Syed Mustijab Haider Rizvi (MM111117)

Composite Baseball BatsManufacturing Process & Comparison with Aluminum Bats

Table of Contents

1. Introduction

2. Shapes

3. Aluminum and Composite Bats

4. Properties of Baseball Bats

5. Manufacturing Process

6. Comparison

7. Conclusions

8. References

Composite Baseball Bats

Introduction

Baseball bats fall within three material classifications

1. Wood 2. Aluminum 3.Composite

Composite Baseball Bats

Shapes

Baseball bats in the early days of baseball came in all shapes and sizes(long, short, flat, and heavy)

• 1859 – Maximum diameter 2.5 inches

• 1869 – Maximum length 42 inches

• 1890 – No more flat bats only round with

maximum diameter 2.87inches

Composite Baseball Bats

Aluminum and Composite Bats

1924 – A patent for the first metal baseball bat1970 – First metallic bat in the game1980 – First composite bat in the game

Worth Aluminum baseball bat Easton Aluminum baseball bat

Composite Baseball Bats

Properties of a baseball bat

Important features

Durability and strength

Stiffness

Swing weight

Trampoline effect

Vibrations

Composite Baseball Bats

Manufacturing Process

Following steps are involved in composite baseball bat manufacturing process

1. Starting material

2. Steel bat frame

3. Winding of polypropylene layer

4. Baking

5. Braided carbon and glass layers

6. Hot pressure molding

7. Extracting steel bat form

8. Inspection and flexibility testing

9. Black primer coating

10. Finishing operations

Composite Baseball Bats

1. Starting Material

Resin infused pliable carbon fiber sheets

• Sheet layers• Hot rolling – melting of resin and diffusion of fibers

Composite Baseball Bats

Sheet layers Hot rolling

2. Steel Bat Form

The fiber sheets are then spiral around the steel bat form at different angles to make a fine bat form.

Composite Baseball Bats

Steel bat form Fiber sheet wrapping on steel bat form

3. Winding of polypropylene

A layer of polypropylene is winded to squeeze out any trapped air between the layers

Composite Baseball Bats

Polypropylene layer

Fiber sheet wrapped bat

form

4. Baking

Baking for two hours Resin curing

Composite Baseball Bats

Placing bats in baking oven

5. Braided carbon and glass layers

After the removal of polypropylene, bat form is wrapped with three layers

• Braided carbon and glass (1)

• A thick layer of carbon (2)

• Aramid Fiber layer (3)

Composite Baseball Bats

(1) (2)

(3)

6. Hot Pressure Molding

The bats are placed in the mold and epoxy resin is injected with high pressure at high temperature

Composite Baseball Bats

Bats in mold

Hole for epoxy resin

injection

7. Extracting the Steel Bat Form

After the removal from the mold steel bat form is extracted

Composite Baseball Bats

Hollow Composite

bat

Steel bat form

8. Inspection and Flexibility Testing

Bat is inspected for any visible defects and tested on flexibility testing machine to ensure that bat has attained desired flexibility

Composite Baseball Bats

9. Black Primer Coating

After inspection black primer coating is applied and bats are hanged to dry

Composite Baseball Bats

10. Finishing Operations

• Spray Paint (1)• Brand• Adjust weight (2)• Adjust balance• In-cap (3)• Grip (4)

Composite Baseball Bats

(1) (2) (3)

(4)

ComparisonComparison of aluminum and composite baseball bats

Composite Aluminum

Swing weight

Lower swing weight and maximum

effect of swing weight by having both

a lower moment of inertia as well as a

center of mass closer to the handle

Relatively higher swing weight

Trampoline effect

The softer barrel allows the ball to

come off with small losses in energy

while maintaining the stiffness of the

bat in the handle

Due to isotropic properties it is

difficult to make different parts with

different stiffness so stiffness of barrel

must be high

Vibration

Very high damping rate causing no

observable vibrationsHigh vibrations cause a sting

Comparison

Composite Aluminum

Temperature effect

Cannot be used at lower temperature Can be used at any temperature

Durability

Relatively low life time Can be used for long period of times

Flexibility in properties

Properties can be tailored at will Difficult to obtain anisotropic properties

Performance with time

Performance improves with usage due

to loosing of fibers up till a certain limit Performance decreases with time

Sweet spot (area of bat which transfer maximum power to ball)

Larger sweet spot Relatively small sweet spot

Cost

High cost Low cost

Conclusion

Composite bats have outperformed aluminum bats by their superior and tailor able qualities;

• The swing weight for these bats is more easily controllable,

• Trampoline effect may be tuned,

• Bending stiffness may be tuned and

• Bending vibrations are more highly damped.

These all properties together made them the first choice of any player

Composite Baseball Bats

Thank You!

References

[1] Mahesh M. Shenoy et al (2001). “Performance assessment of wood, metal and composite baseball bats”, Composite Structures 397-404[2] Matthew Broe et al (2010). “Experimental study of the evolution of composite baseball bat performance”, Procedia Engineering 2 2653–2658[3]http://www.baseball-bats.net/baseball-bats/baseball-bat-history/index.html 18-05-2012 at 1:45 PM[4]http://americanarmchaircricketer.blogspot.com/2012/02/going-batty-or-what-are-those-sticks.html 18-05-2012 at 2:00 PM[5]http://www.bplowestprices.com/easton-sv12-bsv1-baseball-bat-high-school-adult-3.html 18-05-2012 at 2:25 PM[6] http://www.woodbat.org/ 18-05-2012 at 4:00 PM[7]http://science.discovery.com/search/results.html?focus=site&query=baseball+bats&search= 18-05-2012 at 5:00 PM