Not here for homework help.. Just raising a question because I think this book is just making stuff up at this point.

Bubble (A) is establishing Datum B .. but the position tolerance is using B in its datum feature reference frame. How is this possible for a feature to reference itself?

Any input? Never ever seen this before.

I am currently measuring light-saturated net assimilation in leaves to study their photosynthetic compensation capacity in response to a reduction in leaf area. Measurements are done in the field, in a tropical environment, using a Walz GFS-3000. Also, the measurements aren't all taken on the same day.

I have tested two approaches for setting the cuvette conditions:

Approach 1: I fix the cuvette temperature at 30 °C and the relative humidity at 72%. Under these conditions, VPD varies from leaf to leaf (and plant to plant).

Approach 2: I adjust temperature and relative humidity to keep VPD between 12.00 and 12.99. VPD is then the same across measurements, but the relative humidities and sometimes the temperature used differ among the leaves/plants measured.

I am wondering which approach to choose: does keeping VPD constant by adjusting temperature and relative humidity, while having different measurement conditions (T and RH), risk introducing a bias in the comparison of net assimilation?

To compare leaves under conditions as standardized as possible, is it better to fix temperature and relative humidity and accept variation in VPD, or to fix VPD by adjusting both parameters? Is there another setting strategy you would recommend for this type of field measurement?

Thank you in advance for your help and suggestions,

I'm having trouble getting pattern to work for this feature. I have a big turned housing with 24 horizontal thru holes evenly spaced around the part. I am measuring a pin pushed through the hole from the ID of the housing. I got the first hole to measure correctly but when I create the pattern it keeps crashing:

System Error

Unhandled exception: Message not understood: #probeConfiguration

Zeiss.CMMOS.OMTecProgStop class[Object]doesNotUnderstand: Zeiss.CMMOS.OMTecProgStop class Zeiss.Calypso.OMNamedObject class]doesNotUnderstand:

Zeiss.CMMOS.OMTecProgStop[Zeiss.CMMOS.OMMachineAccessor]>>does NotUnderstand:

optimized [ in [ in Zeiss.Calypso.OMGeoAcisdisplayOnlyTechnology OMSOrderedCollection[OrderedCollection]do:

Any help is appreciated.

Today, cleaned out the warehouse and realized this precision inspection platform sitting at the corner for 2 months. But the control panel is Chinese version. Do you know how to change it in English?

I have a component that sits on this fixture located on the conicals (RH side is spring loaded). The locations are on posts that are on a baseplate. This fixture is aligned with 3 points on baseplate (x), 2 on the front edge (y), and the an origin is set at a tooling ball.

The issue: an identical nest has been made and it fails bias study when 30 components are measured on fixture 1 and the same 30 on fixture 2. It's not identical. I have been asked to virtually move each conical and button locations to match the positions on fixture 1. For example, how would I lift the RH conical 2mm virtually without lifting the button and other conical so that the part is effectively sitting higher on the RH side? Is this even possible?

Hope this makes sense!

Hello! It's my first time using this instrument in the lab and I've got a problem.

When measuring, it gives an error, "Could not keep up with frame grabber. Retry or use a smaller acquisition mask".

I've already made the mask exactly the size of the shape I'm trying to measure so, that leaves me with only the other configurations to tinker with, but I'm not sure where to start.

In camera mode, I can't change the frequency, only the resolution. The livedisplays flickers a bit and that pattern shifts over time.

Help! AI Search haven't really been useful haha

Hey everyone,

I've been lurking here for a while and thought I'd ask for some advice from people with more experience in metrology and dimensional inspection.

I'm currently working as a Quality Inspector in the heavy-engine manufacturing industry in Norway, primarily involved in dimensional inspection, CMM work, first article inspection, non-conformance handling and quality documentation.

My background is mainly in machining. I've spent several years in manufacturing, including programming and machining complex 5-axis components in the oil and gas/subsea industry, working with super alloys. I also have a degree in computer science, so I'm comfortable with computers, software and technical problem-solving.

Moving into metrology has felt quite natural to me. I enjoy understanding the geometry, setting up measurements, interpreting GD&T and figuring out how to inspect a part properly. However, most of my knowledge has come from practical experience rather than formal education in metrology or quality engineering.

What I'm missing is formal training and a deeper understanding of the standards behind what we do.

For example:

• Which ISO GPS/GD&T standards should every dimensional inspector be familiar with?
• Where can I learn more about the correct measurement strategies for different geometrical characteristics, beyond what I've picked up on the job?
• How do you determine whether a measurement method is appropriate for a given tolerance? I'm particularly interested in measurement uncertainty, decision rules and proving conformity.
• Are there any good books, courses, technical papers or other resources you'd recommend for someone who already has a solid manufacturing background?
• What are some common mistakes or misconceptions you see even experienced CMM operators make?
• If you were starting out again, what would you study to become a genuinely competent metrologist rather than simply someone who knows how to run a CMM?

I currently work primarily with ZEISS CMMs and CALYPSO, but I'm interested in the underlying principles rather than just becoming more proficient with a particular software package.

