IED Review Sheet Units 7-10 Name:_________________

Unit 7 Documentation

Effective communication of ideas and information has been a goal of humans since the beginning of time. Technical communication became especially important during the Industrial Revolution as manufacturing changed from one-off fabrication of a product by an individual to large-scale mass production of parts and assemblies. To effectively communicate technical information, standards were developed to guide the technical documentation of parts. The drafting, dimensioning, and tolerancing standards are a design language that allow designers to clearly and accurately communicate their ideas about form and function to people all over the world, regardless of what language they speak.

Essential Questions1. What quality makes a set of drawings sufficient to adequately represent the design intent?2. Is it always necessary to indicate a tolerance for every dimension on a technical drawing? Justify your answer.3. Stephen Covey includes Begin with the End in Mind as one of the seven habits listed in his book The 7 Habits of

Highly Effective People. How can this habit make an engineer more effective?

Unit 7.1 More Dimensioning

The basic standard dimensioning method established by the American National Standards Institute and the American Society of Mechanical Engineers (ANSI and ASME) is used to apply measurement to parts to enable clear communication. To communicate effectively, a person needs to understand the rules of the language and to follow the standards set down, so that anyone who reads a dimensioned drawing will understand the intent and then be able to manufacture the part correctly.In Unit 3 you were introduced to dimensioning and practiced applying dimensions to technical drawings. In this activity you will continue your practice by applying the appropriate dimensions and develop an understanding of the thought process that is used to create a clear and concise message regarding the size, form and features of an object or a product.

It is impossible to manufacture a part to an exact dimension. If a part is measured precisely enough, the part configuration will deviate from the specified dimensions. Typically a small amount of deviation from the specified dimension is allowed, but the error can add up in a chain of dimensions compounding the error and resulting in a part that is much smaller or larger than intended. Therefore, specifying the overall dimension (with its small allowable error in that one dimension) will reduce the deviation of the overall part size. We will talk about tolerances, the allowed deviation of a dimension on a manufactured part from the specified dimension, later in this unit.

For now, when chain dimensioning, use the preferred method (Method 2) when possible.

Unit 7.2 Section View

Have you ever noticed that some objects have more going on inside than outside? Take an apple, for instance. How would you communicate the intricate details hidden inside an apple’s core? You would have to cut the apple in half to show someone that there are spaces inside that house seeds. If you were to make a sketch of the apple, you could show the spaces and the seeds as hidden lines, but too many hidden lines can confuse the issue. Sectional views are another alternative.The main purpose of a sectional view is to effectively communicate internal details to enhance the viewer’s understanding of the part. There are several different types of section views that engineers use to communicate internal geometry.

Hole and Hole Notes

Unit 7.3 Tolerance

The term variation describes the degree to which an object or idea differs from others of the same type or from a standard. Examples of variation are everywhere you look. When you see yourself in the mirror, you notice the left side of your face is not exactly the same as the right side. There is a variation. Or when you see identical twins, they are not exactly the same. Likewise, no two manufactured objects are the same. A degree of variation will exist.The use of tolerance in engineering design provides a means by which variance can be controlled within acceptable limits so that parts of a product fit together in a way that allows the product to function properly. In the field of mathematics and science, tolerances are used regularly. You will see reference to an allowanceor tolerance given in many settings. After you experience this activity, take note when you see tolerances given in the media or on product labels.

Tolerance - The acceptable amount of dimensional variation that will still allow an object to function correctly.

Allowance - The tightest possible fit between two mating parts.

Part Drawing - A drawing that contains all the information for making one part of the design.

Limit Dimensions - The largest and smallest possible boundaries to which a feature may be made as related to the tolerance of the dimension.

Bilateral Tolerance - A tolerance in which variation is permitted in both directions from the specified dimension.

Uni-Lateral Tolerance - A tolerance in which variation is permitted in one directions from the specified dimension.

Clearance Fit - Limits the size of mating parts so that a clearance always results when mating parts are assembled.

Interference Fit - Limits the size of mating parts so that an interference always results when mating parts are assembled.

Transition Fit - Occurs when two mating parts can sometimes have a clearance fit and sometimes have an interference fit.

Interference - The amount of overlap that one part has with another when assembled.

Section View - A view that is used to show details not apparent on the exterior of the part.

Datum Dimensioning - A dimensioning system where each dimension originates from a common surface, plane, or axis. Also known as baseline dimensioning.

Datum - A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specific datum feature. The origin from which the location, or geometric characteristic of a part feature, is established.

