Study of Manufacturing System: 2017

Sunday, October 1, 2017

Acceptance Sampling, Producer’s Risk(α), Consumer’s Risk (β) & Acceptable Quality Level (AQL)

Acceptance Sampling

Acceptance sampling is concerned with inspection and decision making regarding the entire lot/production/shipment

A form of inspection used to accept or reject whole lot based on sample information

Not consistent with TQM or Zero Defects philosophy

Producer & customer agree on the number of acceptable defects

A means of identifying not preventing poor quality

Statistical Process Control (SPC)

Statistical evaluation of the output of a process during production

- Goal is to make the process stable over time & then keep it stable unless the planned changes are made
- Statistical description of stability requires that ‘pattern of variation’ remains stable over time, not that there be no variation in the variable measured

Process is in control has only random cause variation (inherent variability of system)

When the normal functioning of the process is disturbed by some unpredictable events, special cause variation is added to common cause variation

Statistical Quality Control (SQC)

A quality control system using statistical techniques to control quality by performing inspection, testing & analysis to conclude whether the product is as stated or designed quality standard

- Relying on the probability theory, evaluates batch quality & controls the quality of processes or products

- Makes the inspection more reliable & less costly

SQC is used to describe the set of statistical tools used by quality professionals

Descriptive statistics

- Used to describe quality characteristics & relationships

Acceptance sampling

- Used to randomly inspect a batch of products to determine acceptance or rejection of entire lot based on the results

- Does not help to identify and catch the in-process problems

Statistical process control (SPC)

- Involves inspecting the output from a process & identifying in-process variation

- Quality characteristics are measured & charted

Inspection

An appraisal activity that compares goods or services to a standard

- Well-designed processes little inspection is necessary, inspection cannot be completely eliminated

In lean organizations, inspection is less of an issue than it is for other organizations, because have extra emphasis on quality in the design of both products/processes & workers have responsibility for quality (quality at the source).

Quality control

A process that evaluates output relative to a standard & takes corrective action when output doesn’t meet standards

- The operational techniques & activities (a system for measuring & checking) used to fulfill the requirements for quality

Incorporates a feedback mechanism system to explore the causes of poor quality or unsatisfactory performance & takes corrective actions
Suggests when to inspect, how often to inspect, & how much to inspect.

Walter A. Shewhart

Pioneer of Modern Quality Control

Founder of the control chart “father of statistical quality control.”

Originator of the plan-do-check-act cycle

Perhaps the first to successfully integrate statistics, engineering, & economics

W. Edward Deming

Theory of variance: controllable & uncontrollable variance

PDCA cycle: Core element is ‘Management Team’

Fourteen points for quality and productivity.

Seven deadly sins and diseases.

Out of Crisis (Having a satisfied customer is not enough)

- Profit in the business comes from repeat customers, customers that boast about your product & service & customers that bring friends with them

Brainstorming

Technique for generating a free flow of ideas in a group of people

- A group of people share thoughts & ideas on problems in a relaxed atmosphere that encourages unrestrained collective thinking

- The goal is to generate a free flow of ideas on identifying problems, & finding causes, solutions, & ways to implement solutions

Bench-marking

Process of measuring performance against the best in the same or another industry

- An approach that can inject new energy into improvement efforts

- Purpose is to establish a standard against which performance is judged, & to identify a model for learning how to improve

Steps in benchmarking process

Identify a critical process that needs improvement (order entry, distribution)

Identify an organization that excels in the process, preferably the best

Contact the benchmark organization, visit it, & study the benchmark activity

Analyze the data

Improve the critical process at your own organization

Quality Problem Solving

Problem Solving

Basic steps in problem solving

Step 1: Define the problem & establish an improvement goal

Step 2: Develop performance measures & collect data (check sheet, scatter diagram, histogram, run chart, & control chart)

Step 3: Analyze the problem (Pareto chart, cause-and-effect diagram)

Step 4: Generate potential solutions (brainstorming, interviewing, surveying)

Step 5: Choose a solution

- Identify the criteria for choosing a solution & select the best one

Step 6: Implement the solution

- Keep everyone informed

Step 7 : Monitor the solution to see if it accomplishes the goal.

