This section provides a brief introduction to the way in which Creo Elements/Direct Modeling handles surface quality specifications. If you do not need to specify surface quality, you can ignore this section entirely and proceed with tolerancing tasks. For this reason, the default setting is set to no surface quality. And if you wish to remove previously specified values, click the Reset. This button is enabled once you have specified a surface quality value and is disabled when no surface quality specification exists.
When a machined hole is assigned a surface quality value, its face is color-coded.
There are several methods available for specifying surface quality values.
Specifying ISO Surface Quality Classes
The ISO specification about Surface Roughness Quality Classes (see DIN ISO 1302) defines the roughness classes N1 ... N12. These classes can be specified by selecting the appropriate entry from the menu.
Arithmetric Average Roughness Height
Depending upon your needs you may specify the Arithmetric Average Roughness Height (Ra), either as a value without tolerances or as a toleranced value (min, max, or min/max). The following values are available:
No Spec'd
Ra value
Ra min
Ra max
Ra min/max
Other Surface Quality Methods
In addition to the methods above there are some other characteristic values which may be used to specify surface roughness quality. A subset of all the possibilities is supported with the additional restriction that the different methods cannot be used in a mixed mode. The following specification methods however, are not supported :
• Maximum profile depth with respect to the median line (Rm)
• Maximum profile height (Ry) which is essentially the same as (Rt)
• Ten-point height (the arithmetric median of the 5 highest mountains and the 5 deepest valleys) (Rz)
