Undercut evaluation ISO

[[Ed...]]

Hello,

Could someone explain me how to evaluate undercut and max edge finish?

 

This is how I made it:

I have arguing our engineers of this topic, because they say the tolerance should be from -20 to 90 microns.  

Edited Thursday at 12:01 PM

[[Ch...]]

would be difficult, pretty sure gear pro does not have this, even if it did, you would need the proper ball to shaft ratio probe tip to not shank.

Looks like you do have it measured - which is a start.

 Looks like you may be able to add a root relief and try that, or possibly add a K-band in this area as well.

Worst case, try reading on chart, counting dots - not ideal, however.

 

[[Ro...]]

Can you provide more background what exactly is meant with Undercut.
Undercut could be in general a root relief or Undercut evaluation characteristic which is not defined in standards.
I know that e.g. Klinglenberg has such an charactersistic but you have to clarify what exatly has to be evaluated.
Same for the other charateristic.
Maybe you can share the drawing and the .act via PM?

[[Ma...]]

I'm not for sure but aren't those surface roughness callouts to be measured with a profilometer?

Rv (maximum valley depth) is one of the options on our formtracer

Re is not but a google search shows it is not a standard primary roughness parameter but may be in reference to Rc or Rp.

I have not used any of these parameters, so I have nothing else

[[Ed...]]

Please sign in to view this quote.

Hello today,

Unfortunately I can`t share full data, but I will try to explain this issue.

On drawing I have undercut max0,09 and max edge finish 0,02

In GearPro I`m evaluating it as root relief, my interpretation from drawing. Because I have this:

 

In my opinion, this is how it should be! In lower right corner our production example, everybody says this is ok, because max edge finish (0,02) allow it. Disagree with it! 

So this is not a max edge finish! Just incorrectly made undercut (root relief), not fully machined! 

 

The question is, I`m I right? 

Edited Friday at 06:48 AM

[[Ro...]]

Does your question regarding "Undercut" refer to a company standard or a competitor evaluation?

I´m asking because acc. to my experience "Undercut" is not what you showed in your sketch on the upper left side.
I mean undercut in root relief zone means no allowance of +material. So for this reason starting with GEAR PRO 2024 the characteristic ffamax was introduced:

For a better explanation I did some comments in your report as follows:

Cf (grenn) is clear, depending from the settings in the GEAR PRO tab you get different intersection points for evaluating the amount of root relief.

ffaCf (blue) is the form only in the root relief zone, in your case between 2.5 and 5.8.

ffamax (red) is the "Undercut" characteristic as I think you are interested in. The regression element from the main evaluation zone (crowning) is extended and parallel shifted to the max material intersection. The distance is the value for ffamax. (Accordingly there exists ffamin which you can use for min material issues).

The only think which does not fit to your sketch is the red marked case as ffamax will detect this as NOT OK:

I´m not sure if this explanation helps you but maybe as a start for an internal discussion?
Does anyone in the forum has other ideas or interpretation of undercut?