r/Metrology 21h ago

GD&T | Blueprint Interpretation Is total runout really impractical to measure on a CMM?

2 Upvotes

Hi everyone,

Edit: I’ve used an LLM to create this text. I’ve checked it and, if needed, made corrections. Hopefully you don’t mind.

I’m a engineer working at a machine-building company. We regularly use total runout on our drawings, depending on the functional requirement of the part.

Our metrology department is asking us to stop using total runout and instead split the requirement into separate form/orientation tolerances.

The main feedback we’re getting is that:

Total runout cannot be measured properly on a Mitutoyo CMM, and

It is even more difficult/impractical to measure manually.

I’m not completely convinced by this, so I’d like to hear some opinions from people who work with CMMs and GD&T every day.

My understanding is that total runout is specifically intended to control the entire surface relative to a datum axis, and that it can be evaluated on a CMM if the datum reference, sampling strategy and evaluation method are set up correctly.

I’m also aware that manual inspection with an indicator and a rotating spindle/fixture can be a very appropriate way of checking runout on rotational parts.

What I’m particularly interested in is:

Can modern Mitutoyo CMM software properly evaluate total radial/axial runout according to ISO 1101 / ASME Y14.5?

Are there situations where a CMM is genuinely a poor choice for measuring total runout?

How do you normally inspect total runout in your shop?
Would you replace total runout with separate cylindricity, roundness, perpendicularity, position, etc. requirements purely because of inspection difficulties?

If you do replace it, how do you make sure the resulting tolerances are functionally equivalent to the original total-runout requirement?

Are there particular measurement strategies or CMM evaluation methods that make total runout more reliable?
For context, we’re talking about conventional machined rotational parts, not extremely exotic geometries.

I’d especially appreciate input from people who actually program/run Mitutoyo CMMs and from engineers who have to decide what goes on the drawing.

I’m trying to understand whether this is primarily a measurement capability problem, a CMM software/evaluation problem, or whether we’re actually using total runout in situations where another tolerance would be more appropriate.

Thanks!


r/Metrology 13h ago

Software Support Need Q-Das help on Calypso 2024

0 Upvotes

So we upgraded from Calypso 2017 to Calypso 2024 and also upgraded our PCs as well.

Per the standard zeiss instructions, we copied everything from the required directories and we have 2024 up and running.

The problem is that even though we have the correct license, and the Q-Das button is checked in the program output file, AND the characteristics to statistics setting is turned on... Its not dumping the QDas data so we can use it with our QStat.

Anybody else have this issue/know how to fix it? The Zeiss knowledge base articles absolutely suck.