1. 1 Teaching Innovation - Entrepreneurial - Global The Centre for Technology enabled Teaching & Learning, N Y S S, India DTEL DTEL (Department for Technology Enhanced Learning)

2. DEPARTMENT OF COMPUTER TECHNOLOGY VIII-SEMESTER AUTOMATION IN PRODUCTION 2 CHAPTER NO.5 AUTOMATED INSPECTION AND GROUP TECHNOLOGY

3. CHAPTER 1:- SYLLABUSDTEL. Automated inspection principles & method 1 Sensor technologies for automated inspection, 2 Machine vision & Other optical inspection methods 3 Group Technology:- Part families parts classification & Coding. 4 3 Machine cell design 5

4. CHAPTER-1 SPECIFIC OBJECTIVE / COURSE OUTCOMEDTEL Understand Automation inspection & Group technology. 1 Analysis machine cell design in Group Technology. 2 4 The student will be able to:

5. DTEL Automated inspection 5 LECTURE 1 Inspection can be defined as the activity of examining the products, its components, sub-assemblies, or materials out of which it is made, and to determine whether they adhere to design specifications. Automated inspection is defined as the automation of one or more steps involved in the inspection procedure. Automated or semi-automated inspection can be implemented in the number of alternative ways. 100% inspection As in manual inspection, automated inspection can be performed using statistical sampling or 100% inspection. Sampling errors are possible when statistical sampling is used. Similar to human inspector, automated system can commit inspection error with either sampling or 100% inspection

6. DTEL Off-line Inspection 6 LECTURE 1 Off-line Inspection Methods In off-line inspection, the inspection equipment is usually dedicated and does not make any physical contact with machine tools 1. Variability of the process is well within the design tolerance, 2.Processing conditions are stable and the risk of significant deviation in the process is small, and 3.Cost incurred during inspection is high in comparison to the cost of few defective parts.

7. DTEL On-line Inspection 7 LECTURE 1 On-line/In-process and On-line/Post-process Inspection Methods If the inspection is performed during the manufacturing operation, it is called on-line/in-process inspection. If the inspection is performed immediately following the production process, it is called on-line/post-process inspection

8. DTEL Coordinate Metrology 8 LECTURE 1 Concerned with the measurement of the actual shape and dimensions of an object and comparing these with the desired shape and dimensions specified on a part drawing. Coordinate measuring machine (CMM) – an electromechanical system designed to perform coordinate metrology. A CMM consists of a contact probe that can be positioned in 3-D space relative to workpart features, and the x-y-z coordinates can be displayed and recorded to obtain dimensional data about geometry

9. DTEL Co-ordinate Measuring Machine 9 LECTURE 2

10. DTEL CMM Components 10 LECTURE 2 Probe head and probe to contact workpart surfaces Mechanical structure that provides motion of the probe in x-y-z axes, and displacement transducers to measure the coordinate values of each axis Optional components (on many CMMs):  Drive system and control unit to move each axis  Digital computer system with application software (a) Single tip and (b) multiple tip probes

11. DTEL CMM Mechanical Structure 11 LECTURE 2 Six common types of CMM mechanical structures: 1.Cantilever 2.Moving bridge 3.Fixed bridge 4.Horizontal arm 5.Gantry 6.Column

12. DTEL CMM Structures 12 LECTURE 2 (a) Cantilever and (b) moving bridge structure

13. DTEL CMM Structures 13 LECTURE 2 (c) Fixed bridge and (d) horizontal arm (moving ram type)

14. DTEL CMM Structures 14 LECTURE 2 (e) Gantry and (f) column

15. DTEL Machine Vision 15 LECTURE 3 Acquisition of image data, followed by the processing and interpretation of these data by computer for some useful application Also called “computer vision” 2-D vs. 3-D vision systems:  2-D – two-dimensional image – adequate for many applications (e.g., inspecting flat surfaces, presence or absence of components)  3-D – three-dimensional image – requires structured light or two cameras

16. DTEL Operation of a Machine Vision System 16 LECTURE 3 1.Image acquisition and digitization 2.Image processing and analysis 3.Interpretation