Total Quality Management (TQM)

A philosophy that involves everyone in an organization in a continual effort to improve quality & achieve customer satisfaction. There are three key philosophies

Never-ending push to improve, which is referred to as continuous improvement
Involvement of everyone in the organization
Customer satisfaction, which means meeting or exceeding customer expectations

Hierarchy of Quality

Follows the evolution of quality management

The Costs of Quality

There are three cost of quality. those are

Appraisal costs

Prevention costs

Failure costs

Quality

Quality is consistent conformance to customers’ expectations, in other words, ‘doing things right’

- Major influence on customer satisfaction or dissatisfaction

Another way to think about quality is the degree to which performance of a product or service meets or exceeds customer expectations

The Dimensions of Quality

Product & service quality is often judged on eight dimensions of quality

The Determinants of Quality

The degree to which a product successfully satisfies its intended purpose

Design

- Quality of design (Intention of designer to include/exclude feature)

How well the product conforms to the design

- Quality of conformance (The degree to which goods/services conform to the intent of the designers)

Ease of use

- User instructions, intended purposes, ways for functioning properly & safely

Service after delivery

- Recall & repair of the product, adjustment, replacement or buyback

Benefits of Good Quality

An enhanced reputation for quality

Greater customer loyalty

The ability to command premium prices

An increased market share

Fewer production or service problems

Lower liability costs

Higher productivity

Higher profits

The Consequences of Poor Quality

Loss of business

Liability

Productivity

Costs

Thursday, September 28, 2017

Supply Chain planning & control, Supply chain management, Procurement, Supplier management, Bullwhip effect, Logistics, Creating an effective supply chain

Supply Chain

The sequence of organizations (facilities, functions, & activities) that are involved in producing & delivering a product or service.

Begins with basic suppliers of raw materials & extends to the final customer

Inventory planning & control

A stock or store of goods

- The stored accumulation of material resources in a transformation system

Allow the flexibility

Exceptional quality

Give a level of dependability

Better return on investment (ROI)

Functions of Inventory

To meet anticipated customer demand
To smooth production requirements
To protect against stock outs & take advantage of order cycles
To hedge against price increases
To permit operations
To take advantage of quantity discounts

Enterprise resource planning (ERP)

Integration of financial, manufacturing & human resource on a single computer system

ERP software provides a system to capture & make data available in real time to decision makers & other users throughout an organization
Provides a set of tools for planning & monitoring various business processes

Material requirements planning (MRP)

A computer-based information system that translate requirements of MPS for end items into time-phased requirements for subassemblies, components, & raw materials

Working backward from the due date using lead times & other information to determine when & how much to order

Master production schedule (MPS)

This schedule indicates the quantity & timing of planned completed production

Breaking down the aggregate plan into specific product requirements
The heart of production planning & control

Aggregate planning

Intermediate-range capacity planning, usually covering 2 to 12 months

A ‘big-picture’ approach to planning, focus on a group of similar products or services, or sometimes an entire product or service line

Capacity management

Capacity: The upper limit or ceiling on the load that an operating unit can handle.

-The maximum level of value-added activity over a period of time that the process can achieve under normal operating conditions

Capacity decisions have a real impact on the ability of the organization to meet future demands for products & services
Capacity decisions affect operating costs
Capacity is usually a major determinant of initial cost
Capacity decisions often involve long-term commitment of resources
Capacity decisions can affect competitiveness
Capacity affects the ease of management

Planning & controlling capacity

Planning & control activities

Planning & control requires the reconciliation of supply & demand in terms of volumes, timing & quality

Loading

The nature of planning & control

Planning & control is concerned with the reconciliation between what the market requires & what the operation’s resources can deliver

- Provide the systems, procedures & decisions which bring different aspects of supply & demand together
- Ensure that the operation’s processes run effectively & efficiently
- Produce products & services as required by customers

Planning concerns what should happen in the future

- A statement of intention

Control copes with changes

- An ‘intervention’ will need to be made in the operation to bring it back ‘on track’

Line Balancing (Designing Product Layout), Cycle time, Precedence diagram, Network analysis, Critical Path Method (CPM)

Line Balancing (Designing Product Layout)

The process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements

The process of deciding how to assign tasks to workstations
Minimizes idle time along line & results in a high utilization of labor & equipment

Perfectly balanced line will have a smooth flow of work

Cycle time

The maximum time allowed at each workstation to complete its set of tasks on a unit

Establishes the output rate of a line

The primary determinant of line balancing is what the line’s cycle time will be

Facilities Layout

An operation or process means how its transformed resources are positioned relative to each other & how its various tasks are allocated to these transforming resources

- The configuration of departments, work centers, & equipment, with particular emphasis on movement of work through the system

The basic objective is to facilitate a smooth flow of work, material & information

To facilitate attainment of product or service quality
To use workers & space efficiently
To avoid bottlenecks
To eliminate unnecessary movements of workers or materials
To minimize material handling costs
To minimize production time or customer service time
To design for safety

The layout decision is relatively infrequent but important

Process Selection

Refers to deciding on the way production of goods or services will be organized

- Occurs as a matter of course when new products or services are being planned, also occurs periodically due to technological changes in products or equipment as well as competitive pressures.
- Has major implications for capacity planning, layout of facilities, equipment, & design of work systems.

