Group 24 - Tippmann 98 Custom - Gate 3

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Figure 1: Tippmann 98 Custom Paintball Marker

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After taking the Tippmann 98 custom apart, the individual pieces were separated and analyzed in much more depth. Each component was looked at individually which allowed us to determine the materials that were used in the marker, along with the manufacturing processes for each piece. These observations gave a better understanding of how the marker was made and what was involved during the manufacturing.

Cause for Corrective Action

Our group has faced little to no challenges leading up to this point of the project. We have been completing all of our work ahead of schedule which allows us to take our time on the individual parts for the project. It also gives us more time to focus on other classes that we are in.

The one problem that we ran into was our grade on gate 2. We weren’t pleased with what we got because we felt that we put in the work necessary work for a decent grade. We found out that we had the correct information but it wasn’t clear. As a group we discussed way to improve for the next gate. We came to a conclusion that we are going to make sure each question is answered and elaborate on them so the information is clear.

We have been meeting every Monday at 5 o’clock and discussing what will be completed during that week. Meeting in the beginning of the week has worked best for us we are allowed to use our time management skills to complete the assignment by the end of the week. Doing this gives the editors time to look over the work on the weekend and then our wiki manager can post it online for everyone to look at.

As we are approaching thanksgiving we plan to get as much work done before so we won’t have work over the short break or when we get back. In order to achieve this goal we will be starting the next part of the project before the break.

Overall the group has been excelling and hope to continue at this pace. If a problem were to come up in the finishing gates of this project we will stick to our original plan of working it out amongst ourselves. A meeting would be mandatory for all members and we would discuss the problem and steps that need to be taken in order to overcome it. We enjoy the project a lot, so we are going to keep putting in our best effort in order to accomplish our goals.

Component Summary

In Table 1 is a list of all of all of the Tippmann 98 Custom's components, with their part number, function, materials used, manufacturing processes used:

