Production management (I + II parziale)

What is production ?

PRODUCTION SYSTEM New product

Production is the crossing development

point of two key company

processes: Market

Analysis

New product development

(vertical dimension) Product

Design

Production & Logistics Product

(horizontal dimension) Production System

Industrialization Design

Production Sales Distribution

Purchasing Production

& Logistics

Production System

Management 3

It’s a set of machines and assets that implements an industrial production process in order to manufacture

goods.

Definition of production system

Usually a production process can be divided into three main stages:

- Acquisition of raw material to be used for production;

- Transformation of raw material into product;

“A production system is a set of machines and assets that implements,

- Distribution of the product on the market.

through an industrial technology, an industrial production process, to make

goods” Industrial Production System

Raw material (Industrial Plant) Product

Energy - Equipment

- Personnel

- Service infrastructures

Information - Know-how

Industrial Technology

or

“The set of resources and procedures involved in converting raw material

into products and delivering them to customers”

Production Process

“Functions have value only if they enhance the ability to do this profitably”

It’s a transformation process by which a set of resources

(process inputs) is converted into goods and/or service 4

(process outputs).

It’s a transformation process by which a set of resources:

- Tangible Inputs

Raw materials, semi-finished good, subassemblies;

- Intangible Inputs

Information, knowledge, ideas.

Different types of transformation:

- Physical

- Chemical

- Location

- Storage

Production System:

Performance Characterization

I. How long

- Lead Time

Value-Added-Process

Time during which a piece remains inside the production system.

Activity Analysis

Time between the initiation and the completion of a production process.

It’s the sum of: processing time + transport time + waiting time.

- Cycle Time

• Create a Process Map (detailed flowchart) for each process

It’s measured in time/unit. It measures the amount of time needed to complete a single step of the

– Identify each step

production system.

Cycle Time = Value-Added Activities + Non-Value-Added Activities

• Create Value Chart

Value-added: increases worth of product or service to a customer. Customer is willing to pay for it.

– Identify stages and time spent in stages from beginning to end of

Non-value-added: increases time spent on product or service but does not increase worth.

process

Unnecessary from customer perspective. Can be reduced, redesigned or eliminated without affecting

market value or quality.

Value-Added: Non-Value-Added:

Processing Time Inspection Time

Service Time Transfer Time

Idle Time

- Bottle Neck (CT): it’s one process in a chain of process that influences and reduces the capacity of

the whole chain. Ex: supply overstock, pressure from customer, low employee morale, ...

I. How fast 52

It measures the performance of the systems in terms of how fast the production system is.

It’s measured by jobs/minute + pieces/hour (! reciproco of bottleneck CT: time/unit)

II. How much

- WIP: Work In Progress

It refers to the amount of material, waiting to the undergo further processing within the process.

The more the parts wait during a process, the more the WIP grows and the more production costs

for the company increase.

It’s a measure of how is going the process.

NB: an high value of WIP involves:

- The need of space for the storage of the corresponding semifinished material;

- An unproductive amount of money, caused by the unfinished pieces inside the process.

I. Design stage output: Engineering Drawings + BOM

Inputs for II. Industrialization Stage: Technological Cycles

! + Processing and Assembly Drawings

III. Production stage can start!

!

NB: There are other methods that carry out, in a more precise way, the planning of a production system’s

capacity Experimental methods: based on discrete model simulation.

! They realize a computer model of the production system and they

emulate the production running.

Supply Chain

A supply chain is a network between a company and its suppliers to produce and distribute a specific

product to the final buyer. This network includes different activities, people, entities, information, and

resources. The supply chain also represents the steps it takes to get the product or service from its original

state to the customer.

Production System Design

Supply chains are developed by companies in order to reduce their costs and remain competitive in the

Different Perspectives (vertical)

business landscape.

Supply chain management is a crucial process because an optimized supply chain results in lower costs and

Higher level IE analysis/business operations

a faster production cycle.

Supply chain design

• The number, level, and location of suppliers

We can recognized three types of flow:

• Delivery, ordering, inventory policies

- Physical flow • The number of distributors and their locations

Process that includes the transformation of raw materials into final products.

• …

- Information or planning flow

It concerns the market analysis and the development of the idea/design of the future products.

- Cash flow/Financial flow

Supply Chain view plan

plan plan

plan plan

source make deliver

deliver source make deliver source make deliver source

Suppliers’ Suppliers A ring of the Clients Clients’

suppliers Supply Chain clients

Process Representation Techniques

To understand how business operations are structured, what sequence of operations is required to 13

produce goods and services and what could drive the performance of the business there is the need to

represent the production processes for documentation communication, analysis, etc.

