Conversion of surface finish measurements

Ron Rompen

Trusted Information Resource
#1
Anyone have a quick reference for conversion (approximate) between Ra and Rz values for ground surfaces?

Print requirement is for Rz 10, I would like to propse to the customer that Ra 1.6 max (by comparison to a recognized standard) would meet or exceed this requirement.

Anyone have any suggestions?
 
Elsmar Forum Sponsor

Jim Wynne

Staff member
Admin
#2
I'm not sure that a reasonable conversion is possible, given that the Ra and Rz are measurements of two different (albeit related) attributes. See this page for more information which nonetheless might help you to make your case.
 

apestate

Quite Involved in Discussions
#4
I always thought it interesting that piston engine cylinders are bored and then honed, but the honing is designed to leave surface pits and imperfections and not totally smooth the surface, which allows oil from the crank case to lubricate the ultra-tight fit of the piston.

The moral of my beautiful vignette is that there are many many parameters for measures of surface roughness, all designed for different attributes of the finish as Jim said.
 

Ron Rompen

Trusted Information Resource
#5
Thanks for the input guys. I realize that the two callouts are 'different', but since it is a cylindrical surface, it is difficult to accurately measure surface finish with my profilometer, and my comparison scale is (of course) in Ra.
 
Thread starter Similar threads Forum Replies Date
S Surface Finish - Conversion factor to transform Rz Jis in Rz Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
Q Surface Roughness - Conversion of RS on a Print to RZ General Measurement Device and Calibration Topics 3
S Quality Objectives for Aerospace Chemical Conversion & other Surface Treatment Plant AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 3
F Conversion of coordinate dimension holes to position dimension Design and Development of Products and Processes 3
D MDD to MDR - Technical File conversion EU Medical Device Regulations 4
S Class II to OTC conversion of a medical device 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
B How do you manage your project? Data Conversion and Digitization Records and Data - Quality, Legal and Other Evidence 9
P Conversion of fraction to decimal for R&R of english ruler Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
P Effective way for DC/DC conversion for 2 MOPP @ 250VAC IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
B Conversion and Rounding Standard for converting metric to english and vice versa Other ISO and International Standards and European Regulations 4
P IEC 60601-1-11 - Conversion to Double Insulation IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
M Customer Conversion and Retention / Satisfaction Measurement Index Benchmarking 4
B QMS Conversion including Documentation and Understanding our Processes ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
R Preparation for AS9100B conversion to AS9100C AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
S FSC Chain of Custody - Volume Control & Conversion Factors Various Other Specifications, Standards, and related Requirements 7
T Specification Conversion from Sets to Individual Measurements? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 5
F Conversion from Agile - Need cheaper FDA compliant software Qualification and Validation (including 21 CFR Part 11) 7
C Conversion Help!! Print with this dimension .2917+/-.0005 :1 Inspection, Prints (Drawings), Testing, Sampling and Related Topics 9
kedarg6500 Unit Conversion Add-in for Excel Excel .xls Spreadsheet Templates and Tools 7
I Medical Device Directive, Conversion from class IIb to class III EU Medical Device Regulations 4
A CMM Software Conversion - Converting from Zeiss/Calypso to Brown & sharpe PCDMIS Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
K Micron to Inch Conversion Misc. Quality Assurance and Business Systems Related Topics 10
P Rockwell, Brinell, Vickers Conversion - Evaluating Aluminum 6061-T6 and 6063-T6 General Measurement Device and Calibration Topics 11
E Cost Savings based on 2005 Production - Metric Conversion Problem Misc. Quality Assurance and Business Systems Related Topics 4
T What is the conversion for PPM defects vs. Sigma Equivalents? Six Sigma 42
Proud Liberal Microfinish conversion - Micrometers (?) to microinches? Manufacturing and Related Processes 3
Courier Conversion TO ISO9001:2000 / TS16949:2002E IATF 16949 - Automotive Quality Systems Standard 7
K Conversion from ISO 9001:1994 to ISO 13485:2003 ISO 13485:2016 - Medical Device Quality Management Systems 4
I ISO 9000:2000 Conversion Presentation Request ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 1
Marc Best 'Units' Conversion Web Site and/or Program Book, Video, Blog and Web Site Reviews and Recommendations 6
S Conversion from ISO 9001:1994 to 9001:2000 ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
S Surface roughness Rz Manufacturing and Related Processes 1
L GD&T Position for surface Inspection, Prints (Drawings), Testing, Sampling and Related Topics 9
K Surface finish (Evaluation Length) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
Ron Rompen Surface Finish Correlation between Ra, Rz and Tp (bearing surface ratio) General Measurement Device and Calibration Topics 3
P Surface scratch measurement General Measurement Device and Calibration Topics 1
D Surface Roughness understanding Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
D Calibration of Digital thermometer with surface probe General Measurement Device and Calibration Topics 1
J Gear Surface Finish - Print with the word "calibrated" Manufacturing and Related Processes 2
R Design and Manufacture Guidelines for Surface Mount Technology Misc. Quality Assurance and Business Systems Related Topics 9
8 Surface Finish - Callout as 8 - 16 Rq Manufacturing and Related Processes 1
M Active Surface Disinfectant Claims - FDA vs EPA and Hands vs Objects Other Medical Device and Orthopedic Related Topics 0
GoKats78 Callout on Surface Finish General Measurement Device and Calibration Topics 11
P Gas Nitriding Surface Hardening of Stainless Steel 304 ISO 13485:2016 - Medical Device Quality Management Systems 4
S Difference between Surface Finish (Ra) and Flatness (GD&T) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
N Creepage - Does a surface mount isolator body negate a PCB slot? IEC 60601 - Medical Electrical Equipment Safety Standards Series 6
CCaantley Where to get a good test indicator stand for a granite surface plate General Measurement Device and Calibration Topics 8
M Interesting Discussion Surface Cleanliness Real Time Test Tools General Measurement Device and Calibration Topics 2
P Romer Arm - Profile of a Surface Changing General Measurement Device and Calibration Topics 4
R Reporting Profile of a surface with U modifier Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4

Similar threads

Top Bottom