Control Plan

By using control plan, you can:

Define and maintain control plans for manufactured, purchased and inventory parts.
Maintain several revisions of a specific control plan.
Use phase-in and phase-out dates to control which revision of a specific control plan is in the Active status.
Connect every manufacturing control plan line to a specific routing operation and work center.
Create sample frequency schedules for control plan inventory.
Decide whether to use statistical process control (SPC) and capability indices.
Connect one or many data points to one or many tools.

Control plans are applicable to a wide range of processes and technologies, and should be viewed as an integral part of an overall quality program.

A control plan is a description of the system for controlling parts and processes to minimize product and process variation. The purpose is to aid in the manufacture of quality products according to customer requirements.

To ensure that all process outputs are in control, a control plan should describe the actions required at each step in the manufacturing process, e.g., at receiving, while in process, and at outgoing. Periodic requirements may also be addressed in the control plan. The control plan does not replace the information contained in detailed operator instructions.

The control plan should be maintained and used throughout the product life cycle. Early in the product life cycle, its primary purpose is to document and communicate the initial plan for process control. Subsequently, it guides manufacturing in how to control the process and ensure product quality. The control plan is to be used as a living document and should be updated as the measurement systems and control methods are evaluated and improved.

Some of the benefits of using control plans are:

Quality – Using control plans reduces waste and improves the quality of products during design, manufacturing, and assembly. Control plans help to identify sources of variation for the process characteristics (input variables), which cause variation in the product characteristics (output variables).
Customer satisfaction – Control plans focus resources on processes and products related to characteristics that are important to the customer.
Communication – Since the control plan should be maintained as a living document, it identifies and communicates changes in the process and product characteristics, control methods, and measurement system.

Control Plan Template

The purpose of a control plan template is to make it easier to create and maintain control plans for a lot of parts. The control plan template is a set of generic data points which specify how a part is going to be controlled or tested. The control plan template can be used to create control plans for many parts or from a control plan header to create control plan lines.

When used for manufacturing parts, it is highly recommended in using routing templates to standardize the routings. Since the data points on the control plan template refer to operation numbers and work centers, this will make it much easier to make sure that the control plan lines refer to the correct operations when applying the control plan template.

The control plan template is site specific, and can be of three types: manufacturing, purchasing and inventory. Control plans can be used from a single control plan or it can be used to create new control plans for several parts.

The control plan template can be used by reference or by copy. When used by reference, ensure when the template changes, these changes can be propagated to the related control plans as well. When copying the template create new control plans with the same content as the template, but with no such reference.

Control Plan Log

Control plan log is a place where you review the messages. Control plan log receives messages mainly when applying template to existing control plan/several parts or when activating control plan template revision. Messages will be logged in for a site.

Log Description

Consists of the details of a process which was executed. It will cause the log ID to be created and the reason will be displayed as a description in the log ID.

Log Reference

Log reference includes, reference type/reference ID 1/ reference ID 2 which indicates what is the base for receiving messages which is indicated in the reference type as template. The other reference will indicate the template ID and the revision number.

Log Detail

Control plan log lines consist mainly of two parts. They are mainly the information about the part/control plan and the information about the message.

Control Plans and MRO

It is possible to use control plans also with parts and shop orders in complex assembly MRO and component MRO flows.

For disposition shop orders, the control plan works as with regular shop orders. All data points for all operations will be included in the control plan connected to the disposition shop order.
Whenever position parts are used on disposition shop orders, disassembly or assembly orders, control plan needs to be set up for the position part.
For MRO shop orders, the repair code decides which operations will be included on the MRO shop order. Since the data points are connected to operations, all data points connected to the operations included in the MRO shop order will be included on the shop order control plan.

Control Plans and Configurable Parts

Control plans can be used with configured parts, at a basic level. This means that control plans for inventory and purchasing are not affected by configuration rules. The same control plan will simply apply whether the part is configured or not. Inventory analyses are created without reference to configuration, which means that samples will be selected from the total stock of the part, not from a specific configuration.

