MAE 52 Final
Hone
+/- 0.0005 to +/- 0.00025
Laser cutting
- Accurate - Multiple types of materials can be cut - Variables thickness cuts
Dimensioning Methods ||
1. Chain Dimensioning A series of dimensions applied on a point to point basis. This method suffers from tolerance stacking. 2. Baseline Dimensioning Dimensions are measured from a common point.
Standard convention tips
1. Choice of views correct 2. Ensure depth is minimized 3. Minimize the number of hidden lines 4. More aesthetically pleasing
Process Flow
1. Design the part 2. Create prototypes 3. Ensure the part functions properly 4. Choose material 5. Create the mold ØMost expensive and most time consuming step 6. Injection mold your parts
2-D Sketching Procedure
1. Sketch the geometry 2. Dimension the geometry 3. Modify the dimension values
Types of lines
1. Visible lines 2. Center lines (has overshoot) 3. Hidden lines
General Procedure
1.Select a sketch plane. Choose a flat 2D surface to define your plane. 2.Sketch a 2D profile. Sketching make use of various geometric relationships and dimensions to define a profile. Think of this as your "cookie cutter". 3)Add a Feature. Features are the building blocks of the part. Features are the shapes and operations that construct the part. In this example, we Extrude the sketch perpendicular to sketch plane to get a base feature.
Rapid prototyping
> Fast turn around > Complex geometry > Limited material available > Additive Manufacturing > Rapidtek
Other geometric tolerances
> straightness > cylindricity > profile tolerances, control arcs, curves > parallelism > perpendicularity
Dimension line
A line located between extension lines ending with arrows and including a numerical value.
Planning
A management function that includes anticipating trends and determining the best strategies and tactics to achieve organizational goals and objectives.
Agile
Advantages: Flexible and Interactive Less complex Less stress on the team Lowers risks Better control of cost Enhance rapid development Increase ability to meet schedule Disadvantages: Team may become confused Team reluctant to change Difficult to see big picture System integration risk higher
PDP Data
All steps in the design process generate data, especially analysis and test
Glass box concept
All views MUST BE aligned vertically and horizontally Front, Top, Bottom, Left, Right, Rear
Smaller CAD Systems
CREO AutoDESK AutoCAD PTC ProEngineer SolidEdge (SIEMENS)
Constructive Solid Geometry (CSG)
Can create complex surfaces or object by using Boolean operators to combine objects. Models can appears visually complex, but is actually little more than cleverly combined or decombined objects. Use in both 3D computer graphics and CAD CSG may or may not be procedural and/or parametric.
Effect of tolerance on dimensioning
Chained: > tolerances stack > each dimension continues from previous one Baseline: > each dimension is specified from a common baseline > tolerances do not stack
CAE
Computer-Aided Engineering (Analysis)
Sheet lamination
Material sheets are stacked and laminated together using either adhesives, chemical, ultrasonic welding or brazing Unwanted sections are then cut layer by layer. Laminated Object Manufacturing (LOM), Selective Deposition Lamination (SDL) Ultrasonic Additive manufacturing (UAM)
Tangent arc
creates an arc that has a smooth transition to an existing sketch entity.
3 Point Arc
creates an arc through three points - the start, end and midpoint.
Dimensional tolerance
define accuracy of features in terms of size and dimensions
Geometric Tolerances
define the allowable error in terms of the shape, form, location, and orientation of features reduces need for more complex notes
Geometric tolerance
define the geometric characteristics of shapes, locations, and profiles
Scope
deliverables - what the project entails and will result
Computer-Aided Design
family of computer-based technologies that are used to create, analyze, and optimize engineering designs
Standard fits
fit defined by two letters and a number that indicates the specific class
Trim
used to delete a sketch segment
Revolve Feature
•A Revolve feature is created by rotating a 2D profile sketch around an axis of revolution. •The profile sketch can use a sketch line or a centerline as the axis of revolution. The profile sketch cannot cross the axis of revolution.
Die Casting
•Injection molding of metal material •Large volume production of metal parts •Material usually is an alloy that has a low melting point •Aluminum, copper, zinc •Die (or mold) is usually made of high strength steel •Withstands heat, lasts a long time •Rough surface finish •Often combined with traditional machining
Sweep Feature
•The Sweep feature is created by moving a 2D profile along a path. •The Sweep feature requires two sketches: §Sweep Path §Sweep Section
Thermal Set / Vacuum forming
•Vacuum forming is a plastic production process in which heated plastic sheets are drawn onto a die using vacuum suction. •The process is used to manufacture various types of plastic items such as: storage trays, seed trays, plates, baths, and packaging, etc. •Sheets made of thermo plastics like: acrylic, CPET (crystalline polyester), LDPE (low density polyethylene), HDPE (high density polyethylene), PP (polypropylene) are used in the vacuum forming process. •Lead Time 2-6 weeks
Symmetry
•When a part is symmetric, the number of dimensions can be reduced •Indicate the line of symmetry with a note.
Dimensioning II
•given on drawings by using extension lines, dimension lines, dimensions, leaders and arrowheads, notes, and symbols.
