Requirements and specifications are separated for the prototype and real life machine. The information is similar but the specific applications and working conditions are different.
Able to roll out plasticine at room temperature
Supplies enough force without frame breaking
Can roll moderate sized plasticine many times without major wear (minutes)
Not too expensive to build
Not toxic and safe to use
Can be built relatively quickly and tested
Strong enough to roll metal into sheets
Able to roll steel without the structure breaking
Rollers can be used many times to produce very large volumes of metal at a time (hours)
Total system is not too expensive
High temperatures do not damage the machine
Machine is not toxic when used
Rollers with strength > 20 MPa and Young's Modulus > 10 GPa: strength and stiffness high enough to compress plasticine
Frame strength > 50 MPa to support necessary loads
Fabrication and manufacturing processes must be available within UC Berkeley premises. Large scale manufacturing processes are unavailable
Wear resistance must allow system to function many times to roll large amounts of plasticine
Cost must be very low to be built within months
Rollers with strength > 100 MPa and Young's Modulus > 200 GPA: high strength and stiffness rollers are needed to be able to roll the steel
Frame strength > 100 MPa with Young's Modulus > 200 GPa to support rollers without deformation
High wear resistance for rollers to allow prolong use
Melting point > 500 C to prevent thermal deformation
Relative cost moderate - exclusive and rare materials are too expensive to use