CNC Shark Problem: Toolpath Shift/Jump

[PCDude]

I have owned the CNC Shark for less than a month and there are some issues that I have been having with my machine.

The machine will Shift/Jump its task in either direct by roughly an inch randomly. When it does this it completely ruins the project and an expensive piece of fine wood. I will press E-Stop on the CNC Control Panel and turn off the router, then have it go back to the "Zero" position. When it goes back to "Zero" you can tell the project completely shifted from its original work area to a new work area roughly an inch in either direction. One particular tool path that I completely recalculate, rename, and save new G-Code always jumps at the same position, same distance, and causes the same damage (Work Area shifts X and Y Axis -1 inch).

This problem has caused damage to clamps, router bits, and wood which all has been expensive to replace. Due to its random nature, it doesn't happen all of the time. We continue to cut our projects with our finger on the E-Stop waiting for the machine to act up so we can react. So far we have been good at stopping the machine before it ruins the project or damages anything.

There is no issue loading G-Code, and there is no issue jogging the machine. The issue is intermittent and is progressively getting worse everyday.

I have tried reinstalling the Control Panel, Updating the Firmware (Again), Updating G-Code with a New Name, Updating a Project by Saving Under a New File Name, Switching Computers, Reformatting SD Card, Unplugging and Plugging USB Cord Back In, Closing the Control Panel After Each Tool Path and Opening for Next Tool Path, Checking the Gantry Guides and Screw Rods (No chips, gunk, or defects), Checking the Screw Rod Guides for Damage, Checking the Wire Connections, and Ensuring the Controller and Power Supply is Free of Dust.

The problem STILL exists after doing everything I just listed above, and it is happening more every day. I see it when it happens, and just continues to run like nothing is wrong with it even though it shifted its work area. I don't understand why it does this.

There is one instance that the problem replicated itself and its cause was a brief power loss where it shifted -Z dramatically. However we have had continuous power fed to the system while cutting projects with the machine and we have gone as far as not doing anything that would cause a sudden surge in power (such as turning on the table saw). The problem still occurs.

My conclusion is that either the controller is faulty or the power supply does not provide continuous uninterrupted power to the controller causing the workspace shift. Does anyone have any input or suggestions on this problem? Should I replace the controller or power supply? Can it be the motors?

[jeb2cav]

I'd say that this is totally unexpected behavior - and obviously not acceptable to you or Rockler/Next Wave. I'd recommend you call Rockler, ask for Al (Shark guru), and get the name and phone number of the Next Wave Automation Shark support guy. Call them and describe. I think the leading culprit is a control box lemon - not wiring, motors, etc. It may be something as smooth as an exchange of control boxes.

You've got a repeatable random catastrophic error going on here - reatable is good in this case.

You listed about the entire laundry list of anecdotal troubleshooting steps. One you didn't list is powering down the control box, then powering it back up. If you have done that and just not on the list, then I still recommend a support call.

I do not, nor could I afford to, sit and watch jobs run at this point in my use - i.e. I'm pretty confident I'm able to remove operator error, and have setup the shark/cables/router/etc in a manner to minimize or remove errors caused by power fluctuations or interference. So, I walk away. Sooner or later it may bite me, but so far, no.

[PCDude]

Yep I have also powered down the controller, just forgot to list it. I'm going to call Rockler and see how they can help out.

[hbutch8]

I just had that same problem. After hours of searching every little thing, I pulled the table to check Y axis. Sure enough the motor connecter had loosened and the lead screw was working intermittantly causeing the 1" difference off zero in Y axis. No problems in same program or others now. Hope this helps

[jeb2cav]

Hi hbutch - when you say the motor connector had loosened, are you talking about the motor shaft connector to the spiral rod - or a wiring connection? It sounds like the connection with the spiral rod - and both are a great point, thanks. You didn't happen to take a picture?...

[hbutch8]

Hey I'm not very good at typing ,but it was the connector from the spiral rod to the y motor. It had caused a burr on the motor shaft so it didn't slip bad unless it was in a heavy cut situation. the set screw on the motor part of the connecter was loose and you can't see it unless you unbolt the motor and slide it out a bit. will try to take pic if you need it

[Wilderness Sign]

Hi there!
I would love it if you could post a pic of the fix. I am having similar problems.
I have two 60vbit toolpaths saved as 1 tap file. the first toolpath will be fine, but, the second is using a different zero than established. So, it carved off centre. I remove the wood, and try again, and it works perfectly fine. I try it again, and it repeats the error that occured the first time. I was wondering if I have to wait 5 min or so before a start another carve (these are short carves: 9 mins), see attached.

Wilderness Sign

[jeb2cav]

I don't have to wait "between jobs" - and this is a CNC machine, so it should be fine under repetition - barring any mechanical defects. A picture would be great - and fortunately I don't need this right now, but any details that can be provided only increase the general knowledge for all. Given the lack of any details in a manual on troubleshooting and routine maintenance, the forum has become the place to go to start looking for this information. If you can find the time for a picture, hbutch8, it will be well received by all.

[dr_when]

Hi PCdude,

You need to be just a little more methodical in your troubleshooting. In this case try to isolate electrical and mechanical issues. When you run a job, try it without the router on and the Z just above your workspace. Does it make all it's moves in the X and Y in a repeatable manner? Are you sure you never have jogging issues? If it runs fine with no load (i.e. jogging or moving with no toolbit) then I would look at mechanics.

Look at the motor coupler to the lead screws as mentioned. Check your speeds. If your cutting speed is slowed WAY DOWN are things improved? Are you sure there is no binding when jogging? When jogging, can you easily stall movement? Once you know that you are OK mechanically, then move on to Electrical.

Check all connectors. Try swapping X and Y connections and see if the problem follows. Are you seeing a problem in both X and Y directions? If so, ask yourself why. Just make sure when you try something that you only change one variable at a time... otherwise you won't know what fixed the problem. If you are methodical, you should be able to isolate the problem in short order.

Bob

[PCDude]

Thanks for the responses.

Sorry for my late response.

I will check all mechanical issues thoroughly. I will post when I have found the issue since I also believe it is more than likely mechanical after doing some diagnostics.

Bob, none of my posts regarding this problem had a detailed method of how I have been troubleshooting this issue. I would like you to know that I have done everything you have listed, however I am going to take the motors and screw rods off the machine and fully inspect them since that's the one step I have not taken yet

Once I have identified the issue I will post a detailed solution.

Thanks for the input and ideas, I will try out all ideas I have not tried yet. I apologize if I do not respond sooner to posts as I have been busy.