mtogos的部落格

- Is the Measurement route honourable ample to direct act raise hard work and to touch user needs?

- Is near a pro forma modus operandi for measuring the variable?

- How have you motivated you do not have option technical hitches (when, how, preview stability, pick the indication jar, etc)?

- What is the logo of the MSA experiment?

- What measuring or pick issues were resolved?

- Were all teething troubles communicated to all due empire (local and globally)?

- Is in attendance a hog outline in pop 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 administration the measurements?

- Have a few measurements interpreted and similitude them?

- Have remaining individuals or "experts" verify our measurements?

- Hope your clientele get the said measurements?

- Don't imagine computers are e'er right?

- Conduct a Gage R&R study?

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

Reproducibility (Operator Variability): Different individuals get contrastive measurements for the said situation.

Repeatability (Equipment/Gage Variability): A fixed not public gets divergent measurements for the self item when plumbed octuple modern world.

- The bit we use to establish the enormity of these two sources of measuring grouping variation is named Gage R&R

- Reproducibility is the fluctuation in the middle of the measurements made by various operators mistreatment the one and the same mensuration device when measurement the identical distinctive on the self fragment.

- Repeatability is the instability betwixt repeated measurements of the one and the same part, aforementioned characteristic, by the one and the same personage using the very implements (gage). Also best-known as audition /re-test error, in use as an estimate of short-term variation

Stability = If measurements do not renovation or fan complete time, the device is well thought out to be stable.

Bias is the lack of correspondence betwixt the determined norm effectiveness of measurements and the creative person plus. The artist worth is strong-willed by meticulous height routinely by calibration tools coupled to an accepted, traceable mention modular. Average of measurements are different by a rigid magnitude.

Bias personal estate include:

- Operator Bias - Different operators get perceptible opposing averages for the very value,

- Instrument Bias - Different instruments get detectable distinct averages for the self measurement, and

- Other Bias - Day-to-day (environment), fixtures, user and outlet (sites).

Discrimination is the ability of police work insignificant changes in the distinguishing anyone sounded.

- The utensil may not be in order to set modus operandi rise and fall or fix own relation personal values if the discrimination is not up to scratch.

- If an means does not permit discrimination linking undivided alteration in the system and privileged exact variation, it is failing.

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

- The height net essential be in legalize (only public bring variation; i.e., in statistical police).

- Variability of the height association essential be itsy-bitsy in proportion to the modus operandi variability.

- Variability of the measurement set of contacts essential be pocket-size compared next to the specification margins.

- The increments of the mensuration must be least virtual to the lesser of:

a) the procedure changeability or

b) the spec limits

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

a) procedure volatility or

b) description precincts)

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

- Short Form - Five samples sounded two modern world by two diametrical individuals.

- Long Form - Ten samples measured 3 example all by three variant individuals.

* For appropriate intelligence into Gage R&R, go to

** Remember that the Measurement System is legitimate if the Gage R&R changeability is squat compared to the route variableness or specification ends.

Preparation for a Measurement System Study:

- Plan the conceptualization.

- Select digit of appraisers, digit of samples, and digit of restate measures.

- Use at lowest possible 2 appraisers and 5 samples, wherever all appraiser measures respectively taster at lowest double (all exploitation aforesaid appliance).

- Select appraisers who usually do the mensuration.

- Select samples from the route that be its whole operational compass.

- Label all token discretely so the label is not visual to the worker.

- Check that the instrument has a favoritism that is identical to or smaller number than 1/10 of the matter-of-course act changeableness or verbal description boundaries.

Setting Up the Measurement Study:

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

- Parts are preferred freeway to be a symbol of the engorged system variation

- Parts should come from both shell the glasses (high on the side and low broadside) and from in the description range

Running the Measurement Study:

- Each token should be sounded 2-3 contemporary world by all worker (2 nowadays is the Short Test).

- Make convinced the surroundings are dotted for mitigate of data album but stay "blind"(unidentifiable) to the operators.

- Be in attendance for the inspection. Watch for ad hoc influences.

- Randomize the surroundings continuously during the examination to prevent operators influencing the mental measurement.

- The archetypical instance evaluating a given mensuration process, let the practice run as it would ordinarily run.

Because in abundant cases we are undecided of how clatter can feeling our breadth system, we propose the subsequent procedure:

- Have the premier worker standard all the samples former in subjective order.

- Have the 2d mathematical function measuring all the samples past in subjective writ.

- Continue until all operators have measured the samples sometime (this is Trial 1).

- Repeat stepladder 2 - 4 for the needed number of trials.

- Use a way to pool news.

- Analyze results.

- Determine piece of work action, if any.

If Process Tolerance and Historical Sigma values are not used in your statistcal package (i.e. Minitab), a negative presumption is past made that the example surroundings designated for the study, really evidence the sincere system variability. In this case, the acceptability of the activity complex is supported upon scrutiny simply to the component ebb and flow seen in the survey. This can be a logical supposition if contemplation is taken in selecting the be taught example environs. AIAG states that "One constituent of criteria whether a breadth complex is bankable to study a system is the percentage of the element moderation or the effective procedure changeability that is exhausted by height group variation".

Remember that the guidelines are:

A. Under 10 % - Acceptable.

B. 10 to 30 % - Marginal. May be bankable supported upon the danger of the application, damage of breadth device, sum of repair, etc.

C. Over 30 % - Not Acceptable. Every endeavour should be made to meliorate the length group.

Repeatability is curbed by using a specific Range Chart wherever the differences in the measurements by respectively hand on all quantity is charted. If the disproportion betwixt the greatest convenience of a measured division and the small utility of the aforesaid slice does not surpass the Upper Control Limit (UCL), after that mary jane and hand are thoughtful to be Repeatable

Reproducibility is uncomparable resolute analytically exploitation the information investigating in the Minitab Session. Graphically it may be seen if location are remarkable differences in the worker patterns generated by each function measurement the one and the same samples.

This information from Minitab builds the % of Study Variation that all spring contributes to a calculated soon-to-be Total Variation seen in the office.

- The 6.0 * SD (Standard Deviation) is how statistically 99.73% of the Total Variation is deliberate and this is acknowledged to the same 99.73% of the faithful action rise and fall unless the Historical Sigma is sign into Minitab.

- The %'s are in use to class the cogency of the measuring scheme to achieve measuring analysis mistreatment %'s simply schooled. If the procedure is playacting well, the % Tolerance is after eminent.

- The sum of the %'s may add to much than 100% due to the scientific discipline.

- The Number of Distinct Categories represents the figure of non-overlapping height groups that this measurement rules can dependably tell the difference in the Study Variation. We would similar to that figure to be 5 or superior. Four is fringy. Fewer than 4 implies that the measure rules can single industry next to dimension data

- Most corporeal length systems use width devices that distribute ceaseless accumulation.

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

- Attribute/ordinal breadth systems utilize adopt/reject criteria or ratings (such as 1 - 5) to find out if an all right horizontal of competence has been attained. Kappa techniques can be previously owned to judge these Attribute and Ordinal Measurement Systems.