Linear Encoder For Rotating Wire
Linear Encoder For Rotating Wire
(OP)
For a current project I am looking for a way to track thin wire linearly as it is unwound from a spool, ground in a grinding machine and then rewound onto another spool on the opposite side of the grinder. The kicker is that due to the nature of the grinder, both the spools are rotating in a single direction and therefore so is the wire. The wire is rotating about its own axis and does not vary due to a number of bushings it is strung through.
(spool)--wire--[grinder]--wire--(spool)
So put simply I am looking for a sensor or system of sensors which could act as a linear encoder for a wire which is rotating about its own axis.
Any help would be appreciated.
Thanks all
(spool)--wire--[grinder]--wire--(spool)
So put simply I am looking for a sensor or system of sensors which could act as a linear encoder for a wire which is rotating about its own axis.
Any help would be appreciated.
Thanks all





RE: Linear Encoder For Rotating Wire
could you magnetize segments of the the wire as it passes, then measure the movement of the magnetized portions?
RE: Linear Encoder For Rotating Wire
RE: Linear Encoder For Rotating Wire
In which case, the only plausible off-the-shelf answer would be a machine vision camera. With backlighting, you could tweak the contrast to essentially give you a black wire on white background, and with software processing, you can verify that the wire is staying on its path.
TTFN
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RE: Linear Encoder For Rotating Wire
I would probably take a stab at rigging two hardened tool steel wheels face to face with wire through, like O|O . One wheel might have a central groove ground into it to help track the wire as it flows through. Build the assembly with springs to keep constant clamp force on the wire as it passes through the wheels. Then mount an encoder on one of the wheels.
TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com
RE: Linear Encoder For Rotating Wire
-use slack tensioner
-no slippage
-use angle encoder and spool diameter
RE: Linear Encoder For Rotating Wire
Slippage using a wheel would produce too much variance for wire grinding which needs to be fairly exact. The magnetized idea is interesting though. I will have to look into it.
dhengr:
This is actually very similar to our current setup. Problems arise due to greasy wire slipping on the wheels. Various wheel materials are being tested.
IRstuff:
I mean the length of wire coming off of the first spool. This figure controls how the grinding machine creates profiles on the wire.
tygerdawg:
The length of wire coming off of the initial spool is the information I need. This translates to the grinding machine and tells it how it should be grinding at any particular time. If the encoder says we have dispersed 3 feet of wire, the spool is X from the grinding center => the grinding machine needs to be grinding the wire profile in accordance with 3 feet + X. Wire material varies but is typically a SS variant but currently is nitinol. Surface condition is stock wire with no secondary finishes or polishing. The wire is quite smooth and small amounts of great from the supplier add to the chance of wire slippage.
jedward:
If I am understanding you correctly it would seem that there would be a problem using the spool diameter in any calculation as the diameter of the spool is constantly changing in no predictable way. Wire spools have wire that is not perfectly laid layer to layer, side to side.
RE: Linear Encoder For Rotating Wire
TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com
RE: Linear Encoder For Rotating Wire
This is how optical mouse works.
Agilent may have something
RE: Linear Encoder For Rotating Wire