Re: [rp-ml] Design for (Rapid) Manufacturing

From: <>
Date: Mon Mar 09 2009 - 09:48:37 EET


You´re right, DFM is well documented for almost all conventional
manufacturing routes while for Rapid manufacturing it is necessary to
compile the info from separate (some times dificult to find) sources.
I'm sending you the link of an interesting material available on the
SME website. It's a DFRM tool questionnaire developed at Loughborough
Univ. Althought it may contain basic aspects its a good starting point
for designers eager to explore the opportunities of RM:


Universidad Politecnica de Cataluña
Barcelona España

"William Watson" <> escribió:

> RP-ML:
> I was recently asked by our local IDSA chapter to write a short note
> on designing for rapid manufacturing processes.  Although there is a
> lot of documentation on design constraints for other manufacturing
> processes (injection molding, sand casting, et al.), there is little
> help for designers in the additive fabrication space. 
> I thought I would open this conversation up to the RP community with
> the hope of finding more help for the designers looking for better
> prototyping guidance as well as developing support for accepted DDM
> constraints. 
> The article below was written for the industrial designer with
> little or no experience with rapid manufacturing.  Obviously there
> is much more detail and depth than I covered.  Hopefully this is a
> good place to start. 
> The original can be found at:
> Here is the
> text: 
> Design for (Rapid) Manufacturing
> Rapid Prototyping (RP), Additive Fabrication, Direct Digital
> Manufacturing, 3D Printing are just four of the many different ways
> to describe the twenty-two -year old industry based on technologies
> that build parts up, layer by layer. For the designers new to the
> technology, the promise is the same:
> Everything drawn in 3D CAD can be sent to a 3D Printer.
> If only product design was that easy. When your design process
> involves rapid prototyping, knowing about the materials and process
> can improve the outcome of your prototype.
> There are two equally false thoughts about prototyping materials:
>   • RP parts are super fragile and super expensive – DON’T DROP THE
>   • RP materials come from “unobtainium” and are a perfect match for
> all designs and assemblies
> Although the first notion was probably true ten years ago, things
> have improved dramatically. Materials are stronger and better mimic
> the engineering polymers intended for production parts. Also, lower
> cost processes have reduced the overhead of many suppliers. For many
> processes, ordering a second piece only adds a fraction of the cost
> of the first. Since your marketing manager is going to keep the
> first model, might as well order two so you have one to use to
> communicate with engineering and manufacturing.
> Of course, the thought that RP machines can make everything is
> equally false. If your design includes sheet metal, expect to make
> some thickness changes before sending the STL file to the model
> shop. Many assemblies incorporate multiple materials to optimize the
> design for strength or weight. Do not expect one RP material to
> cover that very wide range of material properties.
> So, what is a designer to do? First, think about your design and
> product development goals. Then pick a prototyping strategy that
> best meets those goals.
> General design considerations:
>   • When Outsourcing
>     - Match your design with the right process
>       • Small medical device? SLA
>       • Color concept model? Z Corp
>       • Over molded plastic/rubber? Objet
>     - Be realistic about lead times
>       • Start to finish with shipping time, outsourcing takes a week
>       • Give your supplier a heads up when projects are on the way
>     - Understand cost and time drivers
>       • Material Volume
>       • Build Envelope
>       • Post Processing
>   • In House 3D Printing
>     - Know the strengths and limits of your process
>       • Modify the design to make post processing easier
>       • Know when to use assemblies, and when to manually assemble components
>       • Use hollow or sparse builds to minimize costs
>     - Understand support materials and post processing
>     - Determine how to make the build more efficient. What drives time?
> Just like most other manufacturing processes, RP appreciates good
> design. Simple rules like constant or similar wall thicknesses help
> make growing and processing the parts much more efficient.
> Cantilevered beams often need support, and sheet metal features need
> to be thickened. Most importantly, using good design sense and
> understanding how your parts are made will help you make better
> designs in less time with less money
> Bill Watson, IDSA is the managing partner of Anvil Prototype &
> Design (, a Z Corporation partner and RP
> service bureau based in Charlotte, NC.
> Bill Watson
> Anvil Prototype & Design
> 4101 Stuart Andrew Blvd. Suite F
> Charlotte, NC  28217
> Voice:  704-527-8171
Received on Mon Mar 09 09:52:25 2009

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