Cutting properly after debugging - Milwaukee, WI

[tnarch]

Hi everyone

What a great forum!!!

I started reading the forum sometime back in April and started construction in August. It's been a challenge and a "enjoyable" learning curve with zero metal fabrication experience. I've really learned a lot and been having a lot of fun!

Photos to follow soon.

Tuan

[tnarch]

progress

[tnarch]

not sure if someone else posted this technique for handling the clamp strip for the y-rails attachment. the steps below worked for me on the first try with great ease :eek: :D

1. thread a wire through the hole at one end of the tube
2. feed the clamp strip through the gantry tube leaving the end hole visible
3. feed the wire through the hole on the clamp strip
4. attach a stopper -washer in my case- to the underside of the clamp strip
5. feed the clamp strip all the way in and use needle nose to retrieve it on the other side
6. repeat 1-4
7. pull on both wires to bring the clamp strip to bring it up
8. attach fasteners for all the holes accept the end ones
9. once clamp strip is held in place, pull the wires out.

[Gerald D]

A smart fishing technique! :)

[MetalHead]

Very good explanation.

[tnarch]

Gerald: great analogy :)

Mike: Thanks for the compliment. I hope other new builders will find it helpful.

[tnarch]

need some help with cables. some of the resources i found online - charts and rules of thumb - suggested that i would need at least 16 awg to draw the 4.5 amps needed for my motors. is this really case or can i use the 18/4 that's been discussed a lot here on the forum? i'm looking to cut cost.

motors are these: http://www.kelinginc.net/KL34H280_45_4A.pdf

[MetalHead]

Did you get these already? Also if you got them from John did you get matching drivers and power supply? These motors run at over 80 volts which is to high for the Gecko Drives.

http://www.kelinginc.net/KL34H280-45-8A.pdf

8 wire version - ran Bipolar or Unipolar will run at about 48v which is better if your using the Geckos.

Wire guage I think would be 18 to 21 gauge. But I'll let others talk about that while I do aome more research.

[tnarch]

Mike, the motors are purchased. :confused: I did get them from John with 201x geckos and this for power supply http://www.kelinginc.net/KL-6520.pdf He has a MM package with motors at 900 oz-in. I downgraded the motors and upgraded the drives to 201x geckos.

As for the wire gauge, the wiring diagram for the motor specified "UL1430 AWG20# LENGTH 500+-20". I think 18-20 would work too. I thought I double check on here. However, your comment about the voltage is sending me back into research mode for the motors. :o Thanks Mike.

[MetalHead]

I think your motors will run on this config. They will just be derated.
This is more for Mike or Brad to talk to .

[EricW]

holy crap, another guy from wisconsin? Where are you?

[tnarch]

eric, i'm in milwaukee. you?

[EricW]

Eau Claire, but I'll be in waukesha for thankgiving.

[Richards]

The KL34H280-45-4A motors have an inductance rating of 6.8mH, which means that they can use up to 83VDC. The G201 Geckos are limited to 80VDC. The power supply that you specified has an output voltage of 65VDC, 65v / 83 = 78% of possible speed. (The power supply data sheet shows that optimum voltage for that power supply is about 52VDC, which is about 62% of the optimum voltage for those motors.) On a CNC router, that should not be a problem, unless you build a high ratio belt drive.

If you geared the motors down to 3.6:1 with a belt drive, and if you used a 1.25" diameter spur gear, you will move an axis 1.0908" per motor shaft rotation. So, 750 RPM X 1.0908" = 818" per minute or about 13" per second for your jog speed. That is plenty fast. I've never used the KL34H280 motor, but all of the motors that I have on hand can reach at least 750 RPM even with a power supply that delivers only 50% of the optimum voltage.

Normally I recommend that you select a motor based on the torque that you need (direct drive or geared), then you look for a motor that has low inductance that is able to produce that amount of holding torque. (I look for motors that are rated from 1.5mH to 3.5mH bipolar parallel or half-coil.) After deciding on the motor, you then select a power supply that give 75% to 100% of the optimum voltage (32 X SQRT( Inductance)). Add together the current requirements of all motors and then multiply that number by 66% to get the actual current requirements for a CNC router.

Gecko has redesigned the G201 drives and replaced them with the G201x; however, the G201 should work just fine. I have four G202 stepper drivers on my test bench as well as a bunch of G203v stepper drivers. The G202, which is a slightly updated G201, works very well for me. Be sure to add a 470mF capacitor to the power terminals on each stepper driver.

Wire gauge is kind of a black art. The charts give two ratings, chassis and power transmission. 18 gauge wire is rated 16A for chassis wiring, but only 2.3A for power transmission. I have never used anything heavier than 18 gauge on my machine and I've never had any trouble.

[tnarch]

Mike

Thank you! Having an experienced builder saying there "...should not be a problem" is comforting :)

I plan to eventually gear the motors. The goal at present is just to get the machine cutting. One question about the ipm calculation: how did you get the 750 rpm?

