multiple bot issues

[hrdwrkr]

I am experiencing multiple issues with my bot lately. Some have been going on for months now and some are just occuring within the last couple of weeks.
I purchased a new PRS 96/60 with a spindle just shy of two years ago. I am currently running Apire 3.0. My Dell lap top is used only for this machine although my designs are saved on my server. I do not have a vaccum clamping system. I either screw or do a jig to hold down my projects. I have not changed out any cables or USB hubs. Everything that I am using on my system now is the same equipment that I have been running since day one.
Over the past 8 month or so I am finally starting to ramp up and get some bot business. In doing so the issues that I am having are bugging me more and in some cases destroying the project. Let me start by listing a few of the problems and then expand later.
1. V-Carve depth: I have been doing some plaques for my kid's boy scout troop and doing a V carve for each kids name. The depth of each individual letter keeps getting more and more shallow. Then they will get deep again and then shallow again. Very inconsistent in depth.
I do not have a vaccum bed. I resurfaced my top inbetween this happening and it did not make a difference. I changed the collet to see if something was slipping (no change). When I preview in Aspire everything looks great. I have check my rollers, tracks and all hardware and everything seems solid with no slop. To get some of the last names to even show up I have had to re zero my Z at the "low spot". In doing this though the first name digs down another 1/8" still giving me a large discrepsency between the depths.
2.Weird diagonal angle cut out of the blue. I have attached three photos of different projects in different stages where out of the blue the bot decided to run its own path and destroy the project. This has just recently started (about three weeks ago) and I have trashed 5 projects. In aspire they run fine and show no indication of an issue. Most of these projects I run in duplicate. I can get two carves out of one 1"x8"x8'. Meaning I have a left carve and a right carve but I upload both of them to carve under the same saved file so I do not have to change anything on the machine for 3 hours. Oddly enough I have only had this issue occur on the carve to the right. The second carve.
3. And propably the most serious (to the machine) is a large "clunk" noise and a sudden brief stop of the X axis. i have a small video of this happening but even as a zip it exceeds the size limit to attach. I will gladly post the video some other way if anyone has an idea on how to do it. This problem does not occur very often, maybe once a week but it give the machince one heck of jolt. I have checked the gears on each motor and non of them are rubbing on the frame. The four wheels of the main head piece are riding smoothly on the upper ridge (track? not sure of the proper name). As stated above I have not changed the USB or any wires or anything else. Can a motor get a flat spot like a starter in a car? i can't think of anything else making this jolt and noise besides one side (one motor) not working for a split second. Again I am up for suggestions and will gladly email the video to who ever cares to take a gander.
I have read many of the posts in the trouble shooting forum and many suggest grounding the machine. I know that the elecrician grounded the wiring when he hooked everything up but i do not think that there is any additional copper grounding wire ran to an exterior rod or anything like that. Same with the shop vac. It is only grounded through the electrical green ground wire. My ducting is all metal from the vac to each machine grounding it all together (I believe?). But two of the three issues above have only recently started so i don't think it is a grounding issue?

Again, this unfortunately is only the start of my list but lets see how these go.

One thing that I did today is completely shut down the machine by throwing the main cut off switch hoping that it will clear some cob webbs?? I will turn it back on tomorrow and see what happens. I didn't see anything about any other way to "reset" the machine.

[Brady Watson]

Alt + PrintScreen the VR fill-in sheet in SB3 and post your settings.

Also, post the move speeds that you typically run with your files.

If you are absolutely SURE that you table is flat AND that your material is COMPLETELY FLAT then there should be no problem with varying depths. I would guess that your material has a belly in it, hence the variation in Z depths even if you just surfaced the table.

-B

[ken_rychlik]

Check the safe Z settings within aspire. That may cause the bit tearing into your work on the way to the place it wants to cut.

[hrdwrkr]

Brady, I will look into printing the screen for you when I get back into the office this afternoon.

Ken, my safe setting is ok. The sudden cut out occurs while the carve is already underway. It arrives to its proper destination fine. It is during the actual carve when it decides to wander.

[hrdwrkr]

Brady, I was not able to print the screen on either of my computers, so I did the next best thing. I have attached a picture of the VR settings. I hope they come out clear enough for you to view. any ideas on how to down load the video for the "clunk and stop" video. should i try to put it on Youtube and try to link to it?

[zeykr]

Are you running current version of SB3? I had similar problems with the cutting across the work in an old version of the software.

[hrdwrkr]

Hey Ken, I am currently running SB 3.6.3. I just looked and tried to download 3.6.34 but kept getting an error stating "delete file failed. CODE 5 denied". So for now I guess I will stick with 3.6.3.

