

Oh, and I think LinuxCNC could probably replace Mach 3 more or less drop in.

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http://www.birkonium.com CNC Products for Luthiers
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Update - when I first turn on the machine it works great. During long runs (Outline of an electric guitar body) it sometimes gets an offset. I moved the PC so it's right next to the air conditioner vent - same results.

Could the motor or Gecko drive be causing this? Should I slow down the feed rate (Currently 1/2" bit, 0.1" depth cut, 50 IPM) or try to add cooling to the Gecko? Any other thoughts?

There's a few possibilities here. Using the parallel port to control timing is sketchy at best as far as this goes. Tormac has a white paper that shows that irregular timing pulses from the PC can cause dramatic losses in torque from the steppers.

I've not heard of Gecko drives missing steps due to heat but I suppose it's possible. My system is run by a Gecko G540. It's in an enclosure with a fan, no heat sink and just the other day I ran it for like 8 hours straight with no problems whatsoever. At least half the time was spent cutting at 400ipm (radiusing fretboards)

For your feed rate, that seems slow to me. I'd be cutting at least 150ipm, more likely 200ipm for a 1/2" bit and probably .250 DOC.

Something you could try is to lower your acceleration by 25% and see if you've still got problems. My machine used to have problems stalling when cold but it's feasible that a machine could get tighter when hot instead.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Thanks, I'll try lowering the acceleration. Why would it only show up after cutting a long sequence? That's why I thought it might be heat related. My Geckos (6201s) are inside a sealed electrical box on an 1/8" aluminum plate, no fan.

Another update. I set up the machine just running in circles and let it run and sure enough it eventually lost steps. I opened the box and felt the Gecko drives and burned my fingers! I left the box open and blasted in air from a fan and re-ran the test. So far the drivers are only warm no lost steps!

I was having similar problems. Very difficult to reproduce because every time I went to reproduce them, the machine would only be running for and hour or more (compared to when the problem showed itself, at 6-8 hours use).

Make sure your drives do not get too hot. A fan is definitely necessary. Make sure you also have adequate venting for that cool, rushing air (from a fan) to escape. Your steppers can get hot but don't let those drivers get too hot. I have also considered installing another fan in my control box and pointing it directly at the drives.

I'm considering an aluminum heat sink.

Update: I tracked the problem down to the threaded shaft couplers. I replaced the cheap plastic ones with some aluminum couplers. I think that when the plastic ones got warm they would slip. My machine is unique in that it uses two motors for the X axis, one on each side to move the gantry. The motors are slaved together so they move at the same rate. When one side slipped, the gantry would get cock-eyed and bind up. Then I would miss step commands and there would be an offset from the zero references.

Just thought I'd throw something out there - although I'm still planning on switching to Kflop and Kmotion CNC in the long haul, I needed a fix RIGHT NOW due to all kinds of issues with Mach 3's trajectory planner. I purchased a UC100 USB to Parallel control dongle and finally picked up the software to go along with it and ran a few test parts this morning. Results are very promising.

Parts cycled about twice as fast and look much better than parts coming off Mach3. Machine over all runs much more smoothly than mach 3 even though it's running much faster.

I was able to increase my accelerations because unlike Mach 3, the TP on the UCCNC software doesn't violate the acceleration limits.

I still have to write a couple of macros to put it into production but it doesn't look like that should be too hard.

Anyway, worth looking into

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I have the uc100 dongle, but what is the software? I use mach3 with the uc100 plugin. Am I missing something?


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Yes, they have their own control software that you can find here: http://www.cnc4pc.com/Store/osc/product ... cts_id=839

It's not as mature as Mach 3 meaning that it doesn't have a million plugins etc. but as far as machine control goes, the trajectory planner is leaps and bounds better than Mach 3. I was using the UC100 with the Mach3 plug in and saw little improvement in performance.

I'm working on writing macros for Z-probing and automatic tool offset probing.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Here's a link to some info:

http://www.automationtechnologiesinc.co ... l-software

I've only had experience with Mach3 and I'm just in the process of setting up my own shop with a CNC router and CNC mill.

I'm very tempted to make the switch to something other than Mach3 and I've heard great things about Kflop, but your post Andy is my first exposure to UCCNC.


I'd very much love to hear any further comparative thoughts from Andy or anyone else regarding alternatives to Mach3.


Edit: D'Oh! Sniped by Andy himself

I just got an ethernet smooth stepper. Will install soon. Hope to get better motion.


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Ken

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Ken

Unfortunately, don't hold your breath Ken.

If you have a really lousy computer, something like a smooth stepper or UC100 will help but, it doesn't fix the inherent problems with the Mach 3 trajectory planner.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I have heat sinks on all my Gecko Vamp's and 4 fans in the box. Two are out-direction fans right over the drives, and I have ever had these issues at all. I also have a temp sensor on one of the drive/heat sinks which goes to an LED readout on the same box that my E-Stop is mounted. The thermal sensors are cheap, like $5 on eBay.
Heat sinks, more cooling.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Don, I kind of hijacked the thread because it was filled with Mach 3 hate (which I also contain). Jamie ultimately tracked down his problem to a loose coupler but I've been having problems with stalling, corner rounding and general poor performance.

There is a known and well documented bug in the Mach 3 CV mode trajectory planner where at certain times, it will exceed the accel/decel limits by up to 100%. This obviously can lead to stalling and ruined parts. The only solution is to decrease your accels by 50% which leads to slower performance.

With slow accels, you get can get corner rounding and other artifacts in your part which leads to dropping the lookahead setting.

Dropping the look ahead leads to really jerky performance and higher cycle times.