Table 1:Components
Component Number Manufacturer
Part Name Function Material Manufacturing
1 98-33 Long Pin The long pins are designed to align each casing and hold them in place Stainless Steel Drawn and then cut LongPins.jpg
2 98-15 Short Pin The short pin is on the front of the gun and it holds front sight and spring in place Stainless Steel Drawn and then cut ShortPin.JPG
3 98-14 Front Sight The front sight helps the user aim and also acts as a latch in order to hold the elbow feed into place Aluminum Alloy Die Casting FrontSight.jpg
4 98-44 Front Sight Spring Provide resistance for the front sight so it can be pushed down to release the feed elbow Steel Alloy Drawn and then forged FrontSightSpring.jpg
5 FA-18 Ball Latch Hold the paintball in place to prevent from falling out of the barrel Rubber Polymer Injection molding BallLatch.jpg
6 98-43 Elbow Latch Hold the feed elbow into place by latching onto front sight Aluminum Alloy Die Casting ElbowLatch.jpg
7 98-42 Elbow Latch Screws Secure the elbow latch to the feed elbow Stainless Steel Machined then turned ELScrews.jpg
8 98-04 Feed Elbow The feed elbow is a designed to guide the paintball into the barrel Plastic Injection molding and then milled ElbowFeed.jpg
9 98-26 Valve Bolts Secure the power tube to the housing of the marker Stainless Steel Machined and the turned ValveBolts.jpg
10 98-08 Rear Bolt Insert Located inside the rear bolt to provide a guide for the drive pin/drive spring Steel Alloy Metal casting and then drilled RBInsert.jpg
11 98-28P Rear Sight Dovetail Provide a line of sight for the user Plastic Injection Molding RearSight.jpg
12 98-36A Trigger Component Sense human signal to initiate firing process Plastic Injection molding and then drilled TriggerComp.jpg
13 SL2-10 Sear Spring To pull the sear into positon, after firing Steel Alloy Drawn and then coiled SearSpring.jpg
14 SL2-11 Trigger Spring To pull the trigger into positon, after firing and also adds resistance to pulling the trigger Steel Alloy Drawn and the coiled TrigSpring.jpg
15 98-35 Sear The sear prevents the rear bolt from releasing, by holding it in place once the marker is cocked Steel Alloy Die Casting Sear.jpg
16 98-37N Safety To prevent firing by locking the trigger in place Plastic Injection Molding Safety.jpg
17 98-38 Trigger Guard Prevents outside forces acting upon the trigger Plastic Injection Molding TrigGuard.jpg
18 98-05P End Cap Hold the drive pin and spring in place, and prevent over cocking Plastic Injection Molding and then drilled EndCap.jpg
19 CA-15 Drive Spring Guide Pin Guides the drive spring to prevent it from deforming Stainless Steel Drawn and then forged GuidePin.jpg
20 CA-14 Drive Spring Provides force for bolt to move forward upon firing and also adds resistance when cocking the marker Steel Alloy Drawn and then coiled DriveSpring.jpg
21 98-11 Rear Bolt The rear bolt is the driving force for the shooting of the marker and it also provides a place for the sear to catch when cocked Steel Alloy Metal casting and then drilled RearBolt.jpg
22 98-57 Buffer O-Ring Absorb force of rear bolt when marker cocks back Rubber Polymer Injection Molding ORing.jpg
23 98-13 Bolt Handle Located inside the rear bolt to allow the user to cock the rear bolt back Steel Alloy Metal casting, drilled, and then texturized BoltHandle.jpg
24 98-21P Power Tube It holds the pressurized CO2 and releases it when called upon, giving the system the energy to fire. Plastic Injection molding and then drilled PowerTube.jpg
25 O217 Front Bolt It is what the CO2 forces into the paintball, causing it to project out of the barrel Plastic Injection molding and then drilled FrontBolt.jpg
26 98-16 Linkage Arm This piece links/holds the bolt system together by attaching to the front and rear bolt Steel Drawn and then forged LinkArm.jpg
27 N/A Vertical Adapter Connects the expansion chamber to the power tube, providing a path for the CO2 to travel Steel Alloy Metal casting, then welded together, and also turned on both sides VertAdapt.jpg
28 98-06 Tank Adapter The adapter located on the bottom of the marker is used to connect the CO2 tank to the marker, open the tank which allows CO2 to flow into the gas line Aluminum Alloy Machine casting, then drilled and turned TAdapt.jpg
29 98-09C Gas Line Guided path for the CO2 to travel that connects the tank adapter to the expansion chamber Steel Threading Part of it is drawn and then threaded, then mechanically joined with the ends, which are made by metal casting GasLine.jpg
30 N/A Expansion Chamber Allows extra area for CO2 to decompress into a gas, allowing the marker to be more efficient Stainless Steel Turning and then drilled ExChamber.jpg
31 98-06A Tank Adapter Bolts Secure the tank adapter to the base of the marker Stainless Steel Machined and the turned TABolts.jpg
32 CA-08B Tank Adapter Nuts The nuts are located inside the marker and helps secure the tank adapter to the base of the marker by giving something for the bolts to screw into Stainless Steel Machined and the drilled TANuts.jpg
33 98-01 Marker Casing The left and right casing protect the inner components, secure the housing components in place, and also used for aesthetics Aluminum Alloy Die Casting MarkerHouse.jpg
34 98-01A Receiver Bolts Secure both sides of the marker housing together Stainless Steel Machined and then turned ReceiverB.jpg
35 98-39 Barrel Provide a path for the paintball to exit the marker Aluminum Turned and then drilled Barrel.jpg

Here is a part diagram for the Tippmann 98 Custom:

Figure 2: Tippmann 98 Custom Parts Diagram [link to website]

Product Analysis

The scale below is used for the complexity scale for each component:

  • 1 point-not symmetrical
  • .5 point-holes
  • 2 points-compound part
  • 1 point-hollow/inner cavity
  • 1 point-thread
  • 2 points-direct involvement with energy flow
  • 3 points-valves
  • 1 point-each material used
  • 1 point-each manufacturing process

The following scale was used for the interaction complexity, which is the relationship with the component interactions within the marker.

  • Interaction with another component- 1 point per direct interaction
  • Flow of material from one component to another -1 point per flow
  • Flow of energy from one component to another - .5 points per flow

The higher the score is the more complex the component is. The above scale has a direct relationship with the component function, form, and manufacturing methods. The more component functions and manufacturing methods involved the more complex the product is going to be. If the component from is not symmetrical and has multiple materials, it entails that the component will have a high score on the complexity scale. If multiple materials are going through the component then the interaction score is going to be high.

