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Winding springs using Mach control
« on: June 30, 2016, 10:33:24 AM »
Has anyone wound a compression spring using Mach 3/4?

The general steps would be to snag the 2mm piano wire on the spring winding arbor that is in the spindle, start the spindle and then use a threading code to move the tool post to get the required spring pitch. The problem is that it takes at least 10 seconds for S TRUE to reach the required rpm that matches my spring feeder tool post feed rate. In that span of time, the wire coils around the arbor many times before the tool post even starts to move. I tried building a rod to snag the wire so that when the correct S TRUE was reached I would insert the wire and hit CYCLE START. But, the wire is just being deflected at that speed. The only alternative is to groove the thread on the arbor and then hand wind the coil to fit the grooves. Any ideas?


Offline Tweakie.CNC

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Re: Winding springs using Mach control
« Reply #1 on: June 30, 2016, 12:16:22 PM »
Just a thought…

Hard to explain but initially the part which snags the end of the piano wire is free to rotate on the arbour. When the spindle is up to speed, a clutch is tripped which locks the part which snags the wire and the arbour together. Spring winding then progresses in line with the feeder toolpost movement until the spring has been wound. Not sure how you cater for the spring-back but that's another problem.

In the days way back when, IBM patented a flat spring clutch which provided the high-torque drive for their Selectric typewriters (The motor shaft rotated continuously but the main shaft only rotated in 180 deg. increments controlled by this spring clutch). The actual IBM clutch would not be man enough to handle the torque required for 2mm piano wire but the principle of design would be sound.

Just as a distraction, I had lots of fun last year constructing a guitar string winder… http://www.machsupport.com/forum/index.php/topic,28721.0.html

Re: Winding springs using Mach control
« Reply #2 on: June 30, 2016, 09:17:13 PM »
I'd use 2 axis control with the spindle as one axis. I'd leave the tool post as X and make the Spindle Y. So a simple drawing of X vs Y gives you a profile for Mach to follow. I'd set up Y as Steps per degree. So a line of Y = 3600 and X = 50 would wind a spring with 10 turns that is 50mm long, center of first coil to center of last. Programming a curved line would produce a spring with variable pitch. Program a very short X move at both ends and you'd have a spring with closed coils at both ends.  Does this make sense?
Re: Winding springs using Mach control
« Reply #3 on: July 01, 2016, 09:30:48 AM »
Thanks Tweakie and Gary: The idea of the clutch is interesting. Maybe something that pulls a slip ring with the wire attached to it that is pulled by the tool post when it starts its feed? I have to work on it. Gary: I think I understand what you are getting at - so the spindle moves in steps per degree which gets around the acceleration issue and the tool post then just moves lengthwise with no specific feed rate? So, spring pitch is effectively 360 x pitch and X= spring length? I will try this tonight.

Re: Winding springs using Mach control
« Reply #4 on: July 01, 2016, 12:07:38 PM »
Yes, feed rate just determines how fast the spring gets wound. you can use manual override on feed rate to adjust how fast it works as it is working.