New here, is this reasonable ?

Discussion in 'New member introductions' started by Tree, Nov 27, 2019.

  1. DavidF

    DavidF Administrator Staff Member Banner Member

    Just make sure you put what ever you use into some sort of frame, like an aluminum frame.
    We all love to cast things in metal on here, but sometimes casting is not the best route to take when you just need to get to point B...
    Still think your better off with epoxy resin, but doesn't hurt to experiment with other materials...
     
  2. Peedee

    Peedee Silver

    Sorry but even if you lost wax the moulds you'll still need draft to get the plastic part out of it! Industry uses multiple cheeks and moving cores to get parralel sides, say a box, and that gets complicated quickly.

    So it's all well and good getting the mould with no draft but plastic part will be stuck firmly in it. The Chinese spend hours hand polishing moulds by the way.

    I've dealt with a lot of plastic moulding so if I can help any I will. Good luck.
     
  3. DavidF

    DavidF Administrator Staff Member Banner Member

    I just measured a lego and it does appear to have a very slight draft to it, only .002" so if he does take a mold from an original he might be ok.
     
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    Also looking at the Lego block you can see the injection point in the top of one of the pegs.
    There appears to be no ejection pins on the outside so I'm thinking the legos pull free from the female side of the mold and are stuck pretty well on the Male portion of the mold which would be pulled through a stripper plate to remove them....
    Screenshot_20191128-105821_Gallery.jpg
     
    Last edited: Nov 28, 2019
    Tobho Mott likes this.
  5. DavidF

    DavidF Administrator Staff Member Banner Member

    Hmm, actually looks like there are ejection pins on the back side. I see 4 down either side of the lego block....
    Screenshot_20191128-113046_Gallery.jpg
     
    Tobho Mott likes this.
  6. Jason

    Jason Gold

    But he's not making a lego.... or is he?o_O
     
    Tree likes this.
  7. DavidF

    DavidF Administrator Staff Member Banner Member

  8. Jason

    Jason Gold

    The enterprising prowess of the chinese never cease to amaze me.:rolleyes:
     
  9. Tobho Mott

    Tobho Mott Gold Banner Member

    I remember several years ago when one of their competitors won a court case after which anyone could make and sell Lego compatible blocks. Ever since then it's been all about the licensed branding. Want the Harry Potter or Frozen stuff? Then you gotta pay up for real Lego, not that cheap Megablox crap. :rolleyes:
    Whatever happened to Lego being "a new toy every day"?

    I liked the spaceman Lego when I was a kid, sure you'd build the ship on the box once, but then you'd tear it back apart and build a bigger ship combined with pieces from your other Lego kits because the one on the box wasn't anything iconic. Than you'd do it again and again and again.

    The branding on the new kits makes kids want to treat them like they're collectible models, almost like the villain in the actual Lego movie, who superglues all his pieces together once the kits are built!

    Jeff
     
  10. DavidF

    DavidF Administrator Staff Member Banner Member

  11. Tree

    Tree Copper

    Hey that looks pretty reasonable.

    lmao about casting my own mill to mill stuff :)

    About the draft on the lego, I was hoping it would have some from the original part, glad to see it confirmed!

    I happened to see this
    [​IMG]

    Looks easy enough :rolleyes:

    Again, the whole Lego thing is really a test. I feel if I can replicate Lego pieces and have them work with original pieces, I could probably do anything else I wanted. My obsessive thinking with all of this started when I kept breaking RC car parts and did not want to spend 1000% the cost of the plastic on the replacement part. That isn't even exaggerating.

    Glad to see all the responses! Sorry I didn't get back sooner, I stopped getting email updates about this.

    I probably won't start on anything anytime soon, just getting my ducks in a row.

    The casting a mill is a perfect image for how I'm thinking about all this.
    For example I want to...
    shred plastics to be recycled as parts (build shredder, or hack a power tool)
    build plastic injector
    build molds
    build foundry to cast molds out of metal
    who knows what else!

