QRM POLCA

Hans-Heinrich Glöckner - Aldert van der Stoel

Stef Tiggeloven - Vincent Wiegel - Jana Pejchinovska

An initiative of HAN University of Applied Sciences

Based on the work of Rajan Suri This product has been released subject to the creative commons conditions of Attribution-ShareAlike 3.0 Netherlands (CC BY-SA 3.0).

PDCA

PLAN DO

CHECK ACT/ADJUST

3

© 2012 QRM Center @Arnhem – HAN University of Applied Sciences

PLAN DO

CHECK ACT/ADJUST

Title:

Owner:

Version:

Date:

Process:

Sub-process:

Introduction / summary: Roles: Time:

1. Create a steering committee for the POLCA project.

2. Appoint POLCA champion (senior manager) who will be the owner of the process.

3. Determine and implement work cells in the workplace.

4. Determine lead time planning for the work cells involved in POLCA implementation.

5. Determine rough cut capacity planning from the MRP to ensure that POLCA has sufficient capacity .

6. Ensure that the scheduling system used at the company has capability to produce release lists that include release date and next step in the routing.

7. Establish cross-functional POLCA team of personnel who have roles in delivering the specific product family or FTMS

8. Train and educate the team on general concepts of POLCA and specific steps of the implementation.

Suri, R; Krishnamurthy, A, How to plan and implement POLCA

Suri, R. It’s About Time , Appendix C and D

1. Determine lead times per cell.

2. Set the capacity planning per cell.

3. Develop dispatch lists (based on release date and routing from the scheduling system).

4. Identify and design the POLCA loops.

5. Design POLCA cards.

6. Determine the amount of work which a POLCA cards represents.

7. Calculate the number of POLCA cards per loop.

8. Train staff to become familiar wit the basic principles of POLCA and the application of POLCA within your company.

9. Start POLCA implementation.

Suri, R; Krishnamurthy, A, How to plan and implement POLCA

Suri, R. It’s About Time , Appendix C and D

Suri, R, Quick Response Manufacturing

Riezebos, J. Design of POLCA material control systems

QRM POLCA

Jana Pejchinovska

V0.3

31/05/12

POLCA

POLCA design 2.1

Steering Committe, POLCA Champion, POLCA Implementation Team (production managers, operators, schedulers, etc.)

This module focuses on the design, planning and realization of a POLCA-implementation for a product family or a FTMS.

1. Measure performance improvement through the following indicators:

• Lead time per FTMS,

• Throughput time of cells,

• Delivery reliability of orders,

• WIP inventories at certain points in production.

2. Measure productivity improvement

• Make sure you consider the team dynamics influence in addition to individual performance.

3. Measure qualitative improvement through following indicators:

• Stress levels,

• Operator morale,

• Employee satisfaction,

• Communication ,

• Corporate culture and value system.

Suri, R; Krishnamurthy, A, How to plan and implement POLCA

<various activities involved>

3

Before starting with POLCA implementation conduct a POLCA Scan

to determine suitability and readiness for

POLCA.

Assign color to the work cells for

easier identification.

Measuring performance improvement is

necessary step after POLCA implementation.

What How When Status

Activity Roles Date PDCA

Schedule reviews to identify unnoticed issues and follow-up sessions to communicate progress of the project with upper management

POLCA Team During and after implementation

Assign responsibilities and ownership of cells back to the cell teams

POLCA Team, workers

After implementation

Run POLCA Audit to identify opportunities for improvement

POLCA Team, After implementation

If some of the planning steps are not yet

implemented they should be set as activities in the

DO stage .

Achievements of the POLCA team

should be recognized by the

management.

Member of the POLCA team should

be dedicated to these activities full

time.

Measuring productivity improvement is highly

recommended, and qualitative improvement

is beneficial and suggested.

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Instructions

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What and why POLCA

What • POLCA (Paired-cell Overlapping Loops of Cards with Authorization)

is a material system for coordinating and monitoring the flow of the goods on the shop floor.

• Coordination is achieved through organizational flexibility, material planning and release approach, and prevention of congestion.

Why • Companies that manufacture large variety of products or offer

engineered products can not achieve lead time reduction using the traditional scheduling of production based on MRP planning.

• POLCA enables lead time reduction for companies that operate in markets with unpredictable and frequently changing demand, and/or focus on customization.