I did go through the math you described in your recommendation after reading about it in one of the posts on selecting motors or power supply. Perhaps this is the reason I'm not too far off from optimal specs even though the choices were made based on cost.

As for the drives, is the use of the capacitors to regulate to voltage coming from the supply? How did you calculate 470mF (milli-Farad)?

I will follow your lead on wire/cable.

New question: I'm planning to buy this contactor since I'm using a 220V 20amp supply. Does this check out? http://www.factorymation.com/s.nl/it.A/id.99/.f?sc=2&category=16

[MetalHead]

That contactor is a whole other question

I have a Basic Starter Setup listed here.

http://www.mechmate.com/forums/showthread.php?p=46837&postcount=36

It uses the CU-22-F6 contactor. I have been studing this and see that just because you feed 220v to your machine does not mean you need a 220v contactor coil. You can pull off one of your legs to power the coil. In file Part4 drawing 1070130CA (page 3) you will see a 220v feed and a 120c contactor. it is rated at 16 in that drawing but the 22 is what I have here in my BC01 kit.

You can break a contactor down into three parts (in this format without the thermal overloads added) .

You have the following

1. Coil
2. Input/Output (L1,L2,L3 and T1,T2,T3)
3. NC/NO switches on the side of the contactor.

I am working on a write up of how the contactor works.

[Richards]

Tuan,

750 RPM is just a 'standard' figure that I use to that should work with most motors. (When a motor is wired half-coil and the motor/power supply/stepper driver are matched properly, the torque curve usually still has usable torque at 750 RPM.) With a Geckodrive stepper driver, 750 RPM eqates to 25,000 step pulses per second, which should work even with Mach 3 used in evaluation mode.

I assume a 1.25" spur gear (which is 25-tooth with the rack on my old Shopbot). So:

1.25 inch X PI = 3.927 inches per shaft rotation

3.927 / 3 gear ratio = 1.309 inches per shaft rotation with 3:1 belt drive

750 X 1.309 = 981.75 inches per minute

981.75 / 60 = 16.36 inches per second

You caught a 'typo' in my post. It should have read 470uF instead of 470mF. The 470uF capacitor is required with G201 stepper drivers (page 2, 3rd paragraph of the REV: 16, August 6, 2009 Geckodrive instruction sheet).

The power supply should have a large filter capacitor(s). You can determine the value of that capacitor with this formula:

(80,000 X Current of all motors) / Voltage = Capacitance (in uF)

For example, assuming 4 each 5A motors, you would need:

4 X 5A X 66% = 13.2 A

(80,000 X 13.2A) / 48VDC = 22,000 uF

Depending on your actual 'load', you might be fine with a 10,000 uF capacitor, but 22,000 uF would be best.

I agree with Mike (Metalhead) about the contactor. I use 120VAC contactors in my designs; however, the model that you specified should work just fine if you want to use 220VAC to activate the coil. That contactor has the required aux. switch so that it can be wired to self-latch (see Gerald's schematics to see how to wire a contactor to self-latch).

[tnarch]

16/7 Helukabel F-CY-JZ (gray colored) for e-stop and other controls
14/4 Flex-cable for servos (black colored) to be used on spindle
16/4 Flex-cable for servos (black colored) for motors hook up

the strand count for each core of the flex cables is 90! is that good or bad?

[tnarch]

Z-slide and stop block are fabricated. The electronics also came in Tuesday. Took the machine down for painting.

The task list for the up coming weeks:
-Finish painting
-Reassemble
-Las Vegas :D
-Start control box wiring (aka kitchen table project)
-Buy water pump, test VFD wiring and cooling system for Spindle
-Connect motors (waiting on xlr connectors)
-Fine tune (and debug?) Mach 3

I am hoping start cutting by mid January. Lets hope I'll be bringing some luck back from Las Vegas! :D

[smreish]

I like your adaptation of the stop block. Simple and as long as your nuts seat flat, your fine - or you could tap them if it did.

Nice work.

[tnarch]

Thanks Sean. I had some angle left from the rails and decided to use them for the stop blocks. The blocks are tapped. I added to bold for extra threads with the intention of welding them to the block before I paint.

[tnarch]

Hi all

I have one of those water-cooled Chinese spindles and got a cooling flow rate from Keling specs for 20-26 gph. To be on the safe side, I'm thinking about getting model Epp315 from this site (http://www.thepondoutlet.com/home/tpo/page_1679/eco_plus_submersible_water_pumps_1056_gph_epp320__ ..html?utm_source=amazon&utm_medium=ads) because the max lift height specified is well clear of the highest point of the z slide. Will this work with running a water line ~24' inside the cable chain? I'm searching the web for water flow calculation but haven't found something easily digestible for my primer-fume-clogged brain :)

[KenC]

The spindle only need very little flow rate to keep cool... in fact I worked the spindle at 14000rpm for over an hour before I remembered to turn on the pump... Still surviving...

[smreish]

Ken,
That's what the VFD aux contact closure is for! When ever VFD on....pump on....might help you in the future for the cost of a little relay.

Keep up the great work.

