[HN Gopher] Semi-Solid Casting Enables Net Shape Volume Manufact...
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       Semi-Solid Casting Enables Net Shape Volume Manufacturing
        
       Author : baybal2
       Score  : 21 points
       Date   : 2021-05-30 14:49 UTC (8 hours ago)
        
 (HTM) web link (www.engineering.com)
 (TXT) w3m dump (www.engineering.com)
        
       | mikewarot wrote:
       | The article hints that this is the process used to cast car
       | frames, and does _not_ mention Tesla by name. The pressures
       | required in this method require actual dies, and not the sand
       | casting that is within the range of the home shop.
       | 
       | Interesting things to know, but not something directly applicable
       | to me. Thanks for posting it.
        
         | p_l wrote:
         | It's not like Tesla is anything special there, except for
         | buying Italian-Chinese industrial caster for their product
         | line, probably heavily due to being in the right time
         | (combination of availability and building new line for a fresh
         | product meaning they could do new design).
        
         | antattack wrote:
         | Tesla is using high pressure casting which, which supposedly,
         | as per article, is more expensive, requires larger machines,
         | wears out molds faster and requires additives than semi-solid
         | casting.
        
           | baybal2 wrote:
           | Some background to it.
           | 
           | For laptop sized parts, semi-solid rheocasting,thixomolding
           | is much cheaper than conventional casting on per part basis,
           | and usually gives you superior fine features like studs,
           | ribs, thin walls, and thus _greatly reducing the need for
           | final machining._
           | 
           | Downside is that semi-solid casting/molding machines are much
           | more expensive than conventional ones because of powerful
           | hydraulics, up to few times as much ($300k-$600k for making
           | CE parts,) and the cost grows much faster than the maximum
           | part volume. The alloy for them is also much more expensive
           | than common aluminiums.
           | 
           | But on scales of consumer electronics manufacturing, material
           | costs are minuscule in comparison to everything else, and the
           | net shape capability is 100% worth the premium.
           | 
           | Both techniques will give you equally high material strength,
           | but you will be paying much more for quality for conventional
           | casting, to the point the cost advantage is lost.
           | 
           | Stronger low silicon alloys will need higher casting
           | temperatures, and pressures to compensate for lower
           | castability, and will also need degassing equipment, more
           | expensive molds, and more extra equipment in general.
           | 
           | On the size of car chassis, I may bet the material cost will
           | start to make a difference.
           | 
           | As a rule, you will need a lot more extra material to
           | compensate for overall lower strength of cast parts.
        
       | kragen wrote:
       | What are the _disadvantages_? The article left those out.
       | https://en.wikipedia.org/wiki/Semi-solid_metal_casting says it's
       | "typically used for high-end applications" which suggests that
       | it's very expensive. https://en.wikipedia.org/wiki/Semi-
       | solid_metal_casting#Disad... says this is because it requires
       | much more precise control over process parameters.
       | 
       | This augurs well for SSM casting, since precise control is
       | immensely cheaper in 02021 than it was in 01977.
        
         | baybal2 wrote:
         | As I wrote below machines are n-times more expensive, and
         | alloys themselves are far from being common, or cheap too.
        
           | kragen wrote:
           | Thank you very much!
        
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       (page generated 2021-05-30 23:01 UTC)