Product Geometrical Property Specifications (GPS) - Surface properties: Contour curve method (excerpt from JIS B 0601: 2013)

GPS：Geometrical Product Specifications

• Explanation
• Contour curve parameter
• Differences in parameter symbols (excerpt from JIS B 0601: 2013)

Explanation

Surface properties

The shape characteristics of a machined surface such as roughness or swell, or scratches are called in general terms the “surface properties”.
In JIS, the former “Surface texture drawing method” has been significantly revised, and published as “Surface property drawing method” (JIS B 0031: 2003).
Surface property parameters is a general name for contour curve parameters, motif parameters and parameters relating to load curves.

Contour curve method

The measurement method where the outline of the machined surface is traced with the stylus of a stylus type surface roughness measuring machine, and the obtained contour curve is displayed using the parameters found based on that curve is called the contour curve method.
Of the surface property parameters, the contour curve parameters include the roughness parameter, the waviness parameter and the sectional curve parameter, and surface properties are expressed through data processing of these parameters.

Contour curve parameter

Max. height of contour curve (Rz)
Sum of the maximum value of the contour curve mountain height Zp and the maximum value of the valley depth Zv in the standard length

Arithmetic mean height of contour curve elements (Ra)
Average of absolute values in standard length
Contour curve parameter

Differences in parameter symbols (excerpt from JIS B 0601: 2013)

Surface properties parameters (example of roughness parameter)

JIS B 0601:2013 item (For details refer to JIS text)	JIS B 0601:2013 parameters	JIS B 0601:1994 and JIS B 0660:1998 symbols	JIS B 0601:2013 symbols	Contour curve length
				Evaluation length ln	Standard length a)
4.1.1 Max. mountain height of contour curve	Max. mountain height of roughness curve	Rp	Rp b)	ー	○
4.1.2 Max. valley depth of contour curve	Max. valley depth of roughness curve	Rm	Rv b)	ー	○
4.1.3 Max. height of contour curve	Max. height roughness	Ry	Rz b)	ー	○
4.1.4 Average height of contour curve elements	Average height of roughness curve elements	Rc	Rc b)	ー	○
4.1.5 Max. section height of contour curve	Max. section height of roughness curve	ー	Rt b)	○	ー
4.2.1 Arithmetic mean height of contour curve	Arithmetic mean roughness	Ra	Ra b)	ー	○
4.2.2 Root mean square height of contour curve	Root mean square roughness	Rq	Rq b)	ー	○
4.2.3 Contour curve skewness	Roughness curve skewness	Sk	Rsk b)	ー	○
4.2.4 Kurtosis of contour curve Kurtosis of roughness curve	Mean length of roughness curve elements	ー	Rku b)	ー	○
4.3.1 Mean length of contour curve elements	No. of peak counts based on roughness curve element	Sm	RSm b)	ー	○
4.3.2 No. of peak counts based on contour curve element	Root mean square of roughness curve	ー	RPc b)	ー d)	ー d)
4.4.1 Root mean square root slope of contour curve	Square root slope	△q	R△q b)	ー	○
4.5.1 Load length ratio of contour curve	Load length ratio of roughness curve	tp	Rmr(c) b)	○	ー
4.5.3 Section level difference of contour curve	Section level difference of roughness curve	ー	Rδc b)	○	ー
4.5.4 Relative load length ratio	Relative load length ratio of roughness curve	ー	Rmr b)	○	ー
Appendix JA	Ten point average roughness (Deleted from ISO 4287:1997)	Rz	Rzjis c)	ー	○

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