Wire Winder - Wire guide, opinions / suggestions
Jonathan Allison
Posts: 96
Hello all!
Hope everyone is doing well and working on some really cool projects [noparse]:)[/noparse]
Some of you might remember my posts earlier about a "wire-winder" which I am designing. I was trying to hack up a TAB Sumo-bot for the job, but I've given up on that and acquired myself a BS2-IC.
Anyway, one of the sub-systems of my wire winder, is, obivously a wire guide. This device will be 100% responsible for making sure the wire gets on the spool. Not only should it be able to go on the spool in a uniform manner, but it also needs to go on the spool in random patterns.·Spools may vary in width, which is why I have choosen to use a robotic device for this invention. The wire I am dealing with is very fine, fractions of a mm, so a great deal of percision is required.
Attached is a rough diagram of one idea of how I might go about designing this wire-feed-guide.
Please see the picture before continuing, it might actually make sense [noparse]:)[/noparse]
Lets start with the stepper motor, it is attached to a mount. The mount is perpendicular with a parallel attachment at the bottom, which fits tightly (maybe even with a ball barring setup, not sure) over a slide. Attached to the shaft of the motor, is another, longer shaft, which at the opposite end from the motor, has the guide to feed the wire. The guide shaft, C, which is threaded goes through two threaded mounts, d. So, when the motor turns forward, the shaft (c) moves outwards, very slowly. These are very finley threaded mounts (d). This action causes the entire motor and mounts to move ahead as well. When the motor is operated in reverse, the opposite happens. With this type of setup, and it being controlled via the BS2, I should have all the features I need. I can store various spool sizes so that it knows the starting and ending position for each type of spool. It should be able to move in small enough segments that I can lay the wire quite uniformly, but also move freely enough to give me the randomness that I need.
There are other details as well which I don't need to cover at this point like the actuall feed on the end etc, I just want an opinion / suggests before I get too far into design.
Another option was to rip apart either a CD -burner or a printer and use the mechanics already imployed in those, but, I believe this setup would be advantagous due to more strengh and durability, plus, its specificly setup for this job. Also, I like the challenge of making this work.
Jonathan
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Johnny
Post Edited (Jonathan Allison) : 1/14/2005 8:05:01 PM GMT
Hope everyone is doing well and working on some really cool projects [noparse]:)[/noparse]
Some of you might remember my posts earlier about a "wire-winder" which I am designing. I was trying to hack up a TAB Sumo-bot for the job, but I've given up on that and acquired myself a BS2-IC.
Anyway, one of the sub-systems of my wire winder, is, obivously a wire guide. This device will be 100% responsible for making sure the wire gets on the spool. Not only should it be able to go on the spool in a uniform manner, but it also needs to go on the spool in random patterns.·Spools may vary in width, which is why I have choosen to use a robotic device for this invention. The wire I am dealing with is very fine, fractions of a mm, so a great deal of percision is required.
Attached is a rough diagram of one idea of how I might go about designing this wire-feed-guide.
Please see the picture before continuing, it might actually make sense [noparse]:)[/noparse]
Lets start with the stepper motor, it is attached to a mount. The mount is perpendicular with a parallel attachment at the bottom, which fits tightly (maybe even with a ball barring setup, not sure) over a slide. Attached to the shaft of the motor, is another, longer shaft, which at the opposite end from the motor, has the guide to feed the wire. The guide shaft, C, which is threaded goes through two threaded mounts, d. So, when the motor turns forward, the shaft (c) moves outwards, very slowly. These are very finley threaded mounts (d). This action causes the entire motor and mounts to move ahead as well. When the motor is operated in reverse, the opposite happens. With this type of setup, and it being controlled via the BS2, I should have all the features I need. I can store various spool sizes so that it knows the starting and ending position for each type of spool. It should be able to move in small enough segments that I can lay the wire quite uniformly, but also move freely enough to give me the randomness that I need.
There are other details as well which I don't need to cover at this point like the actuall feed on the end etc, I just want an opinion / suggests before I get too far into design.
Another option was to rip apart either a CD -burner or a printer and use the mechanics already imployed in those, but, I believe this setup would be advantagous due to more strengh and durability, plus, its specificly setup for this job. Also, I like the challenge of making this work.
Jonathan
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Johnny
Post Edited (Jonathan Allison) : 1/14/2005 8:05:01 PM GMT
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You need to put a few pounds of resistance while you fill the spool otherwise it'll rats nest and just have too much slack on the spool and you won't be able to get enough on there.
I'd suggest some sort of clamp/roller that will give a little bit of resistance to your line.· This would have to sit about 8-12inches out in front of the spool as your fairlead (wire guide) would need to have enough room to guide the line!· You could also put a small encoder on this roller and count each revolution which would transfer in to a distance/length measurement!· This is better than putting something on the spool and worrying about the wire accumulated at the begginning of a spool wrt the end of the spool (changing diameters).
