How Do I Set Lathe up to Know Where Parts Are?

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ctwo
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by ctwo »

we are open loop here. I was going to use a mechanical switch, the same ones that are on the Bridgeport. I might need some opticals too...
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To measure is to know - Lord Kelvin
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SteveHGraham
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by SteveHGraham »

Would anyone care to give me a clue about mounting optical sensors? I can figure out the electronic part, since it appears to consist mostly of screwing wires into terminals.
Every hard-fried egg began life sunny-side up.
hanermo
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by hanermo »

Either mechnical or optical can work, with opticals being easier/cheaper to get into accurate ranges.

I used an optical on my lathe z, with 2-3 micron repeatability off the bat.
1 micron was doable, with sw filtering (using the centipede motion control engine).

A few microns are reportedly possible with mechanicals.

I used a slit type switch, with interrupter.
I then have a separate hat on top, so any chips/swarf etc. accumulate on the hat.
The interrupter has its own hat.
Theres no contact or loads, so glue, tiny screws etc. and thin-wall alu are all fine.
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SteveHGraham
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by SteveHGraham »

Thanks. My problem right now is that there are millions of switches available, and I don't know which ones are best for my lathe. I am looking around to find out.
Every hard-fried egg began life sunny-side up.
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DICKEYBIRD
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by DICKEYBIRD »

hanermo wrote:...using the centipede motion control engine.
I just checked out the website on the Centipede. Nice looking piece of kit! How long have you had it and did you need a computer engineering degree to get it functioning? I assume it reads an encoder on the spindle so it cuts threads nicely?

What do you have on the X axis for homing?

Sorry, 1 more question: do you have a build thread on the lathe somewhere? I'd love to see more details.:)
Milton in Tennessee

"Accuracy is the sum total of your compensating mistakes."
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SteveHGraham
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by SteveHGraham »

I got another question. What is the limit on cable length for an optical switch? I don't want to have to put my controller right next to the lathe.
Every hard-fried egg began life sunny-side up.
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ctwo
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Re: How Do I Set Lathe up to Know Where Parts Are?

Post by ctwo »

30 feet or you may pick up noise. I think some suggest shielded wiring anyway. These are usually "normally closed" meaning there should be logic voltage levels.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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