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POLCA work cells

• A POLCA cell is a group of different machines and multi-skilled workers (who can operate more than one machine), responsible for quality and delivery performance arranged in a way to perform more than one operation and produce similar products that belong to a product family or FTMS

• To goal of a POLCA cell is to start with a (raw)material and end with a (semi)finished product.

• Questions to ask, when creating the work cells: – How should a work cell be designed? – How should a work cell look?

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Designing the work cells

• Dedication to a product family or FTMS – Question to be asked: Which product family or FTMS

will be served by this cell?

– Issues to consider: • A cell should be a combination of different resources and

operations, located close to each other dedicated to produce similar products that belong to the same product family or FTMS.

• Dedication to a single FTMS allows reduction in setup times and machine down times, smaller lot sizes, quality and process improvements.

– The aim is to create flexible, simple and clear flow.

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Designing the work cells

• Assigning resources to the cells – Question to be asked: What resources and how many are dedicated to a

certain cell? • Workers, • Machines, • Tools, • Information.

– Characteristics of the resources dedicated to a cell: • Cross trained workforce: workers can operate more than one machine to

offset variation in different operations. • Focus on lead time reduction: In POLCA cells workers assign themselves to a

new job, once they become free and keep the focus on lead time reduction. • Self managed teams: workers are responsible for the performance of the cell,

with respect to productivity, quality and delivery accuracy.

– The aim is to create focused structure of people and machines that are dedicated to manufacturing products that belong to a product family or FTMS.

It is often the case that one cell

contains more machines than

workers

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Designing the work cells

• Closeness and collocation of resources – Question to be asked: How close are the workers and

machines located within a cell? – Issues to consider:

• Limitations of physical space, • Size of machines, • Safety requirements for placement of machines, • Size of transfer batches (cells allow use of smaller batches), • Exceptions :

– E.g. expensive machines that need to be shared among several FTMS.

– The aim is to increase the visibility of jobs and establish easier control.

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Designing the work cells

• Processing several operations per work order – Question to be asked: How is the cell capable of

processing several operations for jobs that belong to a specific product family or FTMS?

– Issues to consider: • Product design, material and technology used,

• Order of operations,

• Necessity of processing steps.

– The aim is to complete all the operations for a FTMS within the cell, so that products return to a cell as little as possible.

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Additional tips for designing the work cells

• Large machines which are used as a shared resource can be replaced by smaller machines that are assigned to a cell. Seek for efficiency on a smaller scale by relying on technology.

• Reconsider the sequence of operations for better efficiency that can be achieved with cells.

• If an operation can not be included in a cell, due to space requirements or sharing, planning can be done using time-slicing. This means that different cell teams can be assigned to a shared process for certain amount of time. This is a way to maintain ownership tasks in the cell.

• Work cells should have internal flexibility

when deciding on the mode of operation

and the material handling within the cell.

Sometimes best results can be achieved by

combining several strategies together.

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Cross-functional teams

• Cross-training of workers ensures continuous operation of a cell, despite abseentism, disruptions, etc.

• Cross-functional teams should be managed to ensure increase of productivity in all stages of production.

• Issues to consider: – Motivation of workers to work faster or slower, – Loss of efficiency due to frequent change of tasks.

• In POLCA motivation increases naturally due to real-time feedback made available by working together in same area.

• The degree of worker flexibility is dependant on the specific objective for a cell. These objectives are typically maximum utilization of available capacity and maximum productivity – When the objective is to have maximum utilization of available capacity, there

should be a focus of fully cross-trained workers; – When the objective is maximum productivity, the degree of cross training can be

lower. • Example: In labor intensive cells, where frequent changes of tasks reduce productivity.

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Determining lead times per cell

• The release of orders on the shop floor under POLCA is dependent on the lead times of the cells. The lead time in turn is affected by capacity utilization, variation in processing times, batch size, work content, etc.

• Before starting with POLCA it is important to check if the available data about lead times is accurate. – It is important to establish whether the data from the ERP system

represents the actual production situation. – Lead time should have clear and well defined start and end

points, and measurement units.

• A prerequisite for POLCA implementation is to have estimation on the lead times per cell and information about work content.

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Determining capacity planning

Operating at lower utilization levels will foster lead time reduction and allow spare capacity to accommodate rush orders or other unplanned events in production.

Utilization has great impact on the lead time. The bigger the utilization percentage, the lead time will increase more rapidly.

– Utilization should be considered not as the time when machines are actually running, but as the total time the machine is occupied (for all tasks*) relative to the total time planned.