Sean

[KenC]

LOL!
Procrastination working its best on me...
I still haven't got my y stopper, z-stopper, limit switches, VFD aux contact, joypad HID, x-y lazer zeroing, disco light, vacuum table, belt reduction boxes... even the cover for my collant reservoir made :o
Only managed to conjure enough energy to set up the Z-axis auto touch off & dust collection system... :p
Lucky me... Still managed to churn out enough production to fulfill orders...:D

[tnarch]

Sean & Ken, thank you for the tips. They will be very helpful with wiring coming up next.

An update picture to show the color scheme:
- matte black for all large/frame components
- shiny fire engine red for all other components

Kind of like that Ferrari I always wanted :cool:

[tnarch]

another update photo.

a bit apprehensive as the electronics is up next. any advice? :cool:

[smreish]

Kitchen Project Thread. Read it 3 x before proceeding. Then dive in head first! Ask if you get into any challenges.

SEan

[riesvantwisk]

Tuan,

my advice is : if in doubth, don't do it :D
Don't hurry the kitchen table project and make sure every cable and wire is properly attached and makes good contact. Electronics my die when connections come loos between stepper and driver.
When firing things up (turn on) don't look at your computer screen but at your electronics teh first 10 seconds. Your motors will settle quickly when powered up. Just look around all wires and stuff to see if you see smoke :D
Make sure you have everything fused, preferred even a lower amp quick fuse then the 'standard' fuse.
Take a look at your drivers and see if they turn green, your manual of teh drivers will tell you what's a good situation and what's a bad.

When that's all fine measure some voltages and see if they are what they suppose to be.

Then you are ready to configure your computer and attach your parallel port.

[tnarch]

Thanks Sean and Ries for the advice.

The first picture shows the current configuration of the control box components. Any potential problem? The door mounted on-off push-button have momentary contacts. Is this right?

The second picture is a gantry e-stop enclosure. Do I have my contacts right? I'm not sure about the contacts for the PMDX e-stop circuit.

Going to the shop to connect some wires!

[smreish]

My only concern is the VFD is in the same box. A recommendation is to have the VFD OUTSIDE or in another enclosure. I know others have had success with the spindle drive in the same box...I did not. Bad EMF can be a bugger to troubleshoot.

Otherwise, looks like your in good shape. Be certain to route your mains power to the contactor away from everything else if you can if you plan on keepin the drives on the bottom.

Most of the control cabinets have this arrangement....
DIN RAIL and contactor row on bottom.
Drives in the middle
Power supply and PMDX on top for signal and power type separation.

Your box is large enough to go with mostly any configuration that you like. So just be mindful of to long of parallel runs of power and signal together to minimize cross talk on lines.

an example of my box is here : http://www.mechmate.com/forums/showthread.php?t=460&page=15
Sean

[bradm]

Tuan, in the e-stop enclosure, I would expect to see one set of N.O. contacts on each of the outer (yellow and green) buttons, and TWO sets of N.C. contacts on the big red stop button.

[riesvantwisk]

I second that with Sean (remove the VFD), additionally I would put the power supply on the top left and the BOB on the top right. THis way you can also have a more room for your Gecko's on your cooling plate and you will have more room around your BoB.

Ries

[KenC]

I go with Ries & Sean removing the VFD from box.

I personally will mount the Din rail on the back of the door.

[tnarch]

Thank you for all your suggestions. With regards to the VFD, is there any kind of shielding I can do to keep it all in the same box? As for the layout of the components, I see that the popular arrangement Sean referred to seem to work best taking into consideration all the cabling (w/o the VFD).

I managed to get Mach3 to move one X-axis motor :). It was a great feeling of accomplishment to see motor action with no smoke coming out anywhere :D This exercise yielded two questions.

1) I am using Gecko 201x with these motors (http://www.kelinginc.net/KL34H280_45_4A.pdf). The 201x has 10 DIP switches and I configured it to output 4.4 amps. After running the road runner sample 2 times, the gecko was many times hotter than the motor. I am switching to the 8 wire motors as Mike R suggested from post 8. The drives will be sitting on a heat sink with a fan. Is there anything else I could do to reduce the heat?

2) The picture shows that the power supply is connected directly to the disconnect switch and not the contactor. What exactly is the role of the contactor? I had to buy a this 35 amp contactor (http://www.factorymation.com/s.nl/it.A/id.105/.f?sc=2&category=16) because they were out of the 20 amp when i ordered. Should the current of the power supply and contactor match exactly?

Lastly, any tip for running cables through the chains?

[bradm]

Tuan, the goal of shielding the VFD will fight with the goal of keeping it cool with airflow. In general, VFDs will be happier if they aren't in a box - if you read the manual it will probably give you some guidelines on how much free air space should be around it.

So I agree with Sean, Ries, and Ken: Don't put it in the box. I bet that once you embrace this, you'll come up with a really elegant place to put it and way to wire it.

