Nerf gun

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	== Preliminary Analysis ==		== Preliminary Analysis ==
		+	=== Stakeholders ===
		+	Some of the main stakeholders in nerf guns are the '''children''' who play with them, the '''parents''' who buy them and supervise their use, and the '''retailers''' that stock them.
		+
		+	'''Children:''' The children in this case are the end users, the one who actually use the product. They are also the ones who probably nag their parents into buying them, so it's both important that the guns appeal to them before they are bought, and they are enjoyable. In particular, children will enjoy a gun if it is "fun" to play with (generally involves power, ease of use, & physical appeal)
		+
		+	'''Parents:''' Even though the children play with the toy, the parents have a large stake in it as well. If the gun ever doesn't work, the parent will of course have to deal with returning the gun, or buying a replacement (or replacement ammo). Also, if a child is ever injured while playing with the toy, the parent has to help heal the injured child, and probably reprimand another child. Parents will like most the gun that is safe to use (very little chance of injury) and reliable (no need for extra trips to the toy store).
		+
		+	'''Retailer:''' The retailer has the smallest stake in terms of day to day use, but their profit off the item is what determines if it stays available to purchase. The retailer will only like items that are popular (sell quickly, attract attention), have no customer support issues (no returns), and are easy to keep in shop (not breakable, easily storeable).
		+
	=== DFMA ===		=== DFMA ===

---

Revision as of 00:10, 15 September 2009

Contents 1 Executive Summary 2 Product Study 2.1 Functionality 2.1.1 Big Bad Bow 2.1.2 Rapid Fire 20 2.1.3 Buzz Saw 2.2 User Study 2.2.1 Big Bad Bow 2.2.2 Rapid Fire 20 2.2.3 Buzz Saw 2.3 Performance Studies 2.3.1 Distance Study 2.3.2 Accuracy Study 2.4 Product Dissection 2.4.1 Mechanical Function 2.4.2 Bill of Materials 3 Preliminary Analysis 3.1 Stakeholders 3.2 DFMA 3.3 FMEA 3.4 DFE

Executive Summary

Product Study

Functionality

Big Bad Bow

Rapid Fire 20

Buzz Saw

User Study

Big Bad Bow

User responses:

- Sight was useful for lateral accuracy, not for vertical positioning
- Large learning curve for an accurate shot
- Not good compared to other nerf weapons
- Ammo breaks easily
- Shooting mechanism is complicated, many misfires trying to get ready

Rapid Fire 20

User responses:

- Takes forever to pump and load
- Good for crowds
- Is the most fun: most people would want to buy this gun after playing with all three

Buzz Saw

User responses:

- Very accurate
- Jammed frequently, and the top ball often did not fall into the shooting mechanism from the loading station
- Makes an annoying sound
- Makes an awesome sound
- Is difficult or impossible to shoot at an upwards angle
- Difficult to remember to stop pumping before firing

Performance Studies

Whenever somebody picks up a nerf gun, two of the things they are most concerned about are how far the gun can shoot, and how accurate the gun is to fire. To measure both of these capabilities, we set up two tests.

Distance Study

Set Up: Guns were fired indoors from a horizontal orientation from 33.5" above the ground, and the position where the ammo first hit the ground was measured. The gun was held very steady when being shot so that no extra forward momentum was imparted on the projectile. Tests were performed indoors, so there was no wind or other distractions.

Big Bad Bow: 19.0, 19.2, 18.10, 18.10, 17.10, 17.2, 19.0, 19.1, & 18.7 (Average 18' 7")

Rapid Fire 20: 18' - 22' Spread

Buzz Saw: 26.10, 29.4, 29.5, 30.1, 32.2, 32.9, 29.3, 30.4, & 31.4 (Average 30' 2")

Pictures

Accuracy Study

Set Up: 3 people without previous nerf gun experience were selected at random to participate in the study. Each person was instructed to stand 17' away from a target and fire with each separate nerf gun at the target. Pictures were taken in order to discern their accuracy. Then one of our group members, after practicing with all three guns, did the same accuracy test and the results were recorded as well. By testing both groups, we will be able to figure out how easy each gun is to aim for a beginner, and for somebody with more experience.