Description of Predetermined motion time systems (PMTS) MTM-2 Categories

GET(G)

Action of reaching out with hand or fingers to an object, grasping the object & subsequently releasing it.

The scope of GET

Starts: With reaching out to the object,

Includes: Reaching out to, gaining control & subsequently releasing control of the object

Ends: When the object is released

Three variables of GET Selection:

Case of GET—distinguished by the grasping action employed
Distance reached
Weight of the object or its resistance to motion

Predetermined Motion Time Systems (PMTS)

Also known as predetermined time standards (PTS) or synthetic time standards.

Define the time needed for the performance of various operations by derivation from pre-set standards of time for various motions & not by direct observation & measurement
Established for basic human motions, classified according to the nature of the motion & the conditions under which it is made

Example: Putting a washer on a bolt. The operator will reach to the washer, grasp the washer, move the washer to the bolt, position it on the bolt & release it

Components of a basic PMTS

The standard time

Standard time is the total time in which a job should be completed at standard performance

Standard time for a simple manual job.

Time study: Allowances

It is very difficult to determine precisely the allowances needed for a given job

Factors related to the individual (physical condition)
Factors related to the nature of the work (sitting down, posture during work)
Factors related to the environment (heat, humidity, noise, dirt, vibration)

Calculation of allowances

Rating in time study.

Rating is one of the most controversial aspects of time study.

Rating is the assessment of the worker's rate of working relative to the observer's concept of the rate corresponding to standard pace

A qualified worker is one who has acquired the skill, knowledge and other attributes to carry out the work in hand to satisfactory standards of quantity, quality and safety.

Achieves smooth and consistent movements
Acquires rhythm
Responds more rapidly to signals
Anticipates difficulties and is more ready to overcome them
Carries out the task without giving the appearance of conscious attention and is therefore more relaxed.

Time study

Recording the times of performing a certain specific job or its elements carried out under specified conditions, and analyzing the data so as to obtain the time necessary for an operator to carry it out at a defined rate of performance

Equipment required for time study

A stop-watch (mechanical and electronic)
A study board (placing the time study forms)
Time study forms (recording of substantial amounts of data)

Structured estimating

The basis of past experience to predict future events

Accuracy of estimating depends on the experience of the estimator
Cheap to apply
Can be used to predict times for work which has not been observed
Can be used as a basis for price estimating

Normally used where the required time values are not required in great detail.

Work sampling

Work sampling is a method of finding the percentage occurrence of a certain activity by statistical sampling and random observations.

Also known as "activity sampling", "ratio-delay study", "random observation method", "snap-reading method" and "observation ratio study“

Obtain a complete and accurate picture of the productive time and idle time of the machines

Work measurement

Work measurement is the application of techniques designed to establish the time for a qualified worker to carry out a task at a defined rate of working.

- Eliminate ineffective time.

- Set standard times for carrying out the work.

Work measurement particularly time study acquired a bad reputation in the past, especially in trade union circles.

- Directed exclusively to reducing the ineffective time within the control of the operatives by setting standards of performance.

Ineffective time within the control of management was virtually ignored

- Lack of raw materials

- Plant breakdowns

“Elimination of ineffective time due to management shortcomings precede any attack on the ineffective time within the control of the workers”

Motion Study

Systematic study of the human motions used to perform an operation

Eliminate unnecessary motions
Identify the best sequence of motions for maximum efficiency

An important avenue for productivity improvements

The most-used techniques are the following

Motion study principles

Analysis of therbligs

Micro-motion study

Charts

Method study

Method study is the systematic recording and critical examination of ways of doing things in order to make improvements

Eliminate unnecessary movement

Basic approach to method study consists of the following steps:

Select
Record
Examine
Develop
Evaluate
Define
Install
Maintain

Techniques of Work Study and Their Relationship

Method study is the systematic recording and critical examination of ways of doing things in order to make improvements.

Work measurement is the application of techniques designed to establish the time for a qualified worker to carry out a task at a defined rate of working.

Work study

“Work study is the systematic examination of the methods of carrying on activities so as to improve the effective use of resources and to set up standards of performance for the activities being carried out.”

Examine the way an activity is being carried out.

Simplifying or modifying the method of operation.

Reduce unnecessary or excess work.

Wasteful use of resources.