[riesvantwisk]

Tuan,

if you mean with the contactor 'The big relay' where all currents go through to the motors and fans... Then the role is to cut-off the cabinet when the e-stop safety button is pressed. The E-stop buttons are routed with the 110V/220V volt through one of the relays contractors. If that circuit is broken (you pressed a button) then the machine is turned off.
Second, in some countries you have to have a method in place that removes all power from the machine and cabinet when the cabinet door is open. The poweron and power off buttons are also partof the contractor circuit.

Does that clarify?

Ries

[KenC]

Other advantage of having the VFD out of the box is that you can see what ever that is display on the LCD screen, I always set the Amperage display so that I know how much current is drawn at any time so as to vary my feed rate or spindle speed accordingly. Don't worry about dust getting into the box, if you run a vaccuum dust collector dust won't git that far...

[tnarch]

thanks guys for all the comments.

i ran into a issue. what does it mean when the magnetic contactor doesn't hold latched position? when i pushes the on button, the light goes on and i hear the contactor latches. however, when i release the on button, the light goes off and the contactor releases. any help is much appreciated.

[bradm]

Tuan, it means that you've wired it wrong. You usually use one of the aux contacts to maintain the power to the contactor after the start button is released.

So, you should run from the power source to one side normally-closed off button, then from the other side of that button to both one side of the on switch, and in parallel to one side of a normally-open aux contact on the contactor. From the other side of the on switch and the other side of the NO aux contact to one side of the contactor coil, and from the other side of the contactor coil back to neutral. The on button pulls the contactor in, and the the aux contact holds it there regardless of what the on button does. The off button breaks the circuit, no matter what.

[tnarch]

Hello All

Almost there! Everything is wired. I attempted to do the first cut but the spindle/vfd got in the way. With the power on for motor and vfd, and Mach3 Reset button is solid green, the Reset flashes red as soon as I press Run on the vfd.

I wired the e-stop for main power and BOB using the same 7 core cable. In the attached image, big red line is the cable. 2 small red lines are used for power estop. 2 small blue lines are for BOB estop. The yellow are unused currently. The BOB estop circuit is disconnected in the picture and replaced with the factory jumper. This configuration will NOT trigger the error i mentioned above.

What should I do differently? :confused:

Third picture shows my little celebration for making dust. :D

[Kobus_Joubert]

Working on a MM is THIRSTY work :D

[Alan_c]

In General Config, try unchecking the "Use Watchdogs" check box - see if that makes a difference.

[tnarch]

Kobus, i'm with you ;)

Alan, I looked into Gen Config, Use Watchdogs was already unchecked. I checked it just to test it out. same result either way.

anyone else has any suggestion? thanks.

[Alan_c]

What is your "debounce" value, try something like 2000.

[smreish]

Similar problem happened to me....you can read the drama in thread in trouble shooting section.

http://www.mechmate.com/forums/showthread.php?t=1859

Things I changed in my set up:
- debounce pushed up higher...2000 or above (push it to something like 8000 and see if this helps....then scale back until it repeats again)
- added an isolation transformer for the spindle (but it had other problems too)
- turn off watchdogs
- added isolation transformer to spindle (this fixed the steppers from moving when spindle on - different problem than your seeing)
- added isolation relays to the inputs of the PMDX so inputs would see transients from pushbutton wiring on gantry)

[javeria]

look at this from Matt's thread

http://www.mechmate.com/forums/showthread.php?p=28851&postcount=67

A torroidal ferrite on the output line also helps and I have used it successfully additionally you can try adding a .01uF ceramic cap across the terminals of the Estop on the BOB,

what I have done on most of my machines is use a 24V DC control line across for all external control switches and then use PC817 optoisolators to interface them with the BOB

also look at this

http://www.powerqualityanddrives.com/emi_rfi/

hope this helps

RGDS
Irfan

[tnarch]

thanks everyone. i will try all of your suggestions when i get to the shop tomorrow.

[danilom]

I posted this somewhere else but here is it again, about internal EMC capacitor filter in my VFD (Control Techniques) . I don't know its function but it triggered estop on friends machine so I kept it disabled on mine, and everything is running fine 6+ months. On mine it was a small plastic tongue besides power connectors which should be pulled out.

picture from VFD manual:
http://www.cnc.rs/mechmate/vfdemc.jpg

[tnarch]

increased debounce values mitigated the error! thank you alan and sean!!! :D

[Surfcnc]

Tuan you have omitted an important detail - the debounce number you used !!

Regards
Ross

[tnarch]

Ross

I started up at 8000 like Sean suggested and incrementally decreased it by 500. When I hit 2000 the error came back. Then I "fine tune" it by stepping at 100. 2300 was the magic number. But I set it at 2600 for some buffer.

[Surfcnc]

Thanks Tuan, it is always good to get some feedback on a solution that worked.

Ross

[tnarch]

hi all

getting some really weird action :confused:

in testing the debounce values further, i found that if the z car gets too close to the x-rails and near the x motors, the EStop is triggering. this is intermittent and doesn't always happen along both xrails. in one instant, it reversed my z motor! thank goodness it was only 1 inch and no harm done. at first i thought i might have typed Z-1.0, but i double checked and it was Z1.0.

