Renishaw's PH20 probing system is not anything new to most CMM users anymore. A lot of companies have decided to purchase a cmm (new or retrofitted) with PH20 probe head after seeing the benefit. You can find many articles, videos over the internet related to PH20. In this article I'd like to make a list of benefits of using PH20 so you can quickly review it to make sure you're taking advantage of PH20's unique capability or, maybe you can use it to show your management to get a PH20 as your new toy, J:).
Speed. In a recent sale of a Wenzel XO plus, the customer threw me a question (and he thought maybe difficult for me to answer): what will be the cycle time of using PH20 to measure their current parts compared with using their existing PH10? I said that's quite simple: if we measure exactly same amount of features then PH20 will be about 2-3 times faster and here's the proof:
Almost everyone knows about this famous video. Reason I was on safe side of 2 times is if the part is not that complicated (much less features) then you probably won't get the 3 times.
Accuracy. The head touch of PH20 is more accurate than conventional 3 axis touch is because during the head touch, the machine doesn't move in xyz axis, only the head measures so the error from machine movement is minimised. You might ask how this can be proved. Interesting enough, recently I did a very simple test on one of our Wenzel XO plus cmm in our lab. Before it got calibrated, I measured a setting ring using head touch only vs. 3 axis (like PH10) and reading from head touch is within .0001" but it was over .0003" from 3 axis touch because there's no linear axis error from the head touch.
Flexibility. This is what I've always told my customers: once you have PH20, you'll never worry about "shanking" your probes and you don't really need probes with large rubies like 5mm, or even 3mm ones. When creating feature measurement strategies with PH20, the probe tip can always be placed at a small angle from nearby wall to ensure clearance. And because PH20 can use any probe angle (except that A max. is 115 deg.) so very rarely you'll have to use probe tip larger than 2 mm. One of my customers who deals with complicated machining parts uses 1 mm probe for 95% of their part inspection then another 0.5 mm probe for very small holes.
Very short calibration time. One customer has been using TP200 with a fully loaded rack (6 modules), the calibration time is about 3 hours for all probes. We sold them a Wenzel XO last year and another one in June this year and very possibly a 3rd PH20 by end of year. They're so happy that they've cut down calibration time from 3 hours to less than 30 min. And for most users, you'll probably only need 3 modules on your TCR20 rack. A brand new tool on PH20 requires about 12 min. calibration time but then only need about 8 min. after that for re-calibration.
Reduced programming time. I've been programming various cmm software for more than 20 years, no matter how good or how "bad" a cmm software is, as a programmer you always have to deal with probe angles, especially when programming very complicated parts. In many cases, you need to spend a good amount of time to decide the part set up with limited probe angles. Now with PH20, that amount of time is greatly reduced. And with some very smart software like Modus 2, you don't even need to worry about which probe angle to use in most cases, pretty much just click and go. And also due to the unique PCS of PH20, even your part set up is turned 90 deg. around you don't need to modify your PH20 program, it will run as is!
Low maintenance. Less probe modules needed, less probes needed. PH20 lasts longer than PH10, especially when your PH10 rotates a lot. One customer who needs every 7.5 deg. on B angle due to their unique products got their PH10 worn out very quickly, but now no more worry after purchasing a PH20 machine.
There might be more on this list but I'm sure these are the major ones. After I listing all these huge benefits I feel it's only fair also to mention some limitations on using PH20 (after all there's no such probing system that has no limitation at all), but I won't get into too much detail. Main disadvantages of PH20 are:
Can't carry very long probe extensions: EM2 (75mm) is the max.
Can't use analog scanning probes like SP25M, nor optical scanners
5 axis measurement can't be used in some small tight area, so 3 axis must be used instead
Doesn't work with PC-DMIS or Calypso (for me, it's the other way around: disadvantage of using PC-Dmis or Calypso)
CMM Application Specialist
GDTP S-0605 (ASME Y14.5)
RX Metrology Solutions Inc.
A "1Source Metrology" partner