MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > Personal Build Histories > MechMates already cutting
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #61  
Old Thu 18 January 2007, 10:52
Gerald_D
Just call me:
 
WELL DONE! You achieved in one day what took me about 3 days

In Config > Ports & Pins > Input Signals scroll down to the line EStop and look in the column "Active Low" change from green to red, or vice versa to get the e-stop to work correctly.

The driver LED's are not equally bright - I don't think that this indicates a fault. (Gecko will replace a faulty driver for free, but you have to arrange the transport). I am guessing you have a Mach ports&pins error, so I suggest you swap motors at the PMDX to see what happens.
Reply With Quote
  #62  
Old Thu 18 January 2007, 11:08
fabrica
Just call me:
 
Ok I will swap motors at the PMDX point to see where things have gone wrong and post you the results by tomorrow morning before you start work (we are 2.5 hrs ahead of you). Now it's almost 11.30 pm over here. It's time for me to hit the deck after very strenuous and ejoyable day's of work.
Reply With Quote
  #63  
Old Thu 18 January 2007, 21:30
fabrica
Just call me:
 
Checked the motors. It was was the driver which was faulty. Replaced the driver with new driver motor worked perfectly.From CNCZOne found a simiple way to check Gecko's. Info given below.

"Quick test. Disconnect the main connector, get a multimeter and set it to Ohms. Connect a probe to COMMON, then measure COMMON to STEP, then COMMON to DIRECTION. The reading you want to see is 1.2K give or take 5%. Get that and the drive is probably OK".

I followed the procedure and did the checking. Both readings were perfect. For the monet I will go ahead with the new Gecko and see what could be done with older unit later.
Reply With Quote
  #64  
Old Thu 18 January 2007, 21:33
fabrica
Just call me:
 
I have encountered two more problems today morning while setting up the machine.

One motor on the x drive is getting too heated. The other issue is that the Z axis motor is rotating only in one direction.
Reply With Quote
  #65  
Old Thu 18 January 2007, 21:48
Gerald_D
Just call me:
 
Hot motor: Check your resistor that you fitted to the Gecko. Do not trust your ability to read the colours on the resistor, use an ohm-meter to measure it. Measure all the resistors - if this one is different then that is the cause. If it is the same, then there is a setting under the cover of the gecko which must be checked.

Direction: On the PMDX there is a LED for each motor which shows the direction. Is this LED indicating the direction change correctly? (compare to the behaviour on the other motors) If it is, then check the wire connections between the PMDX and the gecko.

Strange gecko behaviour: nearly a year ago gecko had problems with bad connectors. They changed the supplier. Maybe you have one of these. The connector does not like to be removed many times from the gecko.
Reply With Quote
  #66  
Old Thu 18 January 2007, 22:45
fabrica
Just call me:
 
The problem with motor heating was sorted. After changing the drivers we had not inserted the resistor on to the new driver.

The problem with the Z axis motor still exists. It is only moving in one direction. When we try to move it in the other direction it only makes a noise but the shaft does not turn.

One more thing that I observed was that when pressing the e-stop button, the LED on the PMDX card which is situated just above the output connectors lights up. This is very unusual.
Reply With Quote
  #67  
Old Thu 18 January 2007, 22:49
fabrica
Just call me:
 
With regards to the lights on PMDX. For X,Y and A outputs the light tuns on when moving in one direction and does not light up when moving in the other direction. On the Z outputs the light turns on in one direction but is very faint.
Reply With Quote
  #68  
Old Thu 18 January 2007, 22:55
Gerald_D
Just call me:
 
Is the Z-motor still disconnected from the rack? What happens if you swap that motor's wires to another gecko?

Your e-stop logic, with PMDX jumpers and Mach ports and pins settings is still mixed up. I have little experience to fix this because ours worked right and then I left it alone for more than a year. The only thing I can suggest is to put the jumpers as per the drawing above, put a temporary wire across the e-stop contacts (like the pmdx was supplied - J6 across e-stop and GND), and then play with the Mach settings until it works correctly. When you put the motors against the racks, then you can put the E-stop switch in that jumper wire at J6.
Reply With Quote
  #69  
Old Thu 18 January 2007, 22:59
Gerald_D
Just call me:
 
Regarding the faint LED for the Z: Disconnect the wire below the LED (the one going to the Gecko) and see if it is still faint - maybe there is a short in that wire....
Reply With Quote
  #70  
Old Thu 18 January 2007, 23:35
fabrica
Just call me:
 
The Z axis problem was sorted out, it had been a software issue (mach3).

