touch probe connectivity with ceramic bearings

[voyager1972]

having mounted a spindle which has cermaic bearings the touch probe no longer has connectivity , is there a workaround for this ?

[JohnHaine]

What form does the probe take?

[voyager1972]

form ?

at the minute i just have a simple probe one wire to the probe input ,another wire grounded on the frame .

[JohnHaine]

So I think you mean the probe is a rod of a known diameter which used to be connected to ground through the bearings but is now isolated because the balls are ceramic. So you need to clip a ground connection to it with a "croc clip" or the like.

[voyager1972]

I had thought about the Croc clip , is this the only solution to the problem , how do the big machine manufacture get around this

[pippin88]

The big manufacturers don't use touch probes that involve a circuit through the spindle / machine frame.

They use infra-red or wireless communication often. Probe is battery powered.

[JohnHaine]

Most of the cheaper "professional" touch probes are based on the original Renishaw design (the basis of their present success), which essentially has a normally-closed switch that opens when the probe stylus touches anything causing a microscopic movement. The opening of the circuit can be sensed in several ways, some of which involve a ground connection. You can buy quite low-cost probes (https://www.ebay.co.uk/itm/186254968893?itmmeta=01HTM6N2GBM71TVY31W012ZN37&hash=item2b5da9483d:g:CaoAAOSwzIplpeod&itmprp=enc%3AAQAJAAAA4CEPwi2zy2eCr5cH343OQowPuowB1 DqeqGdqIu2yLHUXPyHA7rqwZJUYMY6Nz6ZpfJjz%2FbaZu%2B6 qDKdCyGN1X%2FXSKLVRVmo15NOqrVl42yDg%2BvBW4HPRp1L4w Tq93cwZD5W%2FDAZelwNY8lQVZqiZxE8wX6ZQoN28ghy1QGVXC 5O19u7paNfJAElKQLxc2oskE9PaktyAcQ9GuurgzzKMJ1LNyjZ qFkSCqU1d99ffaH%2FBww89GeYF531DMgE0rZms1m1hk0TR5ji 0HudOdb%2BV7RYp6gLGmh7nCzT1K8d3Mpsd%7Ctkp%3ABk9SR6 yo1IbVYw) now based on the same principle. Generally use a wired connection relying on power from the machine.

Renishaw have much more advanced systems now often using wireless or optical and the probes can be mixed with tools in an ATC carousel, and also probe whilst rotating. Correspondingly MUCH more expensive!

[marky68]

I think Voyager means a touch off plate for Z height only rather than a true probe.

[voyager1972]

this is the type of tool setter i want to add

[JohnHaine]

Could you post a link please?

[voyager1972]

https://www.ebay.co.uk/itm/144148210623?chn=ps&_ul=GB&_trkparms=ispr%3D1&amdata=enc%3A1oNeoRdFAREmXcc5QMHyPXg41&norover=1&mkrid=710-134428-41853-0&mkscid=101&itemid=144148210623&targetid=1647205089000&device=c&mktype=pla&googleloc=1007277&poi=&campaignid=19926849521&mkgroupid=147378848803&rlsatarget=pla-1647205089000&abcId=9311021&merchantid=430050401&gad_source=1

[JohnHaine]

The product description says:

"Normally closed specification technical parameters

Output mode: BNC (normally closed)"

Which implies that it doesn't depend on a grounded tool/spindle but has a contact which opens on tool touch. This would make sense as it would be compatible with most other probes/setters and machines. Why it says "BNC" I don't know as the connector is nothing like a BNC being a screw lock 4-pin type.

[voyager1972]

Thanks for the reply , that makes things a lot clearer to me now , they operate different from a touch plate.