> Sean
>
> By using RP many of the elements and operations associated with the design
> and production process can be eliminated bringing significant benefits to
> the customer. To justify this a complete overview of the design,
> manufacture and operation of the unit needs to be provided so that this
> approach can be accurately quantified. Time scale, cost and functionality
> implications associated with this should also be analysed and where
> possible compared with a conventionally fabricated system.
>
> Traditionally designers have been forced to adjust product form to permit
> manufacture using conventional processes. This creation of components
> from assembled parts introduces complexity, reduces functionality and
> renders some designs uneconomic. Layered manufacturing offers the
> potential to eliminate these compromises by building individual integrated
> forms cost effectively. Until recently the relatively poor mechanical and
> dimensional properties of RP models has prohibited their use directly in
> real world applications. Progressive development of various RP processes
> has now reached the stage where these systems may be considered as viable
> production platforms for the manufacture of selected, limited run,
> components.
>
> To take the case of a Cryogenic Blasting nozzle, we found that the break
> even point for an additive manufacturing approach (SLA 350) was just 12
> components. With reference to functionality these SL 5190 models were run
> at 6.5 Bar dynamic pressure, with nozzle velocities of 350 m/s and with
> frozen CO2 at below -85 DegC going through them - there was no wear and
> only moderate thermal stress fractures. The models were used to optimise
> 9 design iterations at once and proved to be representative when compared
> with control production spec components. In this instance I wouldn't
> necessarily use this SLA resin for service but might consider specifying a
> high performance epoxy system or an SLS Nylon as the end material. The
> only concession required when using SLS powders rather than liquids would
> be the post reaming of the injector nozzle to reduce frictional losses.
>
> This case study is just one of a number of examples where we are using RP
> models as functional components and I see a huge niche, expanding in line
> with accuracy and material performance, for the Free Form Fabrication
> 'Press & Play' approach. Having said this it is important to remember
> that we must use the strengths of each manufacturing approach (including
> rapid tooling) in parallel to achieve the most effective performance /
> cost result. Using the Cryogenic Blasting nozzle as an example again,
> where the design featured a straight barrel it is best to buy a section of
> pipe rather than build it in layers. Conversely one of the designs we
> trailed featured rifling inside the barrel and this could be economically
> produced via the additive route. Good luck with your Masters.
>
> Regards
>
> Ben (Halford)
> PERA Technology
> England
> ben.halford@pera.com
> 0044 (0)1664 501501
>
> -----Original Message-----
> From: Sean M Gladieux [SMTP:Gladieux_Sean_M@CAT.com]
> Sent: 05 August 1999 19:08
> To: rp-ml
> Subject: RP Project-Die Cast parts
>
> Well, I am taking the leap of faith here. I have been reading this RP list
> for
> quite some time but haven't yet posted any messages. But I think it is
> about
> time.
>
> I am a graduate student at Bradley University, Peoria Illinois and am just
> beginning to develop my masters project proposal for my MS in
> Manufacturing
> Enginering. I am interested in performing a cost analysis of RP part
> manufacture compared to traditional part manufacture. I am thinking about
> selecting a fuel filter base part for a heavy duty industrial engine. The
> part
> is normally die casted. The part has been manufactured with RP technology
> by
> John Howarter of Caterpillar Inc, so I know it can be done. What I plan
> to do
> is to analyize the cost benefit ratios, and cost savings of using RP
> technology to produce over die casting with CNC produced dies.
>
> What I would like from anyone who has lasted this long into my message is
> any
> advice or input as to where I should go with this project. This is an
> open
> ended request. I was just wondering if anyone out there has already
> performed
> this type of analysis and if so would you share your insights with me. I
> would
> like to be able to contact you during my project's development if
> possible
> too.
>
> Any input is always appreciated.
>
> I can be reached via personal email at ssglad@cat.com
>
> Sean M. Gladieux
> Industrial and Manufacturing Engineering and Technology Department
> Bradley University
> Peoria, Il 61629
>
> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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