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1 Engineering Drawing & CAD Creative Design Project I Jongsoo Lee School of Mechanical Engineering Yonsei University Spring of 2003

2 Drawing & Projections Design with Tolerance CAD Modeling

3 Expressions of design

4 Semantic: verbal or textual representation The shear stress is equal to the shear stress on the bolt divided by the stress area. Graphical: drawing of the object scale representation drawing, sketches, artistic rendering tables, charts

5 Analytical: equations, rules, procedures, algorithms, directions. τ = F/A Physical: hardware or physical model of the object

6 Computer Aided Design Computer Aided Drawing Computer Aided Engineering Computer Aided Manufacturing Computer Integrated Manufacturing

8 투상 (projection) 물체로부터일정거리에있는광선에의해 물체의상이화면에만들어진다.

9 정투상 : 광선이화면에수직일때의투상 물체의모양을정확히표현하는방법 orthographic projection 서로직각을이루고있는평면상에물체로부터수직선을내려서얻은 2 개의또는그이상의방향도를이용하여물체의모양을정확히표현하는도법 방향도 - 정면, 평면, 측면

10 투상 (projection) 방향도 : 각점에서화면에이르는수직선을투사하여 개념적인그림을얻는다 ( 수직투상평면 ) 전면에서의투상도표시 이경우, 모양과거리는나타나지않으므로물체의모양을표현하기위해 2 개이상의투상도가필요하다.

12 정투상의종류 정투상법 : 물체의전방에투시판을세우고빛의반사원리에의하여나타나는투상으로써물체를표시하는방법 제 1 각법 : 물체의뒤에투상면을세우고물체의전면의모양이투상면에그림자로나타나도록정투상하는방법 제 3 각법 : 투상면이물체의앞에오는정투상법

13 투상도의배합 정면도, 평면도, 좌측면도, 우측면도, 저면도, 배면도 실제의경우, 6 개의기본투상도전부를한도면에그리는경우는드물며, 3 개의투상도로물체의모양과크기를표시한다. 물체가임의의한좌표축에대해대칭인경우에는 2 개의투상도로표현가능하다

14 투상도의배합

15 투상도의선택

16 물체의면은그면에나란한투상면에투사하였을때실제의크기로나타내어질수있다. - 정투상의기본적표현방법 경사진면을가지고있는경우 경사면 : ABCD 면 ABCD 의실치수와모양을나타내기위해서는시선의방향이면 ABCD 에수직이어야한다. 투사선은 ABCD 에수직이고화면이 ABCD 에나란한투상도가필요하다 - 수직투상도

17 부투상도 직투상도 : 물체의면에나란하투사선이수직인투상도 면 ABCD 의수직투상도를얻기위해 ABCD 에수직인투상도를추가하는데이투상도는정면도에서선으로나타난면으로부터구성한다. >> 부가된부상도 : 부투상도 >> 기본투상도 : 정면, 평면, 측면

18 부투상도 플랜지가 45 도경사진엘보우 불규칙한경사면의실형은어떠한기본투상도에도표시되지않으며, 정투상도에서축소된상태를그리기도어려우므로부투상법에의해표현한다.

19 투상도 정면과측면에대해경사면이있을때

20 부투상도 2 개의경사면이있을때

21 경사면 어떤기본투상도에도나란하지않은경사면의실형을나타내어야할경우에수직투상도는기본투상도에서직접투사하여그릴수없고, 경사면의선으로부터투사하여부투상도를완성해야한다. 2 차부투상도

23 투영의종류와방법 Multiview Projection Axonometric Projection 축측투영 Oblique Projection - 경사투영 Perspective Projection 원근투영

24 Math. Theory on Projection Coordinate of geometry with points Matrix transformation - scaling, shearing, translation, rotation, etc. Matrix operations for projection CAD 및그래픽스 에서배운다.