I am starting to enjoy this Gerald.
Reply With Quote
  #71  
Old Thu 18 January 2007, 23:48
Gerald_D
Just call me:
 
Can I relax now?

Would you agree now that it would be good to have the 4 motors on the kitchen table at home first? Do this in parallel to the steel construction....

Now you can tell us your secret? I am sure you have already connected the motors to the racks and made the beast move....
Reply With Quote
  #72  
Old Fri 19 January 2007, 01:04
fabrica
Just call me:
 
The machine is moving well without any problems. Setting up the home point (0,0) and the limits.

Please educate me on the the rate of accelaration that a normal mechmate should run at. We increased acceleration once and the gantry jumped off the rails. May be we should increase the tension of the springs further. We have kept it at the lowest point.
Reply With Quote
  #73  
Old Fri 19 January 2007, 01:08
fabrica
Just call me:
 
Hope I am not troubling you too much. Fully agreed on the kitchen table project.

Regarding your relaxation matter, no way. You have taught the wrong thing to a wrong guy.
Reply With Quote
  #74  
Old Fri 19 January 2007, 01:39
Gerald_D
Just call me:
 
Our MechMate has direct drive motors, so the settings may not apply to you....Our settings X & Y axes are 500 mm/sec/sec and Z axis is 1500 mm/sec/sec. Our machine is set rather slow and lazy. If we drop the acceleration down much more then we get round corners for square parts.

Mach is developing the Quantum to replace Mach3 and this will completely change those acceleration values again.

The correct accel. values are the ones that feel right for you.

I guess it sounded like the gantry had jumped, or that the teeth of the pinion had jumped out of the rack - but if you look closely you will see that the teeth are not jumping. That noise comes out of the stepper motor when it jumps internal steps. Believe it or not, it is actually harmless - nothing is damaged. You just get a very loud warning that your stepper has lost a step or four. (Some people say you must use servo motors because you don't know if your stepper has lost a step - believe me, you do know when a stepper loses a step. It is loud!)

Regarding the spring tension, you had better check it against a scale. The tension must be about 12kg. link
Reply With Quote
  #75  
Old Fri 19 January 2007, 20:24
fabrica
Just call me:
 
Gerald, I found the reason why the gantry is climbing on to the x rails. The pionion wheel is slipping against the motor shaft. I have fixed only one grub screw.

Now I am fitting another one more screw on all motor shafts.

Can you advice me on setting the limits on the Z axis.
Reply With Quote
  #76  
Old Fri 19 January 2007, 20:53
Gerald_D
Just call me:
 
Those grubscrews must be very tight - sometimes I destroy the spanner/key/wrench when tightening them.

The z-axis limits are now described in this thread.
Reply With Quote
  #77  
Old Fri 19 January 2007, 21:16
Gerald_D
Just call me:
 
Fabrica, once your router works, you need to go through quite a process of getting the axes square to each other. This is the time when you will be finally adjusting the x-axis limits and the shims behind the x-axis V-rollers. I will start another thread when you are ready for this. For now, get your router going so that you can cut the top of your table flat.
Reply With Quote
  #78  
Old Fri 19 January 2007, 23:54
fabrica
Just call me:
 
Ok Thanks.
Reply With Quote
  #79  
Old Sat 20 January 2007, 05:23
fabrica
Just call me:
 
Below given is a photo of the first cut I made with the Mechmate. The letters does not mean anything. Gerald, How is the quality of the cut. Do you think the machine is stable and free of unwanted vibrations.

Reply With Quote
  #80  
Old Sat 20 January 2007, 05:31
fabrica
Just call me:
 
Componets laid out before final wiring and getting mounted onto the box.

