Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: jeffcallahan on March 27, 2011, 08:10:53 PM
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Hello All, new to this forum. I have taken some CNC Classes from a community college, but I am by all means new to Mach3, and the parts of CNC. I run a CNC daily using Mastercam, and am familiar with G and M codes.
I want to build my first CNC, a coil winding machine for guitar pickups. I'm thinkning of using a servo for the spindle, and stepper for the wire guide. All I need is a variable speed spindle and a small amount of Z axis traverse. I don't need much torque, I'll be using 40-45 AWG. My idea is to control the Z feed (wire guide) using a pendant (Vista's iMach?), and the spindle using some sort of foot control to vary the spindle speed.
1. Is this plausible?
2. Could Mach3 duplicate my jogging (not MDI) moves and spindle variations using Teach or Copycat?
Also, any recommendations for parts would be very helpful
Thanks,
Jeff
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Hi Jeff,
Welcome to the forum.
Hood is the man when it comes to coil winders he will know ;)
Tweakie.
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I dont think what you want to do would be an easy task but doing it conventionally should be easy.
I have made a small coil winding machine, coils up to 100mm dia and 500mm long can be wound but also have wound coils as small as 20mm long on a core of 0.5mm Mu metal and 0.1mm dia wire. pic below of that coil and the winder.
I used steppers for spindle and Axis and then for the small core had to add a second stepper as a slave spindle so I could hold the 0.5mm core in tension for winding onto.
Any info you want about my build just ask.
Hood
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Hood,
How do you slave a spindle? In Mach or you just split the signal to the 2 drivers?
Dan
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Dan,
didnt really slave the spindle as such, what I was calling the spindle is actually X axis (if I recall) and it is a linear axis even though its rotating ;D So second spindle was set up as A and slaved to X.
Hood
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OK. Then apparently I don't understand how it operates ;D
Dan
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Its simple enough Dan, the axis that is X is like a spindle but it is a linear axis that rotates and the A which would normally be thought of as a rotational axis is also a linear axis which also rotates and is slaved to the linear axis that rotates like a spindle but is set as X ;D
Hood
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Yep, Hood. Simple indeed ;D ... Spindle which acts like a linear axis... afraid you lost me there.
Is the chuck on the left being called X and the stepper on the right being called A? Aren't they supposed to be rotating continuously, while the longitudinal axis feeds back and forth? How do you achieve the continuous rotation with a linear axis in Mach3?
Dan
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;D
Dan, the spindle on the left is the normal spindle, it is set as X in Mach and it has steps per unit set so that one unit is one revolution. The motor on the right is slaved and it is the same, one revolution equals 1 unit.
To turn a coil I need to know the length, the dia of the wire and the amount of turns required. I enter them into the DROs on my screen and then press the button to generate the code. The Z axis goes the distance that the coil is and then reverses but the X (spindle) continually goes the same direction. So for example that small coil above has a length of 20mm the Z axis will go from zero to 20 then back to zero then 20 then 0 etc until the amount of turns are complete. The X (spindle ) will turn by the amount of turns I have entered into the DRO. Here is a pic of the screenset I made up.
Hood
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Hood,
Pretty much what I guessed. Just didn't know that the number of turns was known... Thought you'd start it and watch it till you think it was enough and then stop it ;D
But I am curious now, how do you generate the G-code from the info you entered in the DROs?
Dan
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Just some VB in the Load G-Code button.
The coils I make are for specific purposes so the amount of turns is usually the important part, I did make up a screenset that I needed the length, the wire dia the core dia and the max dia and the VB calculated the turns but that was never used.
Hood
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Thanks, Hood. It's a bit cleared now. Interesting too!
Dan
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Hi Hood, please explain the necessity of the additional motor in place of a live center or bearing sleeve at the tailstock position.
Just curious,
Russ
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No probs Dan
Hi Russ, the core was 0.5mm dia Mu metal, very soft stuff. At first I tried with a live centre to hold it in tension but it just spun into a spiral in seconds. Had to make up the second spindle so it would rotate at the same pace as the original and I could keep the core in tension for winding the wire on.