17. DTEL Image Acquisition and Digitization 17 LECTURE 3 With camera focused on subject, viewing area is divided into a matrix of picture elements (“pixels”)  Each pixel takes on a value proportional to the light intensity of that portion of the scene and is converted to its digital equivalent by ADC In a binary system, the light intensity is reduced to either of two values, white or black In a gray-scale system, multiple light intensities can be distinguished  Each frame is stored in a frame buffer (computer memory), refreshed 30 times per second

18. DTEL Dividing the image into a Matrix of Picture Elements (Pixels) 18 LECTURE 3 (a) The scene (b) 12 x 12 matrix superimposed on the scene (c) Pixel intensity values, either black or white, in the scene Image Acquisition and Digitization

19. DTEL Types of Cameras 19 LECTURE 4 Vidicon camera  Focus image on photoconductive surface followed by EB scan to determine pixel value  Have largely been replaced by Solid-state cameras  Focus image on 2-D array of very small, finely spaced photosensitive elements that emit an electrical charge proportional to the light intensity Smaller and more rugged No time lapse problem

20. DTEL Illumination Techniques 20 LECTURE 4 ( a) Front lighting, (b) back lighting, (c) side lighting

21. DTEL More Illumination Techniques 21 LECTURE 4 Structured lighting using a planar sheet of light

22. DTEL Image Processing and Analysis 22 LECTURE 4 Segmentation – techniques to define and separate regions of interest in the image  Thresholding – converts each pixel to a binary value (white or black) by comparing the intensity level to a defined threshold value  Edge detection – determines location of boundaries between an object and its background, using the contrast in light intensity between adjacent pixels at the boundary of an object Feature extraction – determines an object’s features such as length, area, aspect ratio

23. DTEL Interpretation 23 LECTURE 5 For a given application, the image must be interpreted based on extracted features Concerned with recognizing the object, called pattern recognition - common techniques:  Template matching – compares one or more features of the image object with a template (model) stored in memory  Feature weighting – combines several features into one measure by weighting each feature according to its relative importance in identifying the object

24. DTEL Machine Vision Applications 24 LECTURE 5 1.Inspection:  Dimensional measurement  Dimensional gaging  Verify presence or absence of components in an assembly (e.g., PCB)  Verify hole locations or number of holes  Detection of flaws in printed labels 2.Identification – for parts sorting or counting 3.Visual guidance and control – for bin picking, seam tracking in continuous arc welding, part positioning

25. DTEL Other Optical Inspection Methods 25 LECTURE 5 Conventional optical instruments  Optical comparator  Conventional microscope Scanning laser systems Linear array devices Optical triangulation techniques

26. DTEL Scanning Laser Device 26 LECTURE 6

27. DTEL Linear Array Measuring Device 27 LECTURE 6

28. DTEL Optical Triangulation Sensing 28 LECTURE 6 Range R is desired to be measured Length L and angle A are fixed and known R can be determined from trigonometric relationships as follows: R = L cot A

29. DTEL Group Technology 29 LECTURE 7 Group technology (GT) is a manufacturing philosophy that seeks to improve productivity by grouping parts and products with similar characteristics into families and forming production cells with a group of dissimilar machines and processes. The group of similar parts is known as part family and the group of machineries used to process an individual part family is known as machine cell. It is not necessary for each part of a part family to be processed by every machine of corresponding machine cell. Group technology begun by grouping parts into families, based on their attributes (Geometry, manufacturing process ). Geometric classification of families is normally based on size and shape, while production process classification is based on the type, sequence, and number of operations. The type of operation is determined by such things as the method of processing, the method of holding the part, the tooling. There are three methods that can be used to form part families: Manual visual inspection Production flow analysis Classification and coding

30. DTEL 30 LECTURE 7 Group Technology GT Job shop production System Batch production System Mass production System

31. DTEL Group Technology 31 LECTURE 7 Manual visual inspection Manual visual inspection involves arranging a set of parts into groups by visually inspecting the physical characteristics of the parts.

