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Revision as of 23:06, 23 September 2007

Executive Summary

Customer Needs

Most paintball players use their guns in tournament play at parks designed specifically for this purpose. On occasion, teams may play in uncharted forests or abandoned buildings to provide a new thrill and lower playing costs. The object of most games is to successfully shoot a paintball (the projectile) at an opposing team’s player to mark them with the paint inside the projectile. Speeds can reach up to 300 feet per second, over which the sport or play can become unsafe. Certain arenas measure and limit the users’ guns to a lower value. The first and foremost requirement is reliability and durability from a gun. There is nothing more frustrating than a gun malfunction in the middle of a game, when the user travels a significant distance to play. This quality can easily be found due to the strong correlation between price and durability. Having a good line of sight is paramount for aiming. Certain hopper and feeder designs go straight up from the gun housing, making it difficult to look at one’s target. For this reason, most designs incorporate an elbow feeder to offset the hopper towards the user. Barrel lengths will vary from 3 to 48 inches, and are usually interchangeable for a given gun. However studies have shown that no increased accuracy can be gained from a barrel longer than 8 inches. Lightness is a requirement for all levels of play, but again it is merely a question of price. Certain parts can be high strength plastics, sometimes even carbon, which would otherwise be of common metal alloys. The compressed air tank is perhaps one of the heaviest single parts on the marker. Carbon fiber is a popular alternative material for a tank, which may need to stand up to pressures of 5 ksi. More advanced users want quick adjustability of their projectile speeds. Bottom end markers require some tooling to change this setting, but more advanced markers, or aftermarket parts allow for on-the-fly adjustability even in the field. Typical low end markers use compressed CO2 (carbon dioxide), but this may cause inconsistent muzzle velocities. Advanced users will sometimes switched to compressed nitrogen, which eliminates this problem.

How System Functions

The paintball gun (or paintball marker) fires a 0.68 inch diameter paintball at speeds of around 280 fps using compressed air in a semi-automatic firing style. This means that after cocking the marker once, when you pull the trigger it will fire a paintball and also recock the marker for you. This allows the user to rapidly fire paintballs.

Before you can fire the gun, the bolt must be in the cocked position. This is accomplished by pulling the cocking pin back until you hear a click. This is only done once at the beginning of use. When the bolt is pulled back, the Venturi Bolt slides back in the marker barrel (shown in red) which allows a paintball to fall through the feed neck and into the marker barrel. The cocking pin is also connected to the striker bolt, which slides back in the striker chamber (shown in yellow) engaging the trigger mechanism (the trigger mechanism will be described separately in the next section). When the striker bolt engages the trigger mechanism, it is locked in the back position. This causes the striker spring to apply a force to the back of the striker bolt.

In this cocked position, the air reservoir (shown in blue) is filled with compressed air. This chamber is sealed off from the rest of the gun by the cup seal and valve pin assembly. This assembly is being pressed against the valve body (shown in green) by the valve spring. The valve body has three holes, one into the the air reservoir, another into the striker chamber, and a final leading up into the marker barrel. The valve pin extends through the valve body and into the striker chamber.

When the trigger is pulled, the striker spring pushes the striker bolt forward. The striker bolt strikes the valve pin, which opens the seal the valve pin and cap seal were creating with the valve body. Since the striker bolt and venturi bolt are connected, the venturi bolt also moves forward. Before the venturi bolt reaches the front position, it comes in contact with the paintball and pushes the paintball forward toward the barrel. Since the seal in the air reservior was opened, compressed air flows through the valve body into the striker chamber and the marker barrel. The compressed air that flows into the marker barrel accelerates the paintball out of the barrel, firing the paintball marker. The air entering the striker chamber forces the striker bolt back into the cocked position. At this point the valve spring pushes the cap seal and valve pin back against the valve body, sealing the air resevior again. With everything returned to the cocked position, another paintball falls into the marker barrel and the gun is ready to be fired again. The whole process from trigger pull until the gun cocks itself again occurs in less than a second.

Full gun view showing different interior chambers and components of the paintball marker