Marker Casing:

Marker Casing
Figure 3: The Tippmann 98 Custom Marker Housing

Component Function

The function of the casing is to act as a strong outer casing in order to protect the inner components of the marker. The marker could not be used without the casing because it is used position and guide each component inside of the marker. The casing helps bring each sub-system in the marker together to complete the action of exporting a paintball. The handle is located towards the back of the casing, this way the user can have a comfortable place to place their hand while in the field of play. The casing is also used as a form of aesthetics because it is the only component that the user can see. This shows how human energy is associated with this piece. It is used to help make the marker look like “gun, brings all of the components together, and it is what the user holds when the marker is in use. The environment that the marker is associated with would be large fields or places of paintball competition.

Component Form

The general shape of the casing is that of a “gun” where the handle is located in the back, handle in the front for another hand to be placed, and then a barrel. This shape is ideal because it allows easier marketing for the marker. Using a gun shape allows a consumer to know the function of the marker at first look. The left side casing is not exactly the same as the right, but they are very similar. The only differences are the aesthetics on the outside and the inner dimensions vary minimally so the inner components can operate. It is three dimensional so the other components can be placed inside of the casings.

The dimensions of the marker are 19.6 inches long, 1 inch wide, 7 inches in height and it weighs 1.2 pounds. The shape of the casing is based on the aesthetics and the assembly of the inner components. In order to keep the size and weight of the marker to a minimum, the casing is designed so that all of the components fit inside the marker and all space is utilized. The handle is located towards the back of the casing, so it can maximize comfort and ease of use. The material used for the casing is an aluminum alloy. The main reason that an aluminum alloy was used was because of its large strength to weight ratio. The lighter the marker is the easier it is to hold and use, but it also has to be able to withstand different forces being applied.

The outside factors of the environment and society have an impact on why aluminum alloy was used for the casing. The environment where the marker is being used is constantly changing so it has to be able to tolerate a lot. If the marker is used outside so it has to be resistant to corrosion from rain, also the marker will be dropped at times so a strong casing is needed to protect the inner components from becoming damaged. If the casing wasn’t reliable the marker would break a lot, resulting in unhappy users which could potentially fail the product. Aesthetically, the casing gives the marker a “mean” look to it. The casing is black which helps the marker look “mean” but also so it cannot be easily seen in the field of play. If a bright color was used, you would not be able to hide as easily because marker would stick out. The surface finish is a dull finish to help add to the look but also to make it easier for cleaning.

Manufacturing Methods

The manufacturing process used to make the casings was metal casting. The reason that we think metal casting was used because of the material and complexity of each side of the casing. Metal casting works by pouring a liquid metal into a vacant mold then letting it sit for a while to allow the metal to solidify. The inside of each casing involves many different indentations and cavities, which would be too complex to mill out or use any other different type of manufacturing process. The mold is probably split into two, a top and a bottom, once the material has solidified the top can be lifted off and then the casing be removed. This process is economic and environmental because the mold is continually being re-used. This helps eliminate any waste that could potentially harm the environment. The metal casting process is rather simple, so it can be adapted in different places of manufacturing.

Component Complexity

The complexity of the casing relies mostly on the category of its component form. The casing has many different designs on the inside of the casing in order to hold all of the inner components in place.

  • Component Complexity- 6 holes, 1 thread, 1 material, 1 manufacturing process, not symmetrical
    • 6+1+1+1+1=10 is the score of the component complexity
  • Interaction Complexity-2 material flowing thru, 1 energy flowing
    • 2+.5= 2.5 is the score of the interaction complexity

Feed Elbow:

Feed Elbow
Figure 4: Tippmann 98 Custom Feed Elbow

Component Function

The main function of the feed elbow is to guide the paintballs into the housing of the marker. This is the only function that the feed elbow possesses, but it plays a key part in the overall function of the marker. For most markers a hopper(large container for paintballs)is connected to the feed elbow. Without a feed elbow the only way that the marker could be loaded would to be to slide a paintball down the barrel. This shows the importance of the component, because it allows for much faster use when in action. The environment in which the feed elbow functions ranges from temperatures just above freezing to high temperatures on summer days. When the marker is in use it functions when people are running around with the marker, but it won’t function if the marker is being held upside down.

Component Form

The general shape of the feed elbow is irregular but is symmetric in the vertical direction. From the top you can see the hole where the ball is guided thru from the hopper, and also a slight bend in the shape. At the base of the elbow are small pins which allow it to be connected to the marker and then eventually latched to the front sight. It is three dimensional so that a ball can be slide thru the hole on top. The hole on top of the elbow measures to 1 inch the height is 2.5 inches and the width is approximately 1.2 inches.

