Sand casting aluminum produces a way worse finish than 3D printing.
Worse case is that you have to do some mild polishing of the runners,
if indeed the fine parallel lines cause any negative anomalies.

On Thu, May 5, 2011 at 3:30 PM, H & J Johnson <hjjohnson@sasktel.net> wrote:
> Hey there Charlie. The technology to produce parts from a substance vs out
> of it [ie; additive fabrication rather than subtractive] is pretty new.
> There are some forms of accomplishing the job but they are not that cost
> effective today [any new technology is this way at the start usually]. The
> other limitation I've seen is the quality of surface finish. My main
> exposure has been in reading about it and from the articles I've seen there
> is generally a secondary machining operation required to get the parts to
> dimension. That is all fine on simple parts but something like a manifold
> brings new challenges as the interior of the various sections need to be
> smoothed out to get clean and consistant airflow. I think the time and cost
> of these two areas might preclude us using it at this point, however as
> things improve and the tech gets more affordable, this will become the way
> things are built in the future. Imagine if everything that was ever built
> had a 95% reduction in waste fro m how it's built today.  Your car would be
> alot cheaper to buy, etc etc.
>
> I love thinking outside the box... [it's how I was able to build my own cnc
> mill!]
>
> Jarrett Johnson
> www.innovention-tech.com
>
> ----- Original Message -----
>
> From: Charlie England <ceengland@bellsouth.net>
>
> Date: Thursday, May 5, 2011 12:53 pm
>
> Subject: [FlyRotary] 'open source' parts
>
>> I'm excited to see all the activity on the accessory cover/adapter
>> plate, & don't want to divert any attention. But Ed's post several
>> days
>> ago describing how he made his intake manifold triggered a thought
>> that
>> might need to go on the shelf for next action.
>>
>> The original idea that started all this was an intake manifold. My
>> intent is to use a very simple manifold similar to Tracy's Otter
>> manifold, but for those who need a more complex layout, what about
>> this:
>> If Jarrett, or anyone else on here, has access to one of the new
>> '3D
>> printers', doing a manifold should be a piece of cake for anyone
>> with
>> CAD skills (it ain't me...). Apparently, there are 3D printers
>> that can
>> use all manner of materials now. I wonder if you could 'grow' an
>> aluminum or other light/strong/chemical resistant manifold
>> directly in
>> the printer. Something similar to the plastic coiled tube
>> manifolds on
>> new V8's comes to mind.
>>
>> OK, back under my rock....
>>
>> Charlie
>>
>
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>
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