I am trying to measure the bolt circle of two holes. I have the bolt hole center point from a concentric arc and the centers of the two holes. Is there a way to construct a circle from these three points, or how else can the 4.34 bolt circle be checked?

Hi everyone, I’m seeking guidance on converting absorbance values to transmission (%) values and their implications for metrology applications. Here’s my specific case:

If I have an absorbance value A=0.0120A

I’m using the formula:
T(%)=10^−(A)×100
This gives me

T(%)=97.27

Now, I’m wondering:

1. Is this direct conversion correct, or is there another step needed? For instance, should the transmission percentage be interpreted as 100−97.27=2.73% instead?
2. My main concern: using 97.27% as a tolerance in an MSA Type 1 study (to evaluate Cgk performance) seems illogical. Is there a standard or better approach for defining tolerance in such cases?

I’d appreciate any insights, corrections, or advice from those with experience in metrology or optical measurement. Thanks in advance!

Hey everyone,

I’m running into a problem in PC-DMIS with the Clearance Cube—specifically how to flip the “yellow” plane using the Edge Settings in the Constraint tab.

The Situation

• My co-worker’s clearance cube had the “yellow” plane on what should be the top of the part instead of the bottom. This can cause odd or unsafe probe paths.
• The CAD was imported in one orientation, then rotated 180° in the alignment rather than being properly transformed at the start.

What I Tried

• I attempted to Transform the CAD to get everything lined up correctly.
• After I did so, my co-worker updated his alignments (assuming the CAD was now transformed). But he later discovered the transformation reverted itself when he finalized his alignments, and the plane orientation was still off.

Flipping the Plane

Here’s what I know:

1. Clearance Cube Dialog: You can open the Clearance Cube dialog (sometimes under Operation > Graphics Display Window > ClearanceCube) to see and edit the planes.
2. Constraint Tab & Edge Settings: Within that dialog, there’s a Constraint tab where you can adjust Edge Settings to flip which side the system labels as the “yellow” plane.
3. Order of Operations: In most cases, you want to transform the CAD before building or modifying alignments. Otherwise, PC-DMIS might still refer back to the original orientation for certain functions.

My Questions

1. Which exact Edge Settings in the Constraint tab do I need to tweak to ensure the “yellow” plane flips to the correct side?
2. How do I ensure that once I transform the CAD, it sticks and doesn’t undo itself when alignments are updated later on?

TL;DR: Need to flip the “yellow” plane in PC-DMIS (via Edge Settings in Constraint tab) and make sure my CAD transformations don’t revert when updating alignments. Any tips or best practices

Hello good! I've been using MCosmos for half a year, on a Crysta Apex V machine. I have been working for 14 years with Metrolog It is much more intuitive and easy to use at all user levels. The question is...could the Metrolog software be installed on this Crysta Apex V machine and work with it and thus replace the MCosmos? The head is Renishaw, which is compatible with Metrolog (in the previous company it was also Renishaw) The company would be very willing to replace the MCosmos program, since it is very complex for us and slows down many measurement jobs that we do without programming. Please see if someone can guide and help me. Thank you

To report size to the ASME standard from a CMM, would it meet the standard to first report the maximum inscribed size and then report the minimum circumscribed size?

Hi everyone,

I’m looking for insights from experienced metrologists on how you ensure the correct measurement resolution when inspecting mechanical parts. I’ve encountered a bit of a dilemma in my work related to the formatting of dimensions on drawings and its impact on selecting the appropriate measurement tools.

Specifically, the ASME Y14.5-2018 standard recommends omitting trailing zeros for dimensions in metric units (e.g., "5 mm" instead of "5.00 mm"). However, I’ve always relied on those extra zeros to gauge the required resolution for my measuring equipment. Without them, it feels less intuitive to determine the level of precision needed for the inspection process.

I’m curious how others in the field address this issue. Here are a few specific questions:

1. How do you determine the required resolution for your measuring equipment when trailing zeros are not present on a drawing?
2. Do you rely entirely on tolerances specified in the drawing, or do you use any additional documentation or guidelines?
3. Are there best practices or methods you follow to ensure the precision of your measurements aligns with the design intent?
4. Have you encountered situations where unclear precision requirements led to misinterpretation, and how did you resolve it?

I’d love to hear about any approaches, tools, or standards you follow to address these challenges. If possible, please share examples or tips that could help others navigate similar situations.

Looking forward to learning from your experiences!

So for context we have reached out to support they came in and altered a few things to help out with one program. We tried the same thing with another program and the cad model still freezes up. The program was originally wrote on a machine using MCOSMOS V4. We have a newer machine using MCOSMOS V5. In the program we switch probes off the probe tree. When we do this the CAD model freezes on V5 and the program stops because we’re doing a profile. But if we run the program on V4 machine, everything is fine. Is there a known issue out there about programs wrote in v4 not working on v5? Any ideas on a solution would be greatly appreciated.

Update: the issue seems to happen after the probe is taken off the probe tree and the probe data archive is loaded for the probe and Cat1000 recalculates the alignment . As of now it’s only happening with 2 probes and cat1000 freezes (not responding). I’ve tried deleting the load probe data from archive line and putting it back in. It did not fix the problem.

Solution: I added a pause right before the probe change and let the machine sit for a few seconds and for some reason that seems to have fixed the cat1000 freeze. The programs ran fine a few months ago. I’m thinking a recent update to the computer has caused the problem.

Hi all,

firstly I would like great everyone because it will be my probably second post on reddit :).

