3d printed crankshaft

Discussion in '3D Printing' started by DavidF, Oct 26, 2017.

  1. DavidF

    DavidF Administrator Staff Member Banner Member

    Well rather than further derail ESC's thread on his crankshaft pattern and casting I figured I would put it up over here in this empty section..LOL
    After seeing ESC's crank I remember seeing a cad file somewhere and wondered how well one could be 3d printed. I found the file here https://grabcad.com/library/chevy-crankshaft The person who modeled the crank also modeled a block and heads to go with it ;):D:D
    I was concerned about all the support material, but figured what the heck give it a try.... here is the print with the support material still in place....
    printed crank2.jpg

    It took about 25 minutes to peel away all that support. The print didnt come out too bad but will still need a bit of finishing to get it right. the interesting thing is that the oil passage ways came out just fine and are clear/open. Well here it is.... Got to love 3d printing.. especially when someone has done the hard work for you and shared his work freely....
    printed crank.jpg

    The block is a 40 hour print....think I better drop in a fresh roll of filament... :D
     
    _Jason, Al2O3 and Mark's castings like this.
  2. PatJ

    PatJ Silver Banner Member

    That is pretty dang far out.
    Technology has come a long way.

    I guess you could add a few layers of tape at the journals to build them up and get a little machining tolerance? assuming that it printed at the finished journal size.
     
  3. DavidF

    DavidF Administrator Staff Member Banner Member

    Yes finished size. The print is measuring about .009" under from what it should be on the mains but I can bump the x y dimensions a bit in the slicer to make them larger without effecting the Z or play with the extrusion width to dial it in closer. I can typically get within .005" or less but this is just more for fun than anything..
    Tape works too LOL
     
  4. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I like it! Gonna (investment) cast it? In iron? I've gotta get into 3D printing.

    Best,
    K
     
  5. DavidF

    DavidF Administrator Staff Member Banner Member

    In a week or two, have a couple other things I need to finish off first...
     
  6. ESC

    ESC Copper Banner Member

    Beautiful David. I spotted it on the new member thread, but just noticed it here.
     
  7. DavidF

    DavidF Administrator Staff Member Banner Member

    It will need some clean up work, the undersides of the counter weights where the support material was is pretty rough.
     
  8. DavidF

    DavidF Administrator Staff Member Banner Member

    did one in 1/4 scale... not nearly as impressive looking as 1/3 scale but it printed better at the smaller scale... two cranks.jpg
     
  9. PatJ

    PatJ Silver Banner Member

    I need a cast one of those (the cranks, not the beer).
     
  10. DavidF

    DavidF Administrator Staff Member Banner Member

    Still playing around... sick as a dog this weekend so im just sitting around printing things. It might be able to cast this as well, but there is no way to get the water jacket to come out.
    I was trying to import the step file of the head and do a boolean subtract to get patterns for cores, but my computer had a serious disagreement with that LOL.
    They will make good test pieces for lost pla casting.
    head print.jpg
     
  11. DavidF

    DavidF Administrator Staff Member Banner Member

    Printed out the block the past couple of days.... The head bolt holes and everything seems to line up right :) The crank is a snug fit and would require a bit of machining from the counter weights to get it to fit right (thats a good thing) The block was a 40 hour print, so I would hate to go screwing it up. But I do wonder if it is possible to pull a mold from it and make a wax pattern.... Although I didnt figure in that much shrink allowance when I printed it...
    20171102_103027_resized.jpg 20171102_103015_resized.jpg
     
  12. DavidF

    DavidF Administrator Staff Member Banner Member

    20171102_121754_resized.jpg
     
    Jason likes this.
  13. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Hey at least you got something out of being sick and laid up. I take the water passages are present in both the block and heads? Yes?

    K
     
  14. DavidF

    DavidF Administrator Staff Member Banner Member

    Yes. but I see no easy way to cast them as is...
     
  15. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    You remarked before about investment no liking blind holes. Ever try modifying the investment with fillers in those localized areas?

    K
     
  16. DavidF

    DavidF Administrator Staff Member Banner Member

    How??
     
  17. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Refresh my memory on the problem.....did the investment break/crush during burn out in the blind holes?

    K
     
  18. DavidF

    DavidF Administrator Staff Member Banner Member

    It likes to crush and break off and lil bits of investment go floating around the mold. The cores in this thing would be very very thin as well. Im thinking about hollowing out the inside of the block and casting it without sleeves sio there is one big center opening. that would make it much easier to do. But looking at it that would create another problem....The bores are Siamese and there would be very little meat to seal the sleeves to... reducing the bore size would conflict with the heads combustion chamber size.... Ill be kicking it around for a few days before attempting to take a mold from them...
    Printing what would look like a head gasket now to be glued to the head and block to add some allowance for machining....So thats one hurdle over come. I would have just extracted the geometry from the head and extruded it, but there are some irregular vertices causing havoc. Much easier to extract the geometry and copy/paste into a new model. Might try to assemble the head to the "gasket" and print that way...
     
  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    So I can see how what you propose could help on the block could work, but not sure I follow on the head. If you glue the extraction back onto the head you still have an intricate core in there that would need to survive burn out. Or are you thinking conventional patterns core prints/chaplets and cores?

    K
     
  20. DavidF

    DavidF Administrator Staff Member Banner Member

    With the head I think I can just drill a passageway below the intake ports, behind the valves...... Should provide ample cooling. Think thats how ESC did his...?? 20171102_140430_resized.jpg
     

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