Ex. 08 Final Machine Construction

img_1934  Current Build
sketch  Iteration 2
preliminary  Iteration 1

Machining:

The actuating wheel is mounted through a bushing. In order to get an accurate spin and no wobble we decided to drill through the aluminum extrusion and press fit the bushing into the hole. We are still waiting for the bushing to show up in the mail, but interestingly enough a 3D printed bushing works well too.

img_1897

img_1930

Machining:

Assembly:

img_1911 The modified assembly has the spinning wheels placed on the side of the fram. This configuration uses gravity to help reduce wobble of the wheel rather than the disk brake thing that we had before.img_1906
img_1909  This 3D printed gear assembly uses a 12V DC motor to turn the conveyor belt. We stepped up the gear ratio to increase torque (even though the conveyor belt doesn’t need much torque or speed at all.)img_1918
 img_1925  img_1907

Components:

elbow-joint Elbow Joint: The basic premise is to transfer the rotational actuation into linear actuation, which will move a chain around. The chain will have tube holders at each link so that the registration of the movement of the chain is done with distribution of sand and cement. For the elbow joint on the actuating arm, We used a magnetic iphone mount, which acts as a ball joint. we then 3d printed couplers that hug the magnetic mount, with inserts for acrylic tubes on either side to place the arms.
conveyor-belt Conveyor Belt Assembly. The initial problem we were face was jamming. we need free movement for the tubes to distribute sand and cement independent of the funnel. The first idea was to have a large reservoir at with a solenoid valve that would let us control how much material is distributed, however powder wants to jam when the force of the material at the top prevents the material from moving freely out of the tube.
actuating-wheel_top  Actuating Wheel: This assembly was design to translate the rotation of the disk into linear actuation. We designed and 3d printed a disk mount that helps prevent wobble. The orientation of this particular assembly is flat, however the most recent iteration of this assembly is mounted on the sides and oriented vertically so the movement doesn’t interfere with the conveyor belt assembly.
sketch  The modified assembly has the actuating wheels mounted on the side and oriented vertically. Below the top frame is a mount for a lazy susan, which is controlled by a stepper mounter / timer pulley system. The conveyor belt assembly spans a foot long so that material distribution into the funnels can be consistent. At the end of the linear actuators will be a chain with a tube attached. The independent movement of each actuating arm will cause the material to be dispersed across the entire rotating build plate.