Setting up a time standard for performing that activity.

Total time of a job

The time taken by a worker or a machine to carry out an operation.

Why Industrial Engineering is required in Bangladesh?

IIE (USA) contends that the following benefits can be directly linked to the work of Industrial Engineers

Leaner, more efficient & profitable business practices while increasing customer service & quality

Improved efficiency & as a result improved competitiveness & profitability

Setting of labor & time standards,

Good organization & improving productivity, essential for long term business

Increased ability to do more with less focusing on optimization

Making work safer, faster, easier & more rewarding

Providing a method for business to analyze their processes & try to make improvements

Reducing costs associated with new technologies

Designing safer & easier to use products, etc.

Industrial Engineering: What & Why

Before Industrial Engineering

Engineering history lies back to the beginning of civilization.
Until the end of 17th century, production meant crafts

A craftsman used to treat material and assemble the pieces

Until then a single person used to

Plan

Select and supply material

Produce and control

History & Development of Industrial Engineering

For the first time the term “Industrial Engineering” appears in 1901 in the journal “The Engineering Magazine” by James Guin

The real beginning are connected with Industrial Revolution (1760 to 1840)

In 1776, James Watt invented the Steam Engine & The beginning of İndustrial Revolution (convert hand production method to machine) & Adam Smith gave the concept of Division of Labour through his book “The Wealth of Nations”

Frederick Taylor (1881) the father of scientific management & industrial engineering, began first motion & time studies & created efficiency principles

Period between 1882 to 1912 was the critical period in the history of Industrial Engineering. The concept of Factory system, Owner, Manager, Equal work, Equal pay, incentives, Scheduling, Cost control & Accounting were evolved

Henry Ford (1913) first used moving Assembly Line & paid workers very well

Henry L. Gantt (1916) invent the measurement of management result by Gantt Chart

Frank & Lillian Gilbreth (1917) developed Method study & Work measurement (micro-motion study) as a tool for work analysis

L.H.C Tippet (1937) developed the concept of Work sampling

Six Sigma (6σ), Six Sigma as a Philosophy & a Metric, Six sigma methodology, Phases of Six Sigma

Six Sigma (6σ)

Sigma (σ) is a Greek term used in statistics to represent standard deviation from mean value, measures how far a given process deviates from perfection

Higher sigma capability, better performance

Six Sigma (6σ) is a highly disciplined process that enables organizations deliver nearly perfect products & services

A Vision & Philosophical commitment to consumers to offer the highest quality & lowest cost products
A Metric that demonstrates quality levels at 99.9997% performance
A Benchmark of product & process capability for comparison to ‘best in classes’
A practical application of statistical Tools & Methods to help us measure, analyze, improve, & control our process

Just in time (JIT)

To have only the right materials, parts & products in the right place at the right time

Only what is needed, nothing more
Continual improvement & a pull system

- Smaller inventories & Improved quality
- Shorter lead times & Lower production costs

- Reduced space requirements
- Increased productivity
- Greater flexibility

Misconceptions

Only an inventory control system
A method to “Push” inventory back to the supplier
A quality control program

Key Performance Indicator (KPI)

Measurable indicators that will be used to report progress that is chosen to reflect the critical success Strategic.

Simply a metric that is tied to a target
Represents how far a metric is above or below a pre-determined target

Generally there are two approaches

KPI based on Strategic themes

Are the tools, use to organize & focus diverse activities (Corporate Plan)

KPI Based on Critical success factors

A factor considered to be most conducive to the achievement

Continuous Flow Production

Producing & moving one item at a time through a sequence of process steps as continuously as possible, with each step making just what is requested by the next step.

The intent of flow production is to increase the velocity of products & make the production cycle predictable

Takt Time

The rate that a product needs to be finished in order to meet customer demand

- Takt Time is “Beat Time”, “Rate Time” or “Heart Beat”

Single piece flow

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

Allows to deliver a flow of products to customers with less delay
Reduces resources required for storage & transport
Less damage, deterioration, or obsolescence
Promotes continuous improvement

- The opposite of one-piece flow is large-lot production

Goods produced in large lots build delays into the process
No item can move on to the next process until all item in lot have been processed
The larger the lot, the longer the items sit & wait between steps

- One-piece flow is an ideal state

- Always not possible or desirable to process items just one at a time, important is to promote continuous flow of products, with the least amount of delay & waiting

Cellular Manufacturing

Equipment & workstations arranged in a sequence that supports smooth material flow through the process, with minimal transport or delay

Derived from the word Cell (Cell consists of people, & machines or workstations required for performing the process steps)
Most work stations are close together so that less time is required to move parts
Helps companies achieve two important goals of lean