The shape of the elbow is correlated with the purpose of it because it needs to remain simple, so the ball can easily be placed in the correct position, but also not interfere with the function of the marker. The paintballs are fed by gravity so the feed is just there to guide the ball thru it. If the elbow feed was located directly above the marker then the user would not be able to use the sight. This is why the feed has a slight bend in it, so it can be position on the side of the marker and still allowing the balls to fall into the marker. The feed weighs about 1 ounce and that is mainly because it is made out of plastic. The plastic that makes up the elbow is one that is very strong and durable. This is important because the feed is located on the exterior of the marker which makes it exposed to environment around it. When used outside it needs to be able to withstand the weather and any other actions taken in the field of play such as dropping the marker.

Economically, the material used for the feed elbow is plastic which is relatively cheaper than metals. There are not much aesthetics associated with feed elbow because it is there for functionality. The position of the elbow is more important than the actual aesthetics of it. The color is black, the same as the casing, in order to keep one solid color throughout the entire marker. It is important that the finish inside of the elbow feed is smooth so that the paintballs can fall with minimal friction and so they don’t break in the process.

Manufacturing Methods

The feed elbow was manufactured by the method of injection molding and then milled. What makes us believe that injection molding was used was not only because most plastic components are usually associated with injection molding but there is a flash line down the middle of the feed. This line shows that a mold was present in the manufacturing process and where it was separated. The use of plastic impacts the manufacturing process. It has an economic impact because plastic is cheaper than metal and injection mold allows us to re-use the plastic that is taken off or not used. Injection molding is preferable because it uses plastic in its entirety and also makes it easier to break down the feed into different molds. We believe that two different molds were used, one for the hole and then the second for the bent part. Once the bent part was molded, it was milled to precision so the feed fits perfectly onto the marker, then the two molds were combined. The environmental impact of injection molding is that it allows you to re-use any extra plastic taken off. This means no toxic waste into the environment.

Component Complexity

The complexity of the feed elbow is basic because it is a simple component that doesn’t have many functions.

  • Component Complexity-4 holes,1 inner cavity,1 material, compound surface, 2 manufacturing process
    • 2+1+1+2+2=8 is the score of the component complexity.
  • Interaction Complexity-1 connection, 1 material flowing (paintball)
    • 1+1=2 is the score of the interaction complexity

Expansion Chamber:

Expansion Chamber
Figure 5: Tippmann 98 Custom Expansion Chamber

Component Function

In order to understand the function of the Expansion chamber, you will need to understand how a paintball marker works. The potential energy source used to fire the marker is CO2, and it is most efficient when it is in its gaseous state. But when in the compressed CO2 tank, it takes the form of a liquid, and needs time to transform states once exiting the tank. This is where the expansion chamber takes effect. The main purpose for the expansion chamber is to increase the time CO2 has to transform into a gas by increasing the distance the gas has to travel to the power tube. The expansion chamber is placed in between the gas line, which connects to the actual CO2 tank, and the vertical adapter, which connects to the power tube. Without the chamber, the gas line would be directly connected to the power tube, so it adds about twice the length the gas has to travel, giving it more time to convert fully to a gas. This really makes the marker more efficient, especially when the weather is colder, which makes the CO2 take longer to change states. Along with increasing the time the CO2 has to convert, the expansion chamber also acts as a front grip for the replacing the stock front grip of the marker. So it is both for functional and aesthetic purposes.

Component Form

The expansion chamber has the look of a normal from grip for a marker. It is approximately 3” long, with a diameter alternately changing from 1.25” to 1.5” 3 times. It also has a threaded piece on the top to be able to screw into the marker that is 0.5” long and 0.75” diameter. The component shows axial symmetry almost throughout the whole part, with the exception of the bottom, which is slightly slanted to add room for the gas line insert.

The alternately changing diameter in the expansion chamber allows for 3 fingers to grip the component rather well. The overall length of it is also specific to allow room for an average hand to hold it comfortably. The added section on the top and bottom are for the functionality of the part, allowing for the input and output of CO2.

The component weighs about a quarter pound, and is made up of some type of metal alloy, perhaps stainless steel, and then coated in a protective black paint. The manufacturer probably decided this material due to the conditions that a paintball marker is exposed to, which varies from sunshine to rain, mud and paint. Stainless steel would decrease the chance that the part rusts, and also makes it able to withstand bumps and direct hits without a problem. So from a regional weather standpoint, and a safety standpoint, stainless steel is a good choice of material. The protective coat of paint also adds to the protection of the part from rust and rain.

