Question for: Cg & Cgk calculation

#1
Hi, everyone

I have some questions on the Cg and Cgk. Could you explain this to me, please?
I got a certificate from the supplier.
Please see the picture below;
Cg and Cgk calculation.GIF


So I tried calculating those based on my experience to find out where the Cg and Cgk come from.

However, there is only Cgk which I cannot get the result the same as mentioned in the certificate.

For example Torque calibration at 2 Nm

My result from calculation is -> (Cg = 2,11) & (Cgk = 2,10) that is not the same at 2,07

Could you help me and explain this to me on how to get the correct Cgk, please?

Thank you so much for your support, everyone.
 
Elsmar Forum Sponsor

Welshwizard

Involved In Discussions
#2
Hi TLim_AC,

The differences you find will be due to rounding I'm sure. For the 2Nm column the process mean is the same as the nominal therefore the Cg and Cgk value should be the same and this column represents data which is stable so it can be characterised with some confidence.

Just for your reference, a quick calculation on this column reveals a probable error of 0.002 Nm. This means that half of the time your recorded values will be greater or less than this value, it's the demonstrable resolution of the process. If we know we have this grain of variation affecting our spread, by the time we multiply it by number which better represents a confidence band it's hardly surprising that the denominator changes and therefore the outcome.

Of course, whether Cg and Cgk represent anything that's useful is another topic!

Hope this helps you!
 
#3
Hi, Welshwizard

Thank you so much for your advice.
However, other nominal torques (6 and 10 Nm), there are some errors as well which is significantly different from the result in the certificate.
I will do the calculation with the correct formula again.

This, Cg and Cgk, are the new one I just jumped into this topic.
Normally, I get used to working with others like Cm, Cp, Cmk, and Cpk.

For the Cgk is the new one, and I believed that the calculation is different from those as well.
That is why I checked the result I got from our supplier to see my result is the same as theirs or not.
 

Welshwizard

Involved In Discussions
#4
TLim_AC,

The nominator can only really change due to some difference with calculating the mean, the other information being your chosen percentage and the tolerance. The denominator is dependent upon the computation of the standard deviation.

Both 2nM and and 6 nM are as near as makes no difference to their ref (if the whole numbers are meant as reference) whilst 10nM is 0.009 nM off its ref. This should meant that only 10nM should slightly differ for its Cgk to its respective Cg.

Cheers
 
Thread starter Similar threads Forum Replies Date
M MSA question on Cg and Cgk Calculation Method and Type of Test Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
I ISO 2233:2000 Question - Medical Device Shipping/Transportation Validation Other ISO and International Standards and European Regulations 0
A Labeling Question (Dietary Supplements/Food) Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 1
N ASL Question for GitHub ISO 13485:2016 - Medical Device Quality Management Systems 6
hogheavenfarm GDT Flatness measurement question Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
A Question on ISO 14001:2015 - Are annual audits required? ISO 14001:2015 Specific Discussions 8
dinaroxentool Question about FDA Classification of a Device 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 3
J Another DFAR question 252.225-7009 AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 0
T GDT Callout Question Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
F Conflict Mineral Smelter Question RoHS, REACH, ELV, IMDS and Restricted Substances 8
R NRTL - Scope Question - Off-the-Shelf Plug In IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
D API 6A Certification Question Oil and Gas Industry Standards and Regulations 4
dinaroxentool Question about qualification as a medical device or accessory in Europe EU Medical Device Regulations 2
R DHR question: Traceability of components ISO 13485:2016 - Medical Device Quality Management Systems 2
C MDR - Question around software accesories EU Medical Device Regulations 2
Watchcat Authoritative References about the Research Question? Quality Tools, Improvement and Analysis 0
T Question about Quality Department employee position titles Quality Manager and Management Related Issues 7
N Question on creepage/clearance requirements for HF Active Accessories for 2nd edition 60601-1 IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
I Question 1 - Nitpicking on Document Approval - can a document approval record be separate? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 6
J Question: How to create an IMDS RoHS, REACH, ELV, IMDS and Restricted Substances 3
K Question on whether IEC 60601-2-62 standard is applied IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
B QMS question in regards to multiple medical devices/products and N/A activities Other Medical Device Related Standards 12
C NB approval - Basic question about Notified Bodies and their role EU Medical Device Regulations 10
G Question about Non-conformances during New Product Introduction Nonconformance and Corrective Action 14
F ISO 13485 8.2.3 Reporting to regulatory authorities: Question regarding a procedure for this clause. ISO 13485:2016 - Medical Device Quality Management Systems 4
O Mitutoyo Digital Caliper to PC USB question General Measurement Device and Calibration Topics 2
R Probability - Need a help to solve the below question Statistical Analysis Tools, Techniques and SPC 5
B Minitab Type 1 Gage Study on True Position Question Measurement Uncertainty (MU) 1
Q Supplier audit question cataloque VDA Standards - Germany's Automotive Standards 0
Ed Panek Inactive key supplier question - We are not actively buying from them ISO 13485:2016 - Medical Device Quality Management Systems 2
T Potential Off-Label Use question 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 5
R Question on determining defective units - I am not recording fixture to part rejected Statistical Analysis Tools, Techniques and SPC 5
Ed Panek Rule 11 Question - CE approvals for software as well as the medical device EU Medical Device Regulations 6
H Question about implications of performing Firmware upgrade via MDDS - Medical Device Data Systems 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 2
D Company Moving - Relabelling Question Medical Device and FDA Regulations and Standards News 0
Ronen E Tolerance intervals (?) question - Flow Rate Probability Range Statistical Analysis Tools, Techniques and SPC 6
S Conformity Assessment Route question for Class IIa medical device under MDR EU Medical Device Regulations 3
K AS9100D 8.4.1.1 external providers question - Walmart, Home Depot, our lawn care team. etc. AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 20
E Question on GD&T added to print - Positional callout for the small holes Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
J IEC 60601-1, ed 3.1 - Blue icon question IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
A PFMEA English language question IATF 16949 - Automotive Quality Systems Standard 4
D GD&T Drawing Question - I have a drawing and it makes no sense to me whatsoever Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
D Yet another torque question... Assembly processes AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 2
A A Question about Continual improvement process in AS9100 AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 4
S Question about a basic additive variance/tolerance example Quality Tools, Improvement and Analysis 2
M Interview question - IMS (Integrated Management Systems) a necessity or an ISO mistake? ISO 14001:2015 Specific Discussions 10
J Question on very low NDC number with tolerable GRR ratio's Capability, Accuracy and Stability - Processes, Machines, etc. 7
M Medical Devices Sterility - Question from A Regulator Other Medical Device Regulations World-Wide 3
N The question asks about sampling plans and AQL Reliability Analysis - Predictions, Testing and Standards 5
L AS9102 Form 1 Section 13 Detail or Assembly Question AS9100, IAQG 9100, Nadcap and related Aerospace Standards and Requirements 2
Similar threads


















































Top Bottom