32. DTEL 32 LECTURE 7 Part Family 1 Part Family 2 Group Technology

33. DTEL 33 LECTURE 7 Parts that go through common operations are grouped into part families. The machines used to perform these common operations may be grouped as a cell, consequently this technique can be used in facility layout (factory layout) Production flow analysis (PFA) is a method for identifying part families and associated machine groupings that uses the information contained on process plans rather than on part drawings. Work-parts with identical or similar process plans are classified into part families. These families can then be used to form logical machine cells in a group technology layout. The procedure in production flow analysis must begin by defining the scope of the study, which means deciding on the population of parts to be analyzed. Production flow analysis

34. DTEL 34 The procedure of Production flow analysis (PFA) consists of the following steps: Data Collection. The minimum data needed in the analysis are the part number and operation sequence, which is obtained from process plans. Sortation of process plans. A sortation procedure is used to group parts with identical process plans. PFA Chart. The processes used for each group are then displayed in a PFA chart as shown below. LECTURE 7 Production flow analysis

35. DTEL 35 4. Clustering Analysis. From the pattern of data in the PFA chart, related groupings are identified and rearranged into a new pattern that brings together groups with similar machine sequences. LECTURE 7 Production flow analysis

36. DTEL 36 Parts classification and Coding LECTURE 8 In parts classification and coding, similarities among parts are identified, and these similarities are related in a coding system. Two categories of part similarities can be distinguished: 1.Design attributes, which concerned with part characteristics such as geometry, size and material. 2.Manufacturing attributes, which consider the sequence of processing steps required to make a part. Reasons for using a classification and coding system: Design retrieval. A designer faced with the task of developing a new part can use a design retrieval system to determine if a similar part already exist. A simple change in an existing part would take much less time than designing a whole new part from scratch. Automated process planning. The part code for a new part can be used to search for process plans for existing parts with identical or similar codes. Machine cell design. The part codes can be used to design machine cells capable of producing all members of a particular part family, using the composite part concept.

37. DTEL 37 LECTURE 8 A part coding system consists of a sequence of symbols that identify the part’s design and/or manufacturing attributes. The symbols are usually alphanumeric, although most systems use only numbers. The three basic coding structures are: 1.Chain-type structure, also known as a polycode, in which the interpretation of each symbol in the sequence is always the same, it does not depend on the value of the preceding symbols. Parts classification and Coding

38. DTEL 38 LECTURE 8 2. Hierarchical structure, also known as a monocode, in which the interpretation of each successive symbol depends on the value of the preceding symbols. 3. Hybrid structure, a combination of hierarchical and chain-type structures. Parts classification and Coding

39. DTEL 39 LECTURE 8 It is intended for machined parts and uses the following digits sequence Form Code 1 2 3 4 5 for design attributes Supplementary Code 6 7 8 9 for manufacturing attributes Secondary CodeA B C D for production operation type & sequence Parts classification and Coding

40. DTEL 40 LECTURE 8 Digits (1-5) for Rotational parts in the Opitz System

41. DTEL 41 LECTURE 8 Example: Optiz part coding System Given the rotational part design below, determine the form code in the Optiz parts classification and coding system. Solution Length-to-diameter ratio: L/D = 1.5Digit 1 = 1 External shape: both ends stepped with screw thread on one endDigit 2 = 5 Internal shape: part contains a through holeDigit 3 = 1 Plane surface machining: noneDigit 4 = 0 Auxiliary holes, gear teeth, etc.: noneDigit 5 = 0 The form code in the Optiz system is 15100

42. DTEL 42 LECTURE 9 Machine Cell Designs 1.Single machine 2.Multiple machines with manual handling -Often organized into U-shaped layout 3. Multiple machines with semi-integrated handling 1.Automated cell – automated processing and integrated handling – Flexible manufacturing cell – Flexible manufacturing system Machine Cell with Manual Handling U-shaped machine cell with manual part handling between machines

43. DTEL 43 LECTURE 9 Cell with Semi-Integrated Handling In-line layout using mechanized work handling between machines Loop layout allows variations in part routing between machines Machine Cell Designs

44. DTEL 44 LECTURE 9 Rectangular layout also allows variations in part routing and allows for return of work carriers if they are used Four Types of Part Moves in Mixed Model Production System Machine Cell Designs

45. DTEL 45 LECTURE 9 THANK YOU