25 Coordinate of Geometry in Robotics

26 Parallel Projection orthographic & axonometric projections from projectors perpendicular to the plane of projection

27 Axonometric Projection Isometric projection Etc

28 Oblique Projection oblique projection - from projectors at an angle with he plane of projection Consider a unit vector in z-direction l : foreshortening ratio of any line perpendicular to the z=0 plane θ : the angle between the projection and the horizontal axis x* = l cos θ y* = l sin θ

29 Perspective Projection Perspective projections are obtained when all projections emanate from a center of projection, so that the size of the object changes as the projection plane moves away from the center of projection.

30 단면 (Sectioning)

31 단면부분의표시 - 중심선에의한절단단면표시 문자사용 해칭의사용 (solid, space 구분 )

32 단면의종류 전단면 물체를완전히건너지르는절단평면으로잘라완전한단면을나타낸다. 물체의내부구조형상에따라절단면을정한다.

33 단면의종류 전단면 offset 절단평면으로잘라낸전단면을표시 단면의위치는평면도에표시하였다.

34 단면의종류 반단면 대칭인물체의반은단면으로표시하고나머지반은정상외형도로표시

35 단면의종류 파단단면 필요한부분까지만절단하여단면표시하는경우

36 단면의종류 회전단면 단면 : 얇은두께의평면으로잘라내어나타낸도면의표현 단면을앞방향으로 90 도회전시킨경우 투상도의외형선과단면이겹치는경우

37 단면의종류 분리단면

38 단면의표현 절단평면기호 A-A 불필요한은선표시 - 보이지않는모서리와면은물체를나타내는데필요한경우가아니면단면도에표시하지않는다. 필요한은선표시 러그의두께를표시하기위해은선을사용한다.

39 단면의표현 해칭의사용 : 45 도경사진가는실선 ( 기본적인표현 ) 2 개또는 2 개이상의인접한부품 : 45 도, - 45 도, 30 도, 60 도,...

40 단면의표현 Ribs Lugs Spokes and Arms

41 단면의회전정렬 홀수개의 spokes 또는 rib 를갖는비대칭의형상의물체에대해서는한개의 arm 을수직절단평면의위치에까지회전시켰다고가정하고이를측면도에투사시킨다. 이경우의 arm 은단면선으로표시하지않는다.

42 단면의회전정렬 (a) 실제의표현 (b) 회전정렬에의한대칭성표현 (c), (d) lug 의구멍들이회전정렬되어있다.

43 정렬및전개투상도 실제로굽은물체는한투상도를전개한모양으로표현하여여러구멍의위치를파악할수있도록한다. 2 개의 arm 이각을가지고연결되어있을경우에는 2 개의 arm 이일직선상에오도록펼쳐그린다.

44 치수 (Dimensioning) 공차 (Tolerance)

45 치수용어 호칭치수 (nominal size) - 일반적인표현을위한호칭, 정확한수치의한계가명시되지않지만어떤기준에근접하여나타난다. 기준치수 (basic size) - 기준치수는이론적인크기를나타내며이것을근거로하여허용범위와공차를적용하여표시할수있다. 제품의오차가없다면기준치수는제품의치수가된다. 허용차 (allowance) - 결합부품의최대한계사이에서계산되는차이를말하며, + 또는 - 가될수있다.

46 치수의통계적의미 기준치수 / 허용차 Thickness t = 평균 / 편차 치수 ( 길이, 두께, 위치, 개수 ) 재료상수 ( 재질, 물질특성 ) 하중조건 ( 주행, 운전조건 )

47 치수용어 허용차 (allowance) - 결합부품의최대한계사이에서계산되는차이 + 허용차 : 축과베어링의윤활틈새를주는결합부품의최소허용틈새 - 허용차 : 압입또는열박음을필요로하는결합부품의최대조임 공차 (tolerance) - 부품도에표시된기준치수로부터허용할수있는전체의오차 즉, 최대허용치수 - 최소허용치수 한계치수 (limit) - 부품에서허용할수있는최대치수

48 부품의조립 공차와허용차를적절하게주면부품이완전히호환성있게가공될수있다. 가끔끼워맞춤에서공차를너무적게주어서호환성부품생산에비용이많이드는경우가있다. 이런경우에는적절한조립선택이필요하다 - 공차와생산비용? - 공차와품질 & 신뢰성??