The expansion chamber also changes the look of the marker, making it more aesthetically pleasing for some. First off, it changes the path of the gas line, so instead of having it go all the way up to the power tube of the marker, it goes straight across to the bottom of the marker, getting a rid of the curved gas line and making it straight, which makes the marker look more rigid. The expansion chamber itself has a shiny black finish to it, replacing the dull plastic front grip that comes stock, so the part matches the marker, but adds a little bit of gloss to make it stand out. The smooth finish is aesthetically pleasing, but also serves a functional purpose, creating a nice area for your hand to grip on to. This part was designed with both functionality and aesthetics in mind.

Manufacturing Methods

Looking at the expansion chamber closer, it is obvious that multiple manufacturing processes were used in the making of this part. Most notably turning, and drilling. Evidence of turning can be seen by the small horizontal lines that go around the entire circumference of the part, and also because it is symmetrical about the center axis. It also has threads, which are made my turning, and a couple groves, which can also be made by turning. Evidence in drilling can be seen in the bottom part of the expansion chamber, where the gas line is inserted, and also in the top where the gas exits. Both look to be drilled because they are in a circular pattern, giving evidence that it was made by a spinning bit. Both drilling and turning make perfect sense when manufacturing, due to the shape of the product. Since it is axis-symmetric, turning is a perfect process.

Economic factors definitely had to have an influence in the manufacturing process as well, specifically with the choice of material. There are materials that are more durable, lighter, and would be better at insulating the CO2 then stainless steel is, but they would be much more expensive and less available. For example, titanium would be lighter, and more durable, but would be much more expensive. Stainless steel is also readily available in our region, so it is an easy choice of material from a global standpoint. From a societal point of view, it is also used widely in the U.S. so the user does not have to question its durability or strength.

Component Complexity

The expansion chamber is responsible for guiding the energy that fires the paintball. So the complexity of the expansion chamber is mostly dependent on the function.

  • Component complexity-1 hollow cavity,2 thread,2 energy flow,2 manufacturing process
    • 1+2+2+2=7 is the score of the component complexity
  • Interaction complexity-2 direct connection (marker, gas line), 1 material flow, 1 energy flow
    • 2+1+.5=3.5 is the score of the interaction complexity


Figure 6: Tippmann 98 Custom Sear

Component Function

The sear of the Tippmann 98 Custom is one of the smaller components of the system, but it holds a very important internal function. It holds the main bolt system back against the main axial spring and, in doing so, translates human input into mechanical signals, activating along with the trigger to release the bolt system. By doing this the Sear acts as both a lock, and a release for the other components of the Marker. Located within the marker, where compact spaces direct its movement, its slight and sturdy translations allow for the control of the system. It is clear that this component of the marker is strictly mechanical, and does not have any visual appeal to the consumer other than its undetected function. The sear is located on the inside of the marker and connects the trigger system with the bolt. Since it is located inside the casing, it is protected from the outside environment.

Component Form

Visually the sear has some compound surfaces, but has distinct corners along all edges. Its side-surfaces are entirely flat, whereas its top and bottom surfaces are curved as to create the proper orientation of the lock end with respect to the trigger end. In the center of the side there is a non-elliptical hole going completely through the sear. Along with this somewhat unique detail, there is a small hinge for a spring located on the bottom of the sear. The metallic material and the unique shape of the hole would suggest that a casting method was used rather than a subtractive process such as drilling, and the lack of flash or seams would suggest investment casting. The sear is technically 3 dimensions, but due to its mirror-style symmetry along its major axis, and it’s orientation within the marker, the component functions primarily in two dimensions.

The Sear measures approximately 2 inches in length, .3 in. width, and has a maximum height of .5 inch. The hole has a general radius of .1 in and a major length of .1 in. Its general dimensions are crucial to its function, mainly because it serves as a bridge between the trigger and the main bolt system. Because of its role in locking back a spring, the material used has to be sturdy and rigid within the marker. The sear itself weighs in at an estimated 15-25 grams, an amount that most likely coincides with the strength of the sear spring. This spring orients the sear by applying a force upon the hinge of the sear, such that the sear retains its position about a pin that is structured through the hole of the sear. This component, being a part of the interior functions of the marker, has no aesthetic purpose, and it is obviously a component made for strictly functional reasons. Its dark color is a result of its material composition, and the grey color would suggest the use of steel.

