Lesson 1.5 Designing for Production

Preface
In this lesson students will learn how to transfer a simple hand sketch to a three-dimensional (3D) model on a computer. Creating the image on a computer has many advantages. For example, one of the problems with hand sketching is that as you change the sketch, you must keep erasing. Erasing or deleting aspects of a drawing on a computer is often done with the click of a mouse button.

Another major advantage of using a computer solid modeling program is that it allows a crude initial sketch to be transferred into a polished drawing with a few simple commands. Many crude sketches can be turned into 3D models that can be converted to a working drawing with dimensions and annotations.

In order to get maximum benefit from this powerful tool, students will study the basic geometric shapes, such as cubes and spheres, and how they are combined to form complex geometry using the aid of the computer. The basic techniques that students will learn may be equally applied to making a model of a human body for medical purposes, creating a soft drink container, or manufacturing a starter motor for an automobile.

Students will build on drafting basics by adding many essential features to their 3D models. They will learn to document, edit, and archive drawings as well as study techniques for adding features such as holes, slots, and chamfers.

Finally, students will see that once they have created a 3D model of an object, the computer can show them the model from a virtually limitless number of viewpoints, greatly enhancing their visualization of the object. This function is also a wonderful tool for multimedia presentations.

Students will have the opportunity to complete the design process by building a prototype, testing and evaluating the models, redesigning to improve their solution to a problem, and communicating their ideas to representatives from the community.

Concepts
1. Simple geometric shapes are combined and joined to create a representation of an object.
2. Engineers use computer-aided design (CAD) modeling systems to quickly generate and annotate working drawings.
3. Three-dimensional computer modeling uses descriptive geometry, geometric relationships, and dimensions to communicate an idea or solution to a technological problem.
4. As individual objects are assembled together, their degrees of freedom are systematically removed.
5. Engineers use a design process to create solutions to existing problems.
6. Teamwork requires constant communication to achieve the goal at hand.
7. The fabrication of a prototype is the opportunity for the designer to see the product as a three-dimensional object.


Performance Objectives
It is expected that students will:
· Create a three-dimensional (3D) model of an object.
· Apply geometric and dimension constraints to design CAD-modeled parts.
· Assemble the product using the CAD modeling program.
· Demonstrate the ability to produce various annotated working drawings of a 3D model.
· Identify the difference between a prototype, a model and a mock-up and analyze what circumstances call for the use of each.
· Explain why teams of people are used to solve problems.
· Brainstorm and sketch possible solutions to an existing design problem.
· Create a decision-making matrix.
· Select an approach that meets or satisfies the constraints given in a design brief.

Assessment
Application
· Apply the design process to solve a design problem.
· Assess 3D models for evidence of effective communication of ideas, such as
a. Do students’ 3D models clearly communicate their ideas?
b. Are 3D models clearly labeled and do they include dimensions?
c. Do all drawings include appropriate annotations and relate clearly to the 3D model?
Empathy
· Participate in a team project where each member is valued for their expertise and contributions.
Self-knowledge
· Decide on best works for portfolio.


Essential Questions
1. Why would engineers use three-dimensional (3D) modeling when solving technological problems?
2. How do assembly constraints differ from geometric and numeric constraints?
3. What is the difference between a hand-drawn sketch, a working drawing, and a 3D model?
4. What is the difference between a part file (.ipt), an assembly file (.iam), and a working drawing (.idw)?
5. What is the difference between a model, a mockup and a prototype?
6. What purpose do annotations serve in an assembly drawing?
7. Why is it important to follow the design process when creating a solution to a problem?
8. Why are teams of people used to solve problems?



