G-Code Tears Thru Project and into Table

[Gs.spencer]

I have one last hunch as to what might be causing this. So far, the only time this seems to happen is on large size carving projects. CRV files larger than 1.5MB seem to be more prone to un-commanded inputs. The only failures I have had so far are on large projects between 18" and 23" wide.

My previous project was a 45"W x 15"T emblem that was split into two separate tile carvings. The CRV file was 2.2MB but the tiled TAP files were only 400KB each and everything carved perfectly. My last project I didn't have to tile but the CRV file was 2.6MB and the TAP file was 628KB. I wonder if certain TAP files are overloading the control box resulting in unwanted paranormal activity.

My control box is in on a UPS truck on its way to Ohio for repair/diagnostics, but I wonder if I would have broke my TAP file into 3 smaller segments if that would have prevented control box overload?

[4DThinker]

I've cut a few hundred jobs with my Shark and never had any of the problems listed here. I do keep my controller and power supply divided from the shark, and suck it out with the shop vac once a week or so just to make sure no sawdust has gotten in there. I could see electrical gremlins potentially occuring at drive motor cable connections, in the SD card slot, the USB cable connection, etc.. As it cools off, static discharge is starting to show up. Even the PC could be part of the problem if it got busy in the middle of a cut. I keep the system running my shark very stripped down, with only cnc related programs installed. Yet my office PC is frequently interrupting me with updates for this or that or the other thing. I know it sucks to have what should be reliable technology screw up, but there is much more in line that contributes to the magic than the Shark alone.

[Gs.spencer]

I'm using a new Panasonic Toughbook laptop which is ruggedized to handle extreme environments; the laptop has no internal fan mechanisms and uses advanced technology to run extended periods without the worry of overheating, etc. So in a dusty environment, I'm using one of the most optimal computers suited for this type of work.

I have removed most software programs and disabled tons of services and capabilities (i.e. bluetooth, wireless, networking, modem, PCMCIA, etc.) so I doubt that my laptop environment is suspect.

Somewhere along the line an un-commanded input starts that the stepper motor/counter doesn't see and then the rest of my project cuts too deep or cuts out of alignment. The last time this happened my problem was identified as having a bad GECO board and 4 axis controller; NWA said my control box wouldn't pass their diagnostic tests. They threw a new board in and then everything worked great. After receiving my repaired control box, my previously failed CRV projects were now carving perfectly.

Now two months later I'm back with the exact same problems; what else could it be other than the control box again?

So either the CNC can't handle certain types or sizes of TAP files or something within the control box circuitry is failing and falling out of tolerance/calibration. The last time it was circuit board failure; this time it might be the exact same thing again. Hopefully NWA can figure this one out.

Greg

[Eagle55]

With size of the tap file being a common mode of failure, I would wonder if maybe the SD card might have some kind of defect that is showing up when more of the card is used. You should be able to go up to almost 2GB of file size with no problem. Have you ever replaced or put a larger SD card in your controller box. Its a long shot but they seem to express that some of the larger SD cards may or may not be compatible. But either way it might be related to a card defect in some way although I don't think that is consistent with the symptoms you list.

[DGPilot]

I bought my machine in November 2012 and due to my work schedule was unable to get the machine operational until March 2013. On my very first project I encountered exactly the same issues that you wrote about in your July 13, 2012 and subsequent postings. I wasn't even able to get one project completed before these issues were apparent. I immediately contacted Rockler and New Wave and received very little help in resolving this problem. Once again, due to my work schedule I was unable to follow through until just recently. After doing a complete check of my system and writing a new V-Carve program, I ended up with the same results as you were describing in your posts from last year. I now have 3 holes in my table and have destroyed several projects, as you described doing. All that said, after reading your final posts, you had as of last year not made any posts indicating whether you or New Wave had resolved the issue. At this point, since it's been many months since your last posting, I am curious as to whether you have had any luck solving this major problem. One thing I did notice after attempting to run a project for about 30 minutes, my control box got extremely hot. Did you have this experience as well? I am writing this because it appears your were at the forefront of reporting and trying to resolve this issue. Until I can get this resolved, my machine is basically junk, which is not what I spent $4,000 for. Any advice you can give me would be greatly appreciated.

[rungemach]

I suggest you get your control box swapped for a replacement, just to eliminate that particular controller as the source of the bad behavior.

The control box heat may have a bearing on some of this.

I had an opportunity to look inside a newer controller a few months back, and was surprised at the lack of active cooling for the circuitry. The controller circuitry, power supply, and solid state relay for the router control are all heat generating sources in the control box. The slots for air flow were quite small and only on one side on the controller I had. I know it has been stated that the outer case is used as a heat sink to dissipate the heat, but I did not find that the heat was carried away very quickly and the controller continued to heat up over time.

I would suggest that you have some airflow around the controller case when the machine is running. Heat is generally regarded as an enemy to reliable electronic operation, and can cause intermittent problems if a marginal component gets too hot.

The older sharks had fans to push air through the circuitry case, and that may be a good idea for the new model cases as well.

[jeb2cav]

For what it's worth - I agree with Rungemach on this. Contact NWA, perform a couple troubleshooting things with them, and it sounds like you might be getting your Control Box repaired.