Because of the necessity for the sear to be rigid, is of metallic composition, most likely consisting of iron or steel, a decision that was likely balanced according to the cost of material and the resultant weight of the component. Thus, the Economics of the marker were placed in scope with the functionality of the components. The metallic seer needed to be made at a certain weight with as little waste as possible. Also, due to the small size of the sear, precise and cost-efficient machining needed to be considered for the mass production of small components. Investment casting, while appearing to be the method used, may have been a costly choice for mass production of this small part. It is possible that instead of this, the sear component was simply machined. However this process may also have resulted in non-retrievable waste.

Manufacturing Method

As mentioned before, the sear appears to be created as a result of investment casting. Evidence for this lies in the fact that the part shows no flash, no extraneous marks, and is lacking any evidence of rough machining processes. Its metallic composition would not be easily cut or milled without damage to the machine, and so it would seem that investment casting was the best viable option. Because it is a small part, it might be the case that very many of these are made at once, on a single frame or compound mold, such that there is a much slower required rate of manufacturing than some of the other, larger parts of the marker. Only minimal amounts of milling, if any, would be required after this step to come up with a final process.


From the categories above, the most pertinent category for the complexity exists within the function of the sear. Whereas the form of the part gives evidence for the complexity, it is the function of the sear that determines its required shape. Both the bridge and stopper functions of the sear require it to be of a shape that acts perpendicular at both ends of the component and requires it to be able to move about its center. For these reasons, the sear has both curved and flat edges, as well as a non-elliptical hole located at its mid-section.

  • Component complexity- 1 hole, compound part, 1 material, 1 manufacturing process
    • .5+2+1+1=3.5 is the score of the component complexity
  • Interaction complexity-3 connections (spring, bolt, trigger), 1 component energy
    • 3+.5=3.5 is the score of the interaction complexity

Power Tube:

Power Tube
Figure 7: Tippmann 98 Custom Power Tube

Component Function

The power tube serves as a vital part to the paintball marker. Its main function is to control the CO2 and release it with the necessary amount of force to shoot the paintball. The power tube also houses some CO2 to allow the marker to be shot quickly when needed. A velocity screw is found on the side of the power tube to allow for the user to adjust firing velocity to their preference. A higher velocity means the paintball will travel farther at the expense of accuracy. The power tube has both importing and exports flows of compressed air. While the CO2 is entering the power tube with relatively low pressure it leaves with a much larger amount of force and pressure. The power tube is an internal part that doesn’t act under any extreme conditions.

Component Form

The power tube is in the general shape of two attached cylinders each of different diameters. It has two screw holes on the one side of it and a velocity screw on the other. It possesses x-axis symmetry if the screws on the one side are not taken into account. The part is primarily three dimensional in that it has to house the CO2. The part is roughly 3 x 1 x 1 in. for the larger cylinder and 2 x .5 x .5 in. for the smaller cylinder. The shape of the power tube allows it to take the CO2 and force it through a smaller area to allow for propulsion. It weighs almost 3 ounces and is made of a plastic polymer with internal parts made of some metal alloy. When manufacturing the part they had to take into consideration that they needed a stable material that wasn’t too heavy or too expensive. Also, the part isn’t very complex geometrically therefore the simplest methods, which usually are the cheapest, could be used. No specific material properties are needed for the part to function other than the ability to hold a compressed gas. The main factors that influenced the component material were economic and global. Material choice was influenced by economic factors of life span and price. They manufacturers needed a material which wasn’t too expensive but wouldn’t deteriorate much over time and need to be replaced. A global influence was finding an abundant material that can be readily used and mass produced. Using a material that would need to be shipped in from other areas would make the part expensive and inefficient. Being an internal part the power tube doesn’t have any aesthetic purpose and is without surface finish other than what the manufacturing process creates itself. The plastic in which the part is made out of is black and therefore the part is primarily black.

