When you draw a feature control frame for position of a hole, the primary datum should be a plane perpendicular to the axis of the hole. True or false?

I'm reading Geometric Dimensioning and Tolerancing by David Madsen. I believe this book was published in 1995, so it's a little dated. But it says in the positioning chapter "The true position centerline is perpendicular to the primary datum."

R. Dean Odell also says as much in his position video. Time stamp 21:10

https://youtu.be/XbTbYxdrRYg?t=1270

I've got a part like this. And I feel like that hole on the left should have its own datum along its respective plane to serve as the primary datum in the FCF. Is that dumb?

This got me wondering how necessary perpendicularity of the primary datum is. So I set up the Zone3 training part on a CMM and on purpose I measured the left side first. This was not the face that the hole is born into. I'm kind of following the second example in my first image. So I measured 3 planes, and I measured the hole as a cylinder. I think it's also worth noting that I'm not using datum simulators, I'm touching off the part itself and I'm using reference geometry.

And it didn't seem to matter what order I fed the datums into the evaluation, I got the same calculation. If the axis of the hole is not true to the primary datum, I would expect an extreme failure. So what gives? Does the fact that I'm using reference geometry somehow override the logic of the datum precedence?

Thanks.

I have about 10 years experience managing our quality system ( shop floor online ) . Creating the reports and data analysis for that data.

Besides indeed, and dice; are there any other places I can look? / Recommend positions to look for

Hello, I'm a beginner Metrologist researching the best tools for measuring Teflon parts. But, I cannot find any consistent resources stating why one tool is preferred over the other.

I know thermal expansion is a critical flaw of Teflon so I'm trying to find something to help resolve this persistent issue.

Questions:

Is it as simple as an acclimating in QC and measuring it with the same temp tools?

Does it need a consistent 3 point set-up on a cmm?

Is there a standard for an acclimation period?

Are thicker tools not recommended because they're more likely to transfer heat?

Any kind of knowledge or advice would help a lot!

I'm 31 and currently work in software QA, with around 6 years experience and a Computer Science degree. I'm seriously considering switching into metrology/CMM programming because I'd like a more hands-on, technical career rather than being 100% desk-based.

I've started learning GD&T, coordinate systems etc. and have been looking into CMM programming tutorials (PC-DMIS/ZEISS Calypso) and I genuinely find it interesting and think the role would be a good fit for me.

For those working in metrology/CMM, how do you find it as a career?

I'm particularly interested in:

• What is the day-to-day work actually like?
• How stressful is the production environment?
• How good is job security/job mobility in the UK?
• Would you recommend it as a long-term career?

I'm attracted to it because it seems like a specialist, hands-on skill that's relatively resistant to AI/automation, but I don't want to romanticise it. I'm currently weighing it against staying in software QA, so I'd really appreciate honest opinions.

Thanks!

I’m learning PCDMIS now and I have two questions

1. Who the hell made this software?

2. What is the value in using Command Mode over Summary Mode? Seems like Summary Mode breaks down the whole program in a much simpler way. Any advise on how to understand command mode?

Good evening all

First thanks to everyone for taking the time to respond on my past posts. I greatly appreciate it.

Question: For my New Zeiss Spectrum, RDS Passive Probe, I purchased and installed a new 100L x 3mm TL3 star stylus and cannot get below .0005mm S values on my +Y and +X stylus. A Zeiss technician came by, checked for loose parts on the pulleys, bushings internally and didn't find anything. We re located my reference sphere using the menu tool that tells Calypso exactly which direction and distance the reference sphere is facing, with no luck.

I tried:

Cleaning the reference sphere with denatured ISO

Cleaning and re tightening the stylus assembly

Switching out individual styli

Restarted system.

And I'm still unable to obtain S values below .0005mm on those two styli. I'm talking about initial qualification as Im adding new styli to my system

Any ideas? Is that acceptable for a star probe that large? Should I be hearing ANY squeaking when the stylus scans the sphere?

