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We purchased a K2 3925 back in 2007 and been having some problems the last few years with Mach 3 and possibly the machine. The frequency of these issues seem to be increasing and sometimes it’s hard to tell where the problem is coming from. I'm thinking of using a different controller program in an attempt find something a little more stable to reduce or eliminate these problems (if it's a problem with Mach3). I’ve looked around and there are some options such as WinCNC and LinuxCNC but my understanding of cnc electronics is very limited. I can put a board in a computer, but adjusting settings for proper communication with the machine is not something I’m experienced with.

Here are examples of problems that have happened:

· When running a program, the machine occasionally shudders and vibrates briefly. Tool position in Mach 3 is shifted. This happened early this week while routing a cavity and it shifted the location of the pocket –Y 4mm and +X 1.5mm. This is the most disturbing problem by far.

· When jogging the head downward to set Z position at tool change, when I let go of the keyboard button the head continues at a moderate feed rate until it hits the work piece or I hit the emergency stop (it’s a race).

· Machine faults out but Mach 3 keeps going. This happened last Friday 5 seconds into the first program.

· Both the machine and Mach 3 fault out.

· Jogging in the -Y direction causes the machine to fault out.

· When I use the Manual Data Input to move the head to a specific position, it won’t move. I can still use the keyboard to jog it, but not the MDI.

All of these problems are intermittent, but I’m losing confidence in the current set up and need to do something to fix this. It’s extremely frustrating and it seems that eliminating Mach 3 should be the first step. I’ve tried contacting WinCNC but have not received a response as yet. I received a quote from K2 for their current controller system for $3500.

Any thoughts or suggestions would be appreciated.

Bob

KFLOP all the way. If you've got steppers, then the KFLOP + KSTEP is a rock solid system. I've now used the KFLOP plus the other necessary Dynomotion boards on four machines: a full size VMC, an industrial CNC router, a little CNC I made for micro-precision parts, and now a linear motor retrofit of a bridge router. It never fails to please.

The online support community is pretty active now, so I think it's not going to be a big deal to get things set up on a basic machine. $250 bucks, and it'll embarrass anything you can get your hands on for under 10K.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

The only problem I recognize is the first one, where the machine shudders. I had this problem when I had the acceleration of the motors set too high. The stepper couldn't keep up so it lost steps, which changed the tool position in Mach3. Go to motor tuning and dial back on the acceleration settings for the motors and see if that helps.

For the other problems, I would suggest that you make sure Mach3 is the only process running.

Thanks guys for your input. I've gone through 3 different computers running XP and simplified the set up as much as I can. The computers are not connected to a network or internet. I've thought about installing Windows 7, but have doubts whether that would have any effect.

Jamie, the acceleration for all 3 motors is set at 20 inches per second per second and are servos. I had set it there a couple of years ago when I was cutting inlay (shell) and just left it.

Bob, I took a look at the Dynomotion/KFlop website at your suggestion. From what I can see, it seems their board would eliminate any problems caused by the operating system. My limited understanding of the information given is, machine controlling software would still be needed (?). I'm assuming this, as they have Mach 3 plugin capability, which is what I've been thinking of getting away from. It looks like a very good product but I need to figure out how it fits in my set up.

A few years ago I was having some problems with one of the axes (X or Y, I don't remember). K2 sent me a replacement Gecko G320 DC servodrive which I installed. It seemed to fix the problem. After visiting the geckodrive website I noticed they have a procedure to tune the driver and motor which I never did as K2 never mentioned it. Don't know if that is needed, but I don't have the equipment necessary to do this.

These issues are emphasizing the need for me to learn more about cnc electronics. My previous experience with electronics has been limited to passive guitar wiring. I've started sifting through youtube videos on that subject and will search for any books or online instruction also. I do appreciate this forum and everyone's helpful advice (or sympathy!).

Bob

Since the problem has been creeping up on you try spraying contact cleaner on the connectors between the controller and motors then connecting/disconnecting several times to try and clean off any corrosion.

Thanks Sheldon, I definitely need to do that. In a similar line of thought, the control box is sitting on the same table as the machine (table top router). I'm going to move it to a separate table to reduce vibrations, which could cause intermittent issues with the connections, especially if they're dirty. In addition, the break out board is slightly bent downwards at the serial connector as it's jammed up against the gecko controllers. This tension on the connector could also contribute to intermittent problems. The box is inappropriate to the components being used and was a poor selection by K2. I think I need to get a new one.

Bob, I sent an email to KFLOP telling them my situation and received a nice response from Tom Kerekes at Dynamotion. Their KMotionCNC program is a free standing machine controller so Mach 3 is not needed. It just doesn't have as many bells and whistles as Mach. I also explained I'm a newbie at cnc electronics and he feels very confident I could get it up and running with his support, as long as I'm not in a rush (which I'm not). I'm going to download KMotioncnc and confirm it'll do the job before purchasing the board. Thanks for the tip!

I have the same machine, I think I got mine on 2009, the inside of my box looks quite a bit different in regards to mounting. I am trying to track down a similar issue with loosing Z positioning. I called K2 and remember them saying that the older Gecko servos tuned themselves or did not need to be tuned but a replacement would need to be tuned also that there were colors associated with identifying servos old vs new Gold and maybe Red. The Z problem for me is becoming unmanageable now so I will switch servo axis and see if it is the servo causing problem.

Please post when you get things resolved.

I have the same machine, similar vintage. I was having problems with my Z as well but eventually tracked it down to a few missing teeth on the drive belt. Installed a new one and have had no problems since.
You've probably checked, but just thought I'd add my experience to the list.
Cheers-

KMotionCNC is nice enough control software, it does everything you need it to. I got all my complaints about lacking features added four years ago when I started using KFLOP, so all the things you'd miss if they weren't there are totally there now

You can also customize KMotionCNC's interface if that maintains the buoyancy of your dinghy, though I haven't seen any need.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

K2 was using a KFlop based controller on their machines after they stopped using Mach. Not sure how customized it was.

I downloaded KMotionCNC and it looks like it'll do the job. It's a very basic controller and not as pretty as Mach3. After playing with it for a bit the only thing I miss a little is the Mach3 command "Go to Zero". I can live with that.

I just received the KFLOP board today and will start a thread in the DynaMotion/KFLOP board on cnczone. I believe I understand most of the wiring connections with a couple of exceptions. Then will come getting all the components talking to each other and playing nice. A bit of a daunting task, but with the help of Tom Kerekes and others on the Dynamotion/KFLOP board I'm looking forward to the results. When all is done I'll post a note here explaining the outcome.

One of the wiring connections I couldn't figure out on my K2 was the emergency stop switch and how to integrate it into the KFLOP system. Mike at K2 informed me that their old set up had the e-stop breaking a connection in Mach3, which means I need to figure out a different method when using KMotionCNC. The Gecko 320 manual indicates an e-stop can be initiated at the servo driver by sending the connection from the Error/Reset pin (terminal 5) to ground. So it seems that the e-stop is a separate function from the KFLOP. If anyone has a different or better way of doing this I'd really like to hear about it.

Rand, when I talked to Mike at K2 he confirmed they were now using a KFLOP based system with a number of other changes to the electronics. We didn't talk about the software, so don't know about that.