Manufacturing Systems at the enterprise level

What is called manufacturing system ?

System: a set of components that are connected in a rational way to perform functions.

Manufacturing systems are a system to make products. So making a product is the function of a manufacturing system.

Resources are needed for a system to perform a function.

Environments are needed for a system to perform a function.

Manufacturing firms are a profit-based organization, so they have to consider the cost of making a product and the return they can get from selling their products

Manufacturing Systems: three levels

Logical (for each manufacturing firm or entity or system):

Firm level

Shop floor level

Machine level All our previous discussions are at the machine level. A machine is considered as a system that processes materials to make a product

Manufacturing Systems: three levels

Physical (for each manufacturing firm or entity or system):

Firm level

Shop floor level

Machine level

A manufacturing system can be one person with one machine. In this case, the three levels are flattened into one but this one physical entity has three logical functions.

Firm view of manufacturing systems

Materials

Capital equipment

Production tooling

Energy

Labor

Manufacturing systems

Completed product

Scraps or wastes

Manufacturing systems at the enterprise level

Classification of manufacturing systems

(1) project,

(2) job shop,

(3) repetitive,

(4) line and

(5) continuous

Manufacturing systems at the enterprise level

Project:

One of a kind (such as ship and nuclear power plant)

Complex

Site building (production tools must get to the site)

Job Shop:

Low volume and production quantities, called lot sizes

Not site building (traditional workshop)

Process-based layout

Product-based layout

Manufacturing systems at the enterprise level

Repetitive:

Orders for repeat business approach 100%.

Blanket contracts with customers for multiple years occur frequently.

Moderately high volume with lot sizes varying over wide range.

Fixed routing for products.

Remark: The system or plant is laid down in either process-based or product-based flow manner.

Manufacturing systems at the enterprise level

Line:

Delivery time (often called lead time) required by the

customer is often shorter than the total time it takes to build the

product.

Product has many different models and options.

An inventory of subassemblies is normally present.

Examples: Car and Truck.

System is laid down as a product-based flow manner.

Continuous:

Manufacturing lead time is greater than the lead time quoted to the customer.

Product demand is predicable.

Product inventory is held.

Volume is high.

Products have few options.

Examples: Chemical components.

System is laid down in a product-based flow manner.

Characteristics of manufacturing Systems

Production strategy classification

To deals with how to market the product

Criteria for classification:

customer lead time (CLD) and

manufacturing lead time (MLD)

Engineer to order:

Product is either in the first stage of the life-cycle curve or

a complex product with a unique design produced in

single-digit quantities.

Example: construction industry (bridge, etc.)

Customer is willing to accept long MLD - permitting this

strategy

Make to order:

All the engineering and design works are completed and the production process is proven.

Example: new residential homes.

The customer’s demand is unpredictable.

Assemble to order:

Primary reason of this strategy: MLD > CLD.

Order is statistically predicable.

Examples; automobiles, personal computers

This strategy is especially adopted in the line manufacturing type

Make to stock:

- Reasons for this strategy: (1) CLD < MLD (2) product

configuration has few options so that the demand

can be predicated accurately.

- Product parts are often stocked in distribution

warehouses located in major population centers.

Manufacturing systems at the enterprise level

Production strategy versus MLD:

Maximal MLD : ETO

Minimal MLD : MTS

It is important to be aware that the

production strategy can be changed with

the product evolution. MTO may not suit

the product which has a high component of

R&D; however MTO may be applied when

that product goes to maturity.

Enterprise organization

Aim: examine different function units and their communications

Manufacturing organization see Figure 1.6 where

boxes represent different function units and

arrowhead lines indicate the communications.

Figure 1.6

Product and Process Definition (Figure 1.7)

Finance and management

Sales and Marketing

ProductionEngineering

Engineering release

ProductDesign

Manufacturing planning and control

Quality

Product design

Production engineering

Engineering release

Quality

Manufacturing planning and control

(See Figure 1.8)

Manufacture process planning

determine the type of machines required to process the parts and the production sequence, called the routing, to be used

Production planning -> scheduling (time factors included)

Manufacturing Planning and Control (MPC)

MPC versus

others

Manufacturing systems at the enterprise level

Production sequence