2Quality Assurance (QA) 1. The operational techniques and activities that sustain the product or service quality to specified requirements.2. The use of such techniques and activities..
3Quality Assurance (QA) 3. Operations intended for the assessment of the quality of products at any stage of processing or distribution .4. Part of quality assurance intended to verify that components and systems correspond to predetermined requirements.
4Quality control (QC)Quality control, focuses on the end result, such as testing a sample of items from a batch after production.Inspection takes place at all stages of the process from design to dispatch
5Quality control (QC)Basically quality control tests that the standards laid out by the quality assurance standards have been met
6Inspection takes place at stages Goods inward During production Quality inspectionInspection takes place at stagesGoods inwardDuring productionFinal inspection
7Quality Assurance vs. Quality Control A series ofanalyticalmeasurements usedto assess thequality of theanalytical data(The “tools”)An overallmanagement plan toguarantee theintegrity of data(The “system”)
8True Value vs. Measured Value The known, accepted value of a quantifiable propertyMeasured ValueThe result of an individual’s measurement of a quantifiable property
9reproducabilityThe ability of a system to achieve the same results when using different operators and different measuring equipment
10Accuracy vs. Precision Precision Accuracy How well a measurement agrees with an accepted valuePrecisionHow well a series of measurements agree with each other
12ISO 9000Is an international standard that many companies use to ensure that their quality assurance system is in place and effective. Conformance to ISO is said to guarantee that a company delivers quality products and services.
13ISO 9001ISO 9001 is for all organisations large or small and covers all sectors, including charities and the voluntary sector. It will help you to be more structured and organised. it is a process standard, not a service or product standard.
14ISO 9001ISO 9001 gives the requirements for what the organisation must do to manage processes affecting quality of its products and services. It does this through the creation of a Quality Management System.
15ISO 9001The standard requires you to have certain documented procedures. They must meet the requirements as described in the following 6 clauses as mentioned in the standard:
16ISO 9001 (clause 4.2.4) Control of records (clause 4.2.3) Control of documents(clause 4.2.4) Control of records(clause 8.2.2) Internal audit(clause 8.3) Control of nonconforming product(clause 8.5.2) Corrective action(clause 8.5.3) Preventative action
18Benefits of ISO 9001Improved consistency of service and product performanceHigher customer satisfaction levels.Improved customer perceptionImproved productivity and efficiency
19BENEFITS of ISO 9001 Cost reductions Improved communications, morale and job satisfactionCompetitive advantage and increased marketing and salesopportunities.
20Standard for quality management systems Products should conform to standards of quality assurance and demonstrate conformity to product requirements. Action should be taken to eliminate non conformity. Action should be taken prevent the use of non conforming products. (without waiting for the customer to complain)
23Outside MicrometerInstrument for making precise linear measurements of dimensions such as diameters, thicknesses, and lengths of solid bodies.It consists of a C-shaped frame with a movable jaw operated by a screw. The accuracy of the measurements depends on the accuracy of the screw-nut combination.
30Reading the Sleeve and Thimble 13Number on SleeveNumber onThimbleImperial Micrometer2Graduation on SleeveThimble numbers go from 0 to 20
31Sample Reading Example using a 0-1” Outside Micrometer Thimble First numberis the size ofthe Mic0.000Second numberis the first numberon Sleeve.000Third numberis .025 graduationsyou see on Sleeve.025 x 2 = .050Fourth numberis read on theThimble.016
32Recording Measurement from Sample Reading First reading – Range of Mic.0 – 1” so the first number would beSecond reading – number on SleeveNumber you see is Zero so it would be .000Third reading – graduation on SleeveTwo graduations exposed so number is .050Final number is number on the ThimbleFinal number is .016
33Total Readings 0.066 First reading – Range of Mic. 0.000 Second reading – number on SleeveThird reading – graduation on SleeveFinal number is number on the Thimble______0.066Total is ?
39IntroductionCalipers can be direct reading or measuring transferring tools.Direct reading calipers are capable of a wider measurement range than micrometer calipers.Six (6), eighteen (18) and twenty four (24) inch are popular.
40Three common designs of direct reading calipers; Vernier Dial Digital IntroductionThree common designs of direct reading calipers;VernierDialDigital
41Vernier CaliperVernier calipers are an old tool that has been mostly replaced by dial and digital calipers.They are manufactured with decimal scales, metric scales and fractional scales.The Vernier scale is still used on many mechanical measuring tools.
42Vernier ScaleA Vernier is a mechanical means of magnifying the last segment on the main scale so addition subdivisions can be made.The reference point is the 0 on the vernier scale.To read a Vernier, the line of coincidence must be located.The line of coincidence (LOC) is the line on the Vernier that coincides with a line on the main scale.Illustration LOC = 19In theory only one LOC is possible, but usually when reading the vernier it appears several exist. When this occurs pick the middle line.
43Vernier Caliper-practice Read the Vernier caliper in the illustration.LOCSmallest whole unit 1.000Tenths of an inch 0.200Twenty five thousandsVernier scale 0.011Sum (measurement) 1.211
44Dial CaliperA dial replaces the Vernier. This makes the caliper easier to read. The reader must still determine the units and graduations.
51Spring Calipers Spring calipers are used to transfer measurements. Three types of spring calipersOutsideInsideHermaphrodite
52DividersDividers are very useful for laying out several equal distances or transferring a distance measurement when other measuring devices cannot be used.