In full disclosure, I am running Mach3 on a laptop while waiting for my lcd touchscreen. Ferrite rings are also on their way. Beside switching to desktop and adding ferrite rings, anything else i should be checking for? (i also will be trying some of the other suggestions from earlier.)

Another BUG, a big one, moving in the positive direction for all axes. I've noticed after having the system on for awhile the following occurs:

1) I can only jog in the negative direction. jogging any axis in the positive direction will only produce motor hums and no movement (Mach3 DRO are increasing.). If there is movement, motors are miss stepping for sure. Motors are ungeared and are tuned to basic specs from Gear Speed Step Frequency excel.

2) If there's movement in the positive direction, jogging in the x will torque the gantry as if only one x motor is turning or the two x motors are turning opposite (if even possible)

The way I've debugged this problem thus far is to shut off the motors and drives. Wait a few minutes. Turn them back on. Open and run the first few lines of the road runner Gcode sample. Back to "normal".

Any thoughts or pointers will be much appreciated as always!

T

[javeria]

Tuan,

Lower you velocity on motor tuning window in Mach, check if you have good ground/earth everywhere. check the grounding thread http://www.mechmate.com/forums/showthread.php?t=4

RGDS
Irfan

[bradm]

Tuan, did you ever switch those motors, or are you still on the 6.8mh inductance units? Are your geckos still running very warm?

When the system is running, is it easy or difficult to cause a motor stall if you (carefully!) push back against the gantry while it's moving? It should be scary difficult to stop the gantry; ideally the springs will let the pinions go before the motors stall. If this isn't the case, you aren't getting enough power from your motors.

Earlier in this thread, the discussions about the motor power calculations were based on using a 3-1 gear-down, but you appear to have direct drive at the moment, so I suspect you have insufficient torque.

Slowing your velocity, and particularly your accelerations settings may make the gantry move, but it will still be very prone to problems once you start cutting - think
about the kind of force a hand-held router can throw back at you.

So, your first problem to solve is: get your electronics and motors running without excessive heating. This may involve switching out the motors, decreasing the amperage, and/or increasing the voltage. Switching the motors is the best.

Your second problem to solve is getting enough mechanical advantage: switch the motors to some with gearboxes, or add belt drive transmissions. Either solution is fine.

The fastest way home is an expensive set of OM geared motors. Next best is 8 wire motors plus building transmissions.

[tnarch]

Irfran, thanks for the link. I will reread the thread to make sure I'm running my ground proper.

Brad, I did switch motor. I'm using these with Bipolar Parallel wiring. (http://www.kelinginc.net/KL34H280-45-8A.pdf) The geckos are not warm at all. These 201x has DIP switch to set their current output. I set them at 5.8. Should I go higher?

I haven't tested pushing against the gantry while it's moving. That does sound scary. Can you explain a bit more by what you mean "...ideally the springs will let the pinions go before the motors stall."

There is current no gearing and there isn't $$$ in the budget for expensive OM. I was hoping to get the machine to acceptable working order and cut transmissions with it.

As for torque and motor tuning, in one experiment, I pushed the motor velocity to 600 in/min and acceleration to 8/in/sec/sec. The gantry was moving smoothly and fast. It was like music to my ears :D However, this also fell ill to the BUG I described in my last post.

[bradm]

Ah, Tuan, that's good news so far. I'll focus elsewhere then.

The springs that hold the pull the motor mount plates to hold the pinions in the rack are designed as a failsafe mechanism - they will let the pinion slip out of the rack in extreme conditions like the gantry or toolhead crashing into an immovable object.

However, given that you've already gotten strong motion and you're on a reasonable motor, that takes us back to why it's shutting down, and then working again after a rest period. That still feels like heat to me, and not noise.

Here's two other thoughts: When the system is in it's failure mode and will only
jog in a negative direction, can you move the gantry or Y car by hand? If yes, then something is funny in the power stage - you aren't getting holding torque from the Geckos/Motors. If no, then the issue is in the control stage - either the computer or the BOB is getting unhappy.

How is the BOB being powered? Is it possible that the power supply to the BOB is unstable when warm? In particular, is there a voltage regulator that is running warm?

In Bipolar Parallel, you should potentially be able to push higher amperage through those motors. You could also try switching to Bipolar half-coil.

[tnarch]

Hi Brad

I tested the spring action you described by running the gantry at very slow speed against the stop blocks. The pinions slipped.

I tested for heat like this:
I isolated the motors for each axis and tested a thousand lines of code for each. Geckos 201x Standby is turned OFF so full current is always flowing to the motors. Motors were tuned to run at 600 in/sec an 8 in/sec/sec. I also changed to Dir/Step pulse setting in Motor Tuning to 5 microsecond. Per axis, I ran the code twice. The motors are warmer than normal after the first run. But the second run did not show any symptoms of the BUG. This led me to believe it is not heat. I should mention that the gcode for each axis is specific only to that axis. For example, the X axis gcode was:

F300
G1 X0
X1
X2.56
X67.32
......