Manufacturing Methods

The power tube is made primarily by injection molding with a plastic substance. Also drilling is used to put in the screw holes and then it is turned for the screw hole threads. Evidence of the injection molding is present on the outside of the part. You can see riser marks all over the part and also a stub from which the part was broken off the mold. Material choice and shape had a large impact on the method because injection molding is one of the most efficient ways of creating relatively small plastic part that isn’t too complex for a simple mold. This part is needed for every marker of this model so the economic factor of production cost impacts the manufacturing decisions. Also the need to make the part to last so that the plastic doesn’t just break and get thrown into landfills is an environmental factor that played a part in the manufacturing.


note-the power tube is not meant to be disassembled so we are taking it as it is seen

  • Component complexity- not symmetrical ,1 hole, compound part, 3 thread, 1 energy flow, 1 material, 2 manufacturing
    • 1+.5+2+3+2+1+2=11.5 is the score of the component complexity
  • Interaction complexity-2 interactions with another component (bolt, expansion chamber), 1 material flow (CO2), 1 energy flow (CO2)
    • 2+1+.5=3.5 is the score of the interaction complexity

Solid Model Assembly

For the solid model assembly the bolt system was chosen to be modeled. The reason for this was because the bolt system is a one of the most important parts of the marker. We thought that it would be better to visual where each bolt (front, back and insert) are located and how they were assembled. Autodesk Inventor Pro was the CAD program of choice because it provides 3-D modeling which can be used to help visualize the bolt system assembly more easily.

Table 2: 3-D Models
Part Name Picture Part Name Picture
Front Bolt 3DCADFB.jpg Linkage Arm 3DCADLINK.jpg
Rear Bolt 3DCADRB.jpg Rear Bolt Insert 3DCADRBI.jpg
Bolt Handle 3DCADPIN.jpg Assembly 3DCADPBA.jpg

For a closer look, here are the actual part and assembly files in Autodesk Inventor:

Engineering Analysis


Design Revisions

After dissecting the marker there are some revisions that could be made in order to help improve the functionality of the marker.

Battery Powered

One component that we would like to change within the marker would be the way that it is powered. By changing the form of energy which powers it from carbon dioxide to electricity, it would impact both the user and the environment. One benefit to the user would be that it makes the marker much lighter. Inside the marker, at the handle, there is a lot of unused space where the battery could be located. This means that the design of the marker does not need to be changed and the user would not have to adapt. An economic impact would be that it would be cheaper for the user. Every time the carbon dioxide tank is emptied you need to pay to refill it. If a battery was used, you would only need to first purchase the battery, and from then on you can just recharge it after each use. Environmentally, every time a paintball is fired using carbon dioxide, excess carbon dioxide is released into the air which affects the air around us and the ozone layer. Using electric power will eliminate this harmful action and still complete the same function of shooting a paintball.

Strengthen Ball Latch

Ball Latch Revision
Figure 8: Ball Latch Revision

When taking the marker apart we noticed that the rubber piece, known as the ball latch, was worn out. The ball latch is designed to hold the paintball in place without letting it fall down the barrel. If this piece becomes warn, the balls will fall with no control which could potentially damage your marker. In order to solve this problem a spring loaded system can be used. It would be designed in a similar way as the latch but a spring would be located under the lip. Also the material of the ball latch would change from a rubber to more rigid material so it could not become easily worn. This design will still hold the ball in place and serve as the same function. Once the marker is triggered, the force of the ball will push the spring down allowing it to be released. This revision will help improve the reliability of the marker because you will not have to worry about firing multiple balls at once. The consistency will fall into a social impact because the safety of the marker is now improved with the insurance of only one ball being fired at a time. The economic impact to the user would be minimal because a small spring is the only item being added and a slight design change, see figure 8.

Cycle Feed

Cycle Feed
Figure 9: Cycle Feed Revision

The marker right now has feed tube that gravity feeds the ball into the barrel. That means that once a ball is fired the force of gravity allows another ball to fall in the same exact spot. This type of feeding system is not reliable because at times the balls may become jammed in the hopper and resulting in a dry fire. Our group has proposed the idea of a cycle feed as shown in figure 9. This design would improve both the reliability and performance of the marker. The way it would work would be that the spindle would spin after each shot. The spindle would use the excess carbon dioxide from the previous shot to spin itself. The ball would then drop down the hole into the barrel. The environmental impacts of this improvement would be that it would prevent dry firing which means less carbon dioxide released into the air. Also by using the excess carbon dioxide to spin the spindle it releases minimal to no carbon dioxide. This new design will appeal to users who either like the aesthetics of it or had previous problems with the marker. This is an economic impact to the makers of the marker because more people would purchase it.