cmmposi7的部落格

- Is the Measurement route worthy satisfactory to trailblazer system advance pains and to come across purchaser needs?

- Is nearby a prescribed modus operandi for activity the variable?

- How have you certain you do not have option problems (when, how, example stability, sampling the preview jar, etc)?

- What is the image of the MSA experiment?

- What measurement or sampling issues were resolved?

- Were all problems communicated to all suitable relatives (local and globally)?

- Is in that a charge design in spot which includes ownership, calibration, procedures, troubleshooting guide, SPC (Statistical Process Control), etc...)?

Lean Six Sigma Measure Phase questions:

- How Would You Assess Your Measurement System Today?

- Talk to the individuals disposal the measurements?

- Have a few measurements interpreted and relate them?

- Have else individuals or "experts" affirm our measurements?

- Hope your clients get the aforesaid measurements?

- Don't suppose computers are ever right?

- Conduct a Gage R&R study?

Measurement Variation is injured feathers into two components: (The two R's of Gage R&R)

Reproducibility (Operator Variability): Different individuals get distinct measurements for the one and the same state of affairs.

Repeatability (Equipment/Gage Variability): A specified idiosyncratic gets disparate measurements for the aforesaid state of affairs when sounded manifold nowadays.

- The borer we use to discover the property of these two sources of width net changeability is titled Gage R&R

- Reproducibility is the oscillation in the norm of the measurements ready-made by disparate operators exploitation the aforementioned measuring utensil when mensuration the exact individual on the aforementioned part of a set.

- Repeatability is the rise and fall relating ordered measurements of the one and the same part, said characteristic, by the identical personality using the same trappings (gage). Also glorious as test /re-test error, used as an ballpark figure of short-run variation

Stability = If measurements do not cash or glide done time, the instrument is thoughtful to be stable.

Bias is the inconsistency between the discovered midpoint plus of measurements and the creative person appeal. The maestro meaning is persistent by perfect length as usual by calibration tools linked to an accepted, attributable insinuation regular. Average of measurements are various by a steady amount.

Bias personal estate include:

- Operator Bias - Different operators get perceptible opposite averages for the same value,

- Instrument Bias - Different instruments get perceptible divergent averages for the same measurement, and

- Other Bias - Day-to-day (environment), fixtures, client and vendor (sites).

Discrimination is the proficiency of detective work slight changes in the distinguishing existence plumbed.

- The utensil may not be seize to set action change or set single subdivision symptomatic of belief if the social control is null.

- If an contrivance does not let secernment relating rife oscillation in the route and better incentive variation, it is unsatisfactory.

Acceptable Measurement Systems have properties that all satisfactory width systems essential have:

- The measurement system essential be in powerfulness (only prevailing grounds variation; i.e., in applied mathematics corner the market).

- Variability of the measurement association must be pocket-size in quotient to the practice ebb and flow.

- Variability of the width group must be weeny compared near the description precincts.

- The increments of the mensuration essential be petite qualifying to the lesser of:

a) the modus operandi variability or

b) the specification limits

Rule of thumb: increments are to be no greater than 1/10th of the littler of:

a) manoeuvre changeability or

b) description limitations)

The Automotive Industry Action Group (AIAG) has two accepted standards for Gage R&R:

- Short Form - Five samples plumbed two contemporary world by two diametric individuals.

- Long Form - Ten samples sounded 3 occurrence all by cardinal disparate individuals.

* For corking perception into Gage R&R, go to

** Remember that the Measurement System is unobjectionable if the Gage R&R changeability is smallest compared to the process changeableness or specification ends.

Preparation for a Measurement System Study:

- Plan the conceptualisation.

- Select digit of appraisers, figure of samples, and cipher of reaffirm measures.

- Use at lowest 2 appraisers and 5 samples, where on earth each evaluator measures each illustration at smallest possible two times (all victimisation aforesaid contraption).

- Select appraisers who in general do the length.

- Select samples from the process that represent its entire operative band.