Left side of Solidworks Window
(left) FeatureManager design tree (middle) Property Manager (right) Configuration manager
Grind
+/- 0.001 to +/- 0.0005
Finish pass
+/- 0.003 to +/- 0.001
Semi pass
+/- 0.005 to +/- 0.003
Rough pass on machine
+/- 0.015 to +/- 0.005
Water jet
- High pressure water jet used to cut through multiple types of material - Low Volume & prototyping > Little tooling investment > Larger cost in piece part pricing
Die cutting
- fixed geometry die cuts out material from sheet stock
Testing
- incredibly expensive to test - it is better to analyze components since it is much cheaper
Cutting
1) tin snips /powered shears. Most modern sheet metal cutting operations are now based either on CNC Lasers cutting or multi-tool CNC punch press. 2) CNC laser involves moving a lens assembly carrying a beam of laser light over the surface of the metal. Oxygen or nitrogen or air is fed through the same nozzle from which the laser beam exits. The metal is heated and then burnt by the laser beam, cutting the metal sheet. The quality of the edge can be mirror smooth. 3) Punching is performed by moving the sheet of metal between the top and bottom tools of a punch. The top tool (punch) mates with the bottom tool (die), cutting a simple shape (e.g. a square, circle, or hexagon) from the sheet. An area can be cut out by making several hundred small square cuts around the perimeter. A punch is less flexible than a laser for cutting compound shapes, but faster for repetitive shapes
Simulation steps
1. Assign materials 2. Specify restrains, which faces are fixed 3. Apply loads, where are the forces or pressures acting on the part 4. Run analysis 5. View the results. What is the factor of safety? What are the resultant displacements or stresses?
Sheet metal
1. Drawing > Drawing forms sheet metal into cylindrical or box shaped parts by using a punch which presses the blank into a die cavity 2. Stretching > A process where sheet metal is clamped around its edges and stretched over a die or form block. This process is mainly used for the manufacture of aircraft wings, automotive door and window panels. 3. Bending > Press brake forming: This is a form of bending, used for long and thin sheet metal parts. The machine that bends the metal is called a press brake. The lower part of the press contains a V shaped groove. This is called the die. The upper part of the press contains a punch that will press the sheet metal down into the v shaped die, causing it to bend. >Manual Brakes are also conventional for prototyping. 4. Forming Roll-forming is a continuous bending operation in which a long strip of metal (typically coiled steel) is passed through consecutive sets of rolls, or stands, each performing only an incremental part of the bend, until the desired cross-section profile is obtained. Roll-forming is ideal for producing parts with long lengths or in large quantities.
Boundary conditions (structural)
1. Fixed - restrict x, y, and moment 2. Roller - restrict x 3. Pin - restrict x and y
Dimensioning holes
1. For dimensioning circles we generally use the diameter. 2. Must use the diameter symbol (ø) before the numerical value. 3. A centermark is always placed at the center of the hole. 4. Centerlines are always placed along the longitudinal view of the hole/cylinder 5. Locate the center line 6. Use notes and designators for repeated hole sizes
Material properties
1. Isotropic 2. Orthotropic 3. Anisotropic 4. Hyperelastic 5. Plasticity 6.
Dimensioning Considerations
1. Pay attention to the spacing 2. Width, height, and depth should all be specified
Placement of Dimensions
1. Place dimensions between views 2. Dimension outside of the part unless you absolutely need to place a dimension inside the part to make it more clear. 3. Dimension outside of the part 4. Arrange extension lines so that the larger dimensions are outside of the smaller dimensions (i.e., always place smaller dimensions nearest to the view being dimensioned) 5. Try to avoid having dimension or extension lines crossing each other.
Dimension types
1. Size dimensions: describe how big a feature is 2. Location dimensions: describe where a feature is
Types of fasteners
1. bolt: externally threaded fastener designed for insertion through holes in assembled parts 2. screw: an externally threaded fastener capable of being inserted into holes in assembled parts 3. studs: shafts threaded at both ends, screws with no heads and threaded at both ends
Controlling variations
1. minimize the number of setups 2. tighter controls on process 3. tighter control on environment 4. improve material quality 5. operator training (CNC)
Basic thread callout (english)
1. numbered diameter of nominal diameter 2. number of threads per inch 3. thread series 4. class of thread fit 5. designation for external threads UNC: course thread series UNF: fine thread series UNEF: extra fine thread series
Other types of machining
1. riveting 2. captive fasteners 3. interference fits
Sketching Techniques
1. sketch an enclosing/bounding box 2. estimate features with respect to the bounding box - light lines 3. complete features with darker lines 4. refine with more details
Sprint/scrum board
1. sprint goal 2. to do 3. doing 4. done 5. impediments 6. commitments 7. definition of done
Standard metric threads
1. symbol of ISO metric threads 2. nominal major diamter in millimeters 3. thread pitch in millimeters 4. tolerance class 5. left blank for right-hand thread or LH for left-hand thread 6. length of thread
Isometric sketching
1. use light construction lines to sketch a bounding box for the object 2. add features to the faces - start with lines that follow the isometric grid lines 3. once lines parallel to the isometric lines have been added, the locaiton of angled lines will be apparent 4. use centerlines to establish the locaiton of circles. sketch a bouding box for the circle and then mark of the radius at four locations, then sketch the resulting ellipse 5. sketch the back side of the hole (an ellipse in this isometric view) - note that a portion of the back side of the ellipse is visible from this view 6. Darken visible lines and erase constructions lines
