QUALITY CONTROL By José María Sanz Juan From the Polytechnic University of Valencia Department of Statistics and Operations Research Applied and Quality Quality Control 1 Introduction

Objetives The use statistical method and others problem-solving techniques to improve the quality of the products used by our society. The control of the characteristic that define the quality of a product and to assure that they accomplish the requirement. The control and the improve of the processes. Quality Control 2 Introduction

Definition of quality Quality means fitness for use (Juran) Quality is inversely proportional to variability (Deming) Quality improvement is the reduction of variability in processes and products. Two aspects of quality: A product has more quality when has more characteristics that satisfy the needs and expectations of the customer. A product has a high level of quality when it not fails. This aspect has incidence at the costs. Quality is the degree to which a set of inherent characteristics of an object fulfils the requirement (ISO- 9001) Quality Control 3 Introduction

Definitions Feature: is a distinguishing feature. It may be inherent or assigned. It may be quantitative or qualitative. Classes: Physical (mechanical, electrical, chemical) Sensory (smell, touch, taste, sight, hearing) Behavior (courtesy, honesty, veracity) Time (punctuality, reliability, availability) Ergonomic (comfort, safety) Functional (speed, maximum weight) Quality characteristic: inherent feature of a product. Customer Satisfaction: perception of compliance with the requirements. Effectiveness: meeting the goals. Efficiency: fulfillment of objectives at the lowest cost. 4 Quality ControlIntroduction

Dimensions of quality 1. Performance (Will the product do the intended job?) 2. Reliability (How often does the product fail?) 3. Durability (How long does the product last?) 4. Serviceability (How easy is to repair the product?) 5. Aesthetic (What does the product look like?) 6. Feature (What does the product do?) 7. Perceived quality (What is the reputation of the company or its product?) 8. Conformance to standard (is the product made exactely as the designer intended?) Quality Control 5 Introduction

More dimensions of quality (for service) 1. Responsiveness. How long did it take the service provider to reply to your request for service?. 2. Professionalism. The knowledge and the skills of the service provider. 3. Attentiveness. The care and personal attention from the service provider. Quality Control 6 Introduction

Other definitions Quality characteristics: are the parameter that define the product. Types: Physical: length, weight, voltage, viscosity. Sensory: taste, appearance, color. Time orientation: reliability, durability, serviceability. Quality engineering: is the set of operational, managerial and engineering activities that a company uses ti ensure that the quality characteristics of a product are at the nominal or required levels and the variability around these desired levels are minimum Quality characteristics are often evaluated relative to specifications. Quality Control 7 Introduction

Management aspects Quality planning: identifies customers, theirs needs, and develop the product or services that meets the customer expectations. Quality assurance: ensures the level of quality and develops a quality system with policies, objectives, procedures, work instructions and specifications. Quality control and improvement: to ensure that the products or services meet the requirements and are improved on a continuous basis. Quality Control 8 Introduction

Quality ControlIntroduction 9 Universal processes for managing quality Quality planningQuality controlQuality improvement Establish quality goalsChoose control subjectsProve the need Identify customersChoose units of measureIdentify projects Discover customer needs Set goalsOrganize project teams Develop product featuresCreate a sensorDiagnose the causes Develop process features Measure actual performance Provide remedies, prove that the remedies are effective Establish process control, transfer to operations Interpret the differenceDeal with the resistance to change Take action on the difference Control to hold the gains

Principle of quality management Quality ControlIntroduction 10 Customers. Organizations depend on their customers and strive and identify their current and future needs, and strive to exceed their expectations. Leadership Leaders should create and maintain an internal environment in which people become involved in achieving the objectives of the organization. Staff The staff is the essence of the organization and its involvement enables their abilities to be used to benefit the organization. Processes A desired result is achieved more efficiently when activities and related resources are managed as a process. Systems approach Identifying, understanding and managing interrelated processes as a system contributes to the effectiveness and efficiency. Continuous improvement Continuous improvement must be a permanent objective. Data-driven decision Effective decisions are based on the analysis of data and information. Alliances with suppliers An organization and its suppliers are interdependent and a mutually beneficial relationship enhances the ability of both to create value.

