MakerBot Educators Guidebook 3rd Edition

MAKERBOT EDUCATORS GUIDEBOOK Chapter 4: Curriculum Project Ideas
PAGE 96
See how 3D printing can help people all around the world by printing and building a snap-together version of the
Robohand and develop a better understanding of the mechanics behind the robohand and how the robohand itself
can expand and contract using one’s wrist.
01
MATERIALS NEEDED:
• Elastic String (approx. 1mm in diameter)
• Nylon String (approx. 1mm or more in diameter)
• 5 x Short Screws
3D PRINTED COMPONENTS NEEDED:
• 1 x RightKnuckleBlock.stl or 1 x LeftKnuckleBlock.stl
• 1 x Set of WristStructure.stl (Made up of four 8-holebeams and 2 6-hole beams)
• 1 x Set of Fingers.stl (Made up of 5 finger tips, 5 finger segments and 5 finger snap pins)
• 1 x Set of *SnapPins.stl
*There are four types of pins that print in the ‘Snap Pins.stl’ file. Two types of pins (long and short) are used to
assemble the Knuckle Block. The remaining pins are divided into #2 and #3 pins. Generally, #2 pins are used
when attaching two components and #3 pins are used when attaching three components.
TIP:
Parts in these plans are represented in two colors, blue and black. These colors correspond to the colors used in
printed examples. In general, blue parts are movable or attachable parts, whereas black parts are static or structural.
ASSEMBLING THE FINGERS
Place one of the Fingertip prints on a table with
the keyed side of the hole facing up and slide
the Finger segment into the Fingertip. Make sure
the segment is oriented with the cable slot on
the bottom and the endstop at the back of the
assembled finger. Use one of the small snap pins
to pin the joint, you may have to use a mallet or
heavy object to lock the pin into place.
A. Check Movement
The assembled finger should move freely around
its joint and the back of the snap pin should be
flush with the side of the finger. Repeat these steps
to complete the other 4 fingers.
02
BUILDING THE HAND
Lay out the three printed parts of either the RightKnuckleBlock.stl or 1 x LeftKnuckleBlock.stl on the table and attach
the sides to the selected knuckle block using the two shorter pins (do not use the #2 or #3 snap pins) from the
SnapPins.stl.
A. Install the First Two Fingers
B. Repeat on The Other Side
Install the first two fingers into their slots (such that
Flipping the knuckle block over, install the other two
you’re installing the fingers that would be the furthest fingers into the other two slots and secure with the
away from the thumb). Use a mallet or heavy object to second longer pin. Check the movement again and if
tap one of the longer snap pins into the hole, securing there is a lot of resistance, move the fingers up and
the fingers to the knuckle block.
down again to loosen them up.
C. Installing the Thumb
Slide the thumb into place and use the last finger snap pins to secure the thumb to the hand. Move the thumb back
and forth a few times until it loosens up if it does not move freely.
03
BUILDING THE WRIST
Place a wrist beam (one of the 6-hole beams)
on the inside of the hand assembly and line the
holes on the beam print to the knuckle block.
Then insert two #2 snap pins into the front two
holes (closest to the fingers) on opposing sides to
attach the wrist beam to the hand. Next, line up
the other wrist beam to the other side of the hand
and secure them in place two more #2 snap pins.
MAKERBOT EDUCATORS GUIDEBOOK Chapter 4: Curriculum Project Ideas
PAGE 97