G-Code Tears Thru Project and into Table

[Gs.spencer]

Tim,

I have a 2.5" hose on my dust shroud that is about 4 feet long. Most of my work is on the left half of the table so I just let the hose drape across the table putting even less weight on the router/gantry. I used to run the hose over the top of the gantry but with all of my Z axis problems I moved the hose as far away from the Z axis servo. My hose is properly grounded all of the way thru to earth ground plus I verified it using my ohm meter.

I have the Pro Plus HD.

All I have seen when I slow the feed rate is that it sometimes makes curved cuts come out a little smoother. I have had very few projects with slight carving flaws; I guess that could be attributed to a feed rate of 100%. The 1st 3 months I had my CNC I carved everything at 100%; only this last month have I been slowing it down and been having relentless Z-axis issues.

The Z axis started failing a few days after installing my new dust shroud. These are the things that I changed which resulted in the Z axis going bonkers:

1. Moved my router power cord plug from the front of my CNC (was plugged into a surge protector) and plugged it directly into the control box.
2. Attached 2 clamps and secured part of the router power cord to the left side of the gantry (see attachment)
3. Attached a 4-foot 2.5" hose section to my dust collection and did not ground it.

From this point on I started having intermittent problems. I've had my CNC for 4 full months, the first 3 months everything basically worked flawless. I did have a few stray carvings where the router bit did some uncommanded carving but it was extremely minor.

Here is what I have done over the past 4 weeks to try and correct my Z axis failures:

1. Moved 3 DeWalt battery chargers to the other side of my shop (the USB cable was touching the chargers)
2. Relocated my laptop AC power adapter as far away from the control box and USB cable
3. Properly grounded my entire dust colection system and hoses
4. Plugged my control box and laptop into a 780 watt UPS/power conditioner
5. Replaced the USB cable with a shielded HD version
6. Slowed the feed rate on all projects to 50%
7. Reseated all 3 RS-232 axis connectors at the control box

Some of the remaining things I have not done yet but don't know if I should or need to:

1. Relocate my router power cord as far away as possible from the XYZ cables
2. Unplug my router from the control box and run it manually from the UPS
3. Turn off or disable my laptop's wireless and bluetooth signal
4. Replace the micro SD card in the control box

Based on my numerous carving errors I know the Z axis isn't getting stray signals forcing the stepper servos to move. At the exact instance the bit starts carving too deep, there is already a sync problem where Z-zero is no longer where it was at the start. Everytime I stop the project with the bit still stuck into the wood or my table, the control panel software will display the current Z elevation as 0.000. After I move the bit back and reset Z zero, I have seen gross errors anywhere between 0.020" to as much as 0.350" off from when the project started.

You can see in the one door sign picture I've attached how the squadron patch started carving out fine in the center but then all of a sudden lost its Z zero reference and started carving 0.050" too deep. Note the light scratch that was made as the bit transversed to the lower right side.

I sure hope you guys can figure this one out. I'm doing a lot of work for the USAF right now and those folks are utterly impressed at the detail my CNC can provide.

Jim sent me a UPS shipping label and I sent my control box Friday morning, hopefully you guys can tweak the box and send it back. Better yet, I hope you can find something wrong with it.

Greg

[dindon]

I have the same problem with the new version 1.5.023...I have return to original version 1.5.021 and my shark pro plus to work now.. with the new version , the button( step) (+ -)on the JOG is not work and more problem with axe Z..... I have change the USB cable and fixed the electric cable on the motor, don't change anything.....l have contacted NWA and this recommandations have not found the solution to the problem....

[maxxxpower1000]

Hey guys a newbie here. I got my Hd in april 2012 w/bosch router (package deal) and had the normal new guy problems, I still am. However, About 2 months and a dozen good v carves later (we wont talk about all my screw ups) my machine had the same problem. It was running fine and then BOOM! its in the table. The bad part is that it had a spiral bit in the router (1/2"). I also called NWA and rockler and complained because you could see one letter was good and the next was through the work and into the table. I thought I had eveything covered, cables, laptop updates and screen savers turned off (ran into that one) etc. Any way what it turned out to be..........the collet in the bosch router and a slightly undersized shank on the router bit. I know this because I am in the habit of marking the shank of the bit when I put it in the router (I habit I picked up repairing machinery at work). After the crash the bit was about 1/8" to 3/16" lower than when I started. After the crash I took the bit out, slightly bent, but no marks from slipping in the collet. The collet didn't seem loose either. Sorry, forgot to tell you its a 2.25hp router w/selfreleasing chuck. Anyway, I took a close look at the bit and compaired it to some of my other bits and found it to be .003" smaller shank than my others, then looking at the chuck I saw that 2 out of 4 splines did not look like the other 2. They looked uneven if that makes sense. I ended up not using either , I replaced the collet and didn't use that name brand of spiral bit again. So far so good. I think only time will tell. After thinking about it, I'm not 100% sure that was the problem but as I said it hasn't happened again. I am very careful changing bits now though, kind of paranoid, clean bits, clean collets, tight, etc. better safe than sorry. Hope this helps................

