Assembly/Gate 4

Revision as of 17:19, 29 November 2012

Purpose

After finishing up most of the analysis of the gun in the last gate, the team moved onto gate 4. In this gate, the main task that was worked on was reassembling the actual product. Also important was analyzing the mechanisms involved with the Nerf gun, as well recommending three design revisions that would help to improve the product as a whole. All of the information was placed neatly onto the group’s wiki page.

Project Management: Critical Project Review

In looking back at the project, the group for the most part has run very smoothly and without any major hiccups. The group has continued to meet once a week for the semester and we have met twice a week before the submissions. In following this plan, we have given ourselves enough time to finish everything, and also make sure everything is neat and orderly in the wiki. We have continued to meet in Greiner Hall and this has proven to be a good location for all of us.

Everyone in the group contributes to the project, and so luckily we have not had to deal with any “lacking” members. We have all learned a lot doing this project, and we have all contributed in different ways. For example, Andy has gotten really skilled at working with the wiki while Ray successfully completed the solid modeling that was part of gate 3. Also important to us is that our grade for the last gate went up from the first gate, so we know that we are improving our work. This is important to us, as we all want to do well on this project.

One of the major challenges we faced was reassembling the gun. The gun had many components and many small screws. In order to overcome this challenge, we had to all work together and go slow through the process. We used a lot of our notes from gate 2 and slowly reconstructed the gun back to its original state. This part took us a couple hours of hard work to do, but in the end, we accomplished this goal.

Other challenges we faced as a group included really understanding how to work the wiki, and having to do the presentation for our project suddenly. The first challenge has been something we as a group have been working on all semester. The skill level for each of us has improved dramatically, but it is still something that we could improve. Each gate, we have gotten better and better at formatting within the wiki. The presentation was not very difficult, but it did require some special attention. However, we feel that it ended up being very good. Overall, we have been pretty successful at overcoming any challenges that have been raised during this project.

Assembly

Max, do your stuff here. Click on the edit right above this

• Mechanisms
• Gear Train w/ worm Drive
  • One mechanism that our device uses which alters specific motion and power is the gear train with worm drive. The gear trains main purpose is to decrease the output speed, while at the same time increase the output torque. As the motor spins, the worm gears are spun by the motor which enable the teeth of the worm gear to be feed into a system of gears, which share multiple axis. The varying sizes and number of the teeth adjust the speed and torque accordingly.
• Equations
  • W f = f.W t / (. cos φ n ) Frictional Force
  • T G = W t .d 1 / 2000 Torque Generated
  • σ a = W t / ( p n. b a. y ) Equation for stress induced in worm gear teeth
• Trigger Mechanism
  • Another mechanism that our device uses is a trigger mechanism. This mechanism generates specific control behaviors for the interactions of other mechanisms that lie withing the trigger subsystem. The trigger mechanism acts as a main support for other mechanisms within the trigger system. This mechanism helps translate forces and energies to different mechanism within the trigger system.
• Equations
  • S= (-t^2/2pi*a)*ln(pi(Tx -Tm)/4(Tc -Tm))
    • t= thickness of molding
    • a= thermal diffusivity of material
    • Tx= ejection temperature of molding
    • Tm= mold temperature
    • Tc= cylinder temperature
  • Ke = (1/2)mv2
  • E = Fd