Surface Tolerance: missing dialogue boxes

[Anonymous]

Hello,

I'm trying to give my pin here a surface roughness of 32 um, but I seem to be missing dialogue boxes, compared to others. I've tried giving the model a surface roughness but to no avail, then I tried in the drawing. 

What I want is essentially upper and lower limit surface roughness (32-63) 

See attached picture. Have I missed something important or is it a bug? 

Best regards, Fredrik

[Anonymous]

Further I will add that I do not seem to have a drop down menu at the top, showing various presets, that others seem to have. 

[Martin.Tomko]

Hi Frederik,

it seems that you have active annotation standard which does not support it. Go to the Styles Editor and active annotation standard, for Surface Texture Symbols,  to ANSI or to  ANSI-mm. Annotation standard can be changed also in the Ribbon>Documents Settings>Annotations.

Regards,

Martin

[AIR_123]

Why Have Newer Standards Shifted Focus or Removed Specific References to Ra?

1. Shift to Functional Surface Requirements:

   • Older standards like ISO 1302:1978 primarily focused on roughness values like Ra because it was a simple way to quantify surface finish.
   • Newer standards have shifted to emphasize the functional requirements of the surface texture. Ra alone doesn't fully describe how a surface performs in terms of friction, lubrication, sealing, or wear. Parameters like Rz (mean peak-to-valley height) and others are more informative for these functions.

2. Limitations of Ra:

   • Ra is not enough: Ra (arithmetic mean of roughness) doesn't provide detailed information about the texture profile. For example:
     • Two surfaces with the same Ra can feel and function very differently due to differences in peak and valley distribution.
   • Functional concerns: Industries like aerospace, automotive, and medical devices now demand more precise control over surface profiles, which Ra alone cannot deliver.

3. Standard Consolidation and Simplification:

   • Standards have become more consolidated, encouraging the use of multiple parameters instead of focusing solely on Ra. This avoids confusion and ensures specifications meet diverse engineering requirements.
   • Instead of prescribing a single parameter, newer standards allow designers to choose a combination (e.g., Ra + Rz + Rp) based on the application's needs.

4. Globalization and Standard Evolution:

   • Standards evolve to meet international needs and modern manufacturing methods (e.g., CNC machining, additive manufacturing).
   • Newer versions align better with global best practices, focusing on comprehensive surface characterization rather than just roughness average.