Creating drawing in SOLIDWORKS
1.Open a blank drawing using the MAE 52 template ØChoose "MAE 52, PG 1" for the sheet format 2.Insert views of your part model (Model Views) 3.Add dimensions using Smart Dimension 4.Add section or auxiliary views if needed 5.Eliminate views that are not necessary 6.Enter information on the title block ØThis can be done at any point while creating a drawing
Off the Shelf (OTS) parts
> Better to not create every part > use parts available "off the shelf" to save cost and time > when designing - create design around OTS parts
SLS (Selective Laser Sintering)
> Considerably stronger than SLA > Laser beam selectively fuses powder materials: nylon and elastomers and metals Advantage over SLA: > Variety of materials and ability to approximate common engineering plastic materials > Living hinges are possible with the thermoplastic-like materials. > Powdery, porous surface unless sealant is used. Sealant also strengthens part
FDM (Fused Deposition Modeling)
> Considerably stronger than SLA > Thermoplastics are liquefied and deposited by an nozzle, which follows a tool-path defined by the CAD file. > The materials are deposited in layers as fine as 0.005-inch thick, and the part is built from the bottom up - one layer at a time. Strong Material like ABS, PC,ULTEM
User Interface
> FeatureManager Design Tree > Command Manager > Menu Bar > Heads-up View Toolbar > Task Pane > Reference Triad > Status Bar
Injection Molding
> Large production volumes > Multiple types of plastics > Lower shot Cost/ Larger Capital Tooling Cost > Draft angle , wall thicknesses and other part geometry need to be considered > Terminology > Lead Time 3 - 12 weeks
Feature Manager Design Tree
> Left side of graphics window > Design tree provides summarized view of active part > Each part of model is called a feature
Short Run Castings off of quick prototypes
> Material typically softer (polyurethane and silicone) > Draft angle , wall thicknesses and other part geometry needs to be considered > Lead-time 1-3weeks
Auxiliary views and planes
> Partial auxilliary view is true scale > Partial auxiliary is more common
Electrical discharge machining (EDM)
> Removing metal by a series of rapidly recurring electrical discharges > Metal material only > Controlled by CNC > Cleans up burrs and poor surface finishes
Machining and Manufacturing
> Safety First > Always wear protective equipment > Know the machinery you are working with >> If you don't know, ask. > Use correct fixtures and jigs to hold work pieces > Plan out how the parts will be fabricated > Ensure Drawings are clean and complete
Right side of Solidworks Window
> SolidWorks Resources > Design Library > Toolbox > File Explorer
SLA (Stereolithography)
> The first Rapid Prototyping technique and still the most widely used. > Inexpensive compared to other techniques. > Uses a light-sensitive liquid polymer. > Requires post-curing since laser is not of high enough power to completely cure. > Parts are quite brittle and have a tacky surface > Uncured material can be toxic. Ventilation is a must.
Negative Cylinders
> cylinder with a hole in the middle •Length and both diameters should be dimensioned. To avoid dimensioning to hidden lines, the inner hole should be dimensioned on the circular view.
Drilled Hole
> diameter > depth
Countersink hole
> drilled hole diameter > depth (blank means through all) > countersink outer diamter > countersink angle
Counterbore hole
> drilled hole diameter > drilled hole depth > counterbore diameter > counterbore depth
Tapped Hole
> drilled hole diameter > drilled hole depth > thread type > thread depth
Flatness geometric tolerance
> only applies to planar surfaces > must be smaller than the tolerance to the surface > refines linear tolerance
Dimensioning Tapers
A Taper is in shape of a cone and is represented by: 1- Diameter at one end length, 2- Length of the tapered feature, 3- Rate of taper, 4- Angle, 5- The taper ratio, ...
Countersinks
A conical recess into a feature to accommodate the head of a countersunk screw. The diameter at the surface and the angle are given.
Cutting Plane Line
A cutting plane line is used to show where the object was cut. It should have associated arrowheads, indicating the direction from which the section view will be observed.
Transition fit
A fit having limits of size so that a clearance or interference fit results between mating parts (bad thing) The allowance is negative Max clearance is positive
Interference Fit
A fit having limits of size so that there is always interference between mating parts (smallest shaft and biggest hole) > max clearance is always negative > negative allowance indicates interference > requires force to press
Clearance fits
A fit where there is always clearance between mating parts Parts designed to never interfere with each other > Allowance and max clearance are positive Largest shaft is smaller than the smallest hole
Counterbore
A flat-bottomed, cylindrical recess that accommodates the head of a screw. The diameter and depth and corner radius are specified.
Working Drawings
A set of all required drawing that allow the part to be manufactured
Spotface
A shallow cylindrical recess in the feature that provides smooth, level seating for a nut or washer. The diameter of the faced area and either the depth or remaining thickness are given
Stress
A tensor: has a magnitude, a direction, and a plane in which it is acting Defined as F/A
Removed and Revolved Sections
A thin slice of the object and rotates it 90 degrees around a center axis toward the plan of projection Used to provide contour information without having to great an additional orthographic view
Internal (female) thread
A thread cut on the inside of a cylindrical body
External (male) thread
A thread cut on the outside of a cylindrical body
Right-hand thread
A thread that screws in when turned clockwise as viewed from the outside end.
Left-hand thread
A thread that screws in when turned counterclockwise as viewed from the outside end.
