Fall 2016 Biped Material Trade-Off Study

Building Material

By: Hector Martinez (Manufacturing Engineer)
Approved by: Ijya Karki (Project Manager)

Introduction

For the Biped Project, we have considered the following materials for manufacturing prototypes as well as for our final robot. The following chart shows advantages and disadvantages for that material.

Material Comparison Chart

Material	Price	Pro	Con
PLA	$20-165 /kg	1. Ideal for small parts2. Higher printing speed 3. Hard, soft, and flexible  variants 4. Wide range of colors 5. Plant based	1. Odor while printing2. Requires additional support while printing. 3. Some printers incapable to print PLA 4. Risks of cracks in finished product
ABS	$19-175 /kg	1. Strong2. Quick solidification 3. Flexible 4. Higher temperature resistance	1. Requires heated printer bed2. Fumes while printing 3. Weak against moisture
Acrylic	$3-122 /sq ft	1. High impact resistance2. Chemical resistance 3. High heat resistance 4. Weather resistance	1. Poor solvent resistance2. Subject to stress cracking 3. Low continuous service temp
Aluminum	$7 / cm3	1. Strong/lightweight2. Non Magnetic 3. Electrically conductive 4. Recyclable	1. Variation in surface texture2. Expensive 3. Abrasive to tooling

Conclusion

Through careful consideration we have decided to move forward and build the Biped robot with a mix of acrylic and ABS. The use of acrylic will be more time efficient. Acrylic will allow us to quickly laser cut less intricate parts such as linkages that simply extrude outwards. The time frame to laser cut is minimal compared to the time frame to 3D print. For example, laser cutting can be accomplished in little as a minute while 3D printing could last for multiple hours. We would use ABS to produce more complicated pieces, such as the foot. The foot is considered a more complicated piece because it consists of a cut that will house the color sensor. Thus, substituting laser cutting for 3D printing intricate pieces is a more practical approach.

 

 

References

1.   http://www.3ders.org/pricecompare/
2.   http://www.absplastic.eu/pla-vs-abs-plastic-pros-cons/
3.   http://www.jwwinco.com/engineeringtips/prosconsaluminum.html
4.   http://elementaluminum.tripod.com/id8.html
5.   https://all3dp.com/metal-3d-printer-guide/
6.   https://all3dp.com/best-3d-printer-filament-types-pla-abs-pet-exotic-wood-metal/#carbon
7.   http://www.makergeeks.com/me3dprfi.html
8.   http://www.3dxtech.com/firewire-carbon-fiber-peek-3d-printing-filament/
9.   https://plastics.ulprospector.com/generics/3/acrylic
10. http://www.sdplastics.com/sdplas2.html