Manufacturing

Basics

 

The device mainly is built from laser-cut 3/16" clear acrylic sheet. This material creates very rigid upright structure, is strong enough to be used for links and gears, and is slippery enough to make bearings unnecessary (in most cases). A few parts, such as the input and output plates, were created using 3D printing. All of the parts were built in the ASME wood shop and the Longhorn Maker Studio, both in ETC.

Some of the acrylic parts on the passive mechanism had to be bent at a 90 degree angle to satisfy the design. We put the straight part in a vice, used a heat gun to heat the acrylic above its glass transition temperature (about 30s of heating on high), then carefully bent the piece into shape using pliers.

When doing this, keep the backing paper on the acrylic or cover the pliers' jaws with tape. This ensures that the pliers' teeth will not scratch or deform the acrylic.

Full BOM

QuantityPartMaterial
1Motor Tee-mount plate1/4" Acrylic
2Horizontal Driving Link1/4" Acrylic
2Horizontal Coupler1/4" Acrylic
2Tower Wall1/4" Acrylic
4Parallelogram Link1/4" Acrylic
2Vertical Driving Gear1/4" Acrylic
2Vertical Driven Gear/Link1/4" Acrylic
1Vertical Coupler1/4" Acrylic
2Vertical Output L-bracket1/4" Acrylic
4Claw Mount1/4" Acrylic (bent)
2Passive Claw Gate1/4" Acrylic (bent)
4Passive Claw Bumper Holder 
23/16x5" Bumper RodAluminum round stock
1Claw PlatformABS (3D printed)
1Input PlatformABS (3d printed)
1Output PlatformPine
1Output Platform SupportPine
1Input Platform Support Pine
23/8x6" D-ShaftHardened steel
23/8" Miter GearNylon
23/8" Horizontal Rotation PinAluminum round stock
63/8" BearingNylon
101/4" BearingNylon
16#10 Lock NutSteel
16#10 1" Machine ScrewSteel
8#10 NutSteel
4#10-32x4" Hex StandoffSteel
8#10 WasherSteel
8#10x5/16" Machine ScrewSteel
14x4x1/4" Tower Turntable supportPine
14" Ball-bearing TurntableSteel
14#8x1/2" Wood ScrewSteel
1Tower BasePine
83/8" Shaft CollarSteel
43/16" Shaft CollarSteel
183/16" BushingNylon
33/8x2.5" Machine ScrewSteel
33/8 T-nutSteel
33/8 T-nutSteel
63/8 WasherSteel
1Arduino Uno 
1SaberTooth 1 Motor Driver 
112V Power supply 
1Pololu 131:1 Gearmotor 
1120V Power switch 
110-Kohm Potentiometer 
1Power cord 
 Hookup wire