Counterbore - A cylindrical recess around a hole, usually to receive a bolt head or nut.

Detail Drawing - A dimensioned, working drawing of a single part. Also referred to as part drawing.

Chain Dimensioning - Also known as point-to-point dimensioning where dimensions are established from one point to the next.

Unit 7.4 Assembly Models

Have you ever pieced together a jigsaw puzzle? The individual puzzle pieces have to be rotated and sometimes flipped around to make them fit. A piece that makes up an outside edge of the puzzle must have its flat edge flush with other pieces of that side. Pieces that have exterior protrusions must be mated to their counterpart interior recesses. The process of putting a jigsaw puzzle together is very similar to building an assembly of components in a CAD program.

Documentation

Assembly Constraints

Technical Writing

Unit 8 Advanced Computer Modeling

PrefaceThis unit presents many of the 3D functions used to develop individual and assembly CAD solid models. You will build your modeling skill and use these modeling functions to develop design solutions to various projects and problems throughout the rest of the course.

Essential Questions1. Are working drawings always necessary to communicate the design of a consumer product? Justify your answer.2. Beyond creating working drawings to document a design, how can 3D computer modeling be used in the design

process? How can it be used beyond the design process?

Unit 8.1 Parametric Equations

Numeric Constraints - A number value or algebraic equation that is used to control the size or location of a geometric figure.

Parametric Modeling - A CAD modeling method that uses parameters to define the size and geometry of features and to create relationships between features. Changing a parameter value updates all related features of the model at once.

Unit 9 Design Team

PrefaceMore and more often design team members are separated by distance. This separation requires a different approach than a design team who can meet face to face. In this unit you will learn and practice processes to solve a design problem with a geographically separate team. You will also experience shared decision-making as your team investigates different materials, manufacturing processes, and the impacts that engineering decisions may have on society or potentially on the world.

Essential Questions1. Is it ever advantageous to create a design or solve a problem individually as opposed to using a team approach?

Explain.2. What strategy would you use to form a design team to obtain the best solution possible?3. What does it mean to be “ethical” in your work? Do engineers need to be taught to be “ethical”?4. It has been said that, “Having a vision without action is a daydream; Taking action without a vision is a nightmare!”

How does this apply to engineering design?

Unit 9.1 Product Lifecycle

Product Lifecycles- Stages a product goes through from concept and use to eventual withdrawal from the market place.

Raw Materials - Any natural resource that is used to make finished products.

Recycle - To reclaim or reuse old materials in order to make new products.

Landfills are filling at an alarming rate. The raw material for some products is becoming scarce. Decomposition requires a long time, etc. Heath issues arriving in and around waste sites are becoming more common. Help keep our earth clean for us and those after us.

Usually products have signs on them indicating whether they can be recycled. If not, you can call your local recycling plant for verification.

Mention to students how important consumers are in the recycling process.

The process is dependent on the material. Discuss newspaper recycling. The collectors of these products have to collect and sell it to a paper dealer. The paper dealer then sells to the user. This is where the actual recycling (manufacturing one product into a new

product) takes place. The user, usually a paper mill, separates the ink from the newspaper fibers through a chemical washing process. A slusher turns the material into pulp which is strengthened by wood chip pulp and then fed through steam heated rollers to flatten for use as paper again.

Ethical - Conforming to an established set of principles or accepted professional standards of contact.

Virtual Teams - A group of people that rely primarily or exclusively on electronic forms of communication to work together in accomplishing goals.

Gantt Chart

An essential concept behind project planning is that some tasks are dependent on other tasks being completed first. It is not a good idea to start building a house before you have designed it! These dependent tasks need to be completed in sequence, with each stage being completed before the next tasks can begin. We can call dependent tasks sequential or linear. Other tasks are not dependent on completion of any other tasks. These may be done at any time before or after a particular stage is reached. These are nondependent or parallel tasks.

Unit 9.4 Team Norms

When you walk into a library, how are you supposed to behave? What do you say when you answer a telephone or end a phone call? If you want to ask the teacher a question in the middle of a lecture, what do you do? All of these scenarios should bring about similar, if not identical, responses from everyone in the class. Each of these scenarios would result in a behavioral response that follows guidelines, protocols, or rules of acceptable behavior, also known as norms. Norms regulate proper and acceptable behavior by and among individuals.

Teams develop and agree upon norms through consensus to ensure efficiency and to avoid potential conflicts. Acceptable and preferred communication protocols, decision-making rules, and methods of conflict resolution are only a few examples of team norms.