Axonometric Projection
A type of Orthographic projection Principle view not parallel to the projection plane Object is titled to reveal all three dimensions
Agile Project Management
A way you can make projects more adaptable and easy in their movements Good for hardware and software integrated products 1. product owner 2. product backlog 3. sprint backlog 4. spring (cyclical) w/ scrum master 5. final product
Sheet Sizes
A- 8 ½" x 11" B- 11" x 17" C- 17" x 22" D- 22" x 34" E- 34" x 44"
Simulations
ANSYS & ABAQUS
Tolerances
Acceptable error on specific dimension
Additive Manufacturing
Advantages > Complex 3D geometries with internal features can be printed without any tooling > Reduced waste compared to machining > Part can be printed directly from the 3D model without the need for a drawing > Prototypes can be made quicker allowing designers to check different iterations resulting in quicker design cycle phase > Less tooling for smaller batches compared to traditional machining > Production tooling can be printed > Different materials can be mixed during the printing process to create a unique alloy > Different sections of the part can be different variant of the same alloy Disadvantages > Build process is slow and costly > High production costs because of the equipment cost > Various post-processing required depending on the type of additive manufacturing used > Small build volume compared to other manufacturing part size such as sand casting > Poor mechanical properties hence need post-processing > Poor surface finish and texture
Dimetric
Axonometric (45 degree rotation about the vertical then a non- 32.264 rotation about the horizontal (at 32.264 we'd be back to Isometric)
ASME Standards
Best practices for standards for drawings
Bspline curves
Bspline Curves are a generalization of Bézier curves that have even more practical application in Design and Visualization Used in Photoshop or vector drawing programs like Flash, Illustrator or Solidworks
PLM II
Business Intelligence (BI) Supply Chain Management (SCM) Customer Relationship Management (CRM)
Trade offs
Cheap Good Fast Good & Fast -> $$$ Cheap & Good -> Time Cheap & Fast -> Low quality
Orthographic projections
Collection of 2-D drawings that work together to give an accurate overall representation of an object Use three mutually perpendicular planes
Sheet metal process materials & gauge sheet
Common sheetmetal Materials Aluminum Steel Copper Gauge & Thickness http://www.engineersedge.com/gauge.htm
CAD
Computer Aided Design
CNC Machining
Computer Numerically Controlled: Good for repeatability in parts Tighter tolerances can be held Many types of material can be machined
CAM
Computer-Aided Manufacturing
Oblique
Create a sketch of the view that most completely describes the object Orient this view as the front view so dimensions appear true size. Depth is represented by parallel lines take from the front view. Not use much since the create to much distortion of the real part.
Drilling
Create holes that are right circular cylinders or chamfers - Metal removed mainly at the"bottom of the hole" and exits through the flutes of the drill. - Hard to cool as the cutting surface is not exposed. - It is estimated that 75% of all metal-cutting material is removed by drilling - Reaming Finishing a hole to enhance feature size and surface finish
Multiple Section Views
Cutting plane lines are identified by large letters and a section line with arrows indicating the direction of the view, one at each end of the cutting Plane line. A - A, B - B, C - C, etc. are used to designate the required section view. Letters I, O, Q, and Z should not be used.
Helix/Spiral
Defined by pitch, revolutions, and height 1. pitch is the width of one complete helix turn, measured along axis 2. revolutions is the number of revolutions on the helix curve 3. height is total helix curve height
Fit
Degree of tightness in mating parts Tolerancing is important in mating parts 4 parameters: 1) tolerance of part 1 2) tolerance of part 2 3) allowance 4) clearance
Allowance
Describes the maximum amount of interference (tightest fit) Smallest hole (SH) - Largest Shaft
Controlling
Determines to what extent the business is accomplishing the goals it set out to reach in the planning stage
CATIA
Developed by Dassault Systemes (also bought SOLIDWORKS) Used by big companies Bought ABAQUS
Unilateral tolerance
Deviate in only one direction 2.00 + .005 - .000
Hatching Dimensions
Dimensions should not be placed in sectioned areas When this is unavoidable, the section lining should be omitted, as shown on the previous slide.
2-D Sketching
Drawing used to demonstrate a 3-D part on a 2-D piece of paper in 2-D views (orthogonal views). Sketching paper: Horizontal and vertical lines that form squares.
Material Jetting
Droplets selectively deposited layer by layer UV cured Material Jetting Drop on demand (DOD) Nanoparticle jetting (NPJ) Can Combine different material in the same part https://www.youtube.com/watch?v=m8n 6FBKgY2g
3-D Object Creation Procedure
Each feature: > 2-D Sketching > 3-D Formation
Spot Welding
Electrical currents flows through the work piece
Pull transfer
Ensuring that stock is always full, that shelves are looking full
Bilateral tolerance
Equal plus and minus deviations 2.00 +/- .003
Extension lines
Extend away from a view to indicate the point or line on the drawing to which the dimension applies. It does not actually 'touch' the feature that is being dimensioned.
Thread classes
External Threads: 1A, 2A, 3A Internal Threads: 1B, 2B, 3B 1 - loose 2 - tight 3 - extra tight
Projection Methods
First-angle projection (ISO): Inside the box (looking out at the walls) used in European and Asian countries Third-angle projection (ANSI): Outside the box (looking in toward the walls) used in U.S., Canada, and many other countries.
Directed Energy Deposition
Focused thermal energy from a laser, electron beam, or plasma arc Fuse materials by melting as they are being deposited Types include LENS, EBAM.
A Tale of Two Companies
For the first 8 years, PDA had flat revenue because it was a service company (doing contracts) PDA and MSC merged together
Jon Hirschtick
Founder of SOLIDWORKS (1993), funded company through blackjack winnings
Three-view drawing
Front, Top, Right side
Section Hatching
General Purpose section drawing is recommended for detail drawings and the material will be specified elsewhere. Exception is wood material.