This influence of the utilization on the lead time is even greater when there is variability present.

Adjust the planning to 70%

or 80% of the available capacity.

*including maintenance, repairs, etc.

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Developing dispatch lists

• Start of work processing in POLCA is controlled by dispatch lists: – A dispatch (release) list is designed specifically for each

cell in the system. It contains list of all the operations that should be performed in a cell, the earliest start date for a cell and the next cell in the routing.

– To determine the earliest start date for a cell it is important to know both the processing time and the waiting time for each cell and then perform backward scheduling • As an alternative data from ERP system can be used, as long

as it is correct and reliable. Check the “Template”

section for an example of a dispatch list

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POLCA loops

B

A

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D

C F

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POLCA loop

POLCA Loops is a pair of cells through which POLCA cards circulate

Loops overlap throughout the routing of a job

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Identifying the POLCA loops

• Identification of loops can be done in a four step process:

1. Determine the product family or FTMS that should be controlled using POLCA.

2. Make an overview of the inter-cell traffic that these products will generate.

3. Create a From-To-Table:

• From-To-Table is a table that displays the number of orders that have been exchanged between a pair of cells (a loop) during a specific measurement period;

• The cells are organized into a matrix structure, where both the rows and the columns contain the name of the cells.

4. From this analysis the actual loops are designed.

• It is important to check if the loops provide

the control that is desired and solve the planning issues.

Designing the POLCA loops is an iterative process

which should involve the entire

POLCA team.

Check the “Template”

section for an example of a

From-To-Table

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POLCA card design

• A POLCA card is a visual representation of the POLCA loop identified in the system. – The loops in turn reflect the routings for the different FTMS.

• The card enables best use of available capacity and helps avoid congestions and bottlenecks. Hence, the card represents a capacity signal.

• A POLCA card is route specific, it represents a pair of cells in the possible routing.

• The card controls the movement between cells. • The card contains information about originating cell and destination cell.

Typically, it is done with an acronym of the names of the originating and destination cell.

• The card is divided in two colors, based on the colors assigned to the cells. • A POLCA card contains serial numbers and labeling for easier identification

and tracking. • The number of POLCA cards can be calculated using a formula.

Create flow charts that represent the flow of POLCA

cards to make the process more visual and understandable

Check the “Template”

section for an example of a

POLCA card design

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POLCA card quantum

• Question to ask: How much capacity should a POLCA card represent?

• The decision is dependent on the production batch sizes and transfer batch sizes between cells.

• Implications from making a choice about the card quantum: – Selecting too large quantum would imply too few POLCA cards

and infrequent signals about available capacity. – Choosing too small quantum will result in too many cards in the

system. – A trade-off between these two situations should be made.

• A POLCA card quantum can represent one order, semi – finished product or component, batch, job expressed in hours, etc.

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How many POLCA cards are needed?

• Calculating POLCA cards between cells A and B (Na/b) can be done using this formula:

Na/b = (LTa+LTb) x (NUMa/b)/D where: Lta, LTb are lead times of the cells, NUMa/b is the number of jobs exchanged from cell A to cell B during the planning period, D is the planning period.

• Considering the right amount of planning period is very important. If the planning period is too short, it would not be a representative of the shop floor dynamics. If the planning period is too long it will average out the variation in demand.

• A month or quarter is typical planning period that can be considered. • In case there are different demand periods, separate analysis can be done

for each period. For example, it can include calculations for peak, normal and low demand period.

Make sure that lead times and

planning period are expressed in same

dimension

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Managing temporary capacity shortages

• In some occasions production can be delayed due to shortage of parts or components supplied by non-POLCA cell or external supplier. This effect can cause the job to wait in a cell, while unnecessary holding a POLCA card.

• Such situations can be resolved by attaching a safety POLCA card to the job order.

– A safety POLCA card looks the same as POLCA card, with some visual distinction to distinguish and bring attention.

– The use of safety cards is done in the following manner: Once the issue has been detected, the POLCA card is replaced by a safety card and the job remains in the cell, while the POLCA card is released back in the system to allow other jobs to be processed.

– Safety cards are typically designed to be 10% of the total number of cards for that loop.

– Safety cards are typically authorized and circulated by one individual on the shop floor (production manager, scheduler, etc). After use, this individual keeps the card out of the system.

– Safety cards are temporary solution for unplanned events. If the problem persists more concrete steps should be taken to resolve the cause.