Trigger Mechanism Function

Components

Part #	Part Name	Qty	Function	Weight (Ounces)	Material	Manufacturing Process	Photo
01	Hopper Connection	1	Connect hopper and feed neck	0.7	Plastic	Injection Molded, finish machiend
02	Hopper Connection Bolt and Nut	2	Apply pressure to plastic hopper connection housing	0.4	Steel	Heading and Thread Rolling
03	Stock	1	Helps stabilize gun against shoulder for improved accuracy	8.7	Aluminum	Cast
04	Barrel	1	Direct paintball exit out of marker	4.7	Aluminum	Cast and finish machined
05	Feed Neck	1	Direct paintballs from hopper into firing chamber	0.6	Aluminum	Cast and finish machined
06	Feed Neck Screw	3	Attach Feed Neck to marker body	0.1	Steel	Heading and Thread Rolling
07	MR1 2" Dovetail Drop Forward	1	Bracket to secure compressed air connection port to trigger handle	1.2	Steel	Cast or Forged
08	Drop Forward Lock Screw	1	Secures Dovetail Bottom-Line to Dovetail Drop Forward	<0.1	Steel	Forging and Thread Rolling
09	MR1 Dovetail Bottom-Line	1	Connection point between compressed air and hose to marker body	3.2	Aluminum	Cast and finish machined
10	Hose Adaptor	1	Connect hose to Dovetail Bottom-Line	0.4	Steel	Forged and Threads rolled
11	MR1 Foregrip	1	Provides cover for hose connection to marker body.	4.9	Aluminum	Extruded or Cast and finish machined
12	Foregrip Fixing Screw w/washer	2	Connect foregrip to marker body	0.4	Steel	Heading and Thread Rolling
13	Braided Hose	1	Connects Dovetail Bottom-Line to marker body	1.8	Steel	Connections Headed and Threads Rolled, hose housing woven from metal sheet
14	Screw and Washer	2	Connects trigger handle to marker body	0.1	Steel	Heading and Thread Rolling
15	Handle Covers	2	Provides comfortable grip for handle	0.8	Aluminum	Cast and finish machined
16	Screw	4	Connects handle cover to handle	0.1	Steel	Heading and Thread Rolling
17	Handle Trigger Assembly	1	Allows user to control firing of paintball. Double trigger controls release of bolt, firing paintball	9.4	Steel	Cast, Finish machined, finish ground, press fitting
18	MR1 Reservoir Plug	1	Seals compressed air resevoir and includes attachment point for valve spring	0.8	Aluminum	CNC Turned
19	M5x12 Screw	1	Attaches Reservoir Plug to marker body	0.1	Steel	Heading and Thread Rolling
20	Valve Spring	1	Provides pressure against cup seal to press valve pin into valve body	0.1	5160 Steel	Coiled
21	Cup Seal and Valve Pin Assembly	1	Seals hole in valve body so air does not leak out of air reservoir	0.2	Aluminum and Plastic (Nylon)	Finish machined and ground, Injection molded
22	Valve Body	1	Routes air to Striker chamber and also to MR1 Venturi Bolt.	0.2	Aluminum	Turned and Drilled
23	MR1 Venturi Bolt	1	Directs air from valve body to paintball. Also stops additional paintballs from entering chamber when firing.	<0.1	Steel	Ground and Turned
24	Cup Seal Guide	1	Centers Cup Seal and Valve Pin Assembly in air reservoir	0.1	Aluminum	Stamped
25	Striker Spring	1	Applies force to Striker Bolt, accelerating it into the valve pin	0.1	5160 Steel	Coiled
26	Striker Plug	1	Seals Striker chamber. Also includes a spring guide for the Striker Spring	0.8	Aluminum	Turned and ground
27	Striker Buffer	1	Helps protect Striker Plug and Striker bolt from damage during use from impact	<0.1	Aluminum	Turned
28	Striker Bolt	1	Strikes Valve Pin, releasing air from air reservoir, through valve body and MR1 Venturi bolt. Striker Bolt releases when trigger is pulled.	2.4	Hardened Steel	Turned
29	Quck Disconnect Pin	1	Secures Striker Plug to marker body	0.3	Steel	Cast
30	MR1 Venturi Bolt	1	Directs air from valve body to paintball. Also stops additional paintballs from entering chamber when firing.	1.6	a;lsdkjf	;laskjdf
31	MR1 Pull Pin Cocking Knob	1	Connects Venturi Bolt to Striker Bolt. When Striker bolt is forced back into the cocked position by the compressed air, this pin pulls the Venturi Bolt back into the cocked position also.	0.4	a;lsdkjf	;laskjdf
32	Marker Body	1	Houses main components of paintball gun including, venturi bolt, striker, and valve assemblies. The barrel, trigger assembly, and stock also attach to the body	14	a;lsdkjf	;laskjdf
33	Misc. O-rings	1	O-rings help seal all the different chambers so compressed air does not leak out. This increases the efficiency of the paintball marker	<0.1	a;lsdkjf	;laskjdf

**Note: Some assemblies and parts were not disassembled in order to avoid destroying the parts.

DFMA

FMEA

DFE

Opportunities for Improvement

How Product is Used

Markers must be stored in an ‘un-cocked’ position, with the safety switch in the ON position, no compressed air connected to the system, and with the barrel safety plug pressed into the end of the barrel. Most manufacturers require that moving parts be lubricated with the provided or recommended lubricants before each use. Caring users will disassemble several parts of their guns internals, to go through the lubricating steps. This will ensure longevity of the marker. Next, the user will check to have proper pressure in their gas canister, and an abundance of ammunition for the upcoming usage session. When users arrive to the arena, or playing area, overalls or certain special outer wear is put on by the users to attenuate the impact of the projectiles. A mask is the most important piece of protective equipment, guarding the eyes, face and sometimes ears from impact. Welt and ‘black and blue’ spots are common marks caused by being hit with a projectile. Most right handed users will hold the handle with their right hand, use their middle and/or index fingers to operate the trigger, and look down the length of the barrel with their right eye, with the left eye closed. While operating the markers, and trying to mark opponents without being marked themselves, users may perform intense physical activity such as running, jumping, diving and crawling. Some of this may include dirt, when done in an open forest-like area. This aspect of the product usage requires the most out of the marker. The marker must be durable enough to not get damaged, while having a constant supply of air and paintballs to fire in any orientation.

Mechanical Analysis