AnnexAnnex.T.03

Roughness Ra and machining processes

Roughness values related to machining processes (extract from ISO 2768)

Process	Process type	Roughness R_a [μm]
Process	Process type	0.012	0.025	0.05	0.1	0.2	0.4	0.8	1.6	3.2	6.3	12.5	25
Casting	in sand moulds											•	•
	in permanent (chill) moulds										•	•	•
	die casting									•	•	•
	precision casting								•	•	•
Forging											•	•	•
Turning	roughing										•	•	•
Turning	finishing								•	•	•
Slotting/planing										•	•	•
Milling	roughing										•	•	•
Milling	finishing								•	•
Drilling	roughing										•	•
Drilling	finishing								•	•
Broaching									•	•	•
Reaming								•	•	•	•
Grinding	roughing								•	•	•
	semi-finishing							•	•	•
	finishing						•	•
Polishing	roughing					•	•
Polishing	finishing				•	•
Lapping	roughing			•	•
Lapping	finishing		•	•
Honing	roughing	•	•
Honing	finishing	•