Apoorv

CELLULAR MANUFACTURING

CELLULAR MANUFACTURING

What is Cellular Manufacturing ?• A lean manufacturing approach that helps companies build a

variety of products with as little waste as possible• Equipment and workstations arranged in a sequence that

supports smooth material flow through the process, with minimal transport or delay

• Derived from the word Cell• A Manufacturing Cell consists of people and machines or

workstations required for performing the process steps• For example - if a process for a product requires cutting,

followed by drilling and finishing, the cell would include the equipment for performing those steps, arranged in that order

• Helps companies achieve two important goals of lean:– One-piece flow– High-variety production

One Piece Flow• One-piece flow is the state that exists when products move through

a manufacturing process one unit at a time, at a rate determined by the needs of the customer

• The opposite of one-piece flow is large-lot production– Goods produced in large lots build delays into the process– No items can move on to the next process until all items in the lot

have been processed – The larger the lot, the longer the items sit and wait between steps

• One-piece flow is an ideal state• In daily operation, it is not always possible or desirable to process

items just one at a timeThe important thing is to promote continuous flow of products, with

the least amount of delay and waiting

High-Variety Production In the early days, a company could produce one type of product

• Customers would buy it even if it wasn’t exactly what they liked Today customers expect variety and customization

• Specific quantities delivered at a specific time If your company is not flexible enough to serve their needs

customers will go to your competitor Cellular manufacturing offers flexibility to give customers the

variety they want • By grouping similar products into families that can be processed on

same equipment in the same sequence• Encourages companies to shorten changeover time between

products• Eliminates a major reason for large-lot production

One-Piece Flow Vs. Large-Lot Production

CMS & Group Technology(GT)• CMS layout are based on recognizing similarities in

products – similarities in geometry, size, materials and processing requirements

• This similar products are collected – “Grouped” instead of being treated as individuals

• Leads to product families that visit similar equipment and populate their ‘cells’ production schedule

• Simpler setups like in a Job shop can follow and the workers become multifunctional and responsible for all aspects of a product – and its quality

• Cells can be scheduled to produce synchronously bringing the various sub-assemblies in as needed at final assembly with greater variety built in

Traditional Processes• Based on FUNCTIONAL approach• ‘Job Shop’ mentality• Pushed in Batches• Very little visibility & linkages

Comparison of Process & Cellular Layouts

U-Turn Cells Layout• People assigned to multiple types of equipment.

People & materials move from station to station.

Clustering Techniques: the Fundamental Issue in Cell Development

• We cluster parts to build part families– Part Families visit cells– Part Families share set-up ideas and equipment

(Family Fixtures)– Part Families follow the same (or similar) process

routing– These are the ideas and activities that offer

reported benefits

Clustering Techniques: The Fundamental Issue in Cell Development

• We cluster Machines to build cells:– Cells lead to Flow Mathematics– Cells contain all equipment needed to produce a part

family– Cells allow development of Multi-functional workers– Cells hold work teams responsible for production

and quality “They Empower” the workers• Empowered to set internal schedules• Empowered to assign tasks• Empowered to train and rotate jobs

Objectives of Cell Design

• Reduce defects.• Increase space

utilization• Decrease WIP• Engaging suppliers

within the cell• Materials at point

of use• Reduce Lead Time

12

1

2

3

4

5

6 7

8

9

10

11

A B C Raw materials

Assembly

Cellular Layouts Example

Parts 1 2 3 4 5 6 7 8 9 10 11 12A x x x x xB x x x xC x x xD x x x x xE x x xF x x xG x x x xH x x x

Machines


Parts 1 2 4 3 5 6 7 8 9 10 11 12A x x x x xB x x x xC x x xD x x x x xE x x xF x x xG x x x xH x x x

Machines


Parts 1 2 4 3 5 6 7 8 9 10 11 12A x x x x xD x x x x xB x x x xC x x xE x x xF x x xG x x x xH x x x

Machines


Parts 1 2 4 8 3 5 6 7 9 10 11 12A x x x x xD x x x x xB x x x xC x x xE x x xF x x xG x x x xH x x x

Machines


Parts 1 2 4 8 3 5 6 7 9 10 11 12A x x x x xD x x x x xF x x xB x x x xC x x xE x x xG x x x xH x x x

Machines


Parts 1 2 4 8 10 3 5 6 7 9 11 12A x x x x xD x x x x xF x x xB x x x xC x x xE x x xG x x x xH x x x

Machines


Parts 1 2 4 8 10 3 6 9 5 7 11 12A x x x x xD x x x x xF x x xC x x xG x x x xB x x x xE x x xH x x x

Machines


12

12 3

4

5

6

7

8 910

11

A BCRaw materials

Cell1 Cell 2 Cell 3

Assembly


Each of A, B, C now visits only one area, minimizing jumping.

Benefits of Cellular Manufacturing• Promoting one-piece flow through cellular manufacturing can

help make your company more competitive• Cut costly transport and delay from the manufacturing process• Shortens the production lead time

– Serves customer needs – Gives an earlier return on the investment in the product

• Saves space in the factory – Can be used for other value-adding purposes

• Promotes continuous improvement – By forcing solutions to problems that block low-inventory production

Disadvantages of Cellular Manufacturing

• Sometimes cells may not be formed because of inadequate part families.

• Some cells may have a high volume of production and others very low. This results in poorly balanced cells

• When volume of production changes, number of workers are adjusted and workers are reassigned to various cells. To cope with this type of reassignments, workers must be multi-skilled and cross-trained.

• Sometimes, machines are duplicated in different cells. This increases capital investment.

Apoorv

Engineering

Transcript of Apoorv