Check the

“Template” section for an example of the

visual outlook of a Safety Card

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Post implementation activities

• Measuring performance – Implementation of POLCA will result in overall improvement of the

system. It is important to measure the degree of the improvement, through evaluation of metrics such as performance improvement, productivity improvement and qualitative benefits from the implementation. Additionally, issues that have been omitted or unnoticed during the design and implementation stages can be recognized and addressed.

• Identifying areas for improvement – Implementation of POLCA is a process of continuous improvement. By

measuring the performance new opportunities for advancement can be revealed.

– It is recommended that an audit is performed periodically, to determine the state of the system and generate directions for re-design if necessary. A POLCA Audit generally revisits all the steps of the implementation to ensure that the main objectives are achieved and kept.

Check the PDCA for more details

on specific metrics

Check the “Template”

section for an example of a POLCA Audit

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Templates

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Dispatch lists

Order number

Earliest start date

Sequence of operations per cell Next cell in routing Step 1 Step 2 …. Step X

[Order id.] DD-MM-YY [Mach.1]/[h] [Mach.2]/[h] ….. [Mach.X]/[h] [Cell Id.]

Enter information about machines and

processing times

Optionally the dispatch list can include

information about availability of material and number of POLCA cards that are required

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From-To-Table

• Used to identify loops

Cell 1 Cell 2 Cell 3 …. Cell X

Cell 1 25 4 140

Cell 2 15 67

Cell 3

….

Cell X

Start horizontally and work your way through the matrix

table

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Creating a From-To-Table

• Procedure for creating From-To-Table:

– Fill in the number of orders that have been exchange between a certain work cell and the other work cell on the shop floor.

– Repeat this step until you have covered all the cells in the system.

– Whenever there is a number appearing in the matrix, it implies existence of a loop.

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POLCA card design

• Example of generic POLCA card design:

[Company Name]

Originating Cell A Destination Cell B

Card Serial Number A/B-001

A/B

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POLCA safety card design

• Suggestion for safety card design:

[Company Name]

Originating Cell A Destination Cell B

Card Serial Number A/B-S001

A/B Safety Card

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POLCA Audit

• Guideline for diagnosing the state of POLCA implementation:

• Evaluation of current cell layout

• Evaluation of available resources

• Evaluation of cellular structure

Evaluation of cells

• Evaluation of the number of operations

• Evaluation of sequence of operations and necessity

• Assessment of product design

• Assessment of existing loops

Evaluation of loops • Assessment of scheduling

system

• Assessment of availably capacity

• Evaluation of lead times per cell

• Evaluation of lead times per product family or FTMS

Evaluation of lead times

•Evaluation of POLCA card number

•Evaluation of release procedures and dispatch lists

•Measurement of performance

•Identification of potential for improvement

Assessment of overall system effectiveness

Notices

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Final considerations

• The approach described in this module is based on the work of Rajan Suri.

• We are grateful for the input received from: – Fried Kaanen, Bosch Scharnieren,

– Jan Riezebos, University of Groningen.

• These activities are conducted by the Research Group Lean of the University of Arnhem and Nijmegen and the QRM Center Europe in Arnhem.

• Funding for these activities has been made available from the RAAK Project QRM and the QRM Center Europe in Arnhem.

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Support

This guide was developed as part of the RAAK QRM Project. The grant was awarded by the Foundation Innovation Alliance and financed by the Dutch Ministry of Education, Culture and Science.

While developing this guide, we gained extensive experience with the projects that we carried out for various businesses. We wish to thank those businesses and their employees for their efforts.

The QRM Center and the founding fathers and sponsors contributed to the development of this guide in a number of ways.

Finally, we were grateful for the expertise and experience of Rajan Suri and Ananth Krishnamurthy.

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Rights

This guide is published subject to the guidelines of the Creative Commons, Attribution – ShareAlike version. This means that •you may use this material freely •you must share any modifications that you make with us and with other users •the material itself may not be sold, but may be used in other commercial activities such as training courses and consultancy •that you must state the modified version as your source if you use it (the text to be used for references is presented on the next page) •This applies only to any material that is not otherwise protected by copyright, which is explicitly listed as such. The precise phrasing of the copyright agreement

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Attribution

• This material was developed by HAN University of Applied Sciences. The authors are Aldert van der Stoel, Stef Tiggeloven, Vincent Wiegel.

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References

Rajan Suri

It’s about time – nederlandse versie

Lean lectoraat

LeanCircle

QRM Centrum @HAN

QRM Center @Wisconsin

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