Unit 8 Measurement and Quality Chapter 19 -Quality Assurance and Control

Quality Assurance and Control- Quality Assurance maintains Product Quality Source Inspection before Manufacturing In-process Quality Control during Manufacturing Product Service and Warranties after production

Quality assurance- All activities in manufacturing are directed toward ensuring production of a high-quality product.

Quality control- One segment of quality assurance often responsible for dimensional inspection (among others) during production.

Source Inspection before Manufacturing Source of materials, parts, subassemblies Sort out/reject poor quality material at the source Visual Inspection – color, texture, surface finish, appearance Metallurgical Testing – hardness, tensile strength, etc. Dimensional Inspection – measuring tools/gages Destructive/Nondestructive Testing – stress/xrays Performance Inspection – testing engines, etc.

In-process Quality Control during Manufacturing Same checks as with Source Inspection Sort out/reject poor quality parts/products Receiving Inspection – parts/matls coming in 1st Piece Inspection – after retooling; 1st part off the line is inspected before production begins In-process Inspection – machine operator/ assembler inspects 100% Inspection – often used for critical parts; too expensive for high-volume production Final Inspection – last chance

Non-dimensional Quality Control Measure Power Output Measure Radiation Output Microwave, radio emissions, interference

Product Service and Warranties after production Guaranty of product performance after purchase Warranty A guarantee of product quality provided by the manufacturer promising parts, service, or replacement in the case of a product failure.

Product Testing Prototype Stage Controlled Markets Endurance Testing

Lean is centered on preserving value with less work. Lean Manufacturing Lean manufacturing or lean production, often simply, "Lean," is a production practice that considers the expenditure of resources for any goal other than the creation of value for the end customer to be wasteful, and thus a target for elimination. Working from the perspective of the customer who consumes a product or service, "value" is defined as any action or process that a customer would be willing to pay for. Lean is centered on preserving value with less work.

Lean Manufacturing http://www.youtube.com/watch?v=cOAKOCxRK8M

Unit 8 Measurement and Quality Chapter 20-Inspection and Measurement

Inspection and Measurement- Why Measure a Product? > Out of Spec Product = Wasted production costs Product failure or non-function Liability for consequences How a Product is Measured Visual Inspection Comparison Inspection Measurement

Measurement standards- Known standards to which production gages and other measurement tools are periodically compared to ensure their conformity and accuracy. Gage blocks are an example.

Fixed gages- Instruments used for comparison inspection that do not display a reading.

Inspection- Inspection Instruments (Inspection) Plugs, rings, templates Steel rules, protractors Micrometers, height gages, coordinate measuring machines Size Specifications and Locations (Meas.) Form Specifications (Meas.) (Fig. 20.30 Perpendicularity, squareness, flatness, straightness, concentricity, etc.

Comparison Inspection- Fixed Gages (Fig. 20.5, .6, .7, .8) Compare part to gage of correct spec. “GO/NO GO” gages (do not display a reading) Screw-pitch gages and Radius Gages (Fig. 20.9 & .10) Worker simply compares, no reading or interpreting data  Many different gages required 

Measurement, Precision, and Resolution- Things affecting Measurement Precision of Instrument Resolution Reliability and Repeatability Condition of Surfaces of Workpiece Worker Skill Temperature and other environmental factors

Precision- Repeatability No larger than 1/10 of the tolerance range The amount of size variation (range variation) in the component or product features created by a manufacturing process. No larger than 1/10 of the tolerance range Tolerance range = 0.010, then Instrument precision = 0.001

Resolution- Smallest deviation the instrument can detect.

Measuring Tools- Direct Reading Instruments (fig.s 20.13- .23) Micrometers, calipers, etc. - measure whole distance (examine Calipers) Deviation-type gages (fig.s 20.25-.32) Measure only deviation from master Transfer-type instruments Telescoping hole gages (fig. 20.36)

Vernier scale- An added scale that improves the resolution of micrometers and other precision measuring instruments mechanically magnifies tiny variations in a dimension.

Measuring Tools- Semiprecision Tools Steel rule – 1/64” accuracy (Fig. 2.12) Combination set (Fig. 20.13) Thickness gage (Fig. 20.14) Rule-depth gage (Fig. 20.15)

Calibration- The processes of comparing measuring instruments and gages against known measurement standards and then adjusting them to conform with the standards.

CMM Coordinate measuring machine a computerized measuring instrument that precisely tracks the movement of a probe in three-dimensional space. The CMM records the location of the probe as it touches the workpiece, making the CMM useful for measurement of size, form, and location.

Surface finish (surface roughness)- A form specification that determines the smoothness of the minute peaks and valleys that compose a machined surface.