[CNYDWW]

I don't have my Bot yet but hopefully coming soon so i don't know if this will work or not. In my old shop with my router i'm currently selling. I had the same issues with a random off path move while in the middle of a run. I was also using a laptop. I found out through help of my old router's manufacturer that due to the lack of grounding in a laptop because of the battery, static electricity builds up. It's not on a grounded circuit and the best thing to do is power off, disconnect everything including the charger. From there, remove the battery and press and hold the power button on the laptop for about 10-15 seconds. This will discharge the static electricity built up in the machine. Once i started doing this on a regular basis i didn't have another issue like this. A regular computer has the same issue with static but the grounding through your electrical system in your shop helps.

Hope this helps and it's worth a try for that issue.

Regards
Randy

[Brady Watson]

VR settings look factory default. How fast are you cutting your projects?

The laptop should not be an issue, provided that there are not background processes or programs looking for updates on the net that are interrupting the communication stream & causing the machine to hiccup.

-B

[hrdwrkr]

Brady, as far as the laptop goes I have all of the automatic updating turned off. I think I will try "uncharging" the computer for grins and see what happens. At this point I am will to try anything.
As far as the speed...these particular projects have all been 3/4" beetle kill pine so I have been running at 14000 RPM, 9% step over. Feed is 3 inchs per second and plunge is 1 inch per second. I am using a .125 ballnose bit. With these small carves I do not do a rough cut. I do with my other projects on harder wood but not with the pine or aspen.

[Gary Campbell]

Dennis...
Have you verified that the Z axis moves freely? Drop out the Z motor and make sure that the extrusion moves freely thruout its full range of motion.

[hrdwrkr]

I checked the Z when I was searching for my clunking noise. I removed the motor and everything was free to move by hand.

[Gary Campbell]

Dennis...
I have seen (and heard) the loud clunk noise a number of times on multiple machines. In each case it has been the result of dust hose static discharging to the machine. As the machine moves back and forth some combination of movement or position allows contact. In each case careful inspection of the DC grounding and recheck of all connections, along with adding a ground wire to the Z extrusion has worked.

My guess is that when doing your left carve the hose is stretched out and when doing the right slack allows contact. We tend to ignore the hose as we watch the machine.

[hrdwrkr]

Gary, I will check that this morning. If there is a static charge and it zapps the machine will it make a quick JOLT and a split second stop (like it's binding) and then continue? The other oddity is that 90% of the time that it clunks the machine is moving from home out into the board. I will certainly check the hose though.

[CNYDWW]

Dennis...
I have seen (and heard) the loud clunk noise a number of times on multiple machines. In each case it has been the result of dust hose static discharging to the machine. As the machine moves back and forth some combination of movement or position allows contact. In each case careful inspection of the DC grounding and recheck of all connections, along with adding a ground wire to the Z extrusion has worked.

My guess is that when doing your left carve the hose is stretched out and when doing the right slack allows contact. We tend to ignore the hose as we watch the machine.

This might also be contributing to the static electricity messing up the cut too. Building up at a quicker rate then it would normally.

[jhedlund58]

i had a friend with similar prob.... i suggested he use a piece of static-cling for clothes dryer to wipe his laptop and shopbot.... further he taped a piece at the dust collection hose at the shopbot...

a miracle he said

[hrdwrkr]

i like the idea of removing the static from the lap top.

[danhamm]

A lot of Industries have a problem with magnetics, static buildup due to there processes, in critical areas they employ "degaussers" these eliminate
or reduce the static charges, I use a small one on my dust collector, retrieved it at a aution...its just a bulk tape eraser but works very well...

[srwtlc]

Dennis,

Have you checked to see how good your laptop is communicating with the controller with the speed test program? It's found in the ShopBot program folder in the diagnostic folder.

Would you say that this happens mostly in a jog situation (also with higher 3D cutting move speeds)? Same with v-carving, could you be losing Z steps with higher settings.

Scott

[CNYDWW]

Another thing came to mind. Use a heavy insulated high end usb cable. Might also help.

[Gary Campbell]

Dennis...
I can best explain the sound as it would resemble the sound of a V roller running over a bolt on the V rail.

Do not ask how I know what that sounds like!!!!;)

Your #'s 2 & 3 can easily be explained by static, with a possible maybe on #1

[hrdwrkr]

Scott, I would say that the LOUDER clunk would be on a jog. It does on occasion make a softer clunk during carves moving up and down the x axis. i have not ran a speed control test. I will look into that tomorrow.

Gary, it sure seems like everyone is weighing in on the static side. I have part of tomorrow that i can work on the machine and try some different grounding ideas. I will see what i can come up with and try a couple of differnet things.

