Flashcards in Materials Deck (16):
what should you consider prior to selecting a given material for your project?
-strength: how strong does it have to be
-workability: do i have the tools and skills to make use of the material
-expense: can i afford the material
what are two types of wood?
hardwood, softwood and plywood
what are the properties of hardwood?
-can be difficult to work with
-more likely to split when nailing or screwing if not careful
-used for decking usually
what are the properties of softwood?
-not as strong
-easier to work with, more forgiving
-can be light and soft
can be used for a range off applications
what are the properties of plywood?
-sheet material, made up of layers of thin sheets of wood(piles) which alternate in sheet direction
-strong in all directions
-resistant to splitting
-good for curved components
-easy to saw but hard to shape with hand tools
in what direciton must the grain be?
in the direction of load
what are the properties of acrylic?
-shatter-resistant alt to glass
-transparent, half as heavy as glass
-difficult to work witih by hand, must use a lazer cutter etc
what are some other names to acrylic?
perspex, plexiglass, polyglass, lucite
what are the properties of aluminium?
-easy to work with
-if thin, can be cut with tin snips
-can make it stronger by folding layers upon layers, highly malleable
how do you convert electrical energy into mechanicall energy?
connecting a shaft coupler to a dc motor
what can i use to mount a motor to the chassis?
how do i convert rotational motion to linear motion?
connecting a lead screw
what are some common types of fasteners?
what are the three types of screws and what distinguishes them from one another?
wood to wood:
wide spaced thread with a threadless shank
sheet metal to wood:
consists of a threaded and threadless shaft combination with wings near the bottom of the nail. wings prevent the threads from engaging with wood. wings break in contact with metal allowing threads to become engaged with metal. must be drilled into wood first then metal
metal to metal:
threads are closer together and the whole shaft is threaded
what are pop rivets good for?
very good for sheet metal, not very good for plastic