One-piece flow

High-variety production

Kanban

Kanban is a Japanese word that means "visual card“, the visual & physical signaling system that ties together the whole Lean Production system

A simple card system
The system works very simply by identifying the material to which it is attached
Kanban is a system that visually indicates when production should start & stop

There are two types of Kanban system

Withdrawal Kanban (signal to refill raw material)
Production Kanban (signal to start production)

Kaizen (Continuous Improvement)

Kai+zen means “change for the better”, A policy of constantly introducing small incremental changes in a business in order to improve quality &/or efficiency

Means improvement in personal life, home life, social life & work life
Employees are the best people to identify room for improvement, since they see the processes in action all the time

Improvements are based on many, small changes rather than the radical changes that might arise from Research & Development.

As the ideas come from the workers themselves, therefore easier to implement.

Small improvements likely to require minor investment than major process changes.

All employees should continually be seeking ways to improve their own performance.

Not the rate of improvement which is important; is the momentum of improvement.

Encourage workers to take ownership for their work & reinforce team working.

There is always room for improvement, so this effort must be ongoing

Value stream mapping (VSM)

A series of steps that must be performed in the proper sequence to create value for a customer & required to bring a product from order to delivery

The entire set of activities running from raw material to finished product for a specific product or product family
The complete value stream includes information, & product or material flow
Includes all steps; value-added & non value-added (avoidable & unavoidable)

Whenever there is a product for a customer, there is a value stream. The Challenge lies in seeing it

SMED (Single Minute Exchange of Dies)

A system designed to reduce the amount of time to perform a changeover or setup

Poka-Yoke

A method that uses sensor or other devices for catching errors that may pass by operators or assemblers, also known as “Mistake Proofing” or “Fail-Safe”

Identifying the defect immediately (Point of Origin Inspection)
Quick Feedback for Corrective Action

Root Cause Analysis

The identification of why an issue occurred vs. only identifying or reporting the issue

Cause (causal factor): A condition or event that results in an effect

Direct Cause: Directly resulted in the occurrence

Root Cause: If corrected, would prevent recurrence of this & similar occurrences

PDCA (Plan–Do–Check–Act) Cycle or Deming cycle

Never ending process of repeatedly questioning & re-questioning the detailed working of a process or activity

An improvement cycle
Problem solving tools

Overall Equipment Effectiveness (OEE)

In an ideal factory, equipment would operate 100 percent of the time at 100 percent capacity, with an output of 100 percent good quality

Way to measure how effectively machine/equipment hours are used (value adding)

Total productive maintenance (TPM)

Approach where workers perform preventive maintenance on the machine they operate

Employees are given greater responsibility for quality, productivity, & the general functioning of the system
Maintenance management which recognizes the importance of reliability, maintenance & economic efficiency in plant design

5S (Five S) Housekeeping

Japanese concept that lays the Foundation to create a Disciplined Mind, Which leads to Disciplined thoughts which leads to Disciplined Actions

Actions which improve Safety, Quality, Delivery, Cost, Moral & Environment
Exposes some of the most visible example of waste
Establishes the framework & discipline required to pursue other improvements

Hoshin Kanri (Policy Deployment)

A statement of desired outcome for a year, plus means of accomplishing that outcome, & for measuring the accomplishment.

“Ho” = Direction “Shin” = Needle “Kanri” = Management & control

“Hoshin Kanri” means management & control of the organization's direction needle (compass) or focus

Heijunka (Production Leveling)

The distribution of production volume & mix evenly over time

Sequencing of production, production smoothing, or “level production”
Converts uneven Customer Pull into even & predictable manufacturing process
A core concept that helps bring stability to a manufacturing process

Jidoka (Autonomation)

Equipment or processes that are “smart” enough to detect an undesired, abnormal state and stop so as not to produce a defective product.

Automation with a human touch
Practice of stopping a manual line or process when something goes amiss
Quality built-in to the process

Standardized Work

Documents (forms) centered on human motion that combine the elements of a job into the most effective sequence, without waste, to achieve the most efficient level of production.

Gemba (The Real Place)

A philosophy that reminds to get out of offices & spend time on the plant floor

The place where real action occurs
The place where value is created

Andon (Process Control Board)

A visual control that enables the operator to inform Team Leader (or responsible line cover) that an abnormal condition exists

Visual Management

9 Visual Management Areas

Bottleneck Analysis

An operation in a sequence of operations whose capacity is lower than the capacities of other operations in the sequence.

Smallest throughput rate
Longest cycle time

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