u/AcceptableActivity33

Hello all,

Hope everyone's been doing alright. Last week I dropped the method I follow to assess the process capability (like I'm sure many of you do) of a Position call-out assigned to a hole or boss.

Many of you agreed with the percent of tolerance used Ratio conversion method (Single Sided Upper of 1 in Minitab using converted value with or without MMC). Well I'm creating a procedure, a very generic, basic guide, on how to assess Position call-out with MMC using this method and ran into a snag that should have been clear from the get go.

When assessing normality to determine what capability report to use I realized that with a single sided upper tolerance, the process spread is usually going to look like a fish tail instead of a single bell curve.

When you take this fish tail process and run normality, it'll give you a P value below .05. From there, I then was selecting the NON NORMAL Capability study report within Minitab, then using the PPK value as my result. Have you all ran across this before? Can I even propose a simple, sequential guide assessing process capability without making it extremely complex? Co-Pilot and ChatGPT can only take me so far and there's not a reliable Validation engineer on staff to run these sort of questions by.

Open to feedback, guidance, examples of what your organization does..anything.

Thank you,

Daniel

Hello all again,

As the title suggests, I've been working on a correlation effort between two different sites that are performing a profile of line evaluation (DRF evaluation) on a challenging brass gear the size of a thumb nail, with a tolerance of .003 or +/- .0015".

One site reports out, one site reports within tolerance, but nearly failing. I've also come to find out that I'm having trouble with Mitutoyo's scanpack form evaluation software....just not intuitive at all. By aligning both teams to use the same point spacing, same datum alignment strategy, same cleaning process, same DRF evaluation I was able to get both sites to report within .001" of each other (.0028" vs .0038") but that's the absolute best I can do right now as I'm limited by both a language barrier and varying vision system comptency.

I'm also seeing a part to part variation of .0005". I'm leaning towards stating that when factoring part to part variation, GR&R results above 15%, vision system accuracy at about 5 micron...all these things combined lead me to believe that we're as close as we're going to get with the equipment we're using, tight tolerances, challenging profile call-out, manufacturing process (stamped die cut brass)....all these things

Thoughts?

Thank you!

Hello all,

Hope everyone is doing well. Any feedback on this or examples of what your validation dept handles the following scenario is greatly appreciated.

Performing a capability study on a hole with MMC applied using Minitab: how do you handle it?

I know there's a few ways to go about this.... historically I've transformed the data into a ratio based on tolerance used vs tolerance allowed, run it as a non normal distribution, single sided upper using 1.0 as your upper.

I've also seen sites that will convert to a radial distance. I also believe there's a strong case for evaluating each axis separately.

With that said, I've also heard of not transforming the data, running as a single sided upper..

Within Minitab or QC CALC, how have you guys handled capability studies on position tolerances?

Thank you!

Hello all,

I hope everyone is doing well. Feedback from experience greatly appreciated. For context, my position at my current employer is brand new, which is a Sr level Metrology Engineer role. I have almost 20 years of experience in roles adjacent or focused on dimensional inspection (CMM programmer, SQE, QE). I believe I have a solid grasp of ASME Y14.5, but I often time have to reference it as a resource instead of remembering each section. I'm fluent with many CMM software, point cloud analysis and SPC packages and would consider myself an SME in dimension inspection but probably not in the application or creation of designs using GD&T.

With this in mind, I felt a bit humbled after this 3 day course as I was the only Metrology focused employee in the class, but there were times where I wasn't able to recite all 14 GD&T symbols, or calculate the bonus tolerance of a given feature at LMC or MMC. The way that the questions were worded used verbiage and syntax that felt foreign at times. The instructor would ask the class questions from each section of ASME Y14.5 2009 and expected the class to answer and there were times where I would keep quiet because the first answer is given on previous answers were wrong.

Now that the class is done I'm worried that I SHOULD have known the standard inside and out and that I should already be a ASME certified GDTP technologist. 99% of my peers in the class are dragon engineers that will apply what they learned to their designs, while I specialize in taking their designs and creating a path forward for each sites inspection team. Is there a difference? Should I feel embarrassed? Have any of you done this before? SHOULD I have been able to recite all 14 symbols by heart (symmetry screwed me up).

Definitely feeling imposter syndrome right now.

Thank you

Hello all,

Before heading back into work I figured I'd ask this as well. Using Calypso 2025, I'm measuring a part that doesn't have a CAD model. It's a long, flat, stamped gear rack, like a saw blade essentially.

Question: I've been able to make do by watching Dean Odell on YouTube, but I feel like I'm not going about programming without a. CAD efficiently. Could any of you provide a basic overview of your standard approach to no CAD workflow? Do you head in and just start taking a PLANE to start off your base alignment? Do you select PLANE from the Feature drop-down, THEN take points once the strategy window is open?

When I take a 2 point line, but I want to transition that line to a 2D scan path line, am I doing it correctly by taking the 2 points, then going back in and select the symbol that looks like dots connected by lines? Easier method? Tips?

Thank you all in advance. Very helpful

Hello all

Hope all is well. Out of curiosity, for people using Zeiss Calypso, what's your go to Distance Tool for measuring the X or Y distance from either a Line to Point or Line to Line, purely from and XY coordinate schema and not factoring in Z/skew?

I've been told Caliper Tool 99% of the time....or Cartesian but wanted to get your input. Thanks in advance

Hello everyone,

Hope all is well. What's everyone's prefered, cleanest, or simplest method for changing the approach, travel, retract or clearance distances within Calypso when measuring a narrow slot?

If you could provide your method and take into account that a Clearance plane has been established all around the part, that would be appreciated.

Thank you

Hello all

I appreciate everyone's response on my earlier thread about the odd issue I ran into with the Master Probe .012d mm error code /Fitting method issue.

Zeiss followed up with me to state that the code shouldn't be an issue during initial "break in" and to worry about it if it keeps happening or requalification reports a bad S value.

As guided, I restarted everything and located my reference sphere. The masterball S value came back as .0000.

I went to add a new stylus negative Z and the initial passive stylus qualification S value also came out to .0000 which I thought was odd.

Question, for a brand new Spectrum CMM, like two months old. Is that possible? Are all INITIAL qualification report out zeros and then during the REQUALIFICATION is when I'll see true S values?

Open to guidance and thank everyone in advance!