Comparison of cheap touch probes

[cnckeith]

stops you from crashing the probe.
yes you can use it without it. just like driving without a seatbelt.

[martyscncgarage]

The KP-3

I notice that the KP-3 uses 3 conductors, and the tormach one only uses 2.
What does the probe detect feature do? Will it work without it?
Thanks for the help

Tells the control you have a probed connected to it. So you don't inadvertently turn on the spindle with it in place.....Safety feature.
It also tells the control you are using a PROBE or a TOOL SETTER, Required if you want to use one input for probe tripped

[swissi]

The KP-3

I notice that the KP-3 uses 3 conductors, and the tormach one only uses 2.
What does the probe detect feature do? Will it work without it?
Thanks for the help

Most mechanical Touch Probes are of type Normally Closed (NC) unless there's a signal conversion somewhere in the design. A NC type Touch Probe does require a Probe Detect signal, otherwise the control will not be able to differentiate a disconnected probe from a probe trip signal as they will look the same. You can only get around this if you connect the Touch Probe permanently and never disconnect it. In such a case, the Touch Probe will function without a Detect Signal but without the protection features that the Detect signal provides (e.g Spindle Prohibitor).

Regarding Probing accuracy, repeatability doesn't tell you anything about the overall probing accuracy you can expect on your system. A good repeatability just tells you that the probe is able to repeat the same probing error very accurately.

To get a good overview of what actual probing accuracy you can expect on your system, you have to run a Probe Trip Map. Check out my post about probing accuracy here: ProbeApp V3: Test and Improve Touch Probe Accuracy

-swissi

[rk9268vc]

well tormach has a 30 day return policy, im going to try it out and if it doesnt work, ill get centroid's.

I have seen some reviews that say the pins in the tormach one get corroded and need to be cleaned over time, but it is a simple enough mechanism to fix. Some people just replace the pins with a different material.
I dont know how the centroid probe works, so cant comment on that.

If the tormach one works then i'll use the cost savings to buy the MPG pendant
thanks!

[rk9268vc]

The KP-3

I notice that the KP-3 uses 3 conductors, and the tormach one only uses 2.
What does the probe detect feature do? Will it work without it?
Thanks for the help

Tells the control you have a probed connected to it. So you don't inadvertently turn on the spindle with it in place.....Safety feature.
It also tells the control you are using a PROBE or a TOOL SETTER, Required if you want to use one input for probe tripped

gotcha
So since the tormach one doesnt have the third wire, i should wire a safety switch in its place. I'm thinking along the lines of a toggle switch I can manually set when probing. Thoughts?

This is basically the same thing tormach does
quote:
"IMPORTANT! When using the probe, disable the spindle by turning the
spindle lockout key on the operator panel to the Off position. On mills with
an enclosure, open the spindle door to release the spindle door switch and
stop motor function. Failure to do so may damage the probe."

[rk9268vc]

The KP-3

I notice that the KP-3 uses 3 conductors, and the tormach one only uses 2.
What does the probe detect feature do? Will it work without it?
Thanks for the help

Most mechanical Touch Probes are of type Normally Closed (NC) unless there's a signal conversion somewhere in the design. A NC type Touch Probe does require a Probe Detect signal, otherwise the control will not be able to differentiate a disconnected probe from a probe trip signal as they will look the same.
:::

To get a good overview of what actual probing accuracy you can expect on your system, you have to run a Probe Trip Map. Check out my post about probing accuracy here: ProbeApp V3: Test and Improve Touch Probe Accuracy

-swissi

The tormach one is normally closed
quote:
"The Tormach passive probe is configured as a normally
closed (NC) switch between pin 4 and pin 5 on the DIN
connector (see Figure 8)"
They intend for you to plug it in when you use it and then turn the spindle lock out key. I will just have to wire up something similar.

Thanks for the link, ill have to check it out!

[martyscncgarage]

Make a connector. Probe side has the jumper that shorts the probe or tool touch off detect.

[cnckeith]

well tormach has a 30 day return policy, im going to try it out and if it doesnt work, ill get centroid's.

I have seen some reviews that say the pins in the tormach one get corroded and need to be cleaned over time, but it is a simple enough mechanism to fix. Some people just replace the pins with a different material.
I dont know how the centroid probe works, so cant comment on that.

If the tormach one works then i'll use the cost savings to buy the MPG pendant
thanks!

exactly, kp-3 is oil filled and sealed, pins never corrode, no maintenance.

[rk9268vc]

Make a connector. Probe side has the jumper that shorts the probe or tool touch off detect.

Thanks! that's a great idea. Ill just take apart the cable plug and solder on a jumper.

Also, I noticed in your wonderful Touch Probe Configuration video [
that you used a ring gage to set the probe pre-travel.
Would it be possible to use something round, like a brass pipe fitting or extrusion instead of a ring gage? Since you repeat the test until it is repeatable?

thanks for the help!

[martyscncgarage]

Make a connector. Probe side has the jumper that shorts the probe or tool touch off detect.

Thanks! that's a great idea. Ill just take apart the cable plug and solder on a jumper.

Also, I noticed in your wonderful Touch Probe Configuration video [
that you used a ring gage to set the probe pre-travel.
Would it be possible to use something round, like a brass pipe fitting or extrusion instead of a ring gage? Since you repeat the test until it is repeatable?

thanks for the help!

You should really get the ring gage. (Fairly inexpensive on ebay) Or something of a calibrated diameter.
You could bore something and use telescoping gages and a micrometer if you have the feel. It might be close enough.
But the time and effort you'd have invested, you could have probably bought the used ring gage.

Marty