49 부품의결합 헐거운끼워맞춤 (clearance fit): 내측부품의최대치수가외측부품의최소치수보다작은경우의끼워맞춤 ex) bolt 가 hole 을통해서끼워맞춤되어야할경우또는, 축이베어링내부에서회전해야할경우 억지끼워맞춤 (interference fit): 두결합부품이힘이나외측부품의열팽창에의해서조립이되어야할경우에사용하는방식 중간끼워맞춤 (transition fit): 결합부품상에서공차가겹치게될때발생한다.

50 Hole Shaft 헐거운끼워맞춤 : 억지끼워맞춤 : / & / 중간끼워맞춤 : / & /1.2503

51 치수의기준 치수는상대적이다?? 예 ) 축의지름 : 0.495~0.498 구멍의지름 : 0.500~0.502

52 (1) 기준구멍시스템 구멍을가공할때사용 치수공차는최소구멍을기준으로결정 (1) 기준축시스템 축을가공할때사용 치수공차는최대축을기준으로결정

53 공차를고려한제품설계 치수, 재료, 하중조건등의문제 - 부정확성, 불확실성 (uncertainty) 부품요소의정밀도 - 오차를갖는부품 제어하기어렵거나겉으로드러나지않는요인 - 기계의수명, 온도, 습도, 설치방법

54 공차를고려한제품설계 설계의초기단계에서, 향후에발생할수있는최악의조건을미리고려하여 외부조건에대해항상일정한또는변화량이적은 목표성능을발휘할수있는제품을설계한다. >>> Robust Design

55 Robust Design & Robust Control robust flight control systems

56 도면과치수 도면은알기쉽고정확하게작성해야만그도면을사용하여완전한물품을제작할수있다. 완전한도면을작성하려면, 그물품이공장에서제작되어나가는여러공정과각각의제작방법을알아야한다. 도면에는필요한공정과정, 즉공정의종류, 요구되는열처리방법, 가공면의정밀도또는가공순서등을치수, 기호등의형식으로기입하게된다.

57 치수의분석 도면분석의목적 : 최종완성제품에있어서제품설계자가원하는바를파악하기위한것 분석의초기단계에서는도면으로부터주요제조공정과정이결정되어야하고, 기능상이나제조공정면에서의중요한부분도결정되어야한다. 제품의품질, 신뢰도및생산원가

58 치수의변형 부품이반복적으로생산되기전에표면은측정될수있도록일정한기하학적형상을갖추어야한다. 평면은다른면을측정하는데가장편리한면이되며, 구멍과같이원통형표면을갖는것은중심선에의해서정의된다. 특수한기하학적형상을갖는부품은측정하기어렵기때문에가능하면가장간단한치수체계로사용되어야한다.

59 치수의변형

60 형상정밀도 : 치수공차 & 형상공차

61 Robust Product Design Noise Parameters - design uncertainty - manufacturing variations - aging effects - material properties

62 Accuracy errors due to inaccuracy errors due to variation The obvious goal in modeling is to develop an accurate model with a small variation.

63 Statistics Mean Standard Deviation Expression of statistic variable ( 확률변수 ) x = N ( µ, σ ) Probability Density Function (PDF) f ( x) = 1 exp[ σ 2π 1 2 ( x µ ) σ 2 ]

64 Example n a shipment of 250 connecting rods, the mean trength is 45 and he standard deviation is 5. (1)How many rods can be expected to have a strength less than 39.5? (2)How many are expected to have a strength between 39.5 and 59.5?

