Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: AlexanderJamesGuitars on August 14, 2014, 08:25:02 PM
-
Hello everyone.
I am new here. I have read through these forums MANY times but today I ran into an issue that I could no longer deal with.
I will try and keep this short and to the point.
My CNC is a Techno Isel 040 H830 with stepper motors. I am using the latest version of Mach 3.
I was running a guitar body today and after completing one toolpath, the CNC started the next toolpath 1" too far to the right. I have only had this problem once before. I was cutting out a guitar headstock shape and the CNC was too far in the Y+ axis by roughly 1". This has never happened to any other AXIS.
Upon reading through some forum posts, my issues are very similar to this post (I am pretty sure my Mach 3 is legit though):
http://www.machsupport.com/forum/index.php/topic,23270.0.html
If memory serves me, the DRO and Toolpath showed the travel was in position. When is reality (looking at the guitar body on the table), it was not.
If I remember correctly as well, the first time I had this issue the CNC had been running all day. This was the case this time as well. I felt the stepper motors today and they were quite warm to the touch. The controller felt warm as well (not as hot as the steppers).
I posted an image of the damaged area. The start of the neck pocket was supposed to be left by about 1"!
(http://i1360.photobucket.com/albums/r658/alexanderjamesguitars/IMG_20140814_153359_zpse4c3b324.jpg) (http://s1360.photobucket.com/user/alexanderjamesguitars/media/IMG_20140814_153359_zpse4c3b324.jpg.html)
This problem has only happened twice but I would like to rectify the issue before destroying any more material.
I hope you all can help!
Thanks.
-
Just a shot in the dark but I would be inclined to look at the stepper motor controller and make sure it has enough circulated air cooling. Perhaps fit another PAPST type fan ??
Tweakie.
-
Hello Tweakie.
I can try that. The controller box is held in a cabinet. I will pull it out of the cabinet and hopefully that will dissipate some of the heat. If it still gets hot, I will look at pointing another PAPST fan at the stepper controllers.
How cool should the whole controller box be? I take it the box shouldn't get hot at all, correct?
-
The driver will run warm but the actual stepper motor driver chip must not be allowed to exceed the manufacturer's specification on working temperature.
(On another forum some have experienced similar problems to those you describe and fan cooling resolved the issue - thus my suggestion :) ).
Tweakie.
-
Tweakie, I apologize for my lack of knowledge but what does a stepper motor driver chip look like? Where would it be located in my control box? Would there be a stepper motor driver chip for each AXIS?
I also wanted to state another thing. My router is a Porter Cable 75182. It does not have a ground in the power cable. Just two prong. Would this cause an issue? (Though the Y positioning problem has only happened twice and when I want to, I can not recreate the issue on cue)
-
Yes, one driver chip for each axis is usually the case.
Most single phase routers are "double insulated" and only have the two wires. If electrical noise was an issue I think you would see the axis position fault on a much more regular basis, if not continually.
Tweakie.
-
I took a picture of my controller box. What parts in here need to be cooled? Are the stepper driver chips in the slo-syn translator motor drives (on the right)?. Or are they on the board closest to the fan, the microstepping system (on the left)?
As you can see, only one fan is in the box. How would I wire in a PAPST fan?
Sorry for my inexperience. Just learning the tech side of it all now.
-
Well, it looks to me like the existing fan is more than adequate to do the job so I don't think adding another fan would serve any useful purpose. I assume that the board closest to the fan is your Z axis and the two slo-syn's are your X an Y ??
Tweakie.
-
Well, it looks to me like the existing fan is more than adequate to do the job so I don't think adding another fan would serve any useful purpose. I assume that the board closest to the fan is your Z axis and the two slo-syn's are your X an Y ??
Tweakie.
It sure 'looks like' a fan, but has it been seen running under power? I've had two fans go down from China (well one gone and the other sounding like it's dying fast :v )
-
Good point DoubleTrouble - is the existing fan operating correctly and efficiently ??
Tweakie.
-
Good point DoubleTrouble - is the existing fan operating correctly and efficiently ??
Tweakie.
Thanks :) it also looks like there is an 'amount' of guitar dust inside the box, built up on the rear vent and cables etc, a can of compressed air is you friend for ridding this problem.
-
Well, it looks to me like the existing fan is more than adequate to do the job so I don't think adding another fan would serve any useful purpose. I assume that the board closest to the fan is your Z axis and the two slo-syn's are your X an Y ??
Tweakie.
I think you are correct Tweakie. The one closest to the fan controls the Z and the slo-syns are for X and Y (I will check to confirm this though)
Good point DoubleTrouble - is the existing fan operating correctly and efficiently ??
Tweakie.
DoubleTrouble, Tweakie, I will check Monday to see if the fan is working adequately enough. I will report back then.
I will also give the box a good shot of compressed air.
-
Hey guys.
I cleaned the box out with compressed air. As well, I checked to see if the fan is working and it is definitely blowing air into the box and onto those stepper controllers.
I had a theory the other day while at home. My thoughts were that the stepper controller furtherest from the fan (closest to the E switch) was probably the Y axis. That would explain it not getting enough air cooling by the fan because the stepper controller in front of it would block air flow. Upon checking today, I can see this is not the case. The middle stepper controller is the Y axis. I have attached a picture of the Axis layout.
Any other thoughts? I am afraid to run any material until I figure this out.
-
Anyone have any ideas what may be causing my issue?
I don't know where to go from here.
-
Hi,
Just going on the problem as you have described it, my money is on it being heat related but I am only guessing because I have no proof.
Perhaps your way forward is to get some cheap MDF (or similar) and carry out a number of test runs (with the machine being left on all day) - if and when the problem happens again check that the Mach3 DRO’s show the correct position when the tool has an incorrect position. This will at least eliminate a Mach3 software problem.
In the meantime you could check your machine to make sure all wiring, plugs and sockets etc. are sound and secure also that the ‘motor to shaft’ couplings are absolutely tight and secure.
If the problem is heat related, as I suspect, then it could be a faulty motor. Swapping the X and Y motors is one way of testing – if the fault moves to the other axis then it points to a motor fault. Alternately, it could be a faulty stepper driver. Swapping the X and Y drivers is a good method of testing and if the fault moves to the other axis then fitting a new stepper driver will most likely be the cure. Also check your PC to make sure it is not getting too hot (internal dust perhaps) and has adequate air circulation etc.
Sorry to be so vague about all this but when something actually breaks it is easy to identify but when something works but has an intermittent fault it is not that easy to be absolutely certain about the cause.
Tweakie.