Reply With Quote
  #81  
Old Sat 20 January 2007, 05:35
fabrica
Just call me:
 
Gerald,

In the baove picture we have pushed the relay (instead of isolator switch)and router relay to the top to isolate A/C signals from the gecko drives.
Reply With Quote
  #82  
Old Sat 20 January 2007, 05:46
fabrica
Just call me:
 
Gerald, I have another problem which needs to be solved with your advice.

When the gantry is moving at some points the motors on the x axis is moving very erratically. This is the reason for the Gantry to climb onto the x rail. When you look at the motors from the other end of the shaft you see it not moving at all but making a noise. It happens to both the X axis motors at the same time.

We changed the current limiting Resistors from 2 amp to 5 amp and finally to 1 amp, but the problem did not get solved. What should be the correct resistor.

We connected the second grub screw to all motor shafts and screwed them in very tightly but the same problem continued. It happens all of a sudden.
Reply With Quote
  #83  
Old Sat 20 January 2007, 06:01
fabrica
Just call me:
 
Below given is photo of the final control we had. In our haste to get the thing going we had got the main wire which provdes a/c cpower to transformer bundled togethr with the screened running to motors bundled together and running out of the control box together through the same bottom hole.

Do you think that this is causing the erractic behaviour of the motors due to A/C riples being piched by the motor wires. The erratic behavou happens on most times when both the X and Y axis are moving together. This means more power running through the A/C power cord.

Reply With Quote
  #84  
Old Sat 20 January 2007, 06:29
Gerald_D
Just call me:
 
I can't see a problem with cut quality in that photo. Are you happy with it?

Does the erratic behaviour start at a certain speed? The current resistors depend on the motors and how you have wired them

Looking very quickly, I am a bit concerned about how close your big power supply is to the PMDX. That is not a toroid transformer and your power supply is maybe "noisy". The cable from the PC to the PMDX also looks thin - is it shielded? What are your motor wire shields connected to?
Reply With Quote
  #85  
Old Sat 20 January 2007, 06:59
fabrica
Just call me:
 
Regarding cutting quality, I am very happy with it.

I have so far noticed any relationship with the erretic behaviour and speeds.

Gerald do you think that this errectic behaviour is noise related.

The transformer which we use were with us we did not bother to do up a toroid. But if everthing fails we could think of it.

The parallele cable is shielded. The motor wire shields are not connected to anything.

Do you think that we should the table as well.
Reply With Quote
  #86  
Old Sat 20 January 2007, 10:07
Gerald_D
Just call me:
 
Fabrica, glad to hear the cut quality is okay for you.

It is very difficult to diagnose this "erratic behaviour" because I can't see/hear it and it is not something that is common......

The ShopBots were fond of getting the shakes when the speed went too high and two axes had to move together. But you say your problem does not depend on speed. (The ShopBot issue was related to resonance of the gantry structure). Does it look like your V-rollers are bouncing up and down because of mechanical flexibility in the structure? I doubt it. (If this was the case, it would happen only at high speeds and dynamic movements).

Therefore, if it is not mechanical, then we must look for something electrical...and interference is the first thing that we worry about. Everything must be properly grounded. The table, the gantry, the y-car, the z-slide, and the shields of the cables. Only ground the cable shields at one end, the end nearest the control box. Also, the negative of the power supply must be attached to the same ground point as the shields, table, cars etc. If you do all this and the problem remains, we can look somewhere else. But it will not be a waste of time to do proper grounding - especially if you plan to use a dust sucker later.
Reply With Quote
  #87  
Old Sat 20 January 2007, 10:54
fabrica
Just call me:
 
The v rollers are properly seated on the Rails while travelling from one end to the other (X and Y both).

I too feel that this is a problem created by electrical noise. OK, I will start work the comming Monday and start with concentrating totally on the elctrical side of issues.

I have a few questions to ask from you about this microstepping issue which I will ask you later.
Reply With Quote
  #88  
Old Sat 20 January 2007, 12:33
Gerald_D
Just call me:
 
Did you adjust the trimpots on the gecko's for the lowest mid-band resonance?
Reply With Quote
  #89  
Old Sat 20 January 2007, 20:32
fabrica
Just call me:
 
No.
Reply With Quote
  #90  
Old Sat 20 January 2007, 21:08
Gerald_D
Just call me:
 
It must be done. See the gecko instructions.
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 03:05.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.