    I'm just having fun thinking about all of this, maybe one day I'll get to do it :D

    Thanks for putting up with my loony mind hah
     
  12. Jason

    Jason Gold

    Yeah this stuff is pretty heavy in the precision machining department. I flew RC helicopters years ago and made the mistake of buying an all cnc aluminum ship.
    What a HUGE mistake that was. It was called the quick 30. I'll tell ya, that piece of shit cracked nearly every component of it after just a few short flights. :( I pawned it off on some unsuspecting sucker and bought a Hirobo Sceadu. It was a 30 size heli with a 50 motor in it and ALL glass reinforced plastic. I learned then that shiny blue and red parts are not worth the metal they were made out of in scrap. Keep in mind, this stuff was CUT and not cast. The real money is in the tooling, not the 3cent parts these guys pound out by the mega-gross.

    If you are real serious about making molds like in that last photo, I would suggest you save your pennies and invest about 20k into a 5axis machine. Old jewelry machines would work well for this small stuff. A buddy of mine here had a beauty that was used to cut intricate waxes for casting. I would cringe when I watched him cut aluminum on it.:eek: It would do it just fine, but at that point, it's jewelry days were probably over.:rolleyes: It was a roland with very low time and in pristine condition. It set him back almost 20. He ran solid works. If you aren't up on CAD, now would be the time to get to learning. It took him 2 solid years before he could draw anything worth a damn. It's a lot of work and any bozo can draw a square with holes in it, but shit gets real deep after that.:eek:
     
  13. DavidF

    DavidF Administrator Staff Member Banner Member

    Inverted landings does have that effect....;):rolleyes:
     
    Jason likes this.
  14. Jason

    Jason Gold

    That stupid thing cracked just learning how to hover! I spent tons of time balancing anything that moved. Just the wrong material for the job. It was PRETTY I'll say that.;)
     
  15. Tree

    Tree Copper

    I made the same mistake, bought some aluminum axles and rims. Looked real pretty but after rolling the RC car they bent and never balanced again.
     
    Jason likes this.
  16. Tree

    Tree Copper

    I plan to reference this thread when I start trying this, so I'm leaving a note to myself (and others!?) If this works...

    I've been stuck thinking how I can create the wax halves of the mold, maybe I figured it out. I don't want to do silicone molds to make wax pieces to then cast the metal. Because once (if) it works I would theoritically never use the silicone mold again, waste...

    So then I thought, ok, pour the melted wax directly on the part to make the first half. Let it cool. Then pour melted wax on the other side of the part for the second wax. Duh they will melt together, ruining both halves... Doh.

    Instead of having both halves made of wax before I start trying to investment cast them, why not do one at a time!!! Pour the first half, let it cool, investment cast that half. Once I successfully create that metal half, I can place the part back in the metal mold half (yes I know it's a no-no to remove the part before both halves are made, but maybe it will work??) Then pour wax directly on the part and metal half to create the second wax half!! Then I can investment cast the second half into metal.

    It's a very lengthy way to end up with something that can only be used as a paperweight and a story to tell my grandkids!:D
     
  17. Jason

    Jason Gold

    Nice theory... but dont hold your breath on this working. You can have the best fitting wax parts and by the time you end up in metal it wont fit for jack shit. Did you see "Barry Luke builds" recent video with the two kids on a swing? That's the name of his channel on yt. Casting is anything but precise.
     
  18. crazybillybob

    crazybillybob Silver Banner Member

    Skip the CNC mill if you want to make lego type molds EDM is where it at! That mold looks like a sinker EDM job. So you'll still need the CNC mill to cut the brass,copper, or graphite sinker. Bonus the EDM machine will be cheaper.
     
  19. Jason

    Jason Gold

    Is EDM finally up to speed now? I remember AvE was trying to do something with edm a few years ago.
    Very interesting.
     
  20. crazybillybob

    crazybillybob Silver Banner Member

    EDM has been the go to for tight tolerance for 10+ years if you have $$$$$$$ for the equipment. AVE was trying to get a rig figured out that the home gamer could afford. Not as many bells and such...With the precision of a 3d printer. not as good but 1000th the price kind of thing.
     

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