Need help with a rubber gripper... - Page 2
Close
Login to Your Account
Page 2 of 2 FirstFirst 12
Results 21 to 24 of 24
  1. #21
    Join Date
    Jan 2013
    Location
    Louisville, KY
    Posts
    3,044
    Post Thanks / Like
    Likes (Given)
    7197
    Likes (Received)
    2577

    Default

    On Friday, I received some supplies and tried out version-1.0 of some "new & improved" grippers. These are pre-cut rubber strips with aluminum backing by Fixture Works/Fairlane. Drilled/counterbored for mounting bolts. Then machined a 5* angle on the contact faces to match the draft-angle on the parts. Lastly, a strip of anti-slip traction tape across the gripping face. Arranged now so that they're parallel with the parting line of the parts, to give more & better contact as well.


    gripper-2.jpg



    Initial thoughts are that they seem to hold well, although I couldn't test them with the problem-child painted parts yet.

    I'll report back with updates to let you all know how they perform. I appreciate everyone's input thus far - Thank you.

  2. Likes BugRobotics liked this post
  3. #22
    Join Date
    Feb 2007
    Location
    Utah
    Posts
    194
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    4

    Default

    If emery cloth solves your friction problem and is durable enough, you can laminate emery cloth to the smooth elastomer faces with 3m VHB tape. VHB tape is pricey but worth it if it solves your problem. I've done this with wet dry shop roll fabric backed sandpaper and 1" wide VHB. Laminate one surface of the tape to the sanding strip, apply pressure between thick plates in an arbor press then cut into circles with a punch. Last step is to laminate those circles onto the gripper face with a press again. VHB tape requires a certain pressure to activate the adhesive and we used a press to reliably apply that pressure. Someone can do a batch of these at a time with less work than molding your own. The vhb tape adds some conformance and does not come off if applied correctly. the tape and cloth backed sandpaper can be had in sheet form as well and with flat gripper faces, you can laminate both sides of the tape in one shot. I made the dots for curved grippers so we pressed in two steps.

    If the textured neoprene from mcmaster works well for friction and durability, loctite 380 and a vacuum bag or clamping plates works well to laminate that material to aluminum. Both faces need to be roughed up with ~120 grit sandpaper and cleaned with a strong solvent like acetone. We've used textured neoprene on aluminum with good results for a different gripper project. Full coverage of the flexible adhesive was key to prevent edge peeling.

  4. Likes Jashley73 liked this post
  5. #23
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,436
    Post Thanks / Like
    Likes (Given)
    549
    Likes (Received)
    1453

    Default

    In marine use for extreme service aka cruising boats, epoxy and a sand (washed, graded) thrown on has worked well for decades.

    Not suggesting to throw sand on the glued grippers -- although it might work well.
    (Until or if the sanding wears).

    But something like plastidip with a sprinkled coating of suitable steel powder or grit might be a good idea.
    Perhaps stainless grit for less contamination.
    The plastidip can provide minimal yield and conformal contact.

  6. Likes BugRobotics liked this post
  7. #24
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    8,324
    Post Thanks / Like
    Likes (Given)
    434
    Likes (Received)
    6862

    Default

    Confused on abrasive use.
    VHB or other to attach emery cloth a good/great idea but?
    Aren't these painted parts? Even if no slip is there not pinholes in the paint if the grit too course or dispersion not fine enough?
    We had this problem with painted axles going though the robots. Still looked okay by eye but under corrosion tests those tiny spots became a bad thing as we had violated the paint.
    Grit size, concentration and grip pressure play a roll.
    Making it work one thing, making it not hurt the part counts too.

    I do not know your parts so this could be just bullcrap but I just thought to mention it as a concern.
    Bob


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •