Need help building a stylus with movable components

[[Da...]]

Lots of questions here...thank you in advance!

When building a stylus with movable parts, what is the trick to getting the movable parts at the correct angles? And how critical is it?

I am building the stylus pictured. It can be rotated 360° (blue arrow) and the knuckle can bend back and forth as well (green arrow). 

Let's say that when the RDS is at 0°/0° I want the stylus to face forwards towards me and be lifted up 45° towards me.

How do I ensure that it is exactly centered / forward and exactly 45° up? What if it is not exact? How far away from that can I be before it creates an issue?

What angle does the reference sphere have to be at in order to qualify it without a collision? So far our reference sphere has always just been straight up. 

If I have to change the angle of the reference sphere, how do I ensure it is at the correct angle?

When I go to qualify it, if it does the thing where it guesses what angle the probe is at, but it's not what I intended, do I change the values to match what I intended, or do I adjust the stylus and try again until it matches?

I believe once it is set up, I could set it up as different probes with different A angles, correct? But the B angle would always be 0° and the probe would always be 45°. Is that correct?

What if in the future I wanted to use this same set up but have the knuckle point the probe at 30° rather than 45°. I imagine I would need to create a whole new stylus system, correct? But wouldn't that require a separate adapter plate so that the CMM would recognize whether it was the 30° setup or the 45° setup? Would it make more sense to leave this one the same and buy an identical setup and make a whole new configuration?

 

[[Ch...]]

Here's what you do to find the exact angle.   Start touching the shaft of the probe against the reference sphere.  Make sure to get points high and low on the shaft and go all the way around the reference sphere.  Your goal is to create a cylinder feature inside of Calypso.  Your A1 A2 angles on the feature are the angle the probe is angled.  You then enter these values into the appropriate spots in Calypso when you qualify it.    

[[Cl...]]

A machinist protractor or an optical comparator also work well.

[[Ri...]]

Get one of these, they are inexpensive and can aid in setting any simple or compound angle you need.

[[Ze...]]

Optical comparators work great for this. Zeiss also makes something called FixAssist that aligns things for you. 

[[Jü...]]

For these stylus, we designed an alignment device and manufactured it using a 3D printer.

[[Ke...]]

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This is a great idea for common angles, when you don't have a dedicated stylus system!

Do you have individual fixtures for single angles, or did you create a fixture for multiple angles?

...is the 3D printer file anything that you can share?

[[Jü...]]

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We designed the fixtures specifically for each stylus. Here, for example, only for rotation to the plate:

[[Ch...]]

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👍🏻Looks nice, maybe that can be modified, with a scale for some angles.👍🏻

 

There used to be a 2D template for adjusting it. 😎 unfortunately, it's for VAST M5. 

Edited 12 hours ago

[[Ke...]]

When building a stylus with movable parts, what is the trick to getting the movable parts at the correct angles? And how critical is it?-Unfortunately, the biggest trick is practice, especially with XXt styli, but the methods described by other users here can help make it easier. How critical the angle is is dependent on the measurement: how far into the part you need to go (the further in the more precise you need to be), the size of the feature (especially hole diameter), and the ratio of the probe tip to the probe shaft diameter. All of these contribute to the potential for shanking the probe.  

I am building the stylus pictured. It can be rotated 360° (blue arrow) and the knuckle can bend back and forth as well (green arrow). Let's say that when the RDS is at 0°/0° I want the stylus to face forwards towards me and be lifted up 45° towards me. How do I ensure that it is exactly centered / forward and exactly 45° up? What if it is not exact? How far away from that can I be before it creates an issue? The way to ensure it is exactly centered is to set the probe through whatever method you choose above, then check the angles on a CMM (ideally the exact one it will be used on, to account for any slight variances in the systems) using the method Chad describes above. I personally will do a quicker version of this check as a go, where I will take 2 points on a sharp cornered object (such as as machinist block) as a quick check, then adjust until I am happy with the result, at which point I will do the full cylinder check. How far away from nominal you can be depends on the factors above, I personally shoot for under +/-0.1degree on most probes, but your actual acceptable values will vary. 

What angle does the reference sphere have to be at in order to qualify it without a collision? So far our reference sphere has always just been straight up. The reference sphere can be set at various angles, so long as the stylus being calibrated can access the sphere about the equator without any component hitting (The angular coverage of the sphere can be adjusted for VAST systems if necessary, dependent on if the calibration is Geometry, Tensor, or Dynamic Tensor). An easy way to ensure this is to effectively point the sphere and stylus at each other. If they make a straight line through their axes, then it should be able to access, but this is not the only viable angle set. 

If I have to change the angle of the reference sphere, how do I ensure it is at the correct angle? If you choose to, you  can measure the exact angle of the cal sphere by measuring a cylinder along the shaft of the cal sphere, but often times you can get close enough for successful calibration with a little care and manual setting(you can probably eyeball it close enough to a 45deg rotation to work, and the tilt is typically controlled by the cal sphere stand, so that should be close as well)

When I go to qualify it, if it does the thing where it guesses what angle the probe is at, but it's not what I intended, do I change the values to match what I intended, or do I adjust the stylus and try again until it matches? This depends. The guessing what angle thing can happen because the probe is too far off, but more often it occurs because you did not probe close enough to the centerline of the sphere while travelling in the direction of the axis of the probe. So ideally, you should confirm your stylus is correct via the method described by Chad above, then you would know that the error is in your manual probing and should be able to be dealt with by  inputting what the values should be. Do be careful as sometimes what Calypso guesses you intended those angles to be may have a different sign than you expect, which can cause confusion. You'll usually know if you had a sign issue as soon as it starts calibrating though, it won't probe even close to along the probe shaft axis. Proper calibration start should visually be probing along the axis of the probe, and the initial point(s) should point to the center of the sphere (mostly, the CNC cal doesnt do this exactly for technical reasons, but it is still close)

What if in the future I wanted to use this same set up but have the knuckle point the probe at 30° rather than 45°. I imagine I would need to create a whole new stylus system, correct? But wouldn't that require a separate adapter plate so that the CMM would recognize whether it was the 30° setup or the 45° setup? Would it make more sense to leave this one the same and buy an identical setup and make a whole new configuration?  This also depends. You would normally want to create a new stylus system in Calypso for the 30deg angle, not just update your existing 45deg one, but there are cases where updating is the right option(the probe created just for Hole27 was at 45deg, they changde the part and now hole27 is cut at 30deg instead of 45 for example) . If you never intended to use the 45deg setup again, you could simply delete it out of  Calypso, and then make a 30 deg probe configuration with the existing adapter plate and teach that into Calypso. If you want to have both a 30deg and a 45deg setup, yes you should have 2 different adapter plates, as fully separate physical configurations as well as separate entries in Calypso. Regarding buying new tooling and making a whole new configuration, I would say this is the best option for common or frequently used configurations, but it may make sense to tear down and use components to build new probes for short term use or one off tools. Personally I am not a fan of reusing those knuckle joints, too many cycles of adjusting them can wear them out to where the no longer hold angle very well. 

There are a number of videos, articles, and guides which may be useful to you on these topics and others. All of these can be found here on the Zeiss Portal, but you can also find much of the video content on the ZeissIQS youtube channel, which may be easier to search videos https://www.youtube.com/@ZEISSIQS/videos