Engineering Design and Graphics 1C03 McMaster Engineering 1 Cornerstone Project

Instructor: Dr.McDonald

Part 1 – Mechanical Design Research Report

Group 9

As a future member of the engineering profession, the student is responsible for performing the required work in an honest manner, without plagiarism and cheating. Submitting this work with my name and student number is a statement and understanding that this work is my own and adheres to the Academic Integrity Policy of McMaster University and the Code of Conduct of the Professional Engineers of Ontario. Submitted by [Keyur Patel] ____________

As a future member of the engineering profession, the student is responsible for performing the required work in an honest manner, without plagiarism and cheating. Submitting this work with my name and student number is a statement and understanding that this work is my own and adheres to the Academic Integrity Policy of McMaster University and the Code of Conduct of the Professional Engineers of Ontario. Submitted by [Griffin Dow] ____________

As a future member of the engineering profession, the student is responsible for performing the required work in an honest manner, without plagiarism and cheating. Submitting this work with my name and student number is a statement and understanding that this work is my own and adheres to the Academic Integrity Policy of McMaster University and the Code of Conduct of the Professional Engineers of Ontario. Submitted by [Abiran Raveenthiran] ____________

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Table Of Contents

Cover Page 1

Table of Contents 2

Introduction 3

Description 3

Calculations 3

Simplified Gear Train 4

Gear Information Chart 4

Team Contributions & Attendance 4

GANTT Chart 5

MapleSim 3D Model 6

MapleSim Plot Graphs 6

MapleSim 2D Model 7

Inventor Models 8

Index Of Drawings 9

Drawings 9

Citations 10

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Group nine consists three members; Keyur Patel, Griffin Dow and Abiran Raveenthiran. We have been hired by XYZ Mechanisms to modify the design of their company product. In order to approve our design the CEO will validate our design functionality through models and calculations. Our model will include a full simulation and a completed prototype. This all will be presented in a technical report, which includes a complete set of engineering drawings.

The company product that Group nine will modify is a mechanism, which is used to control the read-head of a CD-ROM drive. Group nine was provided with an alternate motor with different drive characteristics. Group nine’s input speed is 85500 RPM (1425 rev/sec). Using these different characteristics, group nine has designed a gear train that achieves the original read-head speed as the older design of the company product. The group has also been assigned to design a frame for mounting and containing the components for our gear train.

Description on How Mechanism Works

The motor runs at a constant pulsating speed of 85500 RPM. Our mechanism consists of a gear train which slows down the input RPM to 6000 RPM. The 6000-RPM then leads to a worm with a rack that achieves the linear speed of 0.2121 m/s, which meets the client’s specifications. The rack on the worm gear is attached to a read-head and the pulsating motor speed is what enables the read-head to read CD ROMs.

Calculations

We approached this problem by determining our overall gear ratio. A module of 1.5 was predetermined by the group and only changed the module for one set of gears. We then determined how much space we had to work with and used those dimensional constraints and the gear ratio to determine the number of teeth. The next step in our process was to determine an extremely large multiple of our gear ratio so that we could break it down into multiples, which would represent the number of teeth for the gears in our train. We limited the multiples to be between the range of 12 and 36. The multiples that were used are posted below.

Input Speed: 9*9500 rpm = 85500 rpm

Output Speed: 100*60 rpm = 6000 rpm

Gear Ratio = wi/wf = 85500/6000 = 14.25

14.25/1 = 228000/16000 = (30*19*20*20) / (10*10*10*16)

14.25/1 = (30/10) * (19/16) * (20/10) * (20/10)

We went about calculating the gears by their number of teeth. By doing this we ensured that there was an even amount of teeth. If we approached it by the diameter then we could have had half teeth, which would not work. The first set of gears have 30 and ten teeth, they are then axially connected to another set of gears that have 19 and 16 teeth. That set of gears is then also axially connected to a set of gears with 20 and 10 teeth that are axially connected to another set of gears that have 20 and 10 teeth. A last set of two gears which both had 18 teeth so the train end in the correct position.

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Gear train diagram

Team contributions and attendance

For the first milestone the team met every Monday and Thursday and the team worked together to solve the gear ratios, create them on Autodesk and put them into Maplesim. All members made all the meetings on time and ready to work. The tasks were not exactly specified for any one person to do instead, we worked as a team to accomplish everything that was required to do. Once we finished the first milestone we immediately started worked on the final project.

For the final project the meetings were still held every Monday and Thursday and everyone meet on time and contributed the whole time. Keyur Patel went to all five prints and printed all the files in Epic Lab. Keyur also worked with Abiran Raveenthiran to create the final gear train. Abiran created the final assembly of the gear train on Autodesk Inventor 2011. Griffin Dow created the final Maplesim file to demonstrate how the gears work. Griffin also created the frame on Autodesk for the gear train. The whole team got together to assemble the frame and gears. Keyur and Abiran focused on the gears while Griffin concentrated on putting together the frame.

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Gear Name Pitch Diameter (mm) Module (mm) Number of TeethA 12 1.2 10B 36 1.2 30C 24 1.5 16D 28.5 1.5 19E 15 1.5 10F 30 1.5 20G 15 1.5 10H 30 1.5 20I 18 1 18J 18 1 18

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Gantt chart for group nine

Maplesim

3-D Model

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2-D Model

Inventor Screenshots

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Index of Drawings

A-Top View B-Front View C-Right View D-Isometric View

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IEEE Citations

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A C

B

D

[1] Sham Tickoo, Autodesk Inventor 2011 for Designers, Revised and Updated ed. , 525 St Andrews Drive, Schererville, IN 46375 USA: CADCIM Technologies, 2010.

[2] John A., Burek. "How It Works: CD-ROM Optical Drive”, (Computer Shopper), [online], http://www.computershopper.com/feature/how-it-works-cd-rom-optical-drive (Accessed: 3 November 2013).

[3] Keith, Evans. "How Does a CD-ROM Work?", (eHow), [online], http://www.ehow.com/how-does_4572421_a-cdrom-work.html (Accessed: 3 November 2013).

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