IED Semester 2 Final Exam
Study Guide: Definitions
Variation a difference between an object or idea and other objects or ideas of the same type or from a standard
Tolerance the acceptable amount of dimensional variation that will still allow an object to function correctly
Unilateral Tolerance provides allowable variation in only one direction(either larger or smaller)
Example:
Bilateral Tolerance permits variation in both directions(larger and smaller) from the specified dimension
Example:
Limit Dimensions provide an upper limit and a lower limit for the dimension
Example:
Interchangeable Parts identical components that can be substituted for one another, particularly important in the history of manufacturing. As precision instrumentation became available, large numbers of identical parts could be produced at lower costs.
Mean the average of a data set
Median the ‘middle’ value of a data set
Clearance Fit limits the size of mating parts so that a clearance or space always results when mating parts are assembled
Interference Fit the fastening between two parts which is achieved by friction after the two parts are pushed together, rather than any other means of fastening
Transition Fit occurs when two mating parts can sometimes have a clearance fit and sometimes have an interference fit
Selective Assembly a process that aims to loosen tolerance between mating parts to reduce manufacturing costs. In selective assembly, parts are machined and then measured. These parts are then matched up with an appropriate mating part instead of randomly choosing among the stock of parts.
Allowance The minimum clearance or maximum interference between parts
Adhesives An adhesive is a substance that, when applied to the contact surfaces of two separate components, binds them together and resists their separation.
Examples: glue, paste, or cement.
Fasteners A fastener is a device that joins objects together. Fasteners are often referred to as mechanical fasteners because simple mechanisms, such as a wedge and wheel and axle, are used to cause the objects to be securely connected.
Examples: nuts and bolts, screws, pins and nails.
Joinery Joinery is the process of connecting or joining two components together using one of a variety of joint forms.
Examples: lap, rabbit, dovetail, and mortise-and-tenon joints
Snap-Fit Joints A snap-fit joint (or snap joint) is a simple and inexpensive way to connect two components. Although there are many different forms of snap-fit joints, all snap joints are similar in that one component has a protruding part that is deflected when the two components are pressed together and catches in a depression on the other component. After the two components are connected, the components should return to their initial shape so that the material is not stressed.
Types:
-Cantilever snap joint
-Torsion snap joint
-Annular snap joint
Threads a thread is a helical structure that is used to convert rotational motion or force into linear motion or force. A thread can be located on the outside of a curved shaft or on the inside of a receiving cylinder. Used in bolts and screws.
Reverse Engineering A process that involves the study of an object’s visual, functional, and structural qualities. Reverse Engineering addresses how things work and can provide economic advantages to businesses. It is often used to inform the redesign of an object so that its performance may be improved.
Visual Analysis analysis of the elements and principles of design used in the product
Visual Design Elements
Line the path of a point moving through space
Color described by hue, value, and saturation; has an immediate and profound effect on a design
Shape 3 types: geometric, mechanical, and organic
Form a 3D volume or solid often implied on a 2D surface by careful use of value
Value relative lightness or darkness of a color, object or shape
Space areas between and around parts of an image or the implied depth of that image
Texture the surface look or feel
Visual Design Principles
Balance the distribution of elements within a design; 3 types: symmetrical, asymmetrical and radial
Emphasis used to draw attention to one area (focal point)
Contrast the degree of relative difference between elements
Rhythm a harmonious sequence; repeated use of line, shape, color, texture, or pattern; 4 types: regular, random, gradated and graduated
Proportion Comparative relationship between elements in a design with respect to size; measured by scale
Unity consistent use of design elements
Economy use of the bare minimum of elements; less is more
Color aspect of an object or image that can be described by hue, value, and saturation
Hue ‘base’ color
Saturation purity/intensity relative to grey
Value relative lightness or darkness
Functional Analysis describes what a product does, but not how it does it. Through functional analysis, you try to identify the activity or actions of components and subsystems. A functional model is often developed to represent the product system at a more abstract level.
Input sequence of steps for the operation
Output what happens at the end as a result of the input
Black Box Hypothesis a hypothesis made to explain the sequential operation/function of the product that identifies what goes into and comes out of the product as a system
Structural Analysis used to find the structure of the product of a whole and of each component, and uses disassembly to see how each part interacts with each other to complete the product's function
Systems Thinking looking at things as a whole rather than a jumble of parts. It is the ability to understand how parts connect to make up an entire system
Materials Engineering The study of the properties and structures of different materials to better understand the way materials work and what materials should be used for products.