[Eagle55]

I think that is very important observations and may be right on target with what some others have experienced. The one that really got me upset was when the router would bottom out needing to go deeper and running into the hard stop. That would in effect reset the Z-zero also but in a positive (safe) direction. It would be cutting where it should then all of a sudden would be cutting shallow or even about the work piece. (Lowering the gantry assembly was the answer for that mode. I hope the others having this problem will try marking their bit and gathering this important piece of information like you did. Would be a shame to send the unit back and get a new one that still leaves you with the same problem. I have always marked my bit although I never had this particular problem but then I have been using relatively good quality bits and the Precise Bits Collets for the most part (except on the larger 1/2" shank bits.

Roger

[Gs.spencer]

I think my CNC is finally fixed

NWA had me ship my control box back for repair. I was informed my control box did not pass their diagnostic tests. NWA replaced the GECO system board 4 axis controller (what ever that is?) and sent the unit back.

I have been carving for over a week and done about 2 dozen projects (approx 30 minutes each) and every thing is carving flawlessly. Let's hope this success rate lasts indefinately!

Here's a recap:

I had the CNC for 3 months with near flawless operation and then without really changing anything the Z axis went south and carved uncommanded gouges into my work and tabletop. I discovered the control panel program would lose sync with the Z axis counter and the Z servo would plunge downward without the counter following along. After my projects would get ruined, I would recheck my Z-zero axis and would always discover that when I zeroed my bit back on my project surface it would never display 0.000". It was always a negative number between -0.050" to -0.350".

I received advice from all over the place and did all of the following, but none of the advice fixed my Z axis gouging problems:

1. Fully grounded my dust port from the tip all the way thru earth ground.
2. Purchased a 780-watt UPS/power conditioner
3. Replaced the USB cable with a shielded HD version
4. Slowed my project feed rate to 50%
5. Disabled Bluetooth & Wireless on my laptop
6. Upgraded Control Panel from 1.5.0.23 to 1.5.0.23c
7. Removed EMI sources (i.e. battery chargers, laptop AC power adapter, etc.) away from USB cable

It looks like the true fix was sending my control box back for repair even though all of the above suggestions are good practices anyways.

I'm curious if NWA could create a diagnostic software utility that could perfom a series of checks that we could install on our computers? Having some sort of built-in-test (BIT) would be a great capability seeing how I'm not the only one expieriencing these uncommanded inputs.

Greg

[jeb2cav]

Hi Greg,

Thanks for sharing all the steps and the final resolution. Not everyone does that.

I would say though that in many instances, one or more of the steps you took prior to NWA having you send it back have in fact cured this type of Shark behavior. It's not always going to be a defective control box if this diving of z intermittently occurs.

The 'true fix' for this case was repairing the control box. When I experienced this in the first few months of ownership, what cured it for me was a ups/power conditioner to remove poor voltage and voltage spikes.

I'm glad you're up and running, and again, thanks for posting the steps and the final resolution for your case.

[Gs.spencer]

After a month and a half of flawless operation it's back at it again!!!

This time I had a nice piece of cherry wood 24"W x 10"T and half way thru the project the X-axis lost its reference by 0.675" and the Z-axis dug in an extra 0.125"

I don't care what anybody says, this is just wrong, wrong, wrong! I thought I had a really great investment going with my new CNC Shark and have already made thousands of dollars creating a lot of really neat stuff. Now my business is once again stuck in the mud spinning wheels unable to depend on my control box...

V-Carve rendering of what it's supposed to look like

Carving output after X and Z axis failure

[BillK]

Just a thought on this, you say the piece is 24 inches wide. Are you sure you didn't run up against the machine limit in X? That would explain the difference in X.

[Gs.spencer]

The board was 24.875" wide but the CRV project was only 23.0" and yes, it was perfectly centered across the X axis.

I have previously marked all four corners (and sides) of the table with indelible marker directly on the table top using a limit of 23.75" square inches. This way, when I place a wide piece on my table I can be positively assured the gantry/router housing won't bottom out before reaching its limits.

In my depiction, the X axis went awry exactly 10.5" from the right of dead center and never went beyond 10.9375" to the right of dead center (I still had over 1.5" safety margin to spare). An immediate left-right zigzag (X axis) occured at exactly 10.9375" right of center. I had 3 left un-commanded zigs of exactly 0.225" intermixed with 3 right zags of exactly 0.225" before the paranormal activity stopped and my project continued. These 3 left zigs of 0.225" were un-commanded and not counted by the stepper motor which explains why my project at the end was off in the X axis exactly 0.675" (left zigs of 0.225" times 3 = 0.675").

Zig Zag Depiction

This also outrules a loose/slipping gear coupler because a slipping pawl would not cause a 3-way left and right zigzag movement. Plus, this is all just a repeat problem from before with near identical behavior. The control box commands a movement and the stepper doesn't sense and then before you know it, the project is carving out of alignment or drilling too deep into your wood.

My box was fixed 2 months ago after replacing the GECO board and Axis Controller. It would be nice if NWA could find the cause of my board and/or controller failures.

Greg

[Eagle55]

That is really dis-heartening. Given that they have repaired it and the failure mode has returned, I would hope that they would be willing to replace it with a new controller box and take that one in for in depth study to determine what is going on. Please let us know how it turns out. As for me, I don't have any answers.

Roger