1. MECH 538 Application of Drawing Requirements Tools Fixtures and Gaging

2. Introduction Factors that influence part manufacture in accordance with drawings and specifications. Tooling and fixturing methods for GD&T parts Fundamentals of dimensional metrology Dimensional metrology – science of dimensional measurement Measurement is the language of science and engineering when used to communicate size, position or conditions.

3. Introduction 2 Product production has evolved over the past century thru mass production, CNC, CAD- CAM, to FMS, JIT, and SPC. Zero inventory means more efficient and cost effective workholding devices. Every part produced to an engineering drawing spec must be held while being processed (machined, joined, inspected etc)

4. Introduction 3 Workholding devices are customised to suit each part. There are basic rules for workholding devices (Jigs, Fixtures etc) Simple and cost effective….must save money on production, must cost effective in construction, and have the capacity to perform intended functions.

5. Course Outline 1. Metrology – measurement of parts 2. Verifying Geometric requirements 3. Dimensional Inspection Plans 4. Functional Gauging principals 5. Tool Design 6. Jigs 7. Fixtures 8. DFM

6. Week 1 Introduction 2 Metrology, Tolerance Review 3 Inspecting parts with GD & T references 4 Dimensional Inspection Plan 5 Go and No-Go gauges, Functional Gauging 6 Mid Term Test 7 Coordinate Measuring Machines 8 Tool Design 9 Workholding devices 10 Jigs and Fixtures 11 Construction Methods 12 Fixturing for NC 13 Design for Manufacturing, Kaizen and Set up reduction 14 Final Review

7. Metrology Measurement is the language of science and engineering when used to communicate size, position or conditions. Three reasons to communicate in measurements: 1. to make or manufacture things – tolerances for manufacture. 2. to control the way others make things – inspection and quality control departments 3. to describe things – to others relating to the manufacture of parts

8. Gauging and Measuring principals: The specification of a tolerance on a dimension, or a geometric tolerance of form, orientation, or position, does not necessarily imply the use of any particular method of production, measurement, or gauging. The priority is for whomever is deciding on the measuring or gauging method to be used, to be familiar with the function of the part, the method of production and the quantity produced in a run. One of the best ways of analyzing the effects of limits and tolerances is to establish a measuring or gauging principal that will determine whether or not the feature falls within its theoretical tolerance zone.

9. Measurement & Gauging Dimensional measurement after the part is produced is called “post process” measurement In production engineering, some form of “hard gauge” would be designed to simulate the measuring principals required, called “open set-up”. It is also common practice for manufacturers to use methods in accordance with the drawing specification. Hard Gauges are mechanical; calipers, functional gauges, CMM, snap gauges. Soft Gauges is usually computer software used to compare with exact model.

10. Measurement & Gauging Example: if a diameter on a part was specified without any geometric tolerances: 1. caliper-type measurement, (micrometer) for size only 2. ring gauge, for maximum size, and roundness. 3. If the ring gauge were of sufficient length, it would also control straightness or cylindricity within the same limit.

11. Measuring dimensions Dimension - Perfect separation between two definable points (features), a geometrical feature whose size is specified Tolerance – total permissible variation in size (of a dimension) – difference between limits of size. Feature – a specific portion of a part, hole, slot, edge, profile, thread, etc. – physical

12. Measuring dimensions Linear dimensions are intended to apply on a point to point basis, and are therefore measured accordingly – between opposing points.

13. Measuring dimensions measure normally (perpendicular) to centerline or axis, applies at a, b, c, d

14. Measuring dimensions Cylindrical surfaces

15. Measuring dimensions Thin parts

16. Measuring dimensions Thickness / Length measurement

17. Measuring dimensions Formed parts

18. Measuring dimensions Location measurements

19. Measuring dimensions Angle Measure

20. Measuring dimensions Example: ABCDABCD

21. Tools – open set-up Micrometer Caliper / Vee Blocks Gauge Blocks Reference Profile Projector CMM Probe

22. Measurement Conditions ANSI / ASME Y14.5M: “unless otherwise specified, all dimensions are applicable at 20C (68F). Compensation made be made for measurements at other temperatures. Sites: http://emtoolbox.nist.gov/Temperature/Slide1.asp #Slide1 http://emtoolbox.nist.gov/Temperature/Slide1.asp #Slide1 http://books.google.com.eg/books?id=Ms7lVOepe NsC&hl=en (preview page 301) http://books.google.com.eg/books?id=Ms7lVOepe NsC&hl=en

23. Number of measurements “A sufficient number”……depends on the part function, inspectors experience. British Standard BS 7172 “collection and assessment of mathematical data for the verification of tolerance of geometrical control” Minimum number of measurements: Line5 Plane5 Circle7 Cylinder 15 Cone15

24. Environmental Considerations Temperature of facility Sunlight Noise Vibration Humidity Cleanliness

25. Assignment 1 Due 1 week Handout

26. Assignment 1 Research Write a couple of paragraphs, explaining the effects of temperature rise on the following three materials, while being inspected: Steel, Chrome Carbide, Aluminum. What determines the lab temperature for measuring? Type – d/s; Cite all references.