Deming´s 14 point 1. Create a constancy of purpose focused on the improvement of product and services. 2. Adopt a new philosophy that recognizes we are in a different economic area. 3. Do not rely on mass inspection to “control” quality. 4. Do not award business to suppliers on the basis of price alone, but also consider quality. 5. Focus on continuous improvement. 6. Practice modern training methods and invest in on-the- job training for all employees. 7. Improve leadership, and practice modern supervision methods. Quality Control 11 Introduction

More points 8. Drive out fear. 9. Break down the barriers between functional areas of business. 10. Eliminate targets, slogans and numerical goals for the workers. 11. Eliminate numerical quotas and work standards. 12. Remove the barriers that discourage employees from doing their jobs. 13. Institution an ongoing program for education for all employees. 14. Create an structure in top management that will vigorously advocate the first 13 points. Quality Control 12 Introduction

The PDCA cycle 1. Plan: propose a change for the improvement 2. Do: carry out the change 3. Check: analyze the results of the change 4. Action: adopt or abandon the change. Quality Control 13 Introduction

Production process inputs and outputs Quality Control 14 Introduction

Process management Quality ControlIntroduction 15

Process map Quality ControlIntroduction 16 Identify and manage the sequence and interaction of processes Process A Process B Process C Process D inputs Outputs Controls

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Elements of a process Quality ControlIntroduction 18 Supplier / Customer: Origin of our inputs and recipients of the results of the process Initiation: First activity of the process. End: the last thing to be done. Indicators: Measure and monitoring of the process. Procedure / method: GUIDELINES of how we must perform the activities included in the process Associated documents: DOCUMENTS used while running the process for proper operation. Limits /specifications: Parameters or conditions that must be met for the process to be correct.

Types of process STRATEGICCORESUPPORT Direction Alignment Priorities Action Delivery Results Enabling Learning Improvement Quality ControlIntroduction 19

Example of a process map Quality ControlIntroduction 20

Methods for controlling Statistical process control Inspection. Quality Control 21 Introduction

Example of process fmea Quality ControlIntroduction 22

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Methods for improvement Design of experiments ANOVA Taguchi methods Quality Control 26 Introduction

The ISO standards ISO 9000: QMS- Fundamentals and vocabulary ISO 9001:2015. QMS- Requirements ISO 9004:2009. QMS- Guidelines for performance and improvement. Quality Control 27 Introduction

Models for evaluate the quality The EFQM model The Malcom-Baldrige model The Deming model. Quality Control 28 Introduction

The Six Sigma method The focus is to reduce the variability in the product quality characteristics to the level at which failure or defectsare extremely unlikely. DMAIC Quality Control 29 Introduction DefineMeasureAnalyzeImproveControl Objective: Define the opportunity for improvement Objective: Measure the current efficiency of the process Objective: Analyze the root causes of problems Objective: Improve the process to eliminate the roots causes Objective: Control the process to ensure improvements.

Just in time. Lean production. The eight wastes. 1. Overproduction: making or doing more than is required or earlier than need. 2. Waiting: for information, materials, people and maintenance. 3. Transport: moving people or goods around or between sites. 4. Poor process design: too many/few steps, nonstandarization and inspection rather than prevention. 5. Inventory: raw materials, work in progress, finished goods, papers and electronic files. 6. Motion: inefficient layouts at workstations, in offices, poor ergonomics. 7. Defects: errors, scrap, rework, nonconformance. 8. Underutilized personal resources and creativity: ideas that are listened to, skills that are not used. Quality Control 30 Introduction

Poka-Yoke: to prevent the errors 1. Elimination: Eliminating the possibility of error. 2. Replacement: substituting a more reliable process for the worker. 3. Facilitation: making the work easier to perform. 4. Detection: detecting the error before further processing. 5. Mitigation: Minimizing the effect of the error. Quality Control 31 Introduction

Self-control 1. Knowledge of what they are supposed to do. 2. Knowledge of what they are actually doing. 3. A process that is capable of meeting specifications and can be regulated to meet specifications. Quality Control 32 Introduction

Supplier Chain quality management Supplier qualification or certification: to select the best supplier. Supplier development: to improve the performance of its suppliers. Supplier audits: to ensure that product quality, standards and other operational objectives are met. Quality Control 33 Introduction

Quality Cots Those categories of cost that are associated with producing, identifying, avoiding or repairing products that do not meet requirements Quality Control 34 Prevention costs: -Quality planning and engineering. -New products review. -Product/process design. -Process control. -Burn-in. -Quality data acquisition and analysis. Internal failure costs: -Scrap. -Rework. -Retest. -Failure analysis. -Downtime. -Yield losses -Downgrading Appraisal costs: -Inspection and test of incoming material. -Product inspections and test. -Materials and services consumed. -Maintaining accuracy of test equipment. External failure costs: -Complain adjustment. -Returned product/material. -Warranty charges. -Liability costs. -Indirect costs. Introduction