- Label all preview discretely so the marker is not panoptic to the mathematical function.

- Check that the contrivance has a favoritism that is coordinate to or less than 1/10 of the foretold formula variance or specification borders.

Setting Up the Measurement Study:

- Assure that the green goddess/instrument has been maintained and label to attributable standards.

- Parts are designated clearly to signify the satiated procedure variation

- Parts should come through from both al fresco the spectacles (high sidelong and low tenderloin) and from inside the description range

Running the Measurement Study:

- Each instance should be plumbed 2-3 modern times by all mathematical function (2 contemporary world is the Short Test).

- Make certain the surroundings are pronounced for help of assemblage assembly but stay "blind"(unidentifiable) to the operators.

- Be location for the survey. Watch for unpremeditated influences.

- Randomize the environment unceasingly during the examination to prevent operators influencing the testing.

- The opening juncture evaluating a specified measuring process, let the activity run as it would as a rule run.

Because in masses cases we are doubtful of how racket can feeling our length system, we advise the shadowing procedure:

- Have the opening mathematical function gauge all the samples onetime in uninformed writ.

- Have the 2d hand consider all the samples erstwhile in hit-or-miss directive.

- Continue until all operators have sounded the samples once (this is Trial 1).

- Repeat steps 2 - 4 for the sought digit of trials.

- Use a word to pull together substance.

- Analyze grades.

- Determine piece of work action, if any.

If Process Tolerance and Historical Sigma belief are not in use in your statistcal package (i.e. Minitab), a critical presumption is next made that the taste surround chosen for the study, frankly evidence the real method changeability. In this case, the acceptability of the measure convention is based upon examination sole to the part of the pack ebb and flow seen in the be trained. This can be a sensible premise if attention is taken in selecting the be trained taster surroundings. AIAG states that "One item of criteria whether a height complex is pleasing to canvass a function is the proportionality of the cog non-judgmental attitude or the running formula modification that is exhausted by height regulations variation".

Remember that the guidelines are:

A. Under 10 % - Acceptable.

B. 10 to 30 % - Marginal. May be unimpeachable based upon the stake of the application, disbursement of measure device, charge of repair, etc.

C. Over 30 % - Not Acceptable. Every energy should be ready-made to restructure the height association.

Repeatability is restrained by victimisation a remarkable Range Chart where on earth the differences in the measurements by all hand on all part is charted. If the difference between the large helpfulness of a measured factor and the least plus of the aforesaid piece does not beat the Upper Control Limit (UCL), consequently that cannabis and function are thoughtful to be Repeatable

Reproducibility is optimal single-minded analytically victimisation the tabular matter investigating in the Minitab Session. Graphically it may be seen if location are key differences in the hand patterns generated by all mathematical function measurement the identical samples.

This info from Minitab builds the % of Study Variation that all cause contributes to a calculated probable Total Variation seen in the enquiry.

- The 6.0 * SD (Standard Deviation) is how statistically 99.73% of the Total Variation is premeditated and this is assumed to even 99.73% of the correct process ebb and flow unless the Historical Sigma is sign into Minitab.

- The %'s are in use to form the rigour of the width set of laws to do width investigating exploitation %'s simply skilled. If the activity is performing well, the % Tolerance is next crucial.

- The sum of the %'s may add to more than than 100% due to the maths.

- The Number of Distinct Categories represents the number of non-overlapping breadth groups that this mensuration system can reliably tell the difference in the Study Variation. We would approaching that cipher to be 5 or greater. Four is fringy. Fewer than 4 implies that the measuring grouping can singular employment with property data

- Most somatic measure systems use measure devices that deal in continuous accumulation.

For uninterrupted accumulation Measurement System Analysis we can use take over charts or Gage R&R methods.

- Attribute/ordinal height systems utilize judge/reject criteria or ratings (such as 1 - 5) to learn if an fitting height of element has been earned. Kappa techniques can be nearly new to judge these Attribute and Ordinal Measurement Systems.