Re: [CAD_CAM_EDM_DRO] Re: Magnetic encoders

dandumit wrote:

>> this stuff is NOT
>> cheap. The read heads all run around $300 - 400 each, and the tapes are
>> a couple
>> hundred $ per meter.
>>
>> Jon
>>
>>
> Does anybody knows if this kind of tape can be homemade ? from what is made of ? a casette tape can be used ? I have seen some new products from same company which has some new devices for linear encoders.
>

An audio tape is not a very sturdy material, and the stuff in cassettes
is so thin that somebody moving around in the shop will blow it around.
Also, it is prone to stretching, humidity changes, temperature changes,
etc. as well as deterioration in the presence of oil and coolant, not to
mention HOT metal chips!
The Sony magnescale and similar tapes are some kind of mild steel (so it
can be magnetized) with an adhesive backing. You just stick it down to
the edge of the machine table. Even if the audio tape were OK, how
would you put accurate megnetic stripes on it? Feed a sine wave into a
tape recorder? You might as well use a steel ruler for all the
long-term accuracy you'd get with that technique.

Jon