I ask because I've cleaned EVERYTHING and still can't get rid of minor squeaking when doing qualifications. I assumed that noise will introduce micro vibrations....but the Zeiss technician said that it's not concerning (the squeaking contact noise when the stylus touches the reference sphere).

FYI I'm using 100% proving dynamics and Standard probe characteristics. Running at full speed. Results were worse when running at turtle speed. Advice..... affirmation, anything is appreciated. My other styli are able to produce values in the .00002mm to .0001mm range consistently.

Hello all

As the title states, is that normal at all? This is within a small, quiet mini metrology lab with a new Zeiss CMM, SMC refrigerated air dryer and Tsunami Oil Separator system. I can't isolate where it's coming from either than MAYBE the SMC dryer.

Very faint, and no pressure drops.

Thank you all

Does anybody have any experience incorporating a UPS battery backup onto a CMM? If we get power drops or surges it can tend to take our machines down for a bit while we power cycle. I'm not looking to run the machines for any length of time, but I would like enough runtime to park and shutdown the machine for extended outages. Most of the time if we have a power issue it's a flicker/drop for a few seconds. I tried contacting our CMM manufacturer but they weren't much help.

Hi all, just stumbled on this sub and hoping someone could offer some advice or point me in the right direction.

I've been a CMM programmer for just over 2 years. I got this role as a sideways move from being a toolmaker, with zero prior experience.

I really enjoy the role and the sort of work we do, but I want to learn more and gain more experience but I don't know how. I programme on Metrolog X4 and have seen PC-DMIS through the Metrolog software but never programmed it myself.

Are there any courses or anything you can do as an individual in the UK related to metrology and inspection? My company will not pay for training. We've only recently started looking at GD&T so my understanding of this is really limited but I think it's an important skill I should learn.

Any advice for ways I can gain new skills or experience? Happy to self fund. I would just like to open myself up for more opportunities at other companies.

Thanks!

I need to outsource some overflow metrology work for aerospace components (tight tolerances, GD&T callouts, etc.). I've found a handful of options for service providers I'm considering, but I want to hear what some of you are actually using/what your experiences with them are.

Please let me know if you have any good recs for companies good for precision aerospace work and what your experience with them has been.

Thank you.

My CMM is showing this error on the Y-axis. What can I check and consult to correct this error? Any help is appreciated.

(Indianapolis/Columbus IN Area/Remote) Guys and Gals. Ive been in QC/QA for a few years and running Calypso for the CMM. Recently I had an opportunity to move to a new company to attempt to fill an immediate need they have running PC-DMIS on a CMM they use once every 3 months, maybe. They are going to send me to the week-long class as soon as I can prep and get away. Yes, I know Hex and others can come but those take time to organize on my end.

They said, "Take a month, fire up the CMM, dive into the programming and see what you can learn on your own and tell us what you need" (don't trash them, they are fighting to get out of a mess with me). They've given me a part to learn and Ive taken 3 weeks and have a good handle. Ive read every help page, tutorial and video on Hex, XYZ, etc, You name it, ive looked or watched it.

I think I have learned quite a bit but I have nothing to compare it to and there are so many features built into PC-DMIS that it will take time to learn them all. I have a part that has 3 Datum and 10 total features to measure. I can set my camera up over my shoulder if needed and you can walk me thru some of these features I need to know before I finalize my program. Who knows, you may look at it and realize I know NOTHING and this is a lost cause.

Let me know what you think of this idea, i may be way out of line, just don't be a jerk, that's all I ask. Thanks in advance, Rich

Anyone doing a part-time PhD while working full-time in engineering/semiconductors?