- Production flow

I. Linear production flow

Where the various phases that lead to the finished product follow one another in a linear way.

II. Analytic production flow

Where from an initial component more finished products are obtained.

- Bill of Material (BoM)

It’s a listing of all the raw materials, parts, subassemblies and assemblies needed to produce one

unit of product.

Bill of Material (BOM)

All components are listed by levels.

Product structure tree

Structure:

Hierarchical and structural depiction of all the objects (sub-assemblies,

- Items above given level: parents

components, raw materials) composing a product

- Items below given level: children

Cheeseburger

Bun (bread) Grilled patty Lettuce (leaf) Mayonnaise Cheese (slice)

Formed meat

(patty)

Minced meat

- Process technology routing/diagram

Production processes are multistage process. This means that a sequence of operations are

required to realize the process that allows to obtain a product from a raw material.

The set of data that describes the sequence of such operations is called technology routing.

26

!

The ASME Symbols are typically used for representing technology diagram, which can be drawn in

the form of both:

Example of a process tech. diagram

- Qualitative, describes the relationship between the various processes;

Example of a process tech. diagram

ng / diagram - Quantitative, represents the flow amount of materials used in the different processes.

ge processes: it means that a sequence of

e process that allows to obtain a product from

t from a steel bar though various machining

from a series of chemical – physical

at describes the sequence of such operations

ology routing.

ed Fasi di Fasi di

Operate Store

us trasformazione stoccaggio

gy Fasi di Fasi di

Inspect Wait

controllo attesa

is

ent Fasi di

ng Transfer

trasporto

ASME symbology

(American Society Of Mechanical Engineers) (Process) flow charts

41 Technology diagram for the production of a bar by

forging and machining

Process flowcharts contain detailed sequences of production process

Technology diagram for

They clearly differentiate the value-adding and non-value-adding activ

by 2 alternative processe

42

- Process Flow Charts

The management aspect emphasizes the

procedural aspects of the production

process, it takes into account all the typical

phases of the management process, such as

planning, scheduling and control.

Process Flow Charts is the typical graphic

!

tool used for this representation.

They contain detailed sequences of

production processes. They clearly

differentiate the value-adding and non-

value-adding activities. (Re

Product System Classification

I. Classification by market interaction (standardisation of product)

- Production based on Individual Orders, production to single order;

- Production based on Repetitive Orders;

- Production to Stock,

Based on forecasts, where the firm manufactures a high volume of products before

receiving the customer orders.

II. Classification by production method (way of volume creation)

- Single Unit Production,

Where the variability of the range of manufactured products is very high.

Flexibility. Therefore efficiency is sacrificed dye to the level of changing times (set-up times)

involved.

- Intermittent Production (Batch production),

Where products are manufactured in batches in order to form stocks intended to be used

later.

- Continuous Production,

Where the technology cycle remains fixed even for extended periods, so there’s an

uninterrupted flow of products presenting homogeneous characteristics.

III. Classification by nature of the process (type of production technology)

- Process Production,

Where the components of which the final product is made can no longer be distinguished

at process completion.

In those kind of process the output represents often the raw material for other production

processes.

Ex: process to obtain steel, paper, cement, glass, …

- Discrete Manufacturing Production,

Where the product is made by a number of discrete components, or part, generally of a

different nature.

In those kind of process product can be assembled and disassembled.

Ex: automobiles, shoes, toys, …

The production process includes two phases:

1. Fabrication (manufacture), a set of processes that modify the shape, the dimensions or

the surface of individual parts.

2. Assembly, a complex of operations juxtaposing individual parts to form an assembly.

Production system classification

Classification by market interaction • nature of process: process

(standardisation of product) production, discrete

production (manufacturing)

Prod. to stock • production method:

continuous production,

intermittent production (BP),

Repeat unitary production

• sales: stock production

Prod. to order (forecast-based production),

Single / Batch / to order production

Single Unitary Intermittent Continuous

Classification by production

Fabrication method (way of volume creation)

Discrete Assembly

Process Fabrication

Classification by nature of process

(type of production technology) 58

Classification of Production Systems

Configuration of Production Systems Manufacturing

(Discrete Production)

Fabrication Assembly

(Processing) Fixed Position

Job Shop Assembly Shop

Manufacturing Cell Assembly Cell

Transfer Line Assembly Line

Linear (Manual)

Rotary Paced

Intermittent

Continuous

Unpaced

Asynchronous

Synchronous 73

Workstation

It’s the elementary unit of a production system, which implements a single process phase of the entire

technology cycle.

A production system is a collection of different workstations that perform operations such as

manufacturing, assembly, inspection, testing and finishing; in order to create final products.