I then loaded roadrunner into Mach3. The problem came back at the 6th and 7th line. On the 6th line, the Z did not travel to 0.2. On the 7th line, the X and Y did not move. From here on, the X and Y moved just fine. The Z continued to be a problem. I had moved the spindle to 2 inches above the bed, and then zeroed it out before starting the program. By the time the gcode is done, the spindle is touching the bed. Yikes!

As for holding torque, it's present when the system is in failure mode. BOB is power by a 5VDC from the power supply. No heat present any where BOB or power supply after the exercise I just described above.

After all this, I have two questions:

1) Is is possible that there's a loss of signal and/or power through the length of the cables? They are 16awg. The longest run to the Z is 25 feet.

2) I read somewhere in a post related to the PMDX that the Geckos should be grounded to the box through their neutral power line. Can anyone shed some light on grounding the Geckos if that's required?

I'm running out of ideas and running low on patience as I've been trouble shooting this for the past 2-3 weeks. Help?!?!?! :eek:

[Gerald D]

Tuan, I havn't looked at your full history....
Have you tried other PC's and another printer cable?

[tnarch]

Gerald, I tried two different pcs. We have a few different ones at the shop. I suppose I could try again with a newer pc and cable.

[MetalHead]

I have some questions.

Have you tried to run the motors half coil?

What kind of wire are you using? Can you give us the numbers off the wire?

Measure the resistance of the run of the wire with an ohm meter. Tell us this resistance value.

I would also shorten the hookups and make them as short as you can so as little wire as possible is sticking out of the shielding. Both ends. Also make sure only one end of the sheild wire is grounded.

This may not help, but I would also twist the motor wires so they are not laying patallel to each other.

Show us more pictures of your setup.

Also I would like to see a closupe or the color code of your set resistor on your gecko. If you relied on someone to give you the correct OHM resistor they may have given you the wrong one.

What power supply are you running for the motors? Voltage?

[Richards]

You need to turn the Gecko 'standby' on. Leaving 'standby' off can only be used when the motor's current is 2A or less. You'll eventually get excessive heating unless the stepper drivers are allowed to automatically reduce current.

Isolating electrical noise can be very hard. I would first try disconnecting the spindle and then doing air cuts. If the machine works properly with the spindle off, then further attention must be paid to the spindle and its wiring. If the machine still has problems with the spindle off, then something needs to be changed in the basic wiring of the control box, but, at least you would have an idea where to start.

[tnarch]

Mike & Mike & Team Mechmate

Motor has 8 wires. I tried unipolar (half coil?). No difference. I'm usine 16 AWG cables from here. (http://www.flexcable.com/products/group/motion-control/) They are shielded.

I have a digital mutlimeter. I was able to measure voltage and saw -58V and 58V at the motors. Negative and positive direction I assume. How do measure resistance? Do I measure the same way with the dial on the meter turn to ohm? I tried that and all readins were 0. Not sure what that means.

I did shorten all control signal hookups. From and to BOB. From to Geckos to motors. As for the grounding of the cable shielding, I haven't done this yet. Do I ground the shielding to the same point as earth ground?

I will try twisting wires. Pictures of set to come soon.

Power supply is a Keling 6520 (http://www.kelinginc.net/KL-6520.pdf). 65V 20A.

Geckos Standby are turned back on.

Lastly, I've been trouble shooting this whole time with the spindle off.

Thanks again everyone for the suggestions. Just have to keep trying I suppose....:)

[MetalHead]

So neither end of your cable shielding is grounded?

[bradm]

Hi Tuan, just getting back to this after some time traveling. Back in posts #59 / #60,
I was asking if you had strong motor torque _while the system is exhibiting the problem_. You indicated that you ran the machine against the stops slowly and the pinions disengaged. Did you manage to do this in the direction that the machine won't go?

What I'm after here, is trying to assess if the motor strength is dropping during the time the system is failing; you could also try turning the system on, trying to manually push the gantry in both directions (shouldn't be possible), and then trying again after the issue shows up. If it becomes possible to push it, we're looking at a power stage problem; if not, likely a control stage problem.

Another thing to try is to measure the control signals at the Geckos. You should be
able to clearly see two solid voltage levels on the direction pin (relative to ground), depending on which way you jog. And if you jog several times, you should be able
to observe the step pin stopping in either the on or off state after each jog - you can again see the voltage levels. The question is whether these change in behavior when the system is working correctly vs incorrectly. Choose the Gecko for one of your problem motors, of course.

[danilom]

Are you able to turn stepper axle easily by hand, when there is no power to them? I had problems with some steppers with miss aligned rotor, it too wanted sometimes to go in one way and not the other and would heat fast, if you cant turn it easily it must be the same problem. I solved mine with dr.Hammer knock to the axle from the back of motor, that set the rotor to right position and motor gained in torque and speed.

[Surfcnc]

Hi Tuan

It's no fun when things don't work as they should, but persistence pays off in the end.

