Home sheet metal stamping help needed!!!

Discussion in 'Pro/Engineer & Creo Elements/Pro' started by super88, Sep 27, 2006.

  1. super88

    super88 Guest

    I'm going to post this message to all groups that I feel may be able to
    help. Bear with me, I'm ignorant, but ambitous. I'm tryng to make
    something similar to a cookie sheet. A little larger radius (2 1/2")on
    the corners and about 1 1/4" deep out of 22 ga. cold rolled steel. I've
    built a "press" using I beams and 25 ton bottle jacks to do the
    job.(Keep in mind if I could afford to job this out, or pruchase a
    press, things would be different.) Anyways, I've managed to make the
    part except for the corners wrinkle badly. I'm in the process of
    casting the female to allow me to use binders. The question is where is
    the best place to bind the blank? In the corners, or along the
    straights? Any help, opinions, suggestions, ideas are appreciated! I'm
    doing this with determination and junk layin around the yard. Buy a 10K
    press, hire a die maker...etc. are not the answers I'm looking for.
    Unless someone is willing to produce this for less than a grand. Thanks
    again!!
     
    super88, Sep 27, 2006
    #1
  2. super88

    David Janes Guest

    How about buy a $40 book ~
    http://www.amazon.com/Sheet-Metal-F...ef=sr_1_1/102-8222904-3360145?ie=UTF8&s=books

    Anyway, to cut to the chase, you start with big corner round on a shallow
    draft and gradually "bring it in" dimensions get smaller, radiuses get
    sharper, drafts get steeper (just because draw size gets closer to form. So,
    in two or three draws, you can get localized stretching without the
    wrinkling.

    David Janes
     
    David Janes, Sep 27, 2006
    #2
  3. super88

    David Janes Guest

    If you start your forming process of a 12 by 18 cookie sheet with a 24 by 36
    first draw, you might be clamping it at 25 by 37 inches. For subsequent and
    decreasing draw dimensions, the clamping plate does not change. You just
    keep using smaller draw frames (with smaller and smaller corner radii) until
    they get to the desired size ~ the more steps, the less likely to wrinkle in
    the corners.

    David Janes
     
    David Janes, Sep 27, 2006
    #3
  4. super88

    Stu Guest

    Also, re-drawing with different sizes rads may not be required, but
    just the amount of binder tonnage needs to be increased., along
    spotting the corners to allow the material to thicken to a point just
    before wrinkling occurs.
     
    Stu, Sep 28, 2006
    #4
  5. super88

    David Janes Guest

    Yeah, exactly, it's a highly technical process which is why I mentioned
    buying a book, taking a course, getting a degree, whatever, something,
    anyway, more serious than popping in here for a freebe!! And why I stuck to
    some cartoonish basics. I took that long-forgotten course in a tooling
    apprenticeship and learned 10 times that from guys that did it every day.
    But, nobody's experts here and if we were, we'd be onsite, charging big
    bucks just to look at your setup. But, if you're using bottle jacks, buy
    more of them, in fact, double the number and yeah, definitely lock down
    those corners plus one on the each short side and two on the long sides or
    something proportional. Anyway, the long sides pulling is not as big a
    problem, for wrinkling, as the corners pulling.

    Good luck,
    David Janes
     
    David Janes, Sep 29, 2006
    #5
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