Manual for basic use of minitab

MANUAL FOR THE PREPARATION OF A PARETO GRAPH:

To generate a histogram in Minitab, do the following:

Insert the data in the worksheet columns in this case we will use the column C1 Defect and C2 Total (see image No.-1). Select STAT in the options bar, it will be displayed with a series of options which will select QUALITY TOOLS and then click on Pareto chart (see image No.-2).

minitab-manual-over-pareto-range-histogram-GRR

Image No.-2 minitab menu.

A box will appear on your screen where you will place the default column, in this case it is C1, then the frequency which is C2, press ok and it will graphically give you the Pareto (see image No.-3 and No. 4).

Image No.-3 Pareto menu.

Image No.- 4 Pareto chart.

RANK:

Range is the interval between the maximum value and the minimum value; therefore, it shares drives with the data. It allows to get an idea of the dispersion of the data, the larger the range, the more dispersed the data in a set is.

Example: the difference between the smallest and largest value

In {4, 6, 9, 3, 7} the smallest value is 3, and the largest is 9, so the range is 9-3 equal to 6.

Creating a movable range graph .

Subtract the value from each of the values obtained, this will generate each individual value of the movable range.

Calculating the moving range average.

Add up all the individual values in the movable range and divide by the amount of data generated.

Calculating the control limits of the movable range.

Divide the average result by 1.28 and multiply by 3, then add the average value.

Range Chart:

This shows the lower control limit (LCL), the average (MR), upper control limit (UCL), as well as the individual values of the ranges.

(See image No.- 5).

Image No.- 6 graphs of individual values.

To generate a movable range graph in Minitab, follow the steps below.

Choose Stat > Control Chart > Variable Chart for Individuals > I-MR.

Image No.-7 movable range chart menu.

Next, in the section in the Variables section > select the column with the data to be plotted, finally select Ok (see image No.-8)

Image No.- 9 selection of variables.

Select the I-MR Options > option, the special causes you want to select will appear on the graph (see image No.-10).

Image No.- 10 option I-MR.

In the upper part of the graph you can see the Individual Observations (I) and in the lower graph the value of the Movable Ranges (MR), the latter is the subtraction of each of the individual values consecutively (see image

No.-11 and No.-12).

(In the descriptive statistics table you can see if there are any special features that need to be checked).

Image No.-11 graph of individual values.

Graph of Individual Observations (I) and Moving Ranges (MR)

Image No.- 12 graph of movable ranges.

HISTOGRAM:

To generate a histogram in Minitab, do the following:

Insert the data in the worksheet columns, in this case we will use column C1 Total, then Choose Graph > Histogram (see image No.- 13).

Image No.- 13 menu for histogram graph.

Select the type of histogram that is required, in this case we will select the simple one and click on OK (see image No.-14).

Image No.-14 types of histogram.

In the left part of the window we will select the data for the histogram, in this case we will use the column C1 Total, we will give it a click and then the word " Total " will move to the right side as shown in the image, then we will use the values by Minitab's default to create the histogram and as a final result the histogram will be displayed on the screen (see image No.-16).

Image No.- 16 histogram.

Note: If you want to make a histogram with a curve like the one in the image below, you must select the histogram with fit option in the second step of the tutorial and repeat all subsequent steps. X Graph - R: What is an X graph?

An X chart shows the process mean and process standard deviation over time for variable data in subgroups. This combination control chart is widely used to examine the stability of processes in many industries.

For this, the following steps are carried out:

Insert the data in the worksheet columns in this case we will use column C1 and C2 (see image No.- 19).

Image No.-19 columns of minitab.

Next step in the stat bar. Control Charts, Variable charts for subgroups, and Xbar-R graph (see image No.- 20).

Image No.-21 graphic menu x.

As step 3; We select column C1 to be our variable. And C2 as our subgroup (see image No.-22).

Image No.-22 selection of variables.

Our graph would be as follows, to show us our values higher or lower than the average (see image No.-23).

Image No.-23 graph x.

The X and S charts are shown together because you must interpret both charts to determine if your process is stable. Examine the S chart first because the process must be under control in order to correctly interpret the X chart. The control limits for the X chart are calculated considering both the spread of the process and the center of the process. If the S chart is out of control, then the control limits on the X chart could be inaccurate and could falsely indicate an out of control condition or would not detect it.

Repeatability and reproducibility in measurement systems:

Repeatability

Ability of an operator to uniformly repeat the same measurement of the same part, using the same measurement system, under the same conditions.

Operator 1 measures a part with gage A 20 times and then measures the same part with gage B.

The solid line represents measurements with Measurement System A. The dotted line represents measurements with Measurement System B. Measurement System A has fewer variations, therefore it is more repeatable than Measurement System B.

Reproducibility

Ability of a measurement system, used by several operators, to uniformly reproduce the same measurement of the same part, under the same conditions.

Operators 1, 2 and 3 measure the same part 20 times with the same measurement system.

The three lines represent the measurements of operator 1, 2, and 3. The variation in average measurements between Appraisers 1 and 2 is much less than the variation between Appraisers 1 and 3. Therefore, the reproducibility of the measurement system is Too low.

Steps to build an R&R analysis in minitab.

Step 1 select the analysis information to be evaluated and place in the first measurement column, and in the last column the measurement that has been obtained (see image No.-24).

Choose Stat > Control Chart > Variable Chart for Individuals > I-MR.

Image No.- 24 entry of values in minitab.

Step 2

Configure the analysis (see image No.- 25, No.-26 and No.-27).