Getting Started with SPC

Easson2D includes SPC (Statistical Process Control) functionality, which automatically collects data from repeated measurements into SPC Manager for viewing data variation, statistical results, and control charts.

SPC is especially suitable for batch measuring identical workpieces. For example, if a measurement program checks the circle diameter, a distance, and an angle, you can run the program continuously to measure multiple workpieces, and Easson2D records each measurement result into the SPC in sequence.

The entire process can be simply understood as:

Set tolerances → Open SPC → run the measurement program repeatedly → automatically accumulate sample data → view SPC analysis results

Opening SPC

Easson2D provides several ways to open SPC Manager.

The most common way is to click:

File → Open SPC Software

You can also open it through the SPC button in the main toolbar or the auxiliary toolbar.

In addition, you can use the shortcut key:

F2

to quickly show or hide the SPC window.

After opening, a separate SPC Manager window is displayed.

Which Measurement Data Enters SPC

Not all measurement data automatically enters SPC.

Only measurement dimensions that have been set with:

• A standard value
• An upper tolerance
• A lower tolerance

become SPC control items.

For example, if the measurement program contains:

• Circle 1 diameter
• X coordinate of Circle 1
• Distance 1
• Angle 1

and tolerances are set only for "Circle 1 diameter" and "Distance 1", then only these two control items appear in SPC.

There is no need to perform additional operations such as "Add to SPC" or "Select SPC data".

After a tolerance is set for a dimension, that dimension automatically becomes an SPC control item.

SPC Item List

After opening SPC Manager, the lower part of the window displays the current SPC item list.

Each dimension with a tolerance set corresponds to an independent control item.

The item list shows:

• Item number
• Control name
• Standard value
• Upper tolerance
• Lower tolerance
• Number of samples
• Number of nonconforming items
• Nonconforming percentage

Clicking different control items switches the upper analysis area to the corresponding measurement data and statistical results.

One Workpiece Corresponds to One Sample

SPC is mainly used together with program-based repeated measurement in Easson2D.

After one complete run of a measurement program, the measurement results of each SPC control item for that workpiece are saved into SPC as a new sample.

For example, if the program has three SPC items:

Circle 1 diameterDistance 1Angle 1

After measuring the first workpiece and completing one program run, SPC obtains:

Sample 1

which contains this run's measurement results for these three items.

After replacing it with a second workpiece and running the program again, the following is added:

Sample 2

Continuing the measurement:

Sample 3 → Sample 4 → Sample 5…

Therefore, a "sample" in SPC can be understood as:

the measurement result of one workpiece obtained from one complete program run.

Measuring Multiple Workpieces in Sequence

Suppose you need to inspect 10 identical workpieces in sequence.

The workflow can be:

1. Record the measurement program.
2. Set standard values and tolerances for the dimensions to be analyzed in SPC.
3. Open SPC Manager.
4. Place the 1st workpiece and run the measurement program.
5. After the program completes, SPC automatically adds Sample 1.
6. Replace it with the 2nd workpiece and run the program again.
7. SPC automatically adds Sample 2.
8. Repeat the measurement until all workpieces are finished.

After the measurements, each control item has a series of consecutive sample data.

For example:

Circle 1 diameter: Sample 1, Sample 2, Sample 3… Sample 10

You can then use this data to view simple analysis charts, group statistics, and SPC control charts.

Real-Time Updates during Measurement

During program execution, SPC can display the results currently being measured.

While the program has not finished, this data belongs to the measurement state of the current workpiece.

Only after a complete program run ends is the result added as a new sample to the SPC data.

Therefore, users usually do not need to manually copy measurement results to SPC.

Main Areas of SPC Manager

SPC Manager consists mainly of two areas:

Analysis Area

Located in the upper part of the window.

You can switch between:

• Sample list
• Group list
• Simple analysis chart
• XBar-R control chart
• XMed-R control chart
• XBar-S control chart
• X-Rm control chart

You can also send the current analysis result to Excel.

Item List

Located in the lower part of the window.

It displays all SPC control items along with their standard values, tolerances, number of samples, and nonconforming status.

Clicking one of the items displays the corresponding SPC analysis results.

Basic Workflow

When using SPC for the first time, follow these steps in order:

Build the measurement program → Set tolerances for the dimensions to be analyzed → Open SPC Manager → Run the program to measure the 1st workpiece → Sample 1 is generated automatically → Replace the workpiece and continue running the program → More samples are accumulated automatically → Select a control item to view statistical results and control charts

The main purpose of SPC is not to replace Easson2D for dimensional measurement, but to perform statistical analysis on data obtained from repeated measurements.

After collecting a certain number of samples, you can further use sample grouping, statistics, and control charts to observe changes in the production process.