53Telescoping gagesTelescoping gages are used to measure inside diameters.One or both ends are spring loaded so they can be retracted and inserted into the hole being measured.The measurement is made with a caliper or micrometer.
54Ball GaugesBall gauges are use to transfer measurements that are too small for telescoping gauges.The ball is split and a tapered wedge is used to increase and decrease the diameter of the ball halves.
55Measuring Straightness Measuring straightness manually with (a) a knife-edge rule and (b) a dial indicator.
56Interferometry method for measuring flatness using an optical flat. (b) Fringes on a flat, inclined surface. An optical flat resting on a perfectly flat workpiece surface will not split the light beam, and no fringes will be present.
57(c) Fringes on a surface with two inclinations (c) Fringes on a surface with two inclinations. Note: the greater the incline, the closer together are the fringes.(d) Curved fringe patterns indicate curvatures on the workpiece surface.
58Measuring Roundness(a) Schematic illustration of out-of-roundess (exaggerated). Measuring roundess using (b) a V-block and dial indicator, (c) a round part supported on centers and rotated, and (d) circular tracing.
59Measuring Gear-Tooth Thickness and Profile Figure Measuring gear-tooth thickness and profile with (a) a gear-tooth caliper and (b) pins or balls and a micrometer.
60Optical Contour Projector A bench-model horizontal-beam contour projector with a 16-in. diameter screen with 150-W tungsten halogen illumination.
61Fixed GaUgesFigure (a) Plug gage for holes with GO and NOT GO on opposite ends. (b) Plug gage with GO and NOT GO on one end. (c) Plain ring gages for gaging round rods. Note the difference in knurled surfaces to identify the two gages. (d) Snap gage with adjustable anvils.
63Electronic Gage Measuring Vertical Length Figure An electronic vertical-length measuring instrument with a resolution of 1 μm
64Laser MicrometersFigure (a) and (b) Two types of measurements made with a laser scan micrometer. (c) Two types of laser micrometers. Note that the instrument in the front scans the part (placed in the opening) in one dimension; the larger instrument scans the part in two dimensions.
65Coordinate-Measuring Machine (b)(c)(d)(a) Schematic illustration of a coordinate-measuring machine. (b) A touch signal probe. (c) Examples of laser probes. (d) A coordinate-measuring machine with a complex part being measured.
66Coordinate-Measuring Machine for Car Bodies Figure A large coordinate- measuring machine with two heads measuring various dimensions on a car body.
67Tolerance is the range of sizes in within which a component is acceptable Tolerance Control
68Methods of Assigning Tolerances Various methods of assigning dimensions and tolerances on a shaft:(a) bilateral tolerance, (b) unilateral tolerance, and (c) limit
79'Go' Limit'go' limit is the one between the two size limits which corresponds to the maximum material limitthe upper limit of a shaft and the lower limit of a hole'GO' gauge can check one feature of the component in one pass
80'NO GO' Limit'no go' limit is the one between the two size limits which corresponds to the minimum material conditionthe lower limit of a shaft and the upper limit of a hole.
815.2.1 Limit Plug GaugeLimit plug gauges are fixed gauges usually made to check the accuracy of a hole with the highly finished ends of different diametersIf the hole size is correct within the tolerable limits, the small end (marked “go”) will enter the hole, while the large end (“not go”) will not.
82Plug Gauge Example Dimension on part to gauge The nominal hole size on part to gauge is ”;Tolerance of the hole is ”/-0.000” ;This means the hole must be manufactured somewhere between ” and ” in size;
845.2.2 Limit Ring GaugeLimit plug gauges are fixed gauges usually made to check the accuracy of a shaft with highly finished ends of different diameters is usedIf the shaft size is correct within the tolerable limits, the large end (marked “go”) will go through the shaft, while the small end (“not go”) will not.
86Ring Gauge Example Post on part to gauge is 1.0000”; Dimension on part to gauge:Post on part to gauge is ”;Tolerance of post on part is ”/-0.000”;This means the post will be somewhere between ” and ” in size;
87Standard DeviationFind the mean and the standard deviation for the values 78.2, 90.5, 98.1, 93.7, 94.5.= = 91 Find the mean.( )5xOrganize the nextsteps in a table.––xx – x(x – x)2 = Find the standarddeviation.(x – x)2n234.045=The mean is 91, and the standard deviation is about 6.8.
88One standard deviation away from the mean (μ) in either direction on the horizontal axis accounts for around 68 percent of the data. Two standard deviations away from the mean accounts for roughly 95 percent of the data with three standard deviations representing about 99.7 percent of the data.
90one to six sigma conversion table 'Long Term Yield' (basically the percentage of successful outputs or operations)Defects Per Million Opportunities (DPMO)'Processs Sigma'%3.4699.98233599.46,210493.366,807369.1308,538230.9691,4621
91A six sigma process is one in which 99 A six sigma process is one in which % of the products manufactured are statistically expected to be free of defects (3.4 defects per million),
92Six sigmaSix Sigma team leaders (Black Belts) work with their teams (team members will normally be people trained up to 'Green Belt' accreditation) to analyse and measure the performance of the identified critical processes. Measurement is typically focused on highly technical interpretations of percentage
93Document control There must be evidence of the existence of a system A record of the correct operation must be keptThis is important to trace evidence of inspection in case of future complaints or problems
94MTBFMean time between failures (MTBF) is the predicted elapsed time between inherent failures of a system during operationMTBF can be calculated as the (average) time between failures of a system