Finite elements
Have shapes that are relatively easy to formulate and analyze Three basic types: 1. Beam (1D) 2. Plate (2D) 3. Solid (3D)
Head and drive types
Head is the top of the fastener Drive is the recessed profile cut into the head to enable a driving tool to seat it
How Graphics Systems Store Geometry
IGES (international graphic exchange standard) file from containing only two POINT (Type 116), two CIRCULAR ARC (Type 100), and two LINE (Type 110) entities.
Explicit vs Implicit forms
Implicit is better Explicit: Curve y = f(x) Surface z = f(x,y) Does not work for many cases like: Vertical line y = +/- (r2-x2)1/2 (two or zero value for x) Implicit: Curve y = f(x,y) = 0 ax + by +c = 0 (line) Surface z = f(x,y) ax +by + cz +d = 0 (plane) f(x,y,z) can describe location in the object: f(x,y,z) < 0 inside the object f(x,y,z) > 0 outside the object f(x,y,z) = 0 on the surface of the object
Vat Photo Polymerization
In this process, a liquid photopolymer is selectively cured by light-activated polymerization to create a 3D part. a) Stereolithography (SLA) b) Digital Light Processing(DLP) c) Continuous Digital Light Processing Plastic Only
CommandManager
Include buttons for frequently use commands; showed at top of the window Has many tabs: sketch, feature, surfaces, sheet metal, etc
Cold Rolling
Increases mechanical properties (surface hardness, tensile strength, yield strength) Surface finish of the thread flanks is smoother The compressive stresses on the threads improves fatigue life
Metric thread system
Indicated by capital M Different system of callout as imperial
von Mises stress
Is a positive scalar number with no direction Is shown as color in simulation pictures Uniaxial - in one direction
ISO 10303
Is an ISO standard for Product data representation and exchange. Also know as STEP "Standard for the Exchange of Product model data". Can represent 3D objects in (CAD) and related information. Although it has great promise it has still not lived up to the expectations and IGES is still the main tool for exchange of CAD an other graphics related data
(Reference dimension)
Is shown for clarity only and is not required for manufacturing or inspection purposes. It is redundant information. Shown with parenthesis
Hole tolerance
Largest hole - smallest hole
Shaft tolerance
Largest shaft - smallest shaft
Parametric Cubic Curves
Limitations on the parametric cubic form of a curve; Two points with zero slope Only one point of inflection
Waterfall project management
Linear and sequential approach to managing software design and development projects in which progress is seen as flowing steadily (and sequentially) downwards (like a waterfall). Requirements Analysis Design Implementation Testing Deployment
Perspective
Location of the observer (top image) and view from the observer (bottom image)
Section General Practices
Longitudinal cuts - the web is not hatched Transverse cuts - web is hatched
Math of CAD
Mapping Functions x(u,v) y(u,v) z(u,v) To locate a point on a parametric surface, you need two parameters (u and v )
Static Analysis
Most common type of analysis Equation of motion: F = kx Displacements, x, are solved by F = kx, finding x Assumes linear material behavior and neglects inertia and viscous forces. Body returns to original position when loads are removed
Solidworks Basics
Most features are created with: 1. cut-extrudes 2. sweeps 3. revolves 4. lofts
Auxilary view procedure
Number corners of the inclined surface in a view that it appears as surface not an edge Transfer numbers to the view where the surface appears as an edge Define folding line between views and measure perpendicular distances Folding line location is arbitrary Define auxiliary and establish direction of sight perpendicular to the surface from each number corner Folding line location is arbitrary Define folding lines and measure perpendicular distances from the folding to each of the numbered corners Connect the points using the numbering sequence defined in the first step
Series
Number of threads/inch
Dimension
Numerical value that defines the size or location.
One-view drawing
Objects with very little thickness require only one view. Thickness of part is indicated by a callout in a note.
UG & NXCAD
Owned by McDonnell and Douglass and Unigraphics McDonnell Douglass bought by EDS in 1991, taken private in 2004 for $2B by BainCapital, changed product name to NXCAD, sold in 2007 for $3.5B to SIEMENS Ross Perot owned EDS Mitt Romney owned BainCapital Used by big companies
Dimas's Companies
PDA Engineering & MSC Engineering
Clearance fit II
Positive allowance indicates clearance Male diameter is smaller than female diameter
PDM
Product Data Management Commerical systems: 1. Enovia (Dassault Systemes) 2. Teamcenter (Siemens) 3 steps: 1. Authoring 2. Publishing 3. Viewer
PLM
Product Lifecycle Management: (start to finish) 1. Product Development Process (PDP) - investing profit from previous products Concept Requirements Design Analysis Testing Sourcing Production 2. Generating Revenue & Profit Marketing Selling Support Maintenance Life extension Green disposal
Limit tolerance
Provide maximum and minimum values 2.004 1.998
Grinding
Rapid removal of material, reduce size, remove surface irregularities High speed wheel (200- 1000rpm) coarse abrasive (> 40 μm). Can cause deep subsurface damage in delicate materials.