Performance how materials behave under different types of conditions and forces
Properties the physical and structural qualities and properties of materials
Structure the atomic, molecular and chemical structure/makeup of materials
Processing how materials are processed during manufacturing
Stress measure of internal forces that arise within a material when it is subject to external forces or load
Strain measure of deformation of a material caused by stress
Fatigue Resistance a material's ability to withstand repeated stress cycles without failing
Impact Resistance a material's ability to withstand sudden, high-force impacts without breaking or deforming
Creep the time-dependent, permanent deformation of a material under constant stress, typically at elevated temperatures
Wear Resistance a material's ability to withstand material loss due to mechanical action, while
Abrasion Resistance a material's ability to resist scratches or wear caused by friction
Environmental Performance the environmental impacts and considerations related to the sourcing, production, use, and disposal of materials
Thermal Expansion the tendency of matter to increase in length, area, or volume, changing its size and density, in response to an increase in temperature
Thermal Contraction the process where a substance shrinks as it cools
Fatigue the weakening of a material's strength due to repeated stresses and strains, leading to potential failure
Failure the loss of a material's ability to perform its intended function, typically due to stress exceeding its load-bearing capacity
Metal shiny, malleable, and good conductors of heat and electricity. They can be elements or alloys
Ceramic inorganic, non-metallic materials produced by firing at high temperatures, often from clay or other materials
Polymer a large molecule made up of many repeating, smaller units called monomers. These polymers can be natural, like DNA or silk, or synthetic, like plastics or nylon
Composites materials created by combining two or more materials with significantly different properties, resulting in a new material with enhanced characteristics
Biomaterials substances, either natural or synthetic, used in medicine to replace, restore, or augment body parts or functions
Alloys a metallic substance composed of two or more elements, typically metals, but can include non-metals as well
Yield Strength The maximum stress (or pressure) a material can withstand before it begins to deform permanently(MPa)
Ultimate Strength the maximum stress a material can withstand before it breaks or fractures under a tensile load
Young’s Modulus A material’s ability to resist elastic deformation(GPa)
Density Degree of compactness of a substance(g/cm³)
Tensile Strength A material’s ability to resist being pulled or stretched without breaking(MPa)
Melting Point The specific temperature at which a solid substance changes state and becomes a liquid(°C)
Electrical Resistivity A measure of a material’s ability to resist/impede electrical current(Ωm)
Specific Heat The amount of heat that must be added to a material in order to increase its temperature by a unit in temperature(J/Kg°C)
Coefficient of Thermal Expansion A material property that measures how much a material expands or contracts when its temperature changes(1 part per C°)
Ductility material’s ability to deform without breaking; primarily to do with stretching and tensile stress (pulling apart)
Malleability material’s ability to bend or compress without breaking; primarily to do with flattening and forming
Stiffness materials’ ability to resist deformation and return to its original shape after being acted upon by an external force (Young’s Modulus of Elasticity)
Toughness material’s ability to absorb energy before breaking
Hardness material’s resistance to permanent deformation, indentation and scratching
Brittleness tendency to break when stressed with little deformation before fracturing
Plasticity ability of a material to undergo irreversible deformation, opposite of brittleness
Types of Stress compression, tension, shear, torsion, and bending
Sustainability meeting the needs of the current generation without negatively impacting the ability of future generations to meet their own needs.
Biomimicry copying/imitating the special characteristics of living organisms in material, products, or processes
Cradle to Cradle a product life cycle in which the last phase includes the recycling of the product into a new product(everything goes somewhere)
Design for Disassembly a design approach that enables the easy recovery of parts, components, and materials from products at the end of their life
Green Chemistry reducing the generation and use of hazardous chemicals to decrease pollution at its source
Green Marketing a tactic companies use to promote the environmental responsibility, or just the benefits, of their products
Product Stewardship all those involved in the life cycle of a product should share responsibility for reducing its environmental impact
Human-Centered Design a creative problem-solving process that focuses on designing from the perspective of those you are trying to reach. The design must meet people’s needs, be useful, and be compatible with the capabilities of the user.
Inspiration the phase in which you open yourself up to a multitude of creative possibilities.
Ideation the phase in which numerous ideas are generated, then refined and iterated based on the needs of the users.
Implementation the phase in which the idea is brought to life.
Linear Motion object moves in a straight line
Rotary Motion rotation around a fixed axis that is interior to the object
Circular Motion rotation around a fixed axis that is exterior to the object
Reciprocating Motion back and forth linear motion
Oscillating Motion swinging back and forth motion
Types of Basic Cams
Circular
Off-center circular
Heart
Hexagonal
Pear
Snail