Key Terms
Annotate
To add explanatory notes to.
Browser
A sequential record of the construction steps in a 3D modeling program
CAD (Computer-Aided Design)
The use of a computer to assist in the process of designing a part, circuit, building, etc.
Chamfer
A small angled surface formed between two surfaces.
Coincident
Occupying the same area in space.
Collinear
Lying in the same straight line.
Concentric
Circles or arcs that share the same center.
Constraint
A limit to a design process. Constraints may be such things as appearance, funding, space, materials, and human capabilities. A limitation or restriction.
Counterbore
A cylindrical recess around a hole, usually to receive a bolt head or nut.
Countersink
A conical-shaped recess around a hole that is often used to receive a tapered screw.
Design
An iterative decision-making process that produces plans by which resources are converted into products or systems that meet human needs and wants or solve problems.
Dimension Constraint
Used to describe the size and location of individual geometric shapes.
Documentation
The documents that are required for something or that give evidence or proof of something. A drawing or printed information that contains instructions for assembling, installing, operating, and servicing.
Edit
A change or correction made as a result of editing.
Extend
Make larger in area.
Feature
A distinctive attribute or aspect.
Fillet
A rounded interior blend between two surfaces. Some uses are to strengthen joining surfaces or to allow a part to be removed from a mold.
Fabricate
Construct or manufacture an industrial product.
Fix
Attach or position securely.
Functional
Designed to be practical and useful.
Geometric Constraints
Restrictions applied to geometric entities; for example, horizontal, parallel, perpendicular, and tangent.
Horizontal
Parallel to the X axis.
Isometric
A form of pictorial drawing in which all three drawing axes form equal angles of 120 degrees with the plane of projection.
Mockup
A model devised to expose its parts for study, training or testing.
Model
A visual, mathematical, or three-dimensional representation in detail of an object or design, often smaller than the original. A model is often used to test ideas, make changes to a design, and to learn more about what would happen to a similar, real object.
Offset
The amount by which something is out of line.
Parallel
Lines, planes, or surfaces side by side and having the same distance continuously between them.
Perpendicular
At an angle of 90˚ to a given line, plane, or surface.
Polygon
A closed geometric figure in a plane formed by connecting line segements endpoint to endpoint with each segment intersecting exactly two others. Polygons are classified by the number of sides they have, such as a triangle has three sides, a quadrilateral has four sides, and a pentagon has five sides.
Profile
An outline of something as seen from one side.
Prototype
A full-scale working model used to test a design concept by making actual observations and necessary adjustments.
Revolve
To move in a circle about a central axis.
Right Triangle
A triangle that has a 90 degree angle.
Rotation
Turning around an axis or center point.
Sketch Plane
The surface that 2D profiles can be sketched on.
Specification
A detailed description of the design and materials used to make something
Tangent
A straight line or plane that touches a curve or curved surface at one point.
Trim
Cut off irregular or unwanted parts.
Vertical
Parallel to the Y axis.


