Model label: IMOHolderAssemb, PrimDichroFromSkeleton

Instructions for assembling kinematic mount parts (gluing balls and rods in place on IMOHolder and IMOMount).

  1. Invert the IMOHolder, so that the pockets for the rods are facing up.
  2. Add the rods, balls, and IMOMount, using no epoxy.  Check that the rods and balls fit in their pockets in the proper places, with 6 point contact between the IMOMount and IMOHolder.
  3. Attach the fully assembled IMOTray to the IMOHolder, and adjust so that the IMOMount can be pressed firmly against the IMOHolder by the spring plungers.
  4. Remove the IMOTray (take out hinge pin), IMOMount, rods and balls.
  5. Add epoxy (any, with medium, honey-like viscosity will probably work; 30min-1h working life is probably best) to rod and ball pockets.  Add rods and balls, being careful to make sure epoxy does not cover them where the 6 point contacts will occur.
  6. Assemble the IMOMount onto the IMOHolder again (epoxy should hold the balls in the IMOMount while it is inverted) and add IMOTray such that pressure is applied as the epoxy cures.  The idea is to make sure that as much epoxy as possible is squeezed out of the spaces between the rods and balls, and the reference surfaces that define their positions within the IMOHolder and IMOMount.

 

 

 

 

Imaging objective holder

     Assemble imaging objective mount
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9 Comments

  1. Unknown User (jeromel@alleninstitute.org)

    I remember you showed this at the workshop (just checking) but the balls and sapphire contacts were glued with epoxy in the holes, right?

    1. Daniel Flickinger

      Yes, we used 5 min epoxy.  Any will probably work fine.  It's necessary to make sure that pressure is applied to the balls and rods as the epoxy sets, so that no epoxy sets between the balls and rods and their associated mating surfaces. It would probably be easier to get all of the balls and rods glued at once and the assembly clamped together to apply this pressure if ~1 hr epoxy were used instead.

  2. Unknown User (jeromel@alleninstitute.org)

    We have assembled the IMO holder as well as the tray and I wanted to double check.


    The objective holder doesn't slide in there easily. It is is very close. It looks like the "Mouth" doesn't open enough for the tray to go in.
    I am wondering if I should file the IMOTrayAssby a bit to make the opening wider. Did you do this by any chance?

  3. Daniel Flickinger

    Hm, I'm not quite sure which part doesn't fit with which.  Are you having trouble putting the IMOTray on the IMOHolder, or having trouble putting the IMOMount in, once the IMOTray and IMOHolder are assembled?  We haven't had either problem, and there should be pretty big tolerances for getting these things together.  Could you describe the problem a little more?

    1. Unknown User (jeromel@alleninstitute.org)

      We found out the problem. 
      See attached picture, the nut was not positioned so as to properly flush the flat surface on the side. It was making it more difficult to insert the objective tray. The picture is an example of how it should be.  

  4. Chris Harvey

    In the Harvey lab we're also having trouble fitting the IMOMount into the mouth of the assembled IMOTray and IMOHolder. But our problem is not being caused by the nut pictured above. (We've removed this nut, and all of the other hardware except the 5" dowel pin that hold the IMOTray to the IMOHolder.) The "mouth" of our IMOTray/IMOHolder assembly opens to 4.3 degrees. Do ya'll get more opening? - Joe

     

    1. Daniel Flickinger

      The mouth not opening far enough could be the problem.  It looks like the nominal design should get to 5 deg, which isn't too much more, but the difference from 4.3 deg will give 0.5-1mm more clearance wherever the IMO mount is catching.  The problem is likely with the IMOHolder (the big piece that the dichroic fits into.  This actually happened to me on our first prototype, but I thought I clarified the drawing, and we're using a new, high-quality manufacturer for this part, but these things can still happen I guess. What I would recommend as a quick and dirty fix is to take the IMOHolder and sand (on belt sander) or file down the two little angled stop surfaces that restrict the tray movement.  You should only have to remove about 0.2mm of material to get from 4.3 to 5 deg, so maybe filing wouldn't take so long.  There's not any issue really with removing too much, or removing material from adjacent surfaces, so it's a low-risk mod.

       

      1. Chris Harvey

        That worked great. 2 minutes with a hand file on the IMOHolder opened the mouth up to 5 degrees, and the IMOMount fits great now. Thanks! - Joe 

  5. Rob Campbell

    We also had to do this. I think we had to remove more than 0.2 mm of material, but it didn't take long and we did it with a hand file.