Depending on the type of wire coating you are spooling, you'll need a strong guide.· If you spool that heavy rubberized cabtire stuff then you will HAVE to guide it because the rubber will want to pull up on itself and not spool nicely.· Where the poly coated stuff will pretty well spool on its own (so long as you have some line tension).
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
A few pounds of resistance would snap the wire I am dealing with. The spool size may change however, the wire size will not, at least not significantly. The wire I am dealing with, as I mentioned in the post above is fractions of a millimeter. Lets say .25 MM, pretty tiny. I do realize I will need some resistance though, which I plan to apply through a series of wheels which the wire will rotate upon. The details for measuring the wire need only be how many turns have been applied, which the motor which rotates the spool will be in charge of (well the bs2 really, but ya know what I mean).
By using a stepper motor and very finely threaded guide shaft I *should* have the percision I need. The stepper motor I am currenly looking at does 3.6 degree turns, so thats 100 turns per one rotation of the guide shaft. Now, I'm no mathamitician, and obviously can't even spell it lol Sooo..... my guess is that with the very fine threads and a 3.6 degree turn, the linear motion of the actuall guide should be very little. Hopefully not even noticable. If anyone has any kind of formulas for figuring out the thread angle / turns to linear movement, please, go ahead and humor me [noparse]:)[/noparse] But, I have doubts that will happen so I am guessing this will work, and hoping it takes maybe two, or three turns (3.6 * 2 or 3) to move the guide enough to get the wire to lay in the "next available position" on the spool, making the wire lay uniformly. If I can make at least that much work, I would have achieved half of my goal. The next half, is to lay the wire in a random manner, which will be easier then making it uniform (or at least, pretty close to uniform, it does not need to be perfect).
Some of my concerns are, will the stepper motor be capable in moving itself along the slider (motor mount guide) and is there going to be any free play when switching directions?·I guess that really depends on how "tight" the entire construction is. Either way, I'm starting to ramble.
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Johnny
It only has to be a small mechanical switch; put a fin on the side of the wheel that either clicks a switch or interrupts some opto's or a reed switch magnet combo....
But the wire coming in to those rollers will be as it lies...no angles·to worry about with a smaller diameter at start compared to a bigger wind diameter towards the end.
the 3.6degree step in the stepper....well, you CAN set it up for half steps (not as stable I hear) and I'm not certain if the 3.6 is already the half step.
But your 'step' distance depends on any gearing you might have.· You CAN make that 3.6deg step much smaller by using some reduction gearing.
But if you have a large gear on the end of the shaft...well, you need to step .25mm with each single revolution of the spool.· SO, if you are using a·10mm diameter (core) spool, then you'd have to step a bunch of times to total·.25mm after 1 revolution.· So, you'd have to step 40times for 1 revolution.· Then as you increase the core by a 2mm you should be stepping 50times.· --the idea being that you can't just spool a full turn and then step....you have to gradually step to get the wire in a uniform spirally wind.
So, all that stepping changes with any extra gearing you put on there.· If you put a gear on that's twice the diameter of the one you currently have on...the you have more precision but have to step more times.· Visa versa, if you put on a gear half the size you step half as much but lose resolution.
I think I'm rambling too...been doing it all day! haha· Anyhow, please yell at me if I got my math backwards....it happens often enough!
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
Thanks for your feed back, I definitly appreciate and respect it.
I need clarification however, I do not understand why, as the wire builds up on the spool I would need to adjust the positioning sequences of the guide. I understand that more wire is required for one "wrap" of the spool as the spool starts to fill up. But one turn is one turn. The spool rotating motor is to be a stepper motor as well, so I will know when one revolution has been made. The way I see it, thats all the guide needs to know in order to shift outward, or inward depending on the current direction. No matter how much wire is on the spool (and I do not care how much is, I am interested in the number of revolutions only) one turn will always be enough to cover the area in which the wire needs to cover, if that makes sense lol
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Johnny
The only problem I can foresee is to calculate the EXACT number of steps to move the guide for each rotation of the spool. Preferably, it should be a continuous motion, so you want to gear it down as much as possible to get enough steps on the motor.
The re-positioning of the guide only REALLY matters if the wire itself won't track properly (self-guide) on it's own.
This was what I was saying about those rubberized cables....they don't like to follow themselves since the friction of the rubber will cause the cable to climb all over itself.· But if you wire is small enough you might have a similar problem too....really don't know.
Maybe if you have the right amount of tension on it, it'll track on it's own....BUT, I think most problems occur at both ends of the reel:·wire has followed it's spiraling route to the wall and doesn't want to track back, initially, so ends up spooling up the side of the spool rather than back in the other direction.· So, maybe you'll need to 'help' it.·
And if you're not worried about how much wire you put on a spool, then I guess you don't need to worry about any counters.
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
kelvin
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Johnny