65 Parameter Design by Tolerance

66 How to keep the product robust Tightening manufacturing variations Shielding the product from aging and environment effects Making the product insensitive to noises Need to determine the parameters of tank (r & l) to have less sensitive to variations in volume required

67 Parameter Design by Tolerance l= r= ? l= r=

68 도면 (Drawing)

69 Cleaning of LCD Glass by Water Jet

72 CAD Modeling

73 Geometric Modeling Two major activities associated with a product - Design - Manufacturing Geometric information - Surfaces GEOMETRY OF PRODUCT - Edges - Their dimensions & tolerances

74 Geometric Modeling Wireframe Modeling Surface Modeling Solid Modeling

75 Wireframe Modeling basic method of geometric modeling computer version of traditional drafting method just as a draft person represents entities by drawing lines on paper using pencils. basic entities - points, lines, arcs, circles, conics, curves

76 Wireframe Modeling (a)wireframe modeling (b)solid modeling so ambiguous!!?!!

It does not provide information about the topology of the entities such as the concept of the components' inside and outside, a user is not able to distinguish the interior and exterior of an object

77 It does not provide information about the topology of the entities such as the concept of the components' inside and outside, a user is not able to distinguish the interior and exterior of an object on the monitor. Surface Modeling In wf-modeling, a plane is represented by its boundaries. Nothing about the middle of the plane surface modeling: objects are defined by their bounding faces (surfaces) < some drawbacks.. >

78 Surface Modeling Surface Entities (a) plane surface (b) ruled surface (c) surface of revolution (d) tabulated cylinder (e) B-spline surface

79 Solid Modeling 솔리드모델링을지원하는 CAD 시스템은 보통육면체, 다면체, 원기둥, 구, 원뿔, 원환등의기본형상들을기반으로복잡한솔리드를형성한다. 압출 (Extrusion) 회전 (Revolution): Sweeping Solid

80 3D CAD Modeling of Parts Cylinder Bearings

81 3D CAD Modeling of Features

82 Automatic 3D Model Generator Micro-electronics

83 Micro-Electro-Mechanical Systems (MEMS) Design Micro-pumps

84 Solid Modeling solid model entities (building block)

85 Solid Modeling Boundary Representation (BREP) Constructive Solid Geometry (CSG) Cell Decomposition Etc.

86 Boundary Representation (BREP) - basic entities - exterior & interior by normal vector

87 Constructive Solid Geometry (CSG) Use of Boolean Operators -Union - Intersection - Difference

88 Constructive Solid Geometry (CSG) 1. A U B 2. C U ( A U B) 3. D E 4. (D E) ( C U (A U B) ) - - U C D E U B A

89 3D CAD Modeling Technique - Curve by SolidWorks

90 3D CAD Modeling Technique - Lofting by SolidWorks

91 3D CAD Modeling Technique - Assembly by SolidWorks

92 3D CAD Modeling Technique - Sweep by SolidWorks

93 3D CAD Modeling - Examples by SolidWorks

94 CAD Simulation

95 Damper Module (Automotive) Mounting Bracket (Upper Spring Seat) Upper Insulator Jounce Bumper Lower Spring se Spring Damper

96 Damper Module (Automotive) Assembly of Damper Module

97 Steering Column & Wheel 고유진동개선 Column Structural Analysis Bracket 최적설계 Column 고유진동해석 Column & Steering Wheel esonance 억제

1 Nov-03 CST MICROWAVE STUDIO Microstrip Parameter sweeping Tutorial Computer Simulation Technology

1 Nov-03 CST MICROWAVE STUDIO Microstrip Parameter sweeping Tutorial Computer Simulation Technology 1 CST MICROWAVE STUDIO Microstrip Parameter sweeping Tutorial Computer Simulation Technology wwwcstcom wwwcst-koreacokr 2 1 Create a new project 2 Model the structure 3 Define the Port 4 Define the Frequency