0.5mm tip + TP20

Hello all,

When using a single 0.5x20 ruby tip I have noticed all my Tigo's with TP20 modules give around 5μm of std while calibration. It has always been like this, validated, verified etc. The results between Tigos with X1C and TP20 when using a 0.5mm tip is day and night. The X1C seems to be a whapping 4 times more repeatable and in my company TP20 is always considered to be the less precise option to make programs with. Is it supposed to be like this? (Keep in mind that due to making rather small parts, almost all programs have a 0.5 tip probing something with a TP callout or Datum).

Finally, 0.5 tips seem to work better with Low force modules but the issue applies to standard modules as well.

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0 bfire85 9 months ago

0.5x20 TP20 sees STDEV of 0.003-0.004mm on my 20 year old B&S ONE machine with no vibration isolation. My Global S Blue with same type of probe with the X1 with vibration isolation sees 0.0002-0.0003mm STDEV.

Build of the machine, vibration isolation, probing system, etc... all plays into this.
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0 ArkansasBeeper 9 months ago in reply to bfire85

Back before I moved into Gantry Land, we just used a TP-20 low force with around 1/2 the touch speed of the standard force for the .5mm probe. Never had any issues with accuracy or calibration on our 7.10.7SF with a HH-A-T5
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0 constadin 9 months ago in reply to ArkansasBeeper

Accuracy is not the issue. Repeatability is. Do you remember the values of std you were getting? For me Low force or std TP20 modules seem to not play any role. Still shitty results as opposed to 1 plus mm tips
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0 constadin 9 months ago in reply to ArkansasBeeper

Accuracy is not the issue. Repeatability is. Do you remember the values of std you were getting? For me Low force or std TP20 modules seem to not play any role. Still shitty results as opposed to 1 plus mm tips
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0 ArkansasBeeper 9 months ago in reply to constadin

Yah, that tiny lil shank on there isn't the best. I don't remember the numbers, only that it was deemed "acceptable"
It was always worse than more rigid probes though.
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0 Neil Challinor 9 months ago in reply to constadin

It's not just the force of the module that will affect accuracy but also the touch speed being used. Ø0.5 tips have a very thin stem that is quite flexible, probing at low touch speeds (~1 mm/second) with a low force module should help. Also, remember that you should always calibrate your probes at the same touch speed that you use in your routine when measuring.

Also remember there is an inherent tri-lobing error with touch trigger probes due to the trigger mechanism that you will not be able to eliminate, regardless of which force module or touch speed you use. Those errors are usually in the sub-micron range but are one of the reasons why you can achieve more accurate results with an analogue system (like the LSP-X1-S / HPS-X1S).
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0 constadin 9 months ago in reply to Neil Challinor

Touch speed 0.5mm/s I believe it to be ok. I also measure with the same parameters as calibrated. I ordered new fresh TP20 modules to repeat my tests but until then for me all 0.5 tips are getting around 5 micros of std in calibration results. This does translate indeed in repeatability in my measurements especially in TP callouts where any deviation is doubled.
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