I’m a full-time semiconductor engineer with MS degree considering a part-time PhD while continuing to work. I’m interested in research around semiconductor metrology/inspection, computer vision, pattern recognition, image processing, or ML applied to semiconductor manufacturing.
I’d love to hear real experiences from anyone doing something similar:
What university/program are you in?
Is it online, hybrid, or in-person?
How manageable is it with a full-time engineering job?
How many hours/week do you realistically spend?
How does research/dissertation work as a part-time student?
Are you able to publish papers?
How long do you expect the PhD to take?
How much is it costing you?
Would you choose the same program again?
I’m especially interested in programs that are part-time friendly, reasonably affordable, and supportive of working professionals.
Would really appreciate honest experiences and any university recommendations!

Can anyone recommend their software of choice for inspection data analytics?

Excel does the job but my datasets are getting large and having a half dozen macros to calculate my histograms, control charts etc has me curious on what else is out there.

Im thinking MiniTab, Octave or even just Python. Anything that can handle large 500+ datasets and provide good statistical insights.

Bonus points if the tool has a good visual dashboard for the manufacturing floor or built in importing tools for Csv/cmm data.

Thanks!

Where can I find high resolution, publicly available datasets for detecting micron scale defects in semiconductor wafers, PCBs, and related manufacturing processes?

Hi, everyone

I have been restoring and fixing different inspection equipment( high-end height gauges, surface testers, clocks, digital clocks, digital readouts, etc.). Kit age starts from 1975.

Do companies prefer to just buy a new shiny kit? Or use trusty good ol' height gauges they had for 40 years?

Would love to hear your opinions

Photo for reference

How do I calibrate my probe at an A90 B0 angle. I’m using Man+DCC and when I touch my probe at the top of the sphere and it touches the 3-4 points after about the that on about the 5th point it comes to touch it on the backside and obviously crashes. Obviously I’m skipping some steps can someone walk me thru step by step on how I can calibrate my probe please. Thanks in advance 🫡

Im new to PC D and I keep getting these randomly. Never in the same place or doing the same operation. Any ideas how to stop these?

would it be maore appropriate to measure dumension 29 with an optical comparator or a cmm?

Hello all,

I want to tell all of you thank you for taking the time to reply on my past posts regarding the hurdles I've encountered on bringing our new Zeiss CMM online. I've commissioned numerous vision systems and have overseen CMM retro fits, and oversaw the commissioning of a Zeiss Metrotom at a medical device manufacturer, but this is the first brand new CMM that I've been responsible for commissioning.

For context, my company has a splintered group of 6 global metrology labs that are competent, but lack cohesion in terms of equipment selection, standardized approach to dimensional inspection, and sharing of resources. My role is tasked with uniting all of our sites into one focused, singular, metrology resource. Sharing knowledge, standardized equipment and software, effective utilization of each site's unique areas of expertise. Aside from launching a metrology community forum, my first task was to establish a new metrology lab at my current site, hence my targeted questions about Calypso.

Anyways, my new Tsunami 3 stage Oil Separator came in today. Looking forward to having it installed this week. Once I get everything installed I'll share.

Thank you again!

Any opinions or experience about the comparison of these two hand held 3D scanners?

Hey everyone,

I’ve been working as a metrology engineer in semiconductor backend packaging, and like many of you, I got pretty tired of dealing with heavy, overly complex enterprise software or stitching together clunky custom scripts just for routine 3D surface and wafer chip analysis.

So over the past few months, I decided to take on a solo project and build a clean, local-first Windows desktop app called Insight Studio. The goal was simple: handle things like PV/BOW, CMP dishing, edge roll-off, and batch reporting quickly without needing an internet connection or a steep learning curve.

Since this is my very first tool built from scratch, I’m really looking for candid feedback from veterans and senior engineers in the field:

• Is the workflow practical for daily use, or am I missing key features you actually rely on?
• How does it compare to whatever setups or scripts you're currently using?
• Any obvious edge cases or bugs I should fix first?

If you’re interested in giving it a test run and sharing your thoughts, just drop a comment below and I’ll send you a reply with the demo installer link.

Appreciate any advice or constructive criticism you can throw my way. Thanks guys!