Feature control frame
Rectangular box with a leader line connected to feature of interest 1st box is geometric characteristic symbol 2nd box is allowable deviation in the geometry
Sections
Remove Hidden Lines in Sectional views Cutting Plane line take precedence over other line if there is an overlap Many hidden lines will become visible when the cut is made
Parametric Polynomial curves
Restrict x(u), y(u), z(u) to be polynomial in u Fix degree n Each ck is a column vector Cubic Polynomials are often used: 1st and 2nd derivatives can insure continuity of slope or curvature with neighbors These determine cubic polynomial form
Revolved Sections
Revolved sections are drawn superimposed over the existing orthographic view
Isometric
Rotate object 45 degrees about vertical Tilt 35.264 (arcsin(tan 30 degrees) Insures that all three primary axes from 120 degree angle between one another and 30 degrees from the horizontal
Project management triangle
Scope Time Cost
Polishing
Scratch-free finish. very low speeds and very fine abrasive <3μm
Hatching
Section lines (hatching) are used to show where the cutting plane passed through solid material. They can also indicate the material from which the object is to be made.
Binder jetting process
Selectively deposits bonding agent - a binding liquid to join the powder material together to form a 3D part. Does not employ heat Not as strong as other methods
Assembly Drawing
Shows exploded view of product Details relative locations to show how to assemble the product Has parts list/bill of materials
Two-view drawing
Side view is not required. Front view and top view can fully describe the part
Perspective drawing
Sketching paper: a wide selection
Oblique drawing
Sketching paper: two sets of lines are sloped at 45 angle. Both vertical and horizontal lines pass through the intersecting lines.
Isometric drawing
Sketching paper: two sets of lines are sloped at a 30 angle with the horizon. The third set of lines are vertical and pass through the intersecting lines.
Mating or Matching Parts
Sliding Parts Binding Parts Shaft-Hole
Dimensioning Slopes
Slopes is a slanted line and is represented by either: 1- Ratio combined with slope symbol. Preferred method 2- Slope specified by an angle. 3- Read book for more methods.
Lapping
Smooth, flat, unpolished surface. Accurate specimens to high tolerances. Low speed lapping plate <80 rpm and 5-20 μm abrasive
SIGGRAPH
Special Interest Group on GRAPHics and Interactive Techniques Founded in 1974 as a subgroup of the Association for Computing Machinery (ACM)
Evans and Sutherland
Started by David Evans and Ivan Sutherland, E&S is a computer graphics company. Its students and employees went on to start their own companies such as Nolan Bushnell & Atari and Ed Catmull & Pixar
Dimension symbols
Symbols represent specific information which could be difficult to duplicate in note form.
V diagram
Systems Engineering diagram, decomposing the final product into separate subsystems for connection Then, build all the systems back up for the final product
Surface Finish II
The 3 principal reasons for surface finish control: 1. reduce friction 2. control wear 3. compensate for precision fits Shown in drawings as checkmarks
Catmull-Rom Spline
The default implementation of the Catmull-Rom algorithm is capable of producing loops and self intersections.
Pitch
The distance between two crests of a thread
Major diameter
The largest diameter on an internal or external thread
Hatching Guidelines
The lines for section lining are usually thin and drawn at an angle of 45º unless the lines are parallel to the outline of the object. If the part shape causes the section lines to be parallel or perpendicular to one of the sides of the part, some angle other than 45º should be chosen. Spacing of hatching should be reasonably uniform to give a good appearance. Distance varies between 0.03 to .12 in (1 to 3 mm). Depending on the size of the area. To reduce cost and clutter, large areas are not entirely hatched. Section lining around the outline will be sufficient as long as the drawing is still clear and conveys all information.
Clearance
The maximum amount of space that is acceptable between the two parts Largest hole (LH) - smallest shaft (SS)
Statement of Work
The most important component of project plans Must contain appropriate and sufficient level of detail to clearly define the deliverable to the project team and state holders > must prevent scope creep
Minor diameter
The smallest diameter on an internal or external thread
The Utah Tea Pot
The teapot is made from nine patches - some reflected in two axes, others in one axis only Many, many vertices
Surface Finish
The waviness, roughness, lay, and flaws of a surface. Also referred to as surface texture. Lay - direction of pattern of the texture Roughness - micro irregularities Waviness - macro irregularities Flaws - non patterned, discrete irregularities
Bezier Curves
They're named after Pierre Bézier who did not invent them but was responsible for getting them known to the world He worked for Rénault and publishing his investigations in 1962. Bézier curves are well-suited for design work
Trimetric
Three Different Scales - Not useful in Mechanical Engineering Used mostly in Architecture to show one side of a building
Parametric Form for Curves
Three dimensional curve x = x(u), y = y(u), z= z(u) Circle: x = cos(u), y = sin(u), z=0 Tangent described by derivative
Threaded fasteners
Three types of views: 1) Detailed representation 2) Schematic representation 3) Simplified representation
Conventional welding
Tig, Mig, Arc, Acetylene
Precise vs Tessellated Geometry
To visualize requires models need to be converted to an approximation of the underlying design. These "graphics," "tessellated," or "mesh" models are generated as needed to render the image. Tessellations are generated based on the underlying mathematically continuous representations of the geometry
Sources of variation in manufacturing
Tooling: > location of the part in the fixture > variations in setup > tooling wear Material: > non-uniform > internal stresses > previous process not performed correctly Operator: > inconsistent setuo > manual control > different operators Equipment: > repeatability of the machine > parts of the machine not 100% rigit > feed rate Environment: > non-uniform temperature in the room > non-uniform temperature of the part > humidity
Kanban
Toyota's observations at Piggly Wiggly Make what's needed when we need it (pull transfer)
Lugs in section views
True projection may be misleading: Lugs are aligned to show their true relationship to the rest of the part
Solidworks model type
Type: 1. Part / 3-D Object / .SLDPRT 2. Assembly / Many parts / .SLDASM 3. Drawing / Multi-views / .SLDDRW
Title Block Information
Units & Tolerances Projection Type Grid Part Name Company Name (or course name) Date Material Drawing scale Surface Finish Disclaimers Drafter/Engineer name Professional Engineer stamp BOM (for assemblies)
3D sketching
Use "TAB" to alternate between planes Create reference plane at the tip of 3D sketch to draw profile
Half Sections
Used for cylindrical and symmetrical objects and shows one-half of the view in section. Two perpendicular cutting plane lines extend half-way through the view. One quarter of the view is considered removed. Center line used to divide sectioned part of the object Cutting pane lines is show with one arrowhead Hidden lines are omitted (even those in the unsectioned part)
True position
Used to locate holes, cylinders, or slots, with respect to surfaces
Pictorials
Used to represent three dimensional objects in 2 dimensions Minimize the number of hidden lines
Material Extrusion
Uses continuous filament of thermoplastic or composite material to construct 3D parts. Fused Deposition Modelling(FDM) Plastic and composites can be printed
Designation for external threads
Various factors: 1. Left handedness (LH) 2. Thread length
Digital twin
Virtual replica of a product or plant Unique interface to both technical and management information on the components and processes that compose asset.
