Table of Contents
What is a CG value?
Cgk decreases as the difference between the gage’s mean measurement and the reference value increases. A Cgk value of 1.33 is a common benchmark value to denote a capable gage – one that is both precise (good repeatability) and accurate (low bias). Term. Description. K.
What is CG in quality?
Cg=(allowable variation)/(actual variation). The differences are what we take for allowable and actual variation. For Cp, the actual variation is the process variation, and the allowed variation is the specification range. For Cg, the actual variation is the INSTRUMENT ALONE variation (6 x Sinst).
What is the difference between CPK and CMK?
It describes the capability corrected for position. The formula to calculate Cmk is same as Cpk, but the standard deviation used here is sample standard deviation. But, for Cpk standard deviation is measured from the control chart, as this is a measure of process performance.
What is a Type 1 MSA?
The most fundamental MSA experiment is the Type 1 Gage Study. This involves measuring a single calibrated reference part a number of times, ideally 50 or more. The mean of all the measurement results, minus the reference part’s calibrated value, is the bias.
How do you calculate CG?
Center of gravity (CG) is calculated as follows:
- Determine the weights and arms of all mass within the aircraft.
- Multiply weights by arms for all mass to calculate moments.
- Add the moments of all mass together.
- Divide the total moment by the total mass of the aircraft to give an overall arm.
How do you read MSA results?
If the % Gage R&R is under 10%, the measurement system is generally considered to be an adequate measurement system. If the % Gage R&R is between 10 % to 30%, the measurement system may be acceptable for some applications. If the % Gage R&R is over 30%, the measurement system is considered to be unacceptable.
How is Sigma CG calculated?
Here is the five-step process to calculate your process sigma.
- Step 1: Define Your Opportunities. An opportunity is the lowest defect noticeable by a customer.
- Step 2: Define Your Defects.
- Step 3: Measure Your Opportunities and Defects.
- Step 4: Calculate Your Yield.
- Step 5: Look Up Process Sigma.
What is gage capability?
Gage Repeatability and Reproducibility (Gage R & R) is a methodology used to define the amount of variation in the measurement data due to the measurement system. It then compares measurement variation to the total variability observed, consequently defining the capability of the measurement system.
What is CG in MSA?
Gage capability is also commonly expressed as Cg and Cgk. Cg refers to the ratio between precision and tolerance (the potential capability) while Cgk denotes the ratio between the accuracy and the tolerance (the actual capability).
What is an acceptable MSA?
The %GRR value is then compared to the AIAG guidelines for what makes a measurement system acceptable. These guidelines are: Under 10%: generally considered to be an adequate measurement system. 10 % to 30%: may be acceptable for some applications. Over 30%: considered to be unacceptable.
Why is centre of gravity important?
It is important to know the centre of gravity because it predicts the behaviour of a moving body when acted on by gravity. It is also useful in designing static structures such as buildings and bridges. In a uniform gravitational field, the centre of gravity is identical to the centre of mass.
How do you calculate CG of a load?
In words it reads that the location of the CoG can be found by summing (Σ) the multiplication of the distance by the weight (area) and divide it by the summation of all the weights (areas). Since this is a two-dimensional object, this calculation should be performed in x-direction as well as y-direction.
What is a good MSA score?
What is a ‘good’ index score? A carcase with a higher MSA index will have higher beef eating quality scores for many cuts compared to a lower MSA index carcase. Currently the average MSA Index score is 57. Indexes over 61 are in the top 10% of cattle.
What is a good sigma value?
Usually, a process with a Sigma Level of 6 or greater is usually considered as an excellent process.
What is an acceptable gage R&R?
Why is Cpk 1.33 Good?
From the Cpk value, one can derive that Machine 1 is better than 2. Since Cpk uses specification limits and parts variation (sigma), we can also arrive at the yield processed and losses from the machine. Cpk = or >1.33 indicates that the process is capable and meets specification limits.
What does Cpk 1.33 means?
In general, the higher the Cpk, the better. A Cpk value less than 1.0 is considered poor and the process is not capable. A value between 1.0 and 1.33 is considered barely capable, and a value greater than 1.33 is considered capable.