[jhedlund58]

What r the chances of a worn spot on the gantry rails gears... i could see where a unit gets more work on one end than the other. As much as i like shopbot and the tech's, i have issues with documentation on general maintenance... especially lubrication... they give u a tube of lithium grease and a small bottle of light lubricating oil.... NO INSTRUCTIONS ON HOW 2 USE THEM!!!! Maybe, I am missing something somewhere.... I find nothing on this in forum... but again the search seems to look for only keywords. I am putting an e-mail into shopbot for my own purposes. Keep my lubed ( a light wipe once a month).... just not sure i am doing it correctly... at this point i think the lithium goes on the gantry gear rail.... and lighter stuff goes on smoothe glides that the spindle head rides on y and z axis... and under the table glides for x axis roller guides

just wonderin


i still e-mailing for lubrication instructions

[bill.young]

Hey Jeff,

The section on greasing the racks is toward the end of the "Attaching the Motors" part of the tool assembly manual, though it sounds like it's easy to miss.

"We recommend applying grease to the rack and pinions. A good quality bearing, lithium, or Teflon grease will work well. The grease will keep the rack motion smooth and reduce gear wear. (Surprisingly little debris actually collects in the grease.) Apply it by squeezing a little into the rack every few inches. Moving the tool around will spread the grease and you can wipe off any excess. It’s OK to push the cars around, as long as they are not connected to the control box yet."

Oil should be used to lubricate the felt blocks on the wheel wipers. There's info on how to use it in the YZ car section right before the Attaching the Motors part.

(The manual that's shipped with new tools is printed directly from the online docs at www.shopbotdocs.com (http://www.shopbotdocs.com). If you have a tool that was shipped more than a couple of months ago then this info might not be in the same sections)

Bill

[jhedlund58]

I c said the blind man.... guess my problem was referencing only the shopbot buddy documentation....

thanks and hopefully this helps original post-ee as well

[hrdwrkr]

Hey Jeff, thanks for the advice. I have checked all of the gears on the rails and on the motors. As of yet I have no wear at all on any of the gears. I do keep them lubed. I am going to work today and make sure that everything is grounded well and see where that takes me.:confused:

[Gary Campbell]

Dennis...
Static is a nasty enemy and hard to track down as it usually a moving target. When grounding, double check and recheck everything. A ShopBot is an assembly of powder coated steel and anodized aluminum. Powder coating is an insulator and most regard anodic coatings as an insulator also. So, in my opinion the frame is constructed from conductors (steel and aluminum) separated by insulators.

The rest of the assembly consists of motion connectors, ie. bearings, gears and wheels. All of these are, or should be insulated with grease. There is also the possibility that the motion on precision bearings can generate static also. Incedental conduction can happen in any or some bolted connections and thru bearings, but none can be considered reliable unless there has been removal of the coating on the hard joints and a bypass conductor to both sides of a bearing.

The OEM wiring has a ground to the spindle body (anodized) AND there is a very good connection to the LV grounds to the inputs 1,2 and 3. 1 to the 5V ground on the CNC board. 2 and 3 to the 24V. If a machine has any unconductive connections and/or ungrounded metal components, any static charge could easily discharge into the grounds of the prox switches mounted on the sideplates and Y car. Depending on the location of the ZZero plate and the wago connector, they could also be a target as the machine moves.

This has helped some reduce or eliminate some propblems: http://shopbotwiki.com/index.php?title=Grounding_your_ShopBot

[hrdwrkr]

Gary, this gives me a great place to start. I have not had issues prior. Would I start having static problems out of the blue? Also, do most bot owners have to go through this to get their machine grounded well? It seems like this is a pretty serious and common problem? Or did I miss the memo when I was setting this thing up that I should have done this in the beginning?
thanks.

[srwtlc]

It would seem that some have more problems than others. I have no extra grounding and have had no problems. I live near (shop is just 100' from) some high voltage power lines and I think that the less antenna I have to pick up stray voltage, the better.

This is not to say that extra grounding doesn't help some for these issues.

Scott

[Gary Campbell]

Dennis...
Each ShopBot assembly and installation has it own personality. I Moved my prior machine from one end of a building to another and developed a totally different set of problems. Some that I had dissappeared, some new ones appeared.

Any issue could start "out of the blue". Static or otherwise. Yours is not a confirmed static issue. You havent solved it yet. A small percentage of machines experience similar issues. Could be ambient humidity, building, etc.

There is no memo on this, just a number of owners chasing down common sense items so that the grounding is eliminated as a cause. There is often no rhyme or reason to it all. My previous machine would experience 20 stop hits in a couple hour file while completely grounded in 80% humidity. Current one has 1 every couple weeks in no humidity without a single ground wire attached. Same operator, different computer. 2nd machine assembled at ShopBot in Durham, first by me.

Go figure

[joe]

Dennis,

I trust Gary's description to be accurate. He know's more about this equipment than just about anyone. There were so many unfortunate glitches in my PRT and I was so tired of trying to solve them I threw in the towel and sold it.

I'm not good with the continual updates either. Each time I called with a problem, the first qustion was about the latest update. Which meant I was off for another venture.

Joe Crumley
www.normansignco.com (http://www.normansignco.com)