Control plans for manufacturing are affected by configuration rules, since the control plan lines are connected to operations. The control plan can contain several alternative data points that will apply depending on the configuration. The basic rule is to create a control plan line on the shop order if the operation and work center exists on the shop order as a result of the configuration:

If the operation has a condition rule, the control plan line will only be created on the shop order if the corresponding operation also exists on the shop order.
If the operation has a set work center rule, the control plan line will only be created on the shop order if it is connected to the same work center as the operation on the shop order
If the operation has an insert operation rule, the control plan line will be created if the operation exists on the shop order and is connected to the same work center
If the operation has a set operation number rule, the control plan line will be created if the operation exists on the shop order and is connected to the same work center

Sample Frequency Triggers

An analysis can be created manually or automatically. To create an analysis automatically, sample frequency triggers are used. Whether creating an analysis for a specific control plan is required or not is a basic data requirement setting in quality management. When triggers are defined, analyses will be created according to the defined trigger type. Different trigger types are used for purchased parts and manufactured parts.

Trigger types used for manufactured parts are:

Start Shop Order
Nonconforming
Time Interval

Trigger types used for purchased parts are:

At Arrival
Nonconforming
Time Scheduled
Interval Scheduled

Start Shop Order

The start shop order trigger prompts an analysis to be created every time the shop order is set to Started status. This trigger is triggered by the Status badge on the Shop Order page. When the status of the shop order is changed to Started, this also triggers the start shop order trigger. Then the analysis will be created automatically for all the control plan lines (data points) connected to the start shop order trigger.

E.g., If you have a control plan manufacturing (as given below) where all the data points are connected to the start shop order trigger:

Data Point	Routing Operation No	Work Center No
1	10	WC100
2	10	WC100
3	20	WC100
4	20	WC100
5	30	WC200
6	30	WC200

When the status of the shop order is changed to Started, 3 analyses will be created automatically by the start shop order trigger. One analysis will include data points 1 and 2 (routing operation no=10), next analysis will include data points 3 and 4, and the last analysis will include data points 5 and 6.

Nonconforming

If an existing analysis is not fully accepted, then the nonconforming trigger will create an analysis automatically to assure 100% inspection. When the analysis results are confirmed, the status of the data points will also be calculated automatically. If at least one defective item is found, then the nonconforming trigger will be triggered and a new analysis will be created for all data points connected to the specific routing operation number.

E.g., If the three analyses created by the start shop order trigger (refer the example above) are A, B and C:

Analysis A

Data Point	Routing Operation No
1	10
2	10

Analysis B

Data Point	Routing Operation No
3	20
4	20

Analysis C

Data Point	Routing Operation No
5	30
6	30

When the analysis results are entered and confirmed:

Analysis A - No nonconformities are found. The nonconforming trigger will not be triggered.

Analysis B - Three nonconformities are found. The nonconforming trigger is triggered. A new analysis will be created for all data points connected to routing operation number 20.

Time Interval Trigger

This trigger type will create an analysis by the defined time interval. For instance, once every hour. This trigger creates analyses by a frequency specified in the Value field in Define section on the Sample Frequency Triggers tab on the Control Plan - Manufacturing page.

When the status of the routing operation number is changed to In Progress or Partially Reported, the clock starts counting (from zero). This will create one analysis immediately. The next analysis will be created when the time specified in Value field is reached if the time for creating analysis is during working hours. No analysis will be created by this trigger outside working hours.

E.g., If the value specified is 1 hour: the time interval between creating 2 analyses will be 1 hour.

At Arrival

At arrival trigger will create an analysis at every receipt made. For lot/batch tracked parts, an analysis will be created per receipt and lot/batch number.

Time Scheduled Trigger

Here an analysis is created after the specified time interval is reached since the last analysis, at the time of making the next receipt. In other words once the first analysis is created, the next analysis will be created only after the duration since the last analysis is equal to the time specified, when the next receipt is made. For lot/batch tracked parts, an analysis will be created per receipt and lot/batch number.

