properties of metal printing

Discussion in 'Technologies and Hardware' started by cstratton, Aug 6, 2009.

  1. cstratton
    cstratton New Member
    Are you able to provide the strength and fatigue characteristics of the objects printed in metal 3D printing? Do they compare to, say, cast iron? Or is it more like the strength of zinc?
     
  2. joekneale
    joekneale New Member
    I'd really like some information on this as well. I am considering using this process to rapid prototype some trigger-group components for a firearm, but am worried about the stress and temperature, It would be nice to have even "proxy" data to know what the characteristics of printed material are roughly similar to!
     
  3. GlenG
    GlenG New Member
    I have been working with the exact same composite materials offered by SW's. I do not have the exact strength and fatigue numbers on hand but I can tell you what I have learned while handling, machining, finishing and coloring this metallic witches brew.
    It is a true composite, composed of S.S. alloy 420 and a tin bronze infiltrant (not sure of the CDA#)

    It is somewhat brittle, but has a better tensile strength than grey cast iron. Kind of like malleable cast iron. Thin sections will yield a little bit before fracture. This material is nothing like forged/ rolled material.

    It is quite abrasive and rather difficult to machine. Carbide tooling is really a must.

    It has poor heat conductivity. But this is a plus if it needs to be soldered or welded.
    Silver bearing hard solders flow well and penetrate to fill small voids. I use "Black" paste flux. It can also be welded via TIG. I've not done strength tests and would only use these method for cosmetic repairs or dovetailed joints.

    I have seen prototype turbine rotors used in real test scenarios. But gun parts? Maybe for lever type applications? Probably a bad choice material for sliding surfaces or any part subjected to high impact or sudden pressure.

    Hope some of this helps. I'll dig up some test specs to post soon.

    -G
     
  4. cstratton
    cstratton New Member
    thanks, that's helpful information.
     
  5. Tommy_2Tall
    Tommy_2Tall New Member
    I read somewhere (can't find the post) that SS alloys will produce some posionous gas when they get too hot..

    Do you (or anyone else) happen to know at what temperatures that would start to happen?

    Would it be safe to make a candle/tealight holder out of the SS-alloy that Shapeways is offering.. or possibly use it as a "heatsink" for electronics that don't get very hot?
    (The component I'm thinking about fails internally at 60-70 Celcius so anything above that would be an "epic fail").

    I know GlenG wrote about poor heatconductivity but it would probably better to try it out with an SS-object rather than dangling in thin air in an enclosed space.. right?

    Hmm.. someone was on the same track and got a reply that I had missed:
    http://www.shapeways.com/forum/index.php?t=msg&th=1139&a mp;start=0&S=cf780c85ba1f886bffc4f159c9a59227
    No word about gases there though.. did I get it wrong?
     
    Last edited: Aug 13, 2009
  6. GlenG
    GlenG New Member
    There is a potential hazard in all stainless steel alloys due to the Chromium content. If you Google "Hexelevant Chromium" you can learn more. This is only a real danger if you vaporize the metal, as in melting or welding. Breathing large amounts of metal dust could also be a hazard but only in industrial scale exposures. For your purposes or just about any SW user there is no hazard. Hey , even water can kill you if you drink too much at one time!

    As to using this material for a "heat sink", it would be about as useful as "teats on a boar". Aluminum is the way to go. If you can't find an off the shelf part that fits then you could have it CNC machined to order.

    Hope this helps.

    -G
     
  7. Tommy_2Tall
    Tommy_2Tall New Member
    Thanks for the info! :D

    That project of mine feels 100% feasible now..
    All I have to do is model the heatsink as a separate removable part and send that drawing/model to the local CNC-shop.. wherever that is.. :confused
     
  8. GlenG
    GlenG New Member
    I will have to find the name and url but there is a US company that does short run stuff very inexpensively. You use their software to design the part and you get an instant quote. I'll have to hunt for the link but i will post it. I'm out of town for the weekend but should be able to post it early next week
     
  9. GlenG
    GlenG New Member
    Tommy,
    The shop I mentioned is: <www.emachineshop.com> . Good work, fast and cheap.
    -G
     
  10. Tommy_2Tall
    Tommy_2Tall New Member
    Once a gain, thanks for the help :D

    I'll definitely check out their services but I'm guessing that the delivery costs will make it less appealing to me (living in Sweden) :)
     
  11. joris
    joris New Member