Task 1 Memo Report PDF

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Task 1 Memo Report...

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Team 1

James B. Francis College of Engineering One University Ave Lowell, MA 01854

Mechanical Engineering Students

MECHANICAL ENGINEERING

To: From: Date: Re:

Dr. Jennifer Gorczyca Dylan Forte, James McAuliffe, Daniel Stein 24 February 2018 Task 1

Introduction The objective of this report was to design a three-position four-bar linkage for moving a line on a Bilge Plate through three extreme positions using SOLIDWORKS. The design required each pair of spot welds to pass through the stationary wielding electrodes in the three extreme positions as the linkage is driven by a constant speed motor. The final design was presented in an animation of the linkage along with engineering sketches of each part in the loading position as well as the two weld positions, including the transmission angles and link lengths. Discussion Table 1: Dimensions Associated with Each Student's ID Number

SIDN ****8211 ****8257 ****5737

S1 (in.) 3.937 3.937 4.528

S2 (in.) 1.378 1.378 1.181

S3 (in.) 2.231 2.362 1.968

θ (deg.) 60 55 55

Each team member was responsible for creating a design that was unique to their UMass Lowell student ID number. The corresponding dimensions for each digit could be found in Table 1 of the Project Overview booklet. As portrayed in Appendix A, S1 is the distance between points B and D, S2 is the distance between the bottom of the part and the lower stationary electrode, and S3 is the horizontal distance from point B to G. Additionally, θ represents the angle between line BD and line CD. Table 2: Transmission Angles Relating to Each Design

SIDN ****8211 ****8257 ****5737

Welding Position 1 Angle 1 Angle 2 (deg.) (deg.) 34.0 27.7 42.9 32.7 36.2 25.9

Loading Position Angle 1 Angle 2 (deg.) (deg.) 83.2 89.5 77.5 87.7 59.7 70.1

Welding Position 2 Angle 1 Angle 2 (deg.) (deg.) 26.7 20.6 44.7 14.1 58.0 16.5

Once each design was modeled in SOLIDWORKS, rotation of the Dyad Crank allowed the Bilge Plate to align with the three specified locations. At each position of the four-bar linkage, two transmission angles could be determined to help judge the quality of the linkage. These angles were measured relative to the output link and the coupler. More specifically, Angle 1 is the acute angle between Rocker 1 and the Bilge Plate, and Angle 2 is the acute angle between Rocker 2 and the Bilge Plate. The angles of the chosen design are represented in Appendix A. The transmission angles are the greatest in the loading position. Table 3: Decision Matrix to Determine Preferred Design

SIDN ****8211 ****8257 ****5737

Functionality 9 9 9

Weight 4 7 5

Deciding Factors Toggle Time 8 5 3 4 7 7

Creativity 3 7 5

Total 29 30 33

The team agreed on five separate factors to be considered to determine the final design: functionality, weight, toggle, time, and creativity. Each design was rated on a scale of zero to nine to the corresponding factors, where zero was the worst and nine was the best. Design 5737 was calculated to be the best design for this project. Functionality was the most important since a misalignment between the stationary electrodes and the spot welds at all three extreme positions would mean the linkage would not meet the requirements of the task, which would defeat the purpose of the entire design. Weight was a factor because the weight of the Bilge Plate could affect the position of the spot welds relative to the electrodes. If the Bilge Plate is top heavy, gravity would ultimately push it down when extended above the Base Plate. The Bilge Plate will then no longer be parallel to the base plate, causing the electrodes to no longer align with the spot welds at each extreme position. If the design encounters a toggle, then two moving links would be collinear, allowing the possibility of them to lock in place. The amount of time to manufacture the finished prototype between laser cutting and assembling is critical, as the proceeding steps for the project have deadlines based on the build time. Finally, creativity demonstrates how much thought went into the entire design process. Conclusion The team’s final four-bar linkage design successfully met the requirements for the assigned task, as each pair of spot welds aligned with the stationary electrodes in each extreme position. The transmission angles attribute to the functionality of the linkage because they allow the crank to make a complete rotation without toggle. The optimal design was chosen through means of a decision matrix created by the team.

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