From my reading of your thread grounding does not seem to be in place on your machine yet, so that is where I would invest my time first.
Several grounding strategies are discussed on the forum however my information is that grounding the cable shields at the machine is the typical way grounding is done in an industrial setting.
The machine itself will also need to be grounded, eg Y car to Gantry to Table Base to Earth.

Reducing complexity of the system to the bare minimum while still displaying the unwanted behaviour is really important.

1. As you have indicated you do not operate the spindle (but you have not said if the VFD is still turned on, so actually disconnect this until the issue is resolved)
2. In Mach3 turn off the resume and feedhold buttons in ports and pins, input signals.
3. Do not use any wireless devices to jog, only use the keyboard
4. Turn off or reduce micro stepping on the stepper drivers to a minimum.
5. Ensure the steps per values in Mach are correct for the stepping values you have selected using Gerald's gear speed calculator spreadsheet.
6. Actually check that the system you are using is capable of pulsing reliably enough using the application called drivertest.exe in the root directory of the Mach3 install.
7. Your Power Supply seems good from what I have read, but you might also consider disconnecting any steppers that are behaving well, as this will ensure power is not in short supply to the steppers that are problematic.

Regards
Ross

[tnarch]

Some new development.

The slaved X motors started making really loud grinding noise like the bearings are broken. Lets add insult to injury. I thought. :mad:

After regaining my composure, I decided to decommission the entire line. I disconnected the power to the Gecko for this motor. Connections to the PMDX are also cut (pin 8 and 9). Something clicked! :eek:

Power supply current output is 15A at 56V. My Geckos had always been set to draw more than 4 amps up until this point. Simple math of 4 x 4 = 16 lead me to think the Geckos were over drawing current from the power supply. With the slaved X motor still down, I set all the Geckos to draw 3A. Voila!!!

I ran the roadrunner gcode program at the different feedrate of 15, 60, 100, 150, 300. I also isolated the axes and ran each independently. I also ran combination of 2 axes: XY, YYZ, & XZ before running all three axes at the same time. The spindle returned to correct referenced (0,0,0) at the end of the program everything single time :D

I am reluctant to rewire the slaved X as I am not 100% confident the bug is power. I have a job that needs to be out by the end of May, if this configuration continues to work, I'd rather keep it working before bringing the slave X back online.

Will the gantry get of out square with only one X? I am keeping the the slaved X engaged but not powered.

Again, thank you everyone for your advice and suggestions. Keeps me trucking on. :)

[Kobus_Joubert]

Don't know if it will work so well without both X-motors driving. Long long time ago in the world of Gecko I had a Gecko stop working on my one x-motor and the gantry was WOBBLY...or must I say shaking like a man in need of a stiff drink.

[bradm]

I'm surprised that the gantry moved cleanly with only one X motor. I expect that if you attempt a heavy cut close to the inactive motor, you may have some issues with accuracy. Why not try adding the additional motor at the lower amperage settings?

Another thing to try would be to swap motors to see if the one motor is bad.

However, given that you have a 15 A supply, and you had peak currents set for
over 23 A (you said 5.8 x 4, right?) I think you're on the right track. As mentioned above, you may want to try going to half-coil wiring instead of the parallel. This would match up nicely with your supply. Note that we often have systems with power supplies smaller than the total calculated draw, since all motors drawing at peak doesn't happen. But given a draw of 2.9 * 4 = 11.6a at idle, it's not hard to see that you might go over the top. You won't have that problem at 3A, and I'd bet, not at 4.4A either (half-coil).

I think you've probably solved your own problem here, now you just need to test it!

[tnarch]

Got into the shop and did some more testing.

I can say with 99% certainty the former slaved X Gecko was the culprit for all my troubles. Any motor I hook up to it will make that clicking noise (grinding as I described in #69). I also tried to run this same Gecko from different pins, other than 8&9. Same problem.

Can anyone shed some light on how a bad Gecko would put the whole system into failure?

Also, turned on VFD and spindle and everything is smooth thus far. Ran the spindle at 6000, 8300, and 11250 rpm with no noise problem.

[tnarch]

By the way Brad, is half coil the same thing as unipolar? I ran unipolar and the motors got really really hot.

[bradm]

Tuan, half coil is not the same as unipolar; you would need a different driver to run unipolar (6 wires from each motor, not four). However, it's electrically very similar to unipolar; in both cases, you only energize half of each coil at a time. Unipolar does this by switching from one half to the other half; Bipolar half-coil does it by using one half, but reversing the current through it. In both cases, you would need to keep the amperage down below the 4.4A specification on the motor to prevent excessive heating; so that is probably why the motors ran hot.

Since you've indicated that your gantry runs with just one motor, I would say that it has been doing that all along; the clicking motor was effectively not being driven electrically, just dragged along by the good one. Not surprising that it wasn't 100% repeatable. There's a good chance that your early overheating made that one Gecko unhappy. The clicking is consistent with either thermal or current limiting circuitry kicking in too soon, or with a blown driver MOSFET. In any case, Geckodrive should be able to help you.

