Portland Community College | Portland, Oregon

A study of mechanical drafting with a focus on the development of 3D feature-based parametric part and assembly models for creation of technical mechanical drawings.  Additional drafting topics include: threads and fasteners, weldments and welding symbols, sheet metal, surface finishes, coatings, platings and tolerancing.

Upon completion of the course students should be able to:

• Develop 3D parametric solid models and assemblies using Mechanical Computer Aided Design (MCAD) software.
• Create industry standard orthographic, section, auxiliary, and assembly model documentation using Mechanical Computer Aided Design (MCAD) software.
• Apply an understanding of tolerancing practices used to develop fits and limits to create technical mechanical drawings and use appropriate standard tolerances on a technical mechanical drawing.  
• Analyze a mechanical design in terms of tolerances, fit, form, function, and mass properties.
• Research products on the internet and incorporate them to create technical mechanical drawings.
• Apply appropriate finishes, coatings, or symbols to mechanical drawings.  

Individual and classroom discussions, completed assignments, attendance and classroom participation.  This course will be presented by means of lecture presentations and coordinated laboratory exercises. Lectures are supplemented with selected reading assignments. Individualized instruction will be provided while the student is working on lab projects. This course utilizes and applies Mechanical CAD modeling and drafting techniques learned in previous courses. The majority of assignments will be completed using computer aided design software.   

The following should be assessed:

• Three dimensional CAD modeling of a basic mechanical assembly drawing given piece part dimensions.  Drawings for the detail parts and assembly drawing must meet industry standard (ISO/ANSI/ASME) standards.  

• Create section and auxiliary views from 3D modeled parts that meet (ISO/ANSI/ASME) standards. 

• Given a mechanical assembly design with tolerances errors, calculate the correct tolerances and modify the design to meet fit, form and function requirements.  

• Given a library of off the shelf hardware (including fasteners), select and complete a mechanical design assembly. 

• Given a mechanical part design and its application, specify and appropriate part finish.

• Given a weldment assembly design, create an assembly drawing and apply appropriate welding symbols.  

At least two of the following additional measures must also be used

• Take-home examinations

• Graded homework

• Quizzes

• Projects

• In-class activities

• Portfolios

1.0 THREE DIMENSIONAL MODELING FOR DEVELOPING TECHNICAL DESIGN PACKAGES

1.  Prepare part, assembly, and presentation drawings using mechanical CAD software with a focus on productivity and good design practice.

2. Work in the 3D Cartesian coordinate system.

3. Choose the appropriate modeling techniques for a given problem based on good design practice.

4. Perform design changes.  Modify a part design or assembly to meet new design criteria.  Make updates of 2D drawings and models.  

2.0  TOLERANCING AND MECHANICAL DESIGN

1. Calculate and document appropriate design tolerances using ANSI standards as well as non-standard techniques.

2. Perform a tolerance stackup on a group of at least three or more manufactured parts as an assembly.  Calculate the overall tolerance stack.  Use root sum square method.  

3. Perform an industry standard tolerance analysis on a series of mechanical parts to determine if the fit and functional characteristics will be met.  

3.0  ADDITIONAL TOPICS

1. Determine type & size and specify fasteners (nuts/bolts/rivets/screws/pins) on a drawing.

2. Work with weldment and sheet metal fabrication drawings that meet industry standards.

3. Determine surface finishes and coatings used on manufactured parts using industry standard practices.