Norms –Principles of right action, binding upon the members of a group and serving to guide, control, or regulate proper and acceptable behavior.

Consensus – General agreement.

Protocols -The accepted code of behavior in a particular situation.

Virtual Teammate - A group of people that rely primarily or exclusively on electronic forms of communication to work together in accomplishing goals.

Impact - The effect or influence of one thing on another. Some impacts are anticipated, and others are unanticipated.

Gantt Chart - A time and activity bar chart that is used for planning, managing, and controlling major programs that have a distinct beginning and end.

Effective Research

Citations in APA Style

Introduction

The following style of citation is based on the sixth edition of Publication Manual of the American Psychological Association (APA). It is recommended that this document be purchased and used as a reference in the classroom or laboratory.

StaStatics is the basis for the study of engineering mechanics and specifically rigid-bodymechanics. Mechanics is a branch of physics that deals with the motion of objects at a large scale. The study of motion at the atomic (or smaller) scale is called “quantum mechanics”.Let's start with Newton’s Laws of Motion, which describe the motion of bodies and how they interact. These laws are important for understanding how objects move or stay in place.

Magnitude - The absolute value of a number. Vector - A quantity that has both a magnitude and direction.Rigid Body - A solid body in which the deformation is zero or so small it can be neglected. That is, the body remains exactly the same size and shape regardless of the forces exerted on it.Uniform Motion - Constant velocity; state of rest is constant velocity also, specifically v = 0.Moments - The turning effect of a force about a point equal to the magnitude of the force times the perpendicular distance from the point to the line of action from the force. 

Newton’s First Law of Motion(law of inertia)

An object in a state of rest or uniform motion will continue to be so unless acted upon by a net force.

This law describes the relationship between velocity and forces.

Newton’s Second Law of Motion

The acceleration of an object is proportional to the net force acting on the object and inversely proportional to the object’s mass.

This law describes the acceleration of an object in the direction of the net force applied to it.

Newton’s Third Law of Motion

For every action force, there is an equal and opposite reaction force.

This law describes action-reaction pairs.

Equilibrium

In science, equilibrium refers to a state of balance. A system is in balance if it stays the same. It may stay the same because nothing is influencing it or the influences on it are balanced. There are many forms of equilibrium (i.e., thermal, chemical, economic). Statics is concerned with the equilibrium of bodies that are in a state of rest or uniform motion.

Static Equilibrium A condition where there is not a net external force acting upon a particle or rigid-

body and the body remains at rest or continues at a constant velocity.

That is, when forces acting on an object that is at rest are balanced, then the object is in a state of static equilibrium.

To be in static equilibrium, an object must be in both translational equilibrium AND rotational equilibrium.

Tranlational Equilibrium The state in which there are no unbalanced forces acting on a body.

Rotational Equilibrium The state in which the sum of all the clockwise momentsequals the sum of all the counterclockwise moments about a pivot point.

Static Equilibrium Force Principles

When a system is in static equilibrium, forces always occur in pairs. Force pairs act in opposite directions and have the same magnitude.

For example, when you sit on a chair, you exert a force equal to your weight on the chair, and the chair exerts an equal and opposite force on you, supporting your weight and keeping you from falling to the floor.

If an object is in equilibrium, then the forces acting on the object are balanced. It is important to note that “balanced” is the key word. This concept can be drawn from Newton’s first law of motion.

An object in equilibrium is...

at rest and staying at rest, or in motion and maintaining a constant velocityAfter a bridge collapses and comes to rest, is it in static equilibrium? Why or why not?

What is a Force?

A force is the pushing or pulling interaction of objects. It is a vector quantity and so is always defined by a magnitude and a direction. For example, a 100-pound person sitting on a chair exerts a force of 100 pounds downward (toward the center of the Earth) on the chair.We represent vector quantities with directed line segments (arrows). The length of the line segment represents the magnitude of the force, and the arrowhead indicates the direction of the force.

Force Units

British System of Units pound-force (lbf) 1 lbf = 4.448 N

International System of Units

newton (N) 1 N = 0.2248 lbf

What is a Moment?

A moment is the tendency of a force to rotate an object. This is caused by a force acting on an object at some distance from a fixed point or axis. To fully describe a moment, you must know the magnitude and the direction of the moment.

Think about a penguin on a diving board. The weight of the penguin will try to rotate the diving board about its support point.

STATICS REVIEW

tics