NWA does have recommended operating ranges for temperature. Unfortunately for me, I can't maintain that. My Shark sits in a pole barn in northern KY. When it is 105 outside, it is higher in the pole barn. I have not had a problem in either temperature extremes for what it is worth. I do have a usb fan circulating air in the cabinet the control box is mounted in.

I'd encourage you to perform some air cuts. The kinds of episodes you're describing can be caused by a few things -

1. Electrical interference/poor power. This is somewhat wide ranging in itself, but includes things like:
- Poor power - in my case, the voltage is not consistent, and I also experience momentary on/off conditions. A UPS/battery systems is in front of the shark control box and computer in my case.
- Interference on the same power source (like a shop vac plugged into the same circuit as the Shark Control Panel).
- Dust hose connected to the dust boot (if used) not grounded. A grounding cable should be run inside the hose the entire length - and properly grounded. Rockler does sell a grounding kit - but you can also obtain this stuff at the local hardware store.

2. Poor signal - this is typically a bad cable on one or more of the axis. While the occurrence of this seems to have gone down quite a bit in the past 2 years - the opportunity is always there.
- This ranges from an intermittent connection at one of the motors to a bad connection on the serial connector end of things. This can be narrowed down if the excursion seems to happen along one axis - you can attach that axis' cable to another output on the control box and if it continues - you've narrowed it down to the cable.
- If it is repeatable - even without switching the cables - is it repeatable at a certain location on the table? If so, it may be that tension on the cables is enabling this to occur at that spot(s).

3. Mechanical - this is typically a loose nut on the coupler that connects the motor axis to the lead screw. And one or more of these screws doesn't have to be very loose to get intermittent poor outcomes. This can also be several other things - like you left the hand broom sitting on the gantry and it blocks the travel, bad lead screw nut, loose lead screw nut housing, etc. But the most common problem is loose coupler nuts.

4. Poor setup. For cases of z - this is where the material height is such that when the carriage raises to make a move, it is running into the limit of travel. So, it really doesn't raise as high as it needs to, but it thinks it did. The result is that the next move 'down' is deeper in reality than intended. Similar condition can exist of course in X and or Y - if you set the material right to the edge of the possible extent of the carriage travel.

5. Wrong post processor - if you're not using the CNC Shark post processor, all bets are off.

6. SD card related error - although I don't think this would leave to a dive in the table - it can lead to early termination of the project and perhaps result in a nose dive.

In my own experience, the few times I've had a table engagement - it was caused by electrical interference (cured with small APS (conditioned power) - or a poor setup. I've been Blessed to not experience a control box issue.

To tinker with some of the ideas above - and it's not an exhaustive list - you could create a simple project with a 12 x 12 box that you v-carve and several bits of text - each cut with a separate toolpath (to force movements of the gantry) and air cut fairly quickly. You might be able to get a reproduction of the dive - and this will help you focus your troubleshooting.

[DGPilot]

Thanks very much for your replies, rungemach and jeb2cav. I will definitely be following up on your suggestions. I was concerned about the extreme heat being generated from the control box, and your posts have confirmed those concerns. I will be contacting NWA again concerning these problems. I'm just surprised that this issue hasn't been addressed sooner by NWA since I have had this problem from Day 1 without being able to produce even one good product from the machine. It amazes me after reading all of these posts, that they hadn't addressed these problems sooner. I purchased my machine at least 8 months after the first post addressing this issue, and haven't seen any response from NWA even though they sold me the machine knowing this was happening. Disappointing at the very least. Thanks again for your response and advice.

[KarenW]

I want to add a little something that's recently happened to us.
While zeroing the machine, especially on the z axis, we were getting hesitation where things would just stop briefly then continue.
Or, even worse, while lowering to z zero it would just continue and poke a hole in the board.
Before reading this thread I had checked everything I could from loose bolts and connections to interference with the USB and found nothing. I began to suspect the mouse was the culprit when using the on-screen calculator and getting double numbers with a single click. For instance while trying to input .25 into the calculator I was getting ..2255.
Swapping the old mouse for a new one solved the hesitation/bit burying problem. I took the mouse apart and found the tiny contact button was worn inside - when depressed it wouldn't always release which, of course, translated to the Shark.

Probably not applicable for DGPilot but wanted to get it in this thread for anyone searching for elusive mechanical problems since the title of this post is eye-catching.

[milo30]

Thanks very much for your replies, rungemach and jeb2cav. I will definitely be following up on your suggestions. I was concerned about the extreme heat being generated from the control box, and your posts have confirmed those concerns. I will be contacting NWA again concerning these problems. I'm just surprised that this issue hasn't been addressed sooner by NWA since I have had this problem from Day 1 without being able to produce even one good product from the machine. It amazes me after reading all of these posts, that they hadn't addressed these problems sooner. I purchased my machine at least 8 months after the first post addressing this issue, and haven't seen any response from NWA even though they sold me the machine knowing this was happening. Disappointing at the very least. Thanks again for your response and advice.

Don't expect NWA to give an answer or comment on here about your problem. They will occasionally answer something in here but it sounds like yours is going to need more than a forum to diagnose. It is always best to contact them directly and speak to the support dept. I haven't read through the entire post but I'd try another computer if you have one available.