Sunday 23 December 2018

How to make control chart (map Control)?

Control chart or Map Control is one of the tools of QC 7 tools (7 quality control tools) in the form of graphs and is used to monitor or monitor the stability of a process as well as the study of the process of change from time to time.

Control Chart has the Upper Line (top line) to the Upper Control Limit (highest Control Limits), the Lower Line (bottom line) to the Lower control limit (lowest control Limits) and Central Line (mid line) to average (Average).

The data entered in the form of points that are later described the line to show its graph.

When are we going to use the Control Chart?

  • We want to control the ongoing process by finding and fixing problems that occur

  • When ant to predict or get range (range) of the results of a process

  • To know whether the process we learned is stable (in Statistical control or the control of statistics)

  • When we want to analyze the patterns of variation in process are from specific causes (causes that doesn't happen often or not routinely happen) or common causes which often happens is processed.

  • When we want to determine if the project should aim to improve the quality of prevention on a specific problem or need to make changes to the underlying process.

The main purpose of the use of Control Charts is to control the production process so that it can produce a superior quality by detecting the causes of unnatural variations (Special Causes, the cause of which is not Natural) or called with a process shift (the occurrence of the panning process) as well as to reduce variations found in the process of creating a stable process.

Is a Stable Process being a process that has the same Normal distribution at any time? Please note, that the process of stable is here still have variations, but the variation is very small and can be controlled.

The Procedure of Making Control Charts (Maps Control)

Procedure Control Chart (Map Control) that is not yet known:

  • Select the type of control chart that corresponds to the data that we take.

  • Specify the time period or data retrieval, sampling plan and the amount of data that you want.

  • Data collection and record (a record) of the data, at least 20 to 25 subgroup.

  • Compute each subgroup statistical data, create the tables tabulate to simplify the calculation of the average (X), the average X (X-bar), Range (R) and the average Range (R-bar).

  • Identify the right scale and fit then enter into statistical data.

  • Compute control limits and Central lines (control limit) for UCL and LCL in accordance with their respective control formula chart.

  • Test Chart that has entered the data.

  • Do the investigation and corrective actions if necessary?

Sample Xbar Chart

Xbar Chart

The kinds of Control Chart (Full Map)

There are several kinds of or type of Control Chart depending on the types of Data that we collect to process which we will control:

Control Chart Data Attributes:

  1. NP Chart

  2. p Chart

  3. c Chart

  4. u Chart

Control Chart Data Variables

  1. I – MR Chart

  2. Xbar R Chart

  3. Xbar – S Chart

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