Looks like you're in the home stretch now.

[MetalHead]

I did not think you can wire Geckos up Unipolar?

Isn't half coil where you use half the windings that you have hooked up for Parallel. For Example Blue/Red and Brown/Black. Or Yellow/Green and Orange/White. So you only use 4 of the 8 wires and tape off the other 4 so they do not short.

This way you are only using half the motors coils.

[PEU]

Here is a guide of different wiring configs:

http://img231.imageshack.us/img231/5146/unipolarvsbipolar.jpg

[Surfcnc]

Hi Tuan

Well done, sometimes the amount of disassembly and reassembly to solve a problem can be intimidating - but you did it none the less.

I'm with Kobus on the gantry. I have ran both sides of my gantry with one motor only engaged and the wobble Kobos mentions is evident.
The slaved motor is not only winding up and down the rack it is also locking into a position on the rack when not moving.
This is very different from passively sitting there.

Effectively the locked motor becomes a pivot point for the gantry for any movement induced from the other axis's or any inertial movement from a change in direction or acceleration from the X axis itself.
Accuracy would be compromised and it would show up as an arc line from wherever the cutter position is with its center on the locked (or functioning) X motor.

Regards
Ross

[tnarch]

Hello everyone

First off, thank you everyone for your help! I am happy to report she is live.

I hope this is the last time I'll be talking about my control woes. It turned out that in, addition to the bad Z gecko, the real error was the power supply to the BOB. :o All this time I did not once suspect the trouble was coming from the BOB because there was motion. After contacting tech support at PMDX, I learned 2 things:

1) I wired the regulated +5VDC into the BOB improperly. I should've taken notes and pictures from the kitchen table project so that I could have some reference after putting everything inside the box.

2) The reason why I had intermittent positive motion was that the BOB drew power from the computer.

It's quite embarrassing to learned it's been my carelessness all this time. However, I thought I would write it up as a lesson for future builders. On a positive note, I'm more confident with trouble shooting now :) The lesson is, like Ross said: sometimes starting over from SCRATCH is a good idea.

On an even more positive note, I'm still high on joy and excitement after a first successful run, from CAM to cut!!!

[bradm]

Doh! I was on that trail back when I was asking if the BOB power supply was getting warm. It probably was, but it was inside the computer so none of us saw it! We'll remember to ask the question the next time somebody is having problems, so thanks for sharing the resolution with us.

Very glad to hear you are up and running, hope you have lots of fun and profit with your MM!

[Surfcnc]

Congratulations Tuan

My guess is you are going to appreciate your machine just that little bit more now after such a rocky start.
When I bought my toroidal power supply, it had additional taps for 5 volt and 12 volt so that was what I used as power to the BOB.

Probably a wise lesson for other builders to distrust the PC power supply, not so much as it is a PC power supply but because of the great variability in their build quality.
$10 - $200 last time I looked. I'm sure you could weld with the $200 PSU but not with the $10 one !!

Your test run looks quite artistic, It looks very much like some of the sixties graphics.
Pump out the work and show us a few pics to keep us interested.
If you can match Kobus for speed and variability of your projects, you achieve instant legend status :)

Regards
Ross

[tnarch]

Ross, thanks for the compliment on the design.

I should clarify. I wasn't using power from PC. I had a 5vdc regulated source from my control box power supply. I just wired it incorrectly to BOB.

Brad, I hope you are right about profits :D I'm crossing my fingers for a really BIG job we just bid on. The machine came online just at the right time. ;)

Check out the video. (http://yfrog.com/0yl0jaz)
- 1/4" Solid Carbide Spiral
- 60IPM
- 0.1" to 0.45" Z depth in one pass :D

[tnarch]

1/2" plywood
1/2" Carbide
20 ipm
1/8" Z steps

The striation is the result of the Z axis not plumbed.

[IN-WondeR]

I'm using a USB cable from the PC to power the BOB I have, it works like a charm...

[MetalHead]

Sweet!! I see paint and dust. How bout a logo? Great job on finding your problem !!!

[tnarch]

Been making cold calls to cabinet makers looking for work -no luck yet. Did this little piece to keep me motivated. Current size is 15" x 22". Will cut a bigger one to be used as a mirror frame.

[sailfl]

Tuan,

Take pictures of your work and when you make your cold calls, show the photos. It helps.

[tnarch]

Nils, thanks for the tip. We do have a small portfolio of sample and professional work we've cut. I think I haven't found the right sales pitch yet.

How do you convince someone to give you work that he knows it can be done in house? The time saving doesn't seem to have as much weight as I thought or can explain/pitch to people. I think my rate is competitive, even on the low side being $75-90/hr depending on the job.

I would gladly take any advice anyone can give in approaching and getting new clients.

T

[domino11]

Maybe try to focus on the things that he cannot do in house. Show him how you can add value to the things he does in house.

[Gerald D]

$75-90/hr doesn't sound like the low side, particularly if you don't have orders. I think you will have to start out much lower than that.