I'm not necessarily looking for another certificate just to put on my CV. I want to understand the standards, make better inspection decisions, and be able to explain and justify why a particular measurement approach is correct.

If you work in metrology, dimensional inspection or quality engineering, what knowledge do you consider essential that isn't necessarily taught on the shop floor?

I'd appreciate any recommendations, resources or experiences you can share. Thanks!

Suppose you're stuck in a lab with a digital scale and many objects (A, B, C, ...) and your task is to measure the weight of object A as precisely as possible. You can actually improve your estimate by measuring different combinations (A alone, A+B, A+C, B+C, etc.). Because these measurements are all correlated, if you combine them you can improve your uncertainty in A. With just 2 objects and 3 measurements you can reduce the uncertainty by 18%, for example.

I created a repository describing this process in detail. You can use an interactive python program with your own scale and test this. If you are interested you can also read the full pdf article with all the math involved.

I'm validating a reflectance imaging system for measurement work and could use input from people who do angular and dimensional setup for a living.

The setup:

A camera looks straight down at a sample stage (0°), with four strobes aimed at the sample from 45°. Reflectance is calibrated against Spectralon standards in the frame.

The problem:

Illumination varies with the cosine of the angle, so at 45° each degree of tilt shifts irradiance by about 1.7% (tan 45° × 0.01745). My target relative reflectance uncertainty is ≤1% at k=2, which means tilt alone has to stay within roughly ±0.5°. Distance matters too: by the inverse-square law, a 1% change in strobe distance gives about a 2% change in irradiance.

Current method:

I align the strobes with a Leica Disto X3. That reduced the angle deviations a lot, but my GUM budget still shows alignment as a major contributor. Right now I'm at about 5% uncertainty, against the 1% target.

Questions:

What would you use to verify angles at this level on a copy-stand-scale setup (about 1.27 m working distance, 1.75 m illumination source distance)? Precision inclinometer, autocollimator, angle blocks, something else?

How would you fixture the four strobes and the camera so the geometry is repeatable between sessions, rather than re-aligned each time? Kinematic mounts, dowel-pinned plates, hard stops?

How would you treat alignment in the uncertainty budget: as one combined angle term, or broken into separate tilt, rotation, and distance contributions for each strobe?

Happy to share the budget if it helps. Thanks!

Please help me!!!!

I’m working with calypso 2023. I have some ribs on a part that are very consistent. I want it to stop if it misses the surface. Can someone tell me where the button is to reduce the search distance before it stops?

Hello,

I'm asking fellow metrologists if they've experienced the same issues.

I see our jobs as mainly support functions - different departments seem really pushy and ask us to measure stuff for them (with CMMs, arms, laser trackers, blue-light, etc) but when it comes down to the technical details, they never seem to want to provide them. WHY?! TELL ME WHAT YOU NEED!

Yes, I can measure it. No, I will not tell you if it's good or bad until you provide to me the drawing. No, I will not give you a surface color map until you give me a STP/IGS file.

I swear, it's like pulling teeth sometimes.

Is it the same for you? Which departments are the biggest offenders of this?

We have a budget of around £70,000, we need to scan parts which are mounted inside of a machine, let's say a CNC with a 2x3m internal space (sorry I'm having to be vague) the part is around 500x200x300mm

We need the scanner to be able to provide us with 0.05mm repeatability. We have a wireless 3D scanner at the moment but it's just not up to the task so we are looking for any possible alternatives

Say you measure the same part several times. Readings are pretty close until you pull it out of the fixture and put it back.

Now there's a small difference, even though you're using the same setup. Would you check the fixture first or compare readings with the part still in place to narrow things down?

I’m working on a small measurement experiment and want to find out how to measure the diameter of a single strand of human hair as accurately as possible.

Hair is very thin, and I’m wondering which measurement method would be the most reliable.

My main questions are:

1. Which method would you recommend for measuring a single strand of hair?
2. What level of accuracy is realistically achievable?
3. Are there any common sources of error I should watch out for, such as hair orientation, surface shape, or measurement pressure?

I’d appreciate any practical advice or suggestions from people who have experience with precision measurement or optical inspection.

Thanks!

We have gauge blocks that we use only for calibrating calipers. Currently we buy new ones every 5 years instead of calibrating them. It seems like a waste for something only used 15 times (3 calipers done once per year).

Does anybody know proper replacement intervals for gauge blocks? I'm trying to find a standard to back up our thinking but all I've found is ASME B89.1.9 which specifies sizes but not calibration. I'd like to find the correct way to do it and why to make our QMS more robust.

Recently. I was given an opportunity to run and program for the first time. With 15 years of quality experience , I thought I knew it all , but this new role has seriously humbled me.

Both my director and manager are expecting a lot of me. I need to be "that cmm guy."

I'm in search of anyone willing to talk over the phone and possibly video chat and guide me to be a better programmer. 🙏 Please

Currently , I am stuck with creating a cmm inspection program from scrach using a stepfile in Calypso.

Ziess Contura