Engineering Projects/Rubberband gun/Howard Community College/spring2012/p1501jds

Problem Statement

To create a Rubberband Gun that is powerful and accurate and doesn't expend all our resources.

Team Members

Summary

Everyone in the group had a chance to design a rubber band gun and we took the best ideas from all. We concluded that the double barrel design was best as stated in matrix. Then we started designing all the parts on 123D Auto desk. Once completed we could order the exact amount of wood/materials needed to build our project since we had a design to build off of. Everyone took home wood to create a part and we brought it back into school to assemble.

Poster

this is a link to the design that we came up with design graphic of gun

Story

There was many obstacles not forseen when we took this project. We were not very familiar with 123D autodesk which was used to create our design. Also at first we wanted to build a single barrel gun but found out that it would be unstable and by using a matrix we all voted on different catigories to deside what the best design would be an dwe desided on the double barrle mostly because it would be the most stable. we tested how long the rubber bands would stretch and the best rubber bands we could find could only stretch 18" so that is why our barrel is 18" long so it is of optimun power without rubber bands breaking. In the end we failed at buiding the complete gun and only got 1 barrel done. But in turn we learn more about 123d, engineering process, and will be much more prepared for the next project.

Decision List

LOW IS GOOD

Options	Costs	Total Cost	Time	Total Time	Simplicity	Total Simplicity	Aimability(aim)	Total Aimability	Stability	Total Stability	Overall Total
Single Barrel	1,1,2	4	2,3,2	14	2,2,1	5	1,1,2	20	4,5,4	130	163
Double Barrel	4,2,3	9	3,3,3	18	2,2,3	7	2,2,2	30	1,1,1	30	94
Triple Barrel	5,5,5	15	5,4,5	28	5,5,5	15	5,4,5	70	3,4,3	100	228
	x1		x2		x1		x5		x10

We made the obvious decision of making the Double Barrel Rubber Band Gun. in addtion to that we made desition to use softwear 123d and create design also decided to make barrel 20 in because of how far rubber bands can stretch

Material List

1. List materials used, quantity, size, cost.

24' 1/4" Dowel Rod ($.72 per 4')
16' 2"x3" ($1.89 per 8')
8" Wood Circle (4)($6 each)
Variety of Screws (Taken from workshop)

2. Describe what needs to be purchased in the future to continue working on this project.

24' 1/4" Dowel Rod
2 Cheap Drills
Metal Rod (in shop)
LONG Rubberbands

Software List

1 2 3d by Autodesk

Google Docs

Time

45 hours and 10 minutes

Tutorials

1. We cut 8 inch circles, made out of 1 inch thick wood.

2. Then we made notches in it to put the dowel rods in.

3. We put the dowel rods in notches.

4. We made the tripod to hold the gun.

That is as far as we got, spent most of the time waiting for materials and making the graphic(1 2 3d kept crashing).

Next Steps

The next group that will do this project will need to finish drilling the holes in the turning circles, then they will need to find rubberbands that will stretch 18 inches. The curent problems are setting up the trigger mechanism and gears, then they will have to figure out how to make the gun turn since we did not get that part set up. then they will need to make sure that it is firing correctly and make the wedge move like it is supposed to. When working on this take any part that what you are working on home so you can work on that to.