Temperature Effects Temperature changes cause metals to expand and contract – this affects the accuracy of measurements Standard measuring temperature is 68º F

Interchangeability- The concept that parts manufactured by many different manufacturers to the same dimensional specifications may be interchanged in assemblies. Different parts of same assembly may come from different manufacturers

Standards- Master Measurement Standards Maintained by NIST National Institute of Standards and Technology (formerly NSB – National Bureau of Standards)

Summary- Products must be Measured to ensure proper size and form Measuring Tools used must allow repeatable and accurate measurements Measuring tools may be direct-reading or “Go/No Go” “Go/No Go” measuring tools allow for faster and more accurate comparisons Direct reading instruments produce a readout – can be slow and can be misread “Go-No Go” instruments do not produce a readout but can be used more quickly than Direct reading instruments Semiprecision Measuring Tools rely on average eyesight to achieve reasonable accuracy

Summary- Temperature changes cause metals to expand and contract – this affects the accuracy of measurements Standard measuring temperature is 68º F Interchangeability – parts manufactured by many different manufacturers to the same dimensional specifications may be interchanged in assemblies.

Measuring with Dial Calipers Introduction to Basic Statistics Introduction to Engineering Design TM Unit 1 – Lesson 1.3 – Measurement and Statistics Measuring with Dial Calipers

Dial Calipers Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers At the conclusion of this presentation, you will be able to… identify four types of measurements that dial calipers can perform. identify the different parts of a dial caliper. accurately read an inch dial caliper. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Dial Calipers are arguably the most common and versatile of all the precision measuring tools used by engineers and manufacturers. Regardless of what type of caliper you use, be sure to take the following precautions to avoid damaging the caliper: 1. Wash your hands before you handle the dial caliper to remove dirt and oils that might damage the caliper. 2. Wipe the caliper components clean both before and after you use the caliper. 3. Do NOT drop or otherwise mishandle the caliper. Doing so may damage or destroy the caliper. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Dial calipers are used to perform four common measurements on parts… Outside Diameter or Object Thickness Inside Diameter or Space Width Step Distance Hole Depth Project Lead The Way, Inc. Copyright 2007

Outside Measuring Faces Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Outside Measuring Faces These are the faces between which outside length or diameter is measured. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Example: Outside Diameter of object Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Example: Outside Diameter of object Project Lead The Way, Inc. Copyright 2007

Inside Measuring Faces Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Inside Measuring Faces These are the faces between which inside diameter or space width (i.e., slot width) is measured. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Example: Inside measuring Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Example: Inside measuring Project Lead The Way, Inc. Copyright 2007

Step Measuring Faces Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Step Measuring Faces These are the faces between which stepped parallel surface distance can be measured. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Example: Step Distance Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Example: Step Distance Project Lead The Way, Inc. Copyright 2007

Depth Measuring Faces Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Depth Measuring Faces These are the faces between which the depth of a hole can be measured. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Example: Depth Measuring Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Example: Depth Measuring Note: Work piece is shown in section. Dial Caliper shortened for graphic purposes. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Nomenclature Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Nomenclature Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers A standard inch dial caliper will measure slightly more than 6 inches. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Note: Some dial calipers have blade scales that are located above or below the rack The blade scale shows each inch divided into 10 increments. Each increment equals one hundred thousandths (0.100”). Project Lead The Way, Inc. Copyright 2007

Slider Blade Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Slider Blade The blade is the immovable portion of the dial caliper. The slider moves along the blade and is used to adjust the distance between the measuring surfaces. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Pointer The pointer rotates within the dial as the slider moves back-and-forth along the blade. Project Lead The Way, Inc. Copyright 2007

Reference Edge Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Reference Edge The reference edge keeps track of the larger increments (i.e. 0.100”) as the slider moves along the rack. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Rack The gear-toothed rack is used to change linear motion (slider) to rotary motion (pointer). Project Lead The Way, Inc. Copyright 2007

Dial Calipers Reading the inch dial caliper Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Reading the inch dial caliper Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Note: Dial face divisions and increments are not standardized. The dial is divided 100 times, with each graduation equaling one thousandth of an inch (0.001”). Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers Every time the pointer completes one rotation, the reference edge on the slider will have moved the distance of one blade scale increment (0.100”). Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers To determine the outside diameter of this pipe section, the user must first identify how many inches are being shown on the blade scale. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers 1.000” The reference edge is located between the 1 and 2 inch marks. So, the user makes a mental note…1 inch. 0.400” The user then identifies how many 0.1” increment marks are showing to the right of the last inch mark. In this case, there are 4…or 0.400”. Project Lead The Way, Inc. Copyright 2007

Dial Calipers Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers 1.000” 0.400” + 0.037” 1.437” Next, the user looks at the pointer on the dial to see how many thousandths it is pointing to. In this case, it is pointing to 37…or 0.037”. The user then adds the three values together… Project Lead The Way, Inc. Copyright 2007

1.000” 0.400” 0.002” + 1.402” Dial Calipers How wide is the block? Introduction to Engineering DesignTM Unit 1 – Lesson 1.3 – Measurement and Statistics Dial Calipers 1.000” 0.400” 0.002” + 1.402” How wide is the block? Project Lead The Way, Inc. Copyright 2007