Week 2

Material flow system: How to move products, materials, information inside a facility

Concerns a conceptualization of the process organization.

• Is the product going to the workers, or vice versa.

• Do you only have one product, so that you can design the process specifically for it?

• Or do you need a system that can be used for many different activities?

The conceptual outline for a facility design is mostly about the flow in the facility

Process-oriented strategy

• also called: job shop, functional layout, intermittent, and in the book: process layout

Product-oriented strategy

• Two forms: Repetitive and Continuous

• Also called: Assembly line (repetitive only), production line, and in the book: product layout

• See also section 8.2: Transfer lines

Other & intermediate forms

Batch processing

Mass customization

Fixed-position layout

Retail layout

Office layout

Warehouse layout

A cell is sort of a “mini-facility” inside the plant, dedicated to producing specific part(s).

Process-oriented strategy

• lower investment, more flexible, higher variable cost

• high variety & low volume products

Product-oriented strategy

• higher investment, less flexible, lower variable cost

• low variety & high volume products

Eliminate flows

Minimize flows

Combine flows

(simplify flows)

Group technology

Measuring flows and relations between department / machines.

Looking quantitatively to flow, there are two main aspects:

Distances

Quantities to move.

Multiplying the two gives a measure for the “activity” between departments.

Parking lots

Restrooms

Food services

Health services

Barrier-free compliance

Inclusive environment

Office space

Ergonomics

Moving, storing, controlling, protecting goods and materials throughout the supply chain

However, mostly used as term for internal product/material movement and storage.

Material Handling design is more art than science.

There is a multitude of factors that must be taken into account. No model can take into account everything.

An amount of product or material that is arranged such that it can be moved as a single object.

Important for reducing the amount of work.

But larger loads implies heavier lifting (mechanization needed).

Customer perspective:  Aisles must be wide enough to accommodate customer traffic in both directions, based on the width of the shopping carts. “Like” items should be relatively close to each other.

Employee perspective: The location of the stockroom entrance/exit, is the stockroom entrance/exit located on a main aisle. The angle at which the aisles are located relative to the stockroom. The width of the aisles must be sufficient to allow for whatever means of material movement is used.

Management perspective: Profit, enhance amount of products bought, keep customers in store as long as possible (e.g., place popular items in the back)

Group technology layout using manufacturing cells is popular in JIT facilities because cellular layout encourages small lots, kanbans, simple material handling systems, short setup times, cross trained personnel, teamwork, and quality at the source.

Process layouts can result in complex flows, excessive handling, large inventories, and long production lead-times.

When parking spaces are assigned, there must be a 1:1 ratio between the number of spaces and the number of employees that work in the facility, and the parking space utilization will be low depending on whether or not some personnel are not at the facility during the day. If there is a random parking philosophy at the company, then anywhere between a 1:1.25 to a 1:3 ratio of parking spaces to employees is required, depending on whether or not the facility is serviced by public transportation. Consequently, only 33%- 80% of the space required for an assigned space parking lot is necessary for a random space parking lot.

Advantages of open office structure:

·        Improved communications

·        Improved supervision

·        Better access to common files and equipment

·        Easier to illuminate, heat, cool, and ventilate

·        Lower maintenance cost

·        Reduce space requirements due to space flexibility

Disadvantages of open office structure:

·        Lack of privacy

·        Lack of status recognition

·        Difficulty in controlling noise

·        Easy access for interruptions and interference

Unit Load principle: A unit load is one that can be stored or moved as a single entity at one time, such as pallet, container, etc, regardless of the number of individual items that make up the load. In this principle, product should be handled in as large a unit load as practical. As an example, instead of moving individual products, a number of products can be palletized and move as a single load. However, the size of the load must be considered as excessive unit load can reduce the visibility of the forklift driver or may not be practical in utilizing truck space. Moving as large a unit load as practical must be exercised in the context of just-in-time delivery. There is no point in moving materials if it will not be used for a long duration.

Attributes for comparing automated guided vehicles systems:

·        Weight capacity

·        Volume capacity

·        Safety

·        Travel speed

·        Throughput capacity

·        Vehicle Cost

·        System cost per vehicle

·        Operating costs

·        Mean Time Between Failures (MTBF)

·       Mean Time To Repair (MTTR)

·       …

·       …

Criteria for comparing transfer line and FMS:

·        Volume of production

·        Number of products manufactured

·        Production of families of work parts

·        Reduced flexibility in processing orders because of long production line

·        Manufacturing lead time

·        Machine utilization

·        Direct and indirect labor

·        Management control

A fixed position layout would be recommended when the product is very large, awkward, or expensive to move. It is also a candidate when low or sporadic volume of low variety production occurs.