Day-by-Day Plans
Time: 22 days
In preparation for teaching this lesson, it is strongly recommended that the teacher read the Lesson 1.5 Teacher Notes.
Day 1-2:
· The teacher will present Concepts, Key Terms, and Essential Questions in order to provide a lesson overview.
· The teacher will demonstrate the use of a 3D modeling program by showing a video(s) of projects created using the software. See the Teacher Notes for suggestions.
· The teacher will guide students through Activity 1.5.1 Descriptive Geometry and the Coordinate System.
· The teacher will provide each student with a block to sketch in Activity 1.5.1 Descriptive Geometry and the Coordinate System.
· Students will complete Activity 1.5.1 Descriptive Geometry and the Coordinate System.
· Students will show completed activity to teacher.
· The teacher will check for completion and understanding.
· Students will use appropriate engineering notebook template for daily entries.
Day 3-4:
· The teacher will introduce geometric constraint terms by asking students to use their bodies to demonstrate the following terms:
a. Horizontal
b. Vertical
c. Parallel to each other
d. Tangent to the wall
e. Fixed in one spot
f. Hands coincident (this is where they may not know what to do)
· The teacher will present Computer Modeling Fundamentals.ppt. At several points during the presentation, the teacher will allow students time to practice the skill demonstrated using the 3D modeling program.
· Students will complete Activity 1.5.2 Computer Modeling Fundamentals while the teacher is presenting.
· The teacher will instruct students on how to open the solid modeling software.
· The teacher will instruct students on how to set up project files in the software for organization of GTT classroom projects.
· The teacher will initial on activity to indicate that students have demonstrated the skill in the software.
· Students will use appropriate engineering notebook template for daily entries.
Day 5:
· The teacher will follow the steps in Creating A Custom Titleblock to create a customized titleblock for students to use.
· The teacher will present Parametric Modeling.ppt to demonstrate steps involved in creating 3D objects.
· Students will take notes in their GTT notebook on the presentation.
· After Part 1 of the presentation, students will practice the steps in the software as they were presented by sketching and extruding several shapes. Save this file as Practice.
· Each student will use Project 1.5.3 Parametric Modeling to sketch and dimension the outline of a simple block. Engineering notebook designs from Project 1.5.3 will be exchanged with another student, preferably in another class, for that student to complete the sketch.
· Students will create a 3D model from information provided in a sketch and save file as Partner. Return Project 1.5.3 to original owner.
· Note - Do not share block with partner who is 3D modeling, only the annotated and dimensioned sketch from the student notebook.
Day 6:
· The teacher will review steps in parametric modeling and present Part 2 of Parametric Modeling.ppt, adding a feature.
· Students will take notes in GTT notebook.
· Students will open their Practice file in the software and add at least two features, including a hole and additional extrusion. Save the file.
· Students will sketch and dimension additional features from the original block on their original sketch in Project 1.5.3 Parametric Modeling.
· Students will exchange Project 1.5.3 again with the same student.
· Students will add features to the original model using the software. Return Project 1.5.3 to original student.
· Students may complete Optional Activity 1.5.4 Sketch Plane Cube for additional practice.
· Teachers will continually check for students’:
a. Use of the Engineering Notebook Design pages
b. Accurate and neat sketching and annotating
c. Accurate use of the 3D modeling program
Days 7-8:
· The teacher will use 3D modeling program to demonstrate browser editing.
· Students will practice browser editing in their Practice file.
· Students will make notes on their original Project 1.5.3 Parametric Modeling sketch about two dimension changes that must be made to the model.
· Exchange Project 1.5.3 with same student that previously modeled it using the 3D software.
· Students will open their Partner file and edit it using their browser to complete changes made by the original author.
· Teachers will continually check for students’:
a. Use of the Engineering Notebook Design pages
b. Accurate and neat sketching and annotating
c. Accurate use of the 3D modeling program
Days 9-11:
· The teacher will introduce students to assembly of parts using the Basic Assembly Constraints.ppt.
· The teacher will introduce students to Activity 1.5.5 Pegboard Toy.
· Students will complete the activity.
· The teacher will demonstrate working drawings in the 3D modeling program.
· Students will complete Activity 1.5.5a Pegboard Toy Working Drawings.
· Optional: Students will complete Activity 1.5.5b Pegboard Toy Presentation Drawings.
· Students will use appropriate engineering notebook template for daily entries.
· Optional: The teacher may have students work on the following additional activities and projects:
o Activity 1.5.6 Bracket
o Project 1.5.7 Switch Plate Design
o Project 1.5.8 Hair Brush Design
o Project 1.5.8a Watch Design
Days 12-14:
· The teacher will review the design process.
· Students will locate Project 1.2.3 Furniture Design or Project 1.2.3 Hobby Organizer Design in their GTT notebook.
· Working with the same partner, students will continue with the design process in Project 1.2.3 Furniture Design or Project 1.2.3a Hobby Organizer Design.
· The teacher will guide students through completing the following steps:
a. Make a 3D computer model of your best idea by creating each part file and assembling it (model or prototype stage of the design process).
b. Evaluate the model by having classmates, family, or friends look at the design and see if they would buy it (test and evaluate stage of the design process).
c. Ask reviewers for suggestions for improving the design.
d. Improve the 3D computer model (improve design stage of the design process). Use browser editing if possible.
e. Complete Design Process Steps summary from Project 1.2.3 Furniture Design or Project 1.2.3a Hobby Organizer Design(Communicate Results stage of the design process).
· The teacher will collect and evaluate for completion and accuracy Project 1.2.3, working drawings of furniture or organizer, and GTT notebook entries.
· Students will use appropriate engineering notebook template for daily entries.
Day 15
· The teacher will invite another adult, community member, principal, another teacher, etc. to introduce Problem 1.5.9 Playground Design Problem.]]
· The teacher will use Problem 1.5.9a Playground Design Problem Teacher Support]] to review assembly constraints and see sample .idw files.
· The teacher will guide students through completing the Playground Design Brief.
· The teacher will require students to consider safety as a criteria in the Playground Design. This website contains information on playground safety: **http://www.cpsc.gov/cpscpub/pubs/325.pdf**
· Students will identify their strengths and what part of the design process for this design problem most matches their expertise.
· Students will use appropriate engineering notebook template for daily entries.
Days 16-21
· Students will complete Problem 1.5.9 Playground Design Problem.
· The teacher will continually monitor student progress through the problem by giving suggested deadlines, assisting with design process steps, and dividing students into smaller groups.
· The teacher may act as project manager or assign a student to act as project manager.
· Students will use appropriate engineering notebook template for daily entries.
· Optional: The teacher may wish to assign Key Terms 1.5 Crossword Puzzle]] after all key terms have been introduced.
Day 22
· Students will explain to the playground committee representative how they solved their design problem and what they did at each step in the design process.
· Each student needs to be involved in the presentation.
· The teacher will evaluate using the 1.5.9 Playground Design Problem Grading Rubric. (to be developed)
· Students will use appropriate engineering notebook template for daily entries.
· Students will review activities completed in this lesson and enter their best works in their GTT portfolio. Portfolios should be maintained as students progress throughout the other GTT units.
· The teacher will evaluate student notebooks using the GTT Notebook Grading Rubric.