Meshing
Want nice isometric triangles > try to avoid tapers, warping, skew and internal angles, and bad aspect ratios
Different modes
Waterfall: projects completed in a linear fashion Agile:
Form of thread
What the thread looks like
Ribs in section views
When cutting plane passes through the center of the rib: - to avoid the impression of solidity, a section not showing the ribs section-lined is preferred. It might be necessary to section line the rib if it causes confusion. If rib A was not sectioned, it would appear exactly line rib B in the sectional view and would be misleading.
Sections for multiple components
When the cut slices more than one components hatching must be different
Auxiliary view
When the inclined surface has important characteristics that are needed to be shown clearly and without distortion, an auxiliary (additional or helper) view is used. This view shows the true shape of the distorted surface and is sketched parallel to the inclined surface.
Section View
When the interior details of an object cannot be seen from the outside. To show interior detail that is too complicated to show in regular views containing many hidden lines. Imagine slicing the object in the middle and taking away one half:
Work Breakdown Structure (WBS)
a hierarchy of the tasks required to complete a project > organizes work into manageable sections > defined by the Project Management Body of Knowledge document (PMBOK) Types of structures: > outline > tree > hierarchy > tabular
Closing
a meeting of the seller, the buyer, and the lender of funds, or representatives of each party, to complete the transaction
Graphical User Interface (GUI)
allows the user to create and manipulate both 2D and 3D geometries, produce engineering drawings, to visualize parts and assemblies, etc.
Roundness geometric tolerance
applies only to features with a round cross-section
Notes
are used to simplify or complement dimensioning by giving information on a drawing in a condensed and systematic manner
English fits
clearance, transition, and interference fits can be further classified by degree of tightness Types RC - running fit LC - locational clearance fit LT - locational transition fit LN - locational interference fit FN - force and shrink fit
Head types
flat round oval fillister truss socket hexagonal hex washer
Product Lifecycle Management (PLM)
integrates all aspects of design including other factors such as costs, supply chain management, and maintenance
Boundary Representation (B-Rep)
is a method for representing shapes using the boundary of the shape. A solid is represented as a collection of connected surface elements, the boundary between solid and non-solid.
Budget
labor and materials - funding, resources needed and obtained
Power bed fusion
laser or electron beam to melts and fuses the material together Multi Jet Fusion (MJF) Direct metal laser sintering (DMLS) Electron beam melting (EBM) Selective heat sintering (SHS) Selective laser melting (SLM) Selective laser sintering (SLS).
Poisson's ratio
lateral strain/axial strain
actual size
measured size of a finished part
Mirror feature
mirrors feature/body about an axis, plane, or other reference points
General notes
refer to the information applies to the part or the drawing as a whole
Local notes
refer to the information only applies to the point connected by the leader.
End Milling
remove material by rotating a tool and translating the work piece > Up to 5-axis movement > Can be Automated (CNC)
Turning/Lathe
remove material by rotating the work piece past a cutter that can translate axially or radially - Work Piece rotates on Axis - Turning tool is controlled manually or with a feed - Performed on a Lathe - High precision - Can Be Automated
Circular pattern feature
repeats a feature/body circularly
Linear pattern feature
repeats a feature/body linearly
Scheduling
sequencing - timing and scheduling assessments
drive types
slotted phillips combined hex socket square one way spanner triple square
specifying tolerance
specific - tolerance is added to specific dimension general - tolerance is given in the title block
Young's Modulus
stress/strain
Types of stress
tension compression shear bending torsion fatigue
Nominal size
the approximate size of a part from the print nominal dimension, expressed as fraction
Lead
the distance a screw will advance in 360
Initiating
the project management process that deals with selecting and starting a project and establishing the goals for the project
Executing
the project management process that involves putting the plan in action to reach the project goals
basic size
the theoretical size used as a starting point for the application of tolerances
Decimal Inch
• In general, use a minimum of 2 units to the right of the decimal: 24.00 not 24 • No zero to the left of the decimal: .44 not 0.44 • Inch marks (") are usually not shown with dimensions. • A note such as "DIMENSIONS ARE IN INCHES" must be shown in the drawing on somewhere on the title block.
Cutting Plane
•A cutting plane depicts the exact location from which the section view will be projected. •Section views show how an object would look if a cutting plane cut through the object and the material in front of the cutting plane is removed.