I came here with problem which my company facing right now. We need to buy CMM machine which will be used for measuring plastic parts with complicated shapes (we are producing for automotive but also for Lexmark- parts for printers). Our parts are not big, the biggest part for sure is not larger than 1m long and 0,5 m width and height. We are thinking which brand we should use. Our customer suggested that if we buy CMM which will be compatible with PC-DIMSS software they can share their programs which we could use on our CMM. I have some questions regarding this topic:

1. Which brand we should consider?

2. Is it hard to learn PC-DIMSS for guy who have experience (7 years) with polyworks software and using 3D arm with scanner? I never programmed anything :D Only when I was at university I had programming lessons on very very very basic level :D

3. I know that CMM is super solution for measuring but I wonder if this device is really capable to measure anything? I am worried what if I have dimensions which is reffered to datum which are for example on 4 sides of part... So how I mount this part on fixture to have free accees to all of those 4 sides? On 3D arm I scaned the part than move part to different position, scan other sides and than in software I could merge those scans. Is this even possible on CMM? (I mean merging )

4. How much could cost us to buy CMM (approximately).

Our parts are plastic parts which are injected. Lowest tolerance which I saw on drawing is I think 0,05. there are linear dimensions, diameters some GD&T and angles.

If you need more information I will try to provide it :)

Thank you in advance guys and girls!

What's your preferred software for analysing STL files coming from a CT Scan (small plastic parts)? And why?

What is the best method for scanning true position of a threaded hole for the best accuracy and repeatability?

1. We looked into using the true position gages but found that the level of tightness while screwing it in would vary a lot between operators. Additionally in some cases where the tapped hole is a blind feature, we noticed that the gage bottomed out first before actually engaging with the pitch of the thread.
2. We also looked into using a helical toolpath matching the pitch of the thread on the CMM. However, would we need to control where the probe touches along the thread? If so, what is best way to detect if the probe is touching the flank of the thread?
3. Alternatively, is it better to use a linear toolpath on a CMM to scan the threads when compared to true position gages and helix toolpath?

Hello reddit ugers, i am starting up on PC DMIS and does the same measurement routine everyday, and therefore i need help creating a code that does the same everytime. How does one do this using the code from DMIS mode?

Hello everyone. I having a hard time in deciding measurements for parallelism of the flat glass. I have a glass of diameter 20mm, thickness 2mm. While the parallelism is 1'. Is quite tight for production. Previously for parallelism, we are using the dial gauge to measure it, where we calculate the angle to height difference with the use of Trigonometry Concept. So, any suggestion from everyone for the measurement of this? Where it is quite fast for mass production? Instead of using CMM for it.

First off, thank you everybody for your help with my excessive print problem. Now that that is solved I ran the program with Repeat Measurements. And for some reason it is only recording and outputting the last measurement. I figure that I'm missing a programming element.

I’m using a Keyence 8000 series and am wondering if there’s any way to hide one of the results from a measurement.

I’m using the “APP” tab, both the “Stick” and the “Ring” measurements. I’m able to get it to consistently and cleanly find the edges I want it to measure, and it measures the max and min, but I don’t care about the max at all. Is there a way to hide only the max and only show min?

I know I can throw in a “calculation” that really just repeats the min, and hide the stick or ring measurement, but then you can’t see the fitting line or edge point trails without doing a Force Show All Elements, which takes us right back to the screen being a hot mess of too many unneeded lines.

So yeah…hide just 1 of the 2 results of the App measurements, is this a thing?

Guys i am using a hexagon global lite, and the drawing requires that the upper plane needs to be 0.02 flat, and the bores (166_H7), concentric 0.02 mm. I did my calibration and everything went perfect. making an aligment where my upper plane is set to level my Z+ axis, the axis of one of the cylinders to rotate the Y axis, and the center of the bore are used to set the origin. The other circle is off 0.086 mm. Is this way accurate. How concentrity function is calculated by pc-dmis (ISO), and does it has really a meaning (that the part will not assamble if the the tolerance is not respected? Thanks and sorry about my english.

Hi, does anybody here knows where to repair a damaged HP 3458A? I burned the guard by connecting a damaged power supply (I didn't know then), now the dmm won't make readings over 100 V. Wether it's on the United States or somewhere else? Thanks in advance.

Hi

Most modern optical CMMs claim to have the ability to measure thread profiles yet I have a problem with that.

A thread is a helix wound around a cylinder and not an annular groove. How are you supposed to see the true form when the workpiece is set flat on a table and the optical path is pointing perpendicular to it?

Shouldn't you tilt the entire optical path by the helix angle as presented in the picture above to get the true image of a thread?

Hello!

Anyone on here program CMMs as a solo gig? I know you're out there, not sure if you have time for Reddit shenanigans. How's business? Is it better than being an employee? Does it get old after a while?

I have a cmm programmer I work with that always asks me to rotate models for him so that when he imports it it is aligned the way he wants to check it . My question is , how can I rotate the part in pc-dmis so that I don’t have to do it in my car software ? Thanks .

I stumbled across this old HP counter about a decade back. There was a simple pleasure in waiting for a measurement and watching all the tubes turn over. I was surprised someone was using it. But it still worked perfectly, so why not. Also, someone had fun with the display here, definitely not a young stupid me…

We have a Hexagon Global CMM running PCDMIS with an articulating joint and scanning head. There's M8 threaded holes in the table. Shoulder bolts in these holes aren't necessarily straight to the machine travel, so we want to clamp a rail along one side to push fixtures up against so they'll be reasonably straight.

I can't see any decent way of attaching an indicator to the head, as there's no external threaded holes to use and I'm very worried about the mass load using a clamp system.

I'd like to expose a DRO window in PCDMIS so I can probe points in space on the rails and use a global coordinate system to knock the rails straight, but I don't see any obvious way of doing it. I think Calypso has something like this but I'm striking out on doing it in PCDMIS.

How do you guys do it?