[njitnjau]

Hi,
I have a K2 3925 machine. Ever since we got it we have had problems with the machine stopping in the middle of a program. It can be in any part of the program so I do not think its the G.code. its totally random.
I have tried to upgrade the machine little by little.
Actually we almost changed everything about the machine.

New better home swithces, better shielded cables to block out noise from the upgrade HSD high frequency spindle. New better Z-axis setup (came with the spindle) Stronger powersupply, PMDX breakoutboard...Latest addition are the US digital differential drivers that amps up the signal from the geccos. We read that if you have cables longer that 6 feet you need these... And we have longer cables.
After each upgrade we thought we had fixed the problem but nothing has helped this far
I just installed the drivers And it didnt get any better !! the machine still stops every now and then.

Before I go nuts, ( maybe its too late) Can someone please help???
Does anyone else of you have the same problem?

btw I have the servos not the steppermotors

/Berndt

[dahui]

Have you grounded the frame of the router to earth? We were having similar problems and it seemed like some of it was due to static buildup. I just used some speaker wire to ground it to the conduit mounted on the wall.

[njitnjau]

Hi,
Yes, everything´s grounded. We even have groundcables between all the different parts on the machine...Now we have even changed the computer and tried to tune in the motors better. The latest conclusion was that it had something to do with the motor tuning. When you press feedhold (space bar) the machine stops very brutally and sometimes the geccos trip. We tried to get it to stop more smoothly by tuning the geccos. It got better... but still it stops sometimes. extremely frustrating.

btw Nice trout!

[MrWild]

are the sheilded cables grounded at both ends?

[sploo]

...The latest conclusion was that it had something to do with the motor tuning...

That would match my experience. When I first got my 3925, I spent quite a bit of time seeing how far I could (reliably) push the machine. The answer was that it'll go much faster than I'm currently running, but not without cutting out.

The real killer for me was acceleration time - fast ramping would cause the control box to trip out during jobs. Taking it back to a more conservative setting has helped immensely, and it's pretty rare for it to stop now.

[THend]

And I thought I was the only one.....

I bought my KG3925 used , the prior owner couldn't get it to work at all. After significant rebuild, and re-wiring my machine runs.

Now, I too have the occasional random stop and it is very frustrating.

What I have noticed, after taking the time to look at the Mach3 screen after the trip is that I was tripping due to two different issues.

1. My machine was tripping due to limit switches being activated. This was happening due to vibration of my variable speed router and depended upon the bit I was using. The answer for that was to increase the debounce to about 2500 under the general setup tab. So, if you are tripping on limit switches when you are no where near them, look at your debounce number.

2. My machine was also tripping due to the G320 Gecko drives faulting out. The electronic box provided by K2 has slots in the bottom, but no slots for ventilation on the top. Where is the heat to go? I also noted that the Gecko drives were not heat sinked very well, and with very little area. So, what I have done for now, is to lay the control box on its side so the slots on the bottom are now able to vent, and I have a small fan blowing on it. An attempt to keep the Geckos cooler. So far, it has worked. I have acquired a very large box and plan to completely re-work the entire electronics package. The drives will be seperated out, rather than stacked on each other, and there will be significant cooling added, including nice big aluminum heat sinks.

If you haven't done so, and you are capable, open up the electronics box and take a look. I had to determinate everything, tin the wires, and re-terminate everything. The workmanship was very poor, and in fact my rig was not wired correctly anyway so I re-engineered all of that too.

If your Gecko drives fault out, does Mach3 stop as well for you? When I trip due to limit switches, Mach3 stops, but not when a fault occurs with the drives. Thus, if I am not watching closely, the g-code keeps on running.

So, in short, look at debounce in general config, and look at cooling down the electronics package. If capable, look at the electronics and re-work as deemed necessary.

Good Luck

TH

[sploo]

TH - good post. Very useful.

I suspected my problems were the Geckos tripping out. In fact one of the Geckos was dead when I first got the machine - give them their due, K2 replaced it quickly, without any fuss. As a result, I spent some time taking a look at the control box pretty early in the life of my machine.

When the machine does stop, I notice that Mach does continue unaware. I hadn't really thought about this before, but it is interesting that it's a fault that Mach isn't (made) aware of. In truth it happens exceptionally rarely now, but then in the UK, it doesn't tend to get very warm, so I doubt heat would be a major issue.

I haven't looked at the development state of Mach/Quantum in ages, but I was wondering if Quantum (with its smooth acceleration feature) would make the machine happier. Certainly I can feel the judder when the machine does rapid direction changes.

All that said, I've found it to work pretty well. Whilst I don't run production quantity workloads on it, I'm happy with the purchase.

[dahui]

Just checking to make sure you are running in "constant contour" mode with G64. There is also a diagnostic tool (in the software) that shows you the data transfer speed. I can't remember without looking for it, but it will tell you if the computer is keeping up with the ammount of data that needs to be transfered. We ended up replacing our computer with a newer one...did it help...sometimes

[hindocarina]

I used to have this problem too and did three things: grounded the bed, grounded the dust collector hose with a bare copper wire running through the hose back to the collector housing, and turned off soft limits. I found that it was happening mostly on files that took the router close to the soft limits. K2 recommended that I turn off the soft limits and it solved the problem. I don't think it has happened since.