Results!!!

Product Dissection

Mechanical Function

Bill of Materials

Big Bad Bow

Part No.	Name	Function	Quantity	Material	Mass	Manufacturing Process	Picture
101	Bow Arm and Outer Cog	Cosmetic	2	Plastic	56g	Injection Molded
102	Small Inner Cog	Cosmetic	2	Plastic	5g	Injection Molded
201	Front Left Cover	Priming Mechanism Housing	1	Plastic	117g	Injection Molded
202	Front Right Cover	Priming Mechanism Housing	1	Plastic	118g	Injection Molded
203	Rear Right Cover	Barrel/Action Housing	1	Plastic	123g	Injection Molded
204	Front Left Cover	Barrel/Action Housing	1	Plastic	119g	Injection Molded
301	Nozzle	Air Delivery/Dart Delivery	1	Plastic	17g	Injection Molded
302	Nozzle Tip	Air Restriction/FOD Protection	1	Plastic	<1g	Injection Molded
303	White Tip Holder	Holds Nozzle Tip	1	Plastic	3g	Injection Molded
304	White Air Restrictor + Spring	Air Restriction	1	Plastic/Steel	3g	Injection Molded
305	Rubber Piston	Air Delivery	1	Latex Rubber	5g	Injection Molded
306	Barrel Lock	Action Lock	2	Plastic	2g	Injection Molded
307	Piston Shaft	Air Delivery	1	Plastic	26g	Injection Molded
308	Trigger Lock	Action Release	1	Plastic	2g	Injection Molded
309	Trigger	Action Release	1	Plastic	8g	Injection Molded
310	Spring Stop	Piston-Cylinder Spring Compression	1	Plastic	1g	Injection Molded
311	Cylinder	Air Delivery	1	Plastic	26g	Injection Molded
401	Eyepiece	Cosmetic	1	Plastic	4g	Injection Molded
402	Eyepiece Lens	Cosmetic/Aiming	1	Acrylic	<1g	Die Cut
501	Arrow Dart	Ammo	3	Styrofoam	5g	Molded/Glued
901	Screw	Fastener	18	Steel	0.5g	Forged/Machined
902	Spring for Barrel Lock	Action Spring	2	Steel	<.5g	Rolled/Bent
903	Short Trigger Spring	Release Mechanism	1	Steel	<1g	Rolled/Bent
904	Long Trigger Spring	Release Mechanism	1	Steel	<1g	Rolled/Bent
905	Piston Spring	Air Delivery	1	Steel	12g	Rolled/Bent

Preliminary Analysis

Stakeholders

Some of the main stakeholders in nerf guns are the children who play with them, the parents who buy them and supervise their use, and the retailers that stock them.

Children: The children in this case are the end users, the one who actually use the product. They are also the ones who probably nag their parents into buying them, so it's both important that the guns appeal to them before they are bought, and they are enjoyable. In particular, children will enjoy a gun if it is "fun" to play with (generally involves power, ease of use, & physical appeal)

Parents: Even though the children play with the toy, the parents have a large stake in it as well. If the gun ever doesn't work, the parent will of course have to deal with returning the gun, or buying a replacement (or replacement ammo). Also, if a child is ever injured while playing with the toy, the parent has to help heal the injured child, and probably reprimand another child. Parents will like most the gun that is safe to use (very little chance of injury) and reliable (no need for extra trips to the toy store).

Retailer: The retailer has the smallest stake in terms of day to day use, but their profit off the item is what determines if it stays available to purchase. The retailer will only like items that are popular (sell quickly, attract attention), have no customer support issues (no returns), and are easy to keep in shop (not breakable, easily storeable).

DFMA

FMEA

DFE