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  • plastic moulding vs. aluminum moulding

    Discussion in 'Metal casting & moulding' started by Matti, Jan 24, 2013.

    1. Matti

      Matti New Member

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      I have some experience about plastic moulding, but on experience on metal moulding/casting. I assume metal moulding is more expensive than plastic. What is rough difference of costs if we would use aluminum molding instead of polycarbonate molding today?
       
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    3. tomatlots

      tomatlots Member

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      If we generally compare die casting to injection molding, the tooling costs are in the same ballpark, with die casting usually less expensive. depending on part size, injection molding is usually faster in cycle time. You can go online to get the cost numbers for materials, but be sure to convert them from cost/pound to cost/volume.
      Your best bet is to make two different drawings of the part showing two different materials, and submit them to a few vendors asking for "ball park only" numbers.
       
    4. ojacksonhill

      ojacksonhill New Member

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      Hi, just to clarify Tomatlots' answer, the cost for the part will be cheaper if plastic injection moulded but the capital cost of a die casting tool is could be cheaper depending on the type of die casting. You can have bench die casting which is lower capital outlay for a fully manual process through to semi-automated pressure die casting with a much higher capital outlay. (And you can probably do metal injection moulding of aluminium too - which would be more expensive than a plastic injection mould tool).
      As for actual cost differences, this depends completely on the complexity of the part. A small straight open shut part will differ hugely to a complex part with side actions/unscrewing cores etc.
      Hope this vagueness is somewhat helpful.
       
    5. Suresh Navandar

      Suresh Navandar New Member

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      Apart from cost of tooling, wall thickness for moulding has to considered in calculation so part weight. Aluminium will require min of 2 mm wall thickness with gravity of 2.75 g/cc, ABS material you can design min of 1.5 ~ 1.8 mm wall thickness, sp gravity of 1.05 g/cc.
       
    6. Mikael_Haell

      Mikael_Haell New Member

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      There are some more information needed to fulfill your request:
      - Size of part (roughly WxHxL)
      - Volume (amount mtrl needed)
      - Number of parts planned to produce (10 pcs or 1 million?)
      - For Injection molding, do you need a cooling system or not?

      I do agree with comments above; wall thickness, complexity of part have a large impact on pricing.
       
    7. parneetsinha

      parneetsinha Member

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      It is very nice thread and I am completely agree with all that price is depends on many factors like size and weight of molding, thickness and complexity, types of metal etc.
       
    8. heenaveer

      heenaveer New Member

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      Its all depends on size and type of metal....
       
    9. htmetalstampings

      htmetalstampings Member

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      Firstly, Aluminum will be die casted with high pressure and high temperature(620-650 degree),strength of Aluminum is much btter than plastic, further, anti-heat for aluminum is much better than plastic, plastic can be injection molding around 110-150 degree, so the quality for plastic injection molding will be much easie to control.
       
    10. roserim

      roserim Member

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      Material Differences

      It depends on the application of the molding/casting. You can determine which material would be best if you consider this factor first - talk with a plastic molding company and a metal die casting company directly to discuss what your best options are to fit not only your costs, but your quantities and best use for application.
      Let me know if you have any questions.
       
    11. K.I.S.S.

      K.I.S.S. Well-Known Member

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      Matti,
      Pressure die cast moulds are more expensive than plastic injection moulds, irrespective of comparable complexities.
      This is due to the significantly higher pressure required to squeeze liquid metal into a cavity, relative to having to squeeze liquid plastic into it.
      Because of the higher pressures required, more material is required to contain this pressure in the bolster without deformation (the chunk of metal that your mould cavities are machined into). This means that the bolster has to be larger. As a very general rule of thumb, the material cost of the bolster is approximately half your total cost for the mould.
      Some of the previous comments are accurate regarding wall thicknesses etc, and others not so accurate. Ultimately, your design will dictate what process is used, not the other way around.
      Also, keep in mind that when pressure die casting, Aluminium will degrade the mould cavity surfaces approximately twice as fast as Zinc will. On average, you'll get about 150,000 shots from Ali. and 300,000 from Zinc. I stress that this is very general info. as much depends on specific alloy type, cavity form, sprue placement and mould hardening methods. For plastic, it's even more non specific, depending very much on material type - FFN35 is almost comparable to Zinc, as a worst case scenario.

      K.I.S.S.
       

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