E.g., If the time specified is 3 days, an analysis will be created 3 days after receipts are made.

Interval Scheduled Trigger

This trigger will create an analysis when the number of receipts made becomes equal to the value specified. The value is specified in the Define section on the Sample Frequency Triggers tab on the Control Plan - Purchasing page.
The example given below will explain this more clearly.

E.g., If the number specified is 3, an analysis is created when 3 receipts are made. For lot/batch tracked parts, an analysis will be created per receipt and lot/batch number.

Trigger: Every third receipt (value = 3)

Receipt Date	No of Receipts since last analysis	Trigger Criteria fulfilled	Create Analysis
2004-06-01	0	Yes	Yes
2004-06-05	1	No	No
2004-06-08	2	No	No
2004-06-20	3	Yes	Yes
2004-06-21	1	No	No
2004-07-20	2	No	No
2004-12-31	3	Yes	Yes

Once the sample frequency trigger types are defined, next step is to connect the defined trigger types to the preferred data points. An analysis created by a trigger will only include data points connected to the trigger. A specific data point can be connected to none, one or many triggers.

Tools

It is possible to connect one or several tools for each data point in the control plan. For a data point connected to one or many tools it will be mandatory to select a tool instance when entering analysis results. This means you make sure that the correct tool is used and get traceability regarding what tool instance was used for a specific data point.

Variables, Attributes and Categorical Data

Every defined control plan line (data point) must have a data type. There are three data types available:

Attribute
Variable
Categorical

Attribute are used for qualitative data, i.e. data that approximates or characterizes but does not measure the attributes, characteristics, properties, etc., of a thing or phenomenon. When entering analysis results the number of found nonconformities and nonconforming items is entered. If for example 10 items was inspected and a total of 8 scratches was found on 3 items, the number of nonconforming items is 3, and the number of nonconformities is 8.

Variable are used for quantitative data, i.e. data that can be quantified and verified and is amenable to statistical manipulation. A data point defined as a Variable must have defined specification limits. When entering analysis results the actual result value is entered and evaluated against the specification limits.

Categorical is used for data that can be organized into mutually exclusive categories, for example "Pass/Fail", "Yes/No", "Red/Green/Blue". Categorical is typically used to create surveys and checklists with predefined answering alternatives. There are two options how to enter analysis results for categorical data. If Single Row has been selected in the Category Entry Type field in the control plan, one of the defined category values is selected, for instance "Pass" or "Fail". This is typically used when the inspection sample size = 1. If Multiple Row has been selected the actual quantity of each defined category value is entered. For example 8 "Pass" and 2 "Fail". This is typically used when the inspection sample size > 1.

Restricted and Simplified Revision Handling of Control Plans

It is possible to control on site, part (site independent) and part/site level whether the restricted or simplified revision handling should be used for a specific control plan.

When Simplified Revision Handling is disabled the revision handling is restricted. Control plan revision in status Active or Inactive can not be edited in any way. To edit the control plan, a new revision has to be created.

When Simplified Revision Handling is enabled, the control plan revision, in status Active or Inactive can be edited without having to create a new revision of the control plan.

Control plan lines (data points) can be added, deleted or edited.
Sample frequency triggers can be added, deleted or edited.
Tools can be added, deleted or edited.
General control plan information can be edited.

It is important to notice that any change made to the control plan revision will not in any way affect historical data. Existing analysis results and control plans connected to shop orders and purchase orders will not be affected.

Most, but not all, control plan information can be edited when simplified revision handling is used.

Fields that are used to uniquely identify a specific control plan revision, for instance Part, Site and Control Plan No cannot be edited.
Fields that affect statistical calculations such as for instance acceptance sampling settings, cannot be edited.

When simplified revision handling is used all changes made to the control plan revision can be viewed in the system generated history log (who changed what and when).