And perhaps the worst part is that the Mach 3 guys know about the problem and have stated that it won't be fixed any time soon, delivering Mach 4 is higher on their priority list.

I can't switch over to the UCCNC software full time yet as I don't have a tool change solution and I'm having some issues while air cutting big files (necks) but so far, they have been very responsive to e-mails (so is Dynomotion, the Kflop guys). Let's see how they respond.

To summarize, my feelings are that Mach 3 is absolute crap and should have an asterisk next to it stating that it is "for amusement purposes only". Rant aside, Mach 3 does have some things going for it that it has a huge support base and lots of plug-ins to do various things. For a machine that doesn't get a lot of use and for a user that's ok with slow cycle times, it can be made to work.

Considering that the UC100 + UCCNC software is only a few bucks (like, $185 for UC100+UCCNC vs $150 for mach 3 with no hardware motion controller) more than Mach3 alone, I'd definitely encourage anyone just getting started to stay away from Mach 3 to avoid future headaches.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Agreed. The folks at Mach, while I'm sure a great people, have been struggling with these issues for some time now. Mach four has been in development for many years, and as yet they don't seem to know when or if it will become available.
The same sort of thing happened with Gecko many years ago. They had a product out called the G100, which was supposed to be a really great product that allowed micro-stepping and connection via ethernet (I think...could have been USB...can't recall exactly which).
It was a great idea, but the product was plagued with issues. I bought one, thinking it would be the greatest thing as touted. But they had some bad modules or something, and they frequently could not connect with a computer or with Mach. But they would take the units back, replace the rabbit module or whatever it was called, and send it back, only to have the user still not be able to get it working. The problem was, as I saw it, they were testing on test equipment, and not on actual systems with PC's and cables, etc. The owner of Gecko is a brilliant engineer, but he hired someone on the outside to write the firmware for the product, and it was not good. The product could do so much if it worked, and would have been amazing, but nobody could write the code to get it to do what it should have been able to do...
part of the issues was that the owner of Gecko had put it out as open source code, and allowed folks to try to write the code, but nobody could make it work. I think the owner of Gecko didn't want to spend the necessary cash for the right code designer and the amount of work it would take to make it actually a successful code. Dead product.
Mach was first designed for folks to have a PC based alternative for CNC motion control, i.e. those weekend warriors who make their own machines etc. I just don't think there's motivation enough for them to make it a truly viable product for anything more than that. Then again, perhaps Mach 4 is intended to be just that. I know that more recent versions of Windows and Mach don't play well, which is why most Mach users (like me) are stuck with XP Pro.
There ARE much better solutions out there if you are using the machine commercially, trying to make money and not ruining parts.
All that said, I have not had any Mach related issues... fortunately. But my computer is "clean" and has absolutely no other software running in the background or even loaded that would interfere with Mach.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

I know that Art retired a few years ago and Mach3 stalled. I think they sold it, so maybe the new owner will start fixing things.

I don't normally slam products I don't like but for Mach 3 I'm making an exception. To sprinkle a bit of good in there - Mach 3 did teach me a lot about CNC and it was a decent starting point since there's such a large support community.

To your part Jamie, Mach 4 is already something like two years late. The CV bug I spoke of has been in there since day one and it will never be fixed in Mach 3.

I found a bug in UCCNC's software where in very large files (e.g. a neck) with thousands of very short line segments their TP craps out after about a half an hour. They just sent me a test version of the software that fixed the problem. My cycle time for the program dropped by almost 20min.

To me, Mach 3 is that first girlfriend where you learned a lot and had some fun together but she ended up being way too high a maintenance and costing way too much (I've lost hundreds of dollars due to Mach 3 bugs). I won't miss her.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I've got a CNC router with ATC and servos controlled through an Ethernet Smooth Stepper. Any recommendations for controller software other than Mach3?

I see that Warp9 has a beta Mach4 plugin so Mach4 may be a practical choice sooner than expected.


If I'm understanding correctly, UCCNC's software needs UCCNC hardware, as does Dynomotion's Kmotion/Kflop system.

I'm thinking that unless I'm willing to replace the Smooth Stepper I'll have to try it out with Mach4 and hope that it doesn't have the acceleration problems Andy's talking about.

Just thought I'd throw an update out here - I've finally re-written the macros I'm using in Mach 3 for UCCNC and ran some test parts the other day - results are very promising! I machined a bridge and the cycle time was about 3 minutes faster and the part came out with an extremely good finish. Much better than what I was getting with Mach 3.

I've got a second machine that's set up with a Kflop already and I'll be putting that into service within the next month or two. I've still got to make room in the shop for it and do a little re-wiring. It will be very interesting to compare Mach3, UCCNC and KmotionCNC. I think this is rather unique to have access to three different control systems so it should provide some interesting insight.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I don't have any experience with servos (yet) but depending on your drives, you might be able to use a UCCNC/UC100 combo.

If your drives are something like Geckos that have the control loop in the drive as opposed to the controller, it would be pretty much plug and play. UCCNC also comes with an M6 macro for ATC but that will definitely require some customization. That said, the customization shouldn't be terribly difficult. I haven't written a lick of code in like 20 years and I managed to write my auto tool length measuring macros in a day. And they even work!

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I spoke to Maurice (I think that is the Gecko owners name) about the G100 around 7 or 8 years ago. At the time I think it didn't have any firmware. Although I'm a competent low level programmer, I didn't have any experience with motion control or kinematics and was forced to look for another solution. I ended up building a hobbycnc kit. Tried to use Mach3, but finally gave up and gave the electronics to a friend for his mill.