It can be constituted by:

- Machine (automatic station);

- Human Operators (manual station);

- Both (semi-automatic station);

Those perform in the same operations of the same products.

!

Workload sizing approach

It’s a widely used method to do a first approximation of the size of a production system.

The planning/sizing of the capacity of a period system comes from the assessment of the workload.

It’s applicable to different configurations of the product system.

Disadvantage: this method simplified too much, stationary status.

The design is made referencing to a conventional operating period of one year.

The production target, with respect to which the system is sized, is referenced to that period of time (1

year) According to the production target and the technological cycle of production for each item belonging

to the target, the required working time (workload) on any of the various system resources

(machine/process) can be calculated, also considering the presence of setups and inefficiencies, thus

defining:

Hri annual required capacity (hours) for the i process/machine

!

The availability of each resource is calculated from the theoretical annual availability, appropriately

reduced to take into account of various inefficiency factors (e.g., maintenance, strikes, etc.). This is defined

as:

Hai available hours per year for the resource

!

The number of resources needed of any i type (Ni) is simply the ratio of the required capacity (i.e. the

workload) on the resource and its availability Ni = Hri / Hai

Fabrication

Technology

- Not reversible physical/shape transformations of raw materials and components

- Not fixed technology route, variants and flexibility are allowed

- Not particular relevance of process technology parameters

- Product technology parameters are relevant

Management

- Relevance of management parameters (WIP, lead time, delays, synchronizations, …)

- Multiple resources with flexible utilization (operators, machines, tools, programs, …)

Cost Structure

- Relevance of fixed assets

- Labour intensity depending from automation and characteristics of machinery.

Concerning the organization of the workstations there are three possible solutions for the fabrication phase

of discrete parts:

I. Job-shop manufacturing

It’s a manufacturing system with different types of machines (! able to process a high variety of

products), grouped and organized in work centres: shops or departments.

NB: - The same type of machines are placed in the same work centre.

- Machines are aggregated in shops by the nature of technological process (and skills) involved.

- Work centres are built according to technological affinity.

- In the shops there are machines and resources with the same nature/skills involved in

technological

process.

Characteristics

- Each product has its own technological cycle that defines a route through several types of

machines;

- Processing can be flexible, cause a product can be flexible, cause a product can be processed by

more than one machine, so its route can be modified. There are several alternative cycles

(routings);

High Flexibility despite of unorganized material flow;

!

- Flows are extremely interwoven (interfacciati);

- Products pass most of the time waiting of queuning (in coda);

- There are space used as wharehousing space (deposito)

- There are operators who work at only one department and are highly skilled;

- There’s a process layout;

When it could be adopted?

- When there’s an high variety of products or parts to be processed;

- When for each product or part, the production volume is low with respect to the overall volume;

- When the production mix is variable with the passing of time.

- Manufacturing products very differentiated by type and with low unit volumes, in combination

with a management method of batch production.

It’s not suitable for:

- High volume manufacturing

Pro

- Flexibility;

- General-purpose machines -> ability to produce a potentially infinite mix of items;

- Alternative cycles (routings).

Con

- Difficult to keep product flows under tight control;

- High Work in Progress values;

- Low machines saturation;

Job Shop Characteristics

- Uneven quality level;

- Difficult to Manage Production;

- Difficult to foresee (prevedere) bottlenecks (arrestamento/rallentamento processo produttivo);

Since each shop may contain several machines, and jobs are not

High dependence of performance on the mix of

- products to be manufactured;

necessarily constrained to be processed by a single machine, that

- Problem: high material handling and lead time.

gives this production system a relevant processing flexibility.

Drilling

Lathe Milling

Department Department

Department M M D D D D

L L M M D D D D

L L G G G P

L L G G G P

L L Painting Department

Grinding

Department

L L A A

A

Receiving and

Shipping * Assembly 12

II. Manufacturing Cell

It’s intermediate between job-shop and transfer line.

It’s made up of a group of machines not technologically homogeneus, but fully capable of working a

set of pieces called family: a set of pieces that are similar from a morph-technological point of view.

!

In this type of manufacture, the machines necessary for the processing of the same part families are

arranged close to each other into the so-called cells, in order to make the management of the part

flow easier.

Machines are grouped and placed according to the product/part families manufactured.

Inter-cellar flows aren’t allowed.

Manufacturing cells, together with product/part families, are constituted by applying models of group

technology (GT) GT: Is strongly related to cellular manufacturing

! Has a wide operation range both in terms of volume and product mix.

Characteristics

- Fewer products than job shop but higher production volume;

- Often a re-arrangement of a part of a job shop

- Products are produced in batches (satisfying fro