High Precision Homing Switch

[m_c]

I used an opto slot sensor on my old lathe, and there was never any measurable variation. I used RS part number 480-5231 however I see that part has now been discontinued. The only problem was I had to make sure a bit swarf hadn't landed in the slot prior to homing, as I never bothered enclosing it.

The new lathe uses proximity combined with servo index homing.

You could combine a proximity or microswitch with a slot sensor on the stepper, provided you can add a suitable slot to the stepper/ballscrew, to essentially give you a poor mans index homing.

[audioandy]

Chaz

I have a Balluff mechanical switch which are very good, I don't mind sending it over for you to try.

Just pm me your address if you want to try it. I will post a link to the switch if I can find it on the RS site.

Regards

Andy

[Chaz]

Chaz

I have a Balluff mechanical switch which are very good, I don't mind sending it over for you to try.

Just pm me your address if you want to try it. I will post a link to the switch if I can find it on the RS site.

Regards

Andy

Thanks, will send you the address. What do they cost?

[audioandy]

I have a spare one Chaz if it works ok we can sort something out.

We use them at wok and they are built very well.

Andy

[audioandy]

Here is a link to the pdf Chaz

http://www.balluff-ua.com/pdf/mechan..._single_EN.pdf

[Chaz]

I used an opto slot sensor on my old lathe, and there was never any measurable variation. I used RS part number 480-5231 however I see that part has now been discontinued. The only problem was I had to make sure a bit swarf hadn't landed in the slot prior to homing, as I never bothered enclosing it.

The new lathe uses proximity combined with servo index homing.

You could combine a proximity or microswitch with a slot sensor on the stepper, provided you can add a suitable slot to the stepper/ballscrew, to essentially give you a poor mans index homing.

Thanks, something like this - https://uk.rs-online.com/web/p/photo...nsors/1254515/ ?

[Chaz]

I used an opto slot sensor on my old lathe, and there was never any measurable variation. I used RS part number 480-5231 however I see that part has now been discontinued. The only problem was I had to make sure a bit swarf hadn't landed in the slot prior to homing, as I never bothered enclosing it.

The new lathe uses proximity combined with servo index homing.

You could combine a proximity or microswitch with a slot sensor on the stepper, provided you can add a suitable slot to the stepper/ballscrew, to essentially give you a poor mans index homing.

Does this need a 'receiving part' or anything that it can pick up in the slot?

[m_c]

Does this need a 'receiving part' or anything that it can pick up in the slot?

You need something that goes through the slot. It doesn't have to be anything fancy, I just used a bit bent bar suitably mounted on the cross slide -

[Gary]

we use these on our machines and linear stages we build.
https://www.zappautomation.co.uk/bes...on-sensor.html
The repeatable accuracy is 1% of the distance of the metallic material used to sense.
other things also need to be taken into account as well to see the accuracy though.
Also very low profile, but not the cheapest.

[JohnHaine]

Chaz, I have made something based on the "touch plate" concept used for mill Z homing.

(I hope that works!)
Repeatability seems to be better than 10 microns, and in conjunction with my tool setter on my first trial of homing/applying set tool offset/turning I achieved indicated microm accuracy on diameter. This cost nothing to make, it's essentially a bit of PCB laminated on to 6mm of tufnol superglued to the apron front. Obviously there are issues of wear and tarnishing so I intend to upgrade it with one where the contact surface is beryllium copper.