Hood
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Ah, sort of what I expected but wasn't sure.
Thanks
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Sorry for the delayed response, I've been out of town for awhile.
Hood, very nice looking winder, close to what I was envisioning. What did you use for the wire guide? Looks nice! Also, being the nature of guitar pickups, I wind to a specific number of turns as well. What do you recommend for varying the traverse feed rate throughout the coil? I feel confident writing the code, but would rather have the machine copy my more subtle manual moves. Also, I'll be using a laptop to run Mach3, so what plugin would you reccomend to control the spindle and traverse. Last question, are there any reccomendations you could suggest for trying to record the manual movement of the motors?
Thanks,
Jeff
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What did you use for the wire guide?
For the heavier (0.7mm) wire I wind it needs to be sort of decoiled so I made up a series of 3 delrin rollers that the wire snakes round, this seems to straighten the wire out and keep a bit of tension on it. For thinner wires I dont use the rollers, I just feed straight off the coil. The nozzle part is actually a mig welding contact tip for the heavier wire and for thinner wire I have a delrin nozzle that slips over that with a hole to suit the wire dia being wound at the time.
I have the bobbin holder, nozzle and rollers all fixed to the same part of metal and this can then slide in or out to get the feed nozzle as close to the finished dia of the coil as possible. It is totally manual and just locks by tightening a knurled screw to hold it in place.
What do you recommend for varying the traverse feed rate throughout the coil?
Not really sure what you mean here. I dont vary the traverse rate at all, the Z axis moves back and forth at a constant rate. It does slow down, stop and reverse obviously but Mach should keep the rotating axis in sync with it by slowing it slightly, it is hardly noticeable though.
I feel confident writing the code, but would rather have the machine copy my more subtle manual moves. Last question, are there any reccomendations you could suggest for trying to record the manual movement of the motors?
Only real way I can see that could be done is by jogging the motors and having that recorded by one of the teach wizards/plugins (copycat, Jcode)
Also, I'll be using a laptop to run Mach3, so what plugin would you reccomend to control the spindle and traverse.
If using a laptop that has a parallel port then you may be lucky and get it to work, some laptops are ok but the vast majority will have timing issues due to their power saving features. You can get round this by using an external pulsing device, the SmoothStepper is what I use and it connects via USB.
Hood
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Thanks again Hood, really helpful.
1 -- Delrin sounds like a good choice for the smaller wire, the mig tip is great, looks like it was meant for the job, but I'll be using too thin of wire for that. The adjustabilty of the wire guide is a feature I didn't think of, and will have to work into the plans.
2 -- I realize you probably didn't adjust the feed throughout the wind, but that is a feature pretty important to my application. I was thinking of using an iMach pendant for the z axis, and an iMach spindle tach for the spindle. Would this work? Would I still need the smooth stepper you mentioned? I realize I am very new to this all, and I'm sure I'm missing something, so please let me know if I'm not thinking correctly.
3 -- Will copycat or jcode work with a handwheel such as the iMach pendant, or is jog and handwheel not compatible?
4 -- My laptop does not have a parallel port, so will I need the smooth stepper (or simialar) to run off the laptop regardless of whether or not I buy an iMach pendant?
Thanks again,
Jeff
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I have the mig tip there all the time and just have a bit delrin that slips over it, the other end of the delrin has a hole approx the size of wire I am using. 0.07mm is the thinnest I have used I think, gotta be careful with that, breath on it and it snaps ;D
So you are not winding at a uniform distance per revolution?
Yes you should be able to use the JCode or CopyCAT with the pendant but you will still need a smoothstepper. You need to control the motors from Mach and as you dont have a parallel port that will output the signals to your drives you will need something else. The smoothstepper connects via USB and does the pulsing instead of the computer doing the pulsing. The smoothstepper still gets its instructions from Mach.
Hood