Chapter 20 Notes Engineering Products
A. Specifying Designs - So we know what parts are needed - So we know how things fit in relation to each other - To determine materials are needed - Product Engineers specify this information about product characteristics in 3 ways: a. Engineering Drawings b. Bill of Materials c. Specification Sheets 1. Engineering Drawings a. Consist of three types 1. Detail drawings 2. Assembly drawings 3. System Drawings b. These drawings specify how to make/build the product 1. They are drawings of individual parts, and the completed product c. Detailed Drawings 1. Give the exact size and shape of the part(s) as well as the location of the products features a. The features include all curves, notches, tapers, & holes b. They are labled, dimensioned, and have annotations about how the part is made 2. They show the parts form several sides using various projections, a. Orthographic Projections Top, Front, Right, Primary Views Left, Bottom, Back Secondary Views b. Note: The front of the object is always indicated by the side with the most detailed features. c. You can present the drawing in 2 - 3 views d. How to show parts 1. Round Parts - Shown in an End or Side View 2. Square Parts - Shown in the 3 Orthographic Views T, F, R e. Each view is seen in 2 Dimensions 1. Height and Width 2. The views that are necessary are determined by how much information is required to fully define the part.
3. Detail drawings give as much information about the product as possible so that the product can be manufactured 4. Without good drawings, parts cannot be reproduced d. Assembly Drawings 1. Are used to show how products are assembled 2. The parts are coded then placed where they are supposed to go in the product when fully assembled 3. They can be 2 dimensional or 3 dimensional 4. The Assembly drawing can be produced as pictorial drawing that represent the illusion of 3D Example Hand Drill
Notice the Design is exploded
a. Isometric, Dimetric, & Trimetric b. In this method the drawing has width, depth & height refereced 5. Often the drawing is presented as an exploded view in which the parts are separated from the product in the order that they go in which to buildthe product 6. They Must Communicate what is going on and how the product is assembled a. They give information on how the product is put together b. It does the following 1. Identifies the parts by number or name 2. Shows part locations c. System Drawings 1. Used to show how electrical, pneumatic, & hydraulic systems operate. a. How they are assembled 2. They show the locations of the parts in the system and how they are connected 3. This system is also called a Schematic a. Giving the information needed for assembly and service of the system 4. Workers can easily see the components, & how they fit in the system. 5. The dimensions are not always present. a. The run of pipe or the diameter of the pipe may be given
2. Bill of Materials a. This tool is designed to identify the materials that are needed to build the product b. Usually located near the end of the plans, it is one of the most important parts in plans c. By using this tool, you know what is needed, how much is needed, and the cost of the completed product d. The Bill of Materials consists of the following: 1. Part Number Example 2. Part Name 3. Quantity of each part needed 4. Size (Dimensions) 5. Material to be used Size Prt# Prt Name Material Qty T W L
e. Sizes are given logical order Thickness, Width, Length 3. Specification Sheets a. Used when certain items or qualities cannot be shown on a drawing (Sheet of Steel ) How would you show that in a drawing? b. Specification sheets are then used c. These sheets share important characteristics for the material, Not the Size or Shape d. They can describe the size or shape but usually don't, they only list the attributes of the material e. They are used for: 1. Identify the characteristics of Glues, Finishes, Metals (Sheets) just to name a few 2. Identification of the Strength, Hardness, Weather Resistance and many other aspects of the materials f. This information is presented in Technical Data Sheets 1. From these sheets the design Engineer will pick which one to use and it will be applied in the production of the product g. Smaller manufacturers cannot afford to have materials developed for them. 1. The manufacturer will call a distributer with the specifications 2. The Distributor will send a Technical Data Sheet for the material a. The Technical Data Sheets describe the properties of the material, and how to use it, and apply it,