Dimensioning Rules
•A gap must exist between the part profile lines and the extension lines. •A centerline may be extended to serve as an extension line. • Display only the number of decimal places required for manufacturing precision. • When extension lines cross objects or other extension lines, no gap should exist. (but only do this if you have to - avoid crossing lines if possible!) NEVER DIMENSION TO HIDDEN LINES
Positive Cylinder
•Both length and diameters should be dimensioned in the non-circular view. (NOTE: Compare negative and positive cylinders)
Dimension Chamfers
•Chamfering is cutting away an inside or outside piece to facilitate assembly. • Usually dimensioned by using leaders to specify the angle and the length. • If not specified, an angle of 45° is assumed.
Oblique surface
•Characteristic shape in three views. •Not the real size in any of the views.
Inclined Surface
•Characteristic shape in two views. •Not the real size in any of views. •In the form of line (edge) in the third view.
Interpolation by Cubic Polynomials
•Curves: -Given 4 control points p0, p1, p2, p3 -All should lie on curve: 12 conditions, 12 unknowns
Dimensioning Arcs
•Dimension by their radii. •Dimension line passes through the radius center and terminates with an arrowhead touching the arc. •A small centermark should be drawn on the center when dimension is given to the center of the radius. •Use symbol R before the numeric value. •Read other rules and exceptions from the books.
Other Dimensioning Rules
•Dimensions should be indicated on a view that shows the true size of the feature, particularly when the feature lies on an oblique angle. •This is why we use auxiliary views •NEVER dimension to hidden lines •Avoid a complete chain of dimensions and an overall dimension. THIS MAKES THE DRAWING OVER-DIMENSIONED!!!
Inferencing
•Dotted lines appear when you sketch, showing alignment with other geometry. §Orange inference lines capture and add a geometric relation such as Tangent. §Blue lines show alignment and serve as an aid to sketching, but do not actually capture and add a geometric relation.
Hole Callout
•Hole diameter •Hole depth •Thread type (if there are threads) •Depth of threads (if different than hole depth) •Counterbore depth •Counterbore diameter •Countersink diameter (largest diameter) •Countersink angle •"THRU" if the hole goes all the way through the material •Symbols (depth, counterbore, countersink, diameter)
Leaders
•Lines drawn at an angle (never horizontal or vertical) extending from a note to a feature to which the note applies. •Leaders are used to direct notes, dimensions, symbols, item numbers, part numbers, or any other pieces of information that are needed on the drawing
Line Weights
•Object lines are thick (approximately 0.030-0.040") •Hidden lines are a medium thickness (0.015-0.02") •Extension, dimension, and center lines are thin (0.007-0.010")
Broken Out Sections
•Only a partial section of the part needs to be seen • An Irregular Break Line is used. Remove a small portion of the object to reveal the inner details
Millimeters
•Place no zeroes to the right of the decimal point: 2 not 02 or 2.0 •Must place zero to the left of the decimal point: 0.2 not .2 or .20 (This is different than when using inches!) •The word METRIC must be displayed on or near the title block.
Units Common in Both Systems
•Ratios: 0.006:1 •Angles Angular Units: measured in degrees. Decimal degree is preferred over the use of degrees, minutes and seconds, and radians
Extruded Cut with Draft Angle
•Same process as extruding a boss except it removes material instead of adding it. •Draft tapers the shape. •Draft is important in molded, cast, or forged parts.
Dimensioning
•Specifies the geometric characteristics (size of the object), location of the features, and other characteristics of the features, such as diameter of the hole, tolerances, etc.•Specifies the geometric characteristics (size of the object), location of the features, and other characteristics of the features, such as diameter of the hole, tolerances, etc.
Dimensions Methods
•Style A: Dimension line is broken for insertion of the dimension •Or dimension can be placed above the line. |<------ 2.00 ------>| •Style B: if gap is smaller than 0.5in. -->| .500 |<-- • Style C: if gap is smaller than 0.375 in. |<->|-- .375 Style D: for very small gaps -->| |<-- .125
Standard Convention
•The most informative view of the object is normally chosen as the principal view (front view in here). •Not all the 6 views are necessary to represent the object. They have to be chosen in order to: Use the minimum number of views necessary to completely describe the part. Avoid unnecessary repetition of the detail Choose the views: > That show the shape most clearly. > Have the fewest hidden lines. > Show the object in a usual, stable, or operating position. > Take the view with most details as your front view.
Offset Sections
•To include features that are not in straight line.
Dimensioning Drilled Holes
•Use abbreviation THRU for through holes if not clear from drawing. • Use the depth symbol to define the depth of the drilled hole. • Simple fillet or corner radii may be dimensioned by a general note like: "ALL RADII R.5" • Size, quantity and depth may be shown on a singe line or on separate lines
Feet and Inches
•Used in installation drawings, drawings of a very large object, or floor plans in architectural work. (probably won't be used in this class)
Orthographic Projection
•You can project the information on the views to construct the third view once two views are established by using a Miter Line (at 45 degree to the horizon). •Start with a surface in the top view, then find the corresponding edge or surface, in the front view. •Intersection of projected lines coming from each point is the same point in right view. •Connecting the points shows the way the red surface looks in the right view. •Project lines from the points to the right of the top view. Intersect the miter line, and drop vertical projection lines. Then project horizontal lines to the right of the front view.
Principal Surface
•characteristic shape in one views with the real size. •in the form of a line (edge) in two other views.