Automotive Brake Drum

ME 324 ProjectGroup 912/5/05Jon Richardson Jared ChezikKelly McGeough Bryan JohnsenMatt Creswick

Outline

Problem Statement Common materials CGI Machining of CGI Manufacturing Process Safety Cost References Questions

Problem Statement

Analyze the current processes involved with manufacturing an automotive brake drum

Develop a manufacturing process based on our research and other acquired knowledge

Common Materials

Cast iron Inexpensive Widely used Easily machined

Aluminum Lightweight Easily warped

Cast Iron Drum

Aluminum Drums

Our Material of Choice

Compacted Graphite Iron, CGI High casting

productivity Special machining

considerations Nearly 2x stronger than

grey iron due to its structure Parts can be made

lighter High heat transfer rate

Cast iron microstructures

Machining of CGI

Machining considerations Requires 30% more

power than grey iron Requires more rigid

tooling than grey iron Requires a specialized

rotary insert cutting tool Cost is justified by a

high machining speed (1000m/min)

Rotary Insert Cutting Tool

Manufacturing Process

1) A sand mold is made from a pattern that represents the final casting

2) Molten iron is poured into the mold cavity

3) The cooled casting is cleaned by mechanical methods

4) Casting is painted

5) Casting is turned to final dimensions using a lathe

6) The bolt circle is then drilled into the drum

7) Drum is balanced to eliminate vibrational forces

8) Drum is ready for shipment

Casting

A sand/chemical compound forms the pattern

Molten iron is poured into the hardened cope/drag mold combo

Results in a rough brake drum casting

Bead blasting

Removes sand and flash from rough casting Tiny abrasive particles impact drum

surface at high velocity Propelled by compressed air

Can’t remove large imperfections or large amounts of flash Must be ground off with abrasive wheel

Painting

Powder Coating Durable coating Professional finish Little waste

Dipping Dip-and-spin Barrel enameling

Industrial Spray Painting

Machining

The friction surface is machined on a lathe Tolerances not good

enough Final dimensions and

surface finish is reached in a secondary operation Friction surface is honed

Vertical Brake Drum Lathe

Machining cont.

Bolt pattern varies greatly between applications Typically 4 to 8 bolt

holes Varying bolt circle

pattern Varying bolt hole

diameters Holes bored and

measured with aid of a computer to ensure accuracy

Bolt pattern showing bolt circle

Safety

Casting Safety Various protective equipment when casting the

drums High-temp resistant gloves Sand floor Protective leathers Helmet with face shield Foot protectors Respiratory protection (if needed) Heat resistant suit or jacket Safety glasses

Safety cont.

Machining Safety Eye protection Hand protection Proper clothing

Painting Safety Eye and skin protection Respiratory protection

Cost

Material choice greatly affects all costs More expensive material cost

compared to grey iron More expensive machine tools High speed machining justifies cost

Use of CGI not recommend for small scale production Large scale production is needed to

dampen material cost burden

Cost (cont.)

Actual production cost per unit Dependent on production application

Size, Quantity produced, etc.

Predicted future of CGI Reduced cost with increased production

usage More brake drum manufacturers using CGI Ford beginning to use CGI for engine blocks

References

Neil Shroff – DuraBrake Co. www.sintercast.com www.mmsonline.com www.manufacturingcenter.com www.moderncasting.com

QUESTIONS?