BASIC INSPECTION AND PROCEDURES CHAPTER 2 GMI Production

BASIC INSPECTION AND PROCEDURES CHAPTER 2 GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Learning Objectives �Define and differentiate measuring and gauging �List the advantages of measuring & gauging �List the disadvantages of measuring & gauging �Identify various types of gauges �Describe direct, indirect and comparative measurements �Explain factors of consideration in selecting testing appratus �Define the term calibration, traceability & measurement error �Identify the sources of measurement error �Identify the root cause of the problems �Explain the needs for calibration, inventory and care of apparatus GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Testing and Inspection Procedures Measuring Gauging • A method of inspection by means of comparing the dimensional characteristics of products against the scale of a measuring instrument. • Measured value is read off directly from these instruments • A method of inspection by means of comparing the dimensional characteristics of products against a gauge • True dimensional value cannot be obtain • This method only determine whether the product is within the allowable limits GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Measuring Measured value is read off directly from the measuring instrument GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Gauging True value is unknown, only determine ‘good’ or ‘bad’ parts only GMI | Production Technology

Measuring vs Gauging Measuring Characteristics Gauging more difficult Information Ease of use less easy Slow Time fast Expensive Cost/process Cheap High skill Operator Less skill 6

BASIC INSPECTION AND PROCEDURES �Types of Measurement Direct Measurement • Compared directly against the line of measuring instruments Indirect Measurement • Obtained by using an intermediary (transfer) measuring device Comparative Measurement • Comparison between standards blocks or products GMI | Production Technology

Types of Measurement (cont) Indirect Measurement �Measure value obtain using intermediary �Measurement directly use instrument, value determine by math (density, volume) 8

Types of Measurement (cont) Comparative measurement q. Comparison between standard/either known value. Dial gauge Gauge block Measure workpiece 9

BASIC INSPECTION AND PROCEDURES �Factors in selecting Testing Instrument 1. The Rule of 10 2. Repeat accuracy 3. Stability 4. Magnification 5. Resolution(sensitivity) 6. Inspection Cost – maintaining & installing GMI | Production Technology

BASIC INSPECTION AND PROCEDURES GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Calibration �Definition : q a periodical act of checking/comparing two measuring instruments, one of which is traceable to national standards �Purpose : q to detect any discrepancies in accuracy and adjust it to bring it within its tolerance for accuracy GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Calibration �Inventory and Classification � Systematic 1. 2. 3. 4. approach of calibration control Calibration Masterlist Record card Equipment Marking with Control number Calibration sticker GMI | Production Technology

Calibration (cont) 14

BASIC INSPECTION AND PROCEDURES GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Calibration �Function of Calibration room 1. 2. 3. 4. 5. 6. 7. To detect deteriorations of instruments and provide services for rectification or adjustments To ensure that newly purchased instruments are within the specified limits To keep instruments in proper condition to maintain accuracy Centralized location for gauge issuing Place for development and verification of test methods Acceptance inspection prior to production Room temperature 20+ 1°C and humidity at 55%+3. GMI | Production Technology

BASIC INSPECTION AND PROCEDURES �Care of Measuring Instrument 1. Calibrate the instrument periodically before use 2. Do not use instruments as tools 3. Protect the instruments from dust, rust, shock and wear 4. Store the instruments in a proper place 5. Do not store the instruments with other tools 6. Avoid rough handling and dropping the instruments GMI | Production Technology