Assembled end effector.
Assembled end effector.

The following steps are identical regardless the type of ball joint (magnetic or tie rod end). Assembly of the effector for use with magnetic ball joints is treated separately below.

  1. Cleaning end effector.
    The end effector is printed with two "floors" towards the top of the interior where the hot end slides into it. Much of this material must to be removed with a sharp knife. Remove the floor material linking the hot end slot to the interior walls of the end effector. Clean the hot end slot with a small blade screwdriver ensuring that no protrusions exist on the walls of the slot. Shave off floor material that extends into the slot area from the top.
  2. Ream the Bowden sheath opening with a 3mm drill bit, working the bit like a file. Ensure that the Bowden sheath fits through the opening - it should be snug but not difficult to push through.
  3. Wires for the heating resistor and thermister pass through a hole located on the side opposite the opening for the fan. Floor material for the hot end retainer covers a large portion of the hole. Remove the floor material with a sharp knife and ream the hole with a 3mm drill bit, using the bit like a file. Note that a second hole is present within the wire passage hole. This small hole is provided for pushing the hot end out of the slot should maintenance be required. A 2.5mm allen key works perfectly as a pushing tool.
  4. Cleaned end effector.
    Clean out the Bowden sheath retainer recess (small hexagonal opening on the top interior of the hot end retainer) with a sharp knife and ensure that an M4 nut fits snugly in the recess.
  5. Tapered Bowden sheath.
    Prepare the Bowden sheath by tapering the ends in a pencil sharpener.
  6. Plastiforming threads into Bowden sheath.
    Slide a 2mm (1/16") drill bit into the end of the Bowden sheath and plastiform threads into it by twisting an M4 nut onto it. Use a wrench to twist the nut onto the sheath. Ream the sheath with the drill bit insuring that all restrictions are removed. Form about 12mm (1/2") of thread on one end of the sheath and about 6mm (1/4") on the other end. (The drill bit keeps the tubing from collapsing, thereby forming better threads.)
  7. Thread the large conductor (heating resistor wire) through the large opening in the base of the effector and push it through the hole in the back of the effector so that it extends out the top of the effector. Remove any twist in the conductor. Pull the conductor from the top of the effector until the hot end is partially within the effector.
  8. Conductors threaded through end effector.
    Repeat the process with the smaller conductor (thermistor wire) being very careful to minimize straining the thermistor leads or solder joints.
  9. Work the two conductors until they are neatly straight and aligned with the exit hole in the effector.
  10. If the Bowden sheath retainer (M4 nut) is not in the recess, replace it.
  11. Carefully pull the conductors from the top of the effector while angling the slotted end of the hot end out the fan opening. Align the top of the hot end with the slot in the effector and simultaneously push the hot end into the slot while carefully pulling up slack in the conductors from the other side.
  12. The slot for the hot end is purposfully tight-fitting; considerable force maybe required to fully insert the hot end in the slot. Be careful to minimize straining the conductors and assure that the retainer is not in the way of the hot end.
  13. Check that the hot end is fully seated by looking down through the top of the effector using a flashlight if necessary. The entry to the hot end should be centered under the Bowden sheath opening.
  14. If the hot end refuses to fully seat in the slot, push the hot end out using a 2.5mm allen key in the hole provided (careful with conductors!), clean the slot again with a small blade screw driver and knife and try inserting the hot end again.
  15. Hot end inserted in end effector.
    Once the hot end is fully seated in the retainer, plastiform an M2 x 10mm screw through the top of the end effector. Tighten the screw fully so that its end extends past the top of the hot end.
  16. Only two M3 x 10mm screws are required to afix the fan to the end effector: Place the fan over the opening with the wires exiting the fan towards the top of the effector and the fan spider facing the interior of the effector. Align the fan's mounting holes with the holes in the fan opening and plastiform M3 x 10mm screws into oposite corners of the fan.
  17. Thread the 12mm-long threaded end of the Bowden sheath into the end effector. A full 12 to 14 revolutions will be requried to thread the sheath into the hot end. Do not over-tighten the sheath or the end will be deformed, impeding the filament. (Some insurance may be had by pushing a sufficiently long piece of 1.75mm filament through the sheath and then into the hot end and then threading the sheath into the end effector.)
  18. Assembled end effector.
    Secure the fan, thermistor and heating resistor wires to the Bowden sheath with a small wire tie immediatly above the Bowden sheat opening.
  19. Set the assembled end effector aside.

Affixing Magnets for Magnetic Ball Joints

NOTES:

  • Do not let the magnets slam together! They are very brittle and will break surprisingly easily if mishandled. They are exceptionally strong and will slam together with enough force to break them.
  • Do not use "steel" epoxies as many really do contain steel. They'll flow uncontrollably all over the surface of the magnet, which isn't fun to clean up.
  • A non-magnetic tool for pushing the magnets into their recesses (a wooden spoon handle or aluminum x-acto knife handle works nicely).
  • Do not let the magnets slam together!
  1. Thoroughly clean the magnet mount recesses with a sharp knife. Be careful to not remove too much material as the magnets should fit snugly in them.
  2. The magnets come in pairs with pairs being identified as those attracted to each others' same face, that is the sides with the larger diameter recesses should attract each other. Magnets should be placed in the end effector such that nearest-neighbors attract rather than repel.
  3. Magnets are placed in their recesses with the larger diameter opening facing outward. This is the surface that mates with the ball bearing on the end of a tie rod.
  4. Test fit the magnets in each of their recesses - they should fit snugly and all should fit flatly against the bottom of their recess. Do not let the magnets slam together!
  5. After ensuring the magnets fit properly in their recesses, remove them all (a small screwdriver can be inserted in their interior and then used to pry them out).
  6. Mix enough epoxy to coat the recesses.
  7. Coat the interiors of all the magnet recesses with a thin layer of epoxy.
  8. Press the magnets into their recesses keeping in mind that the large diameter opening in the magnet points outward and the nearest neighbor magnets should attract each other.
  9. Press the magnets all the way into the recesses using a non-magnetic tool or fingers.
  10. Wipe excess epoxy from the faces of the magnets and ensure that they are clean. After curing, excess epoxy that remains on the face of the magnets can be removed with a sharp knife.
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