Creature Design Enabled by 5-Axis CNC

Details on the product design and build process are rarely presented in the comprehensive, concise fashion of this video from John Cox’s Creature Workshop. Sure, he’s building limited run sculptures for the entertainment industry but the process of sculpting, scanning, processing, machining, and assembling is common to many design industries. Plus, I love seeing practical applications of 5-axis CNC machining.

Here are some photos of the process:

Sculpture Scanning




Beautiful Deconstruction

Photographer Todd McLellan takes the product take-apart to a new level by artistically arranging the parts and photographing them, then photographing the parts, presumably, being tossed into the air.

The products he takes apart are a few technological generations old but it is still insightful to see how they look on the inside and marvel at the complexity. Younger engineers will be amazed at the level of detail achievable in the pre-CAD era.

More at; click the “New Work” link on the left and have a look at the video of the deconstruction and photography process.


Dieter Rams’ 10 Principles of Good Design

It’s a classic that you have probably seen before and here it is again for quick and easy reference:

  • Good design is innovative
    The possibilities for innovation are not, by any means, exhausted. Technological development is always offering new opportunities for innovative design. But innovative design always develops in tandem with innovative technology, and can never be an end in itself.
  • Good design makes a product useful
    A product is bought to be used. It has to satisfy certain criteria, not only functional, but also psychological and aesthetic. Good design emphasises the usefulness of a product whilst disregarding anything that could possibly detract from it.
  • Good design is aesthetic
    The aesthetic quality of a product is integral to its usefulness because products we use every day affect our person and our well-being. But only well-executed objects can be beautiful.
  • Good design makes a product understandable
    It clarifies the product’s structure. Better still, it can make the product talk. At best, it is self-explanatory.
  • Good design is unobtrusive
    Products fulfilling a purpose are like tools. They are neither decorative objects nor works of art. Their design should therefore be both neutral and restrained, to leave room for the user’s self-expression.
  • Good design is honest
    It does not make a product more innovative, powerful or valuable than it really is. It does not attempt to manipulate the consumer with promises that cannot be kept.
  • Good design is long-lasting
    It avoids being fashionable and therefore never appears antiquated. Unlike fashionable design, it lasts many years – even in today’s throwaway society.
  • Good design is thorough down to the last detail
    Nothing must be arbitrary or left to chance. Care and accuracy in the design process show respect towards the consumer.
  • Good design is environmentally friendly
    Design makes an important contribution to the preservation of the environment. It conserves resources and minimises physical and visual pollution throughout the lifecycle of the product.
  • Good design is as little design as possible
    Less, but better – because it concentrates on the essential aspects, and the products are not burdened with non-essentials.

    Back to purity, back to simplicity.

Copyright Dieter Rams, amended March 2003 and October 2009

Though Dieter was primarily an industrial designer every one of these points are equally applicable to product engineering.

Check out the interview for some additional context.


Moldflow and FEA

Moldflow Algor Interop

I’ve said it before and I’ll say it again, there’s nothing like having a prototype to evaluate (The Value of Physical Prototypes & Moldflow and Part Visualization). This is mostly due to the fact that simulations that represent real-world performance are timely and costly to develop. I can’t remember an instance when I relied on FEA alone without empirical testing to establish actual performance of the simulation.

Autodesk is getting closer to bridging this gap between simulation and the real world by integrating key features of its large software portfolio. The first thing they did that impressed me was their integration of Moldflow and Showcase to aid in the visualization of cosmetic defects on plastic parts (re-link: Moldflow and Part Visualization).

Even more interesting and, in my opinion, useful, is their interoperability between Moldflow and Algor (FEA/mechanical simulation) which addresses the issue of simulated material properties vs. real-world material properties. Typically material properties are applied to FEA models with the assumption they are isotropic. But most injection molded plastics are anisotropic. The real material properties of injection molded plastic parts are dependent on many factors. Flow of material through the mold is an important one since it is the material flow that determines fiber and molecular orientation. This is especially important in the case of glass-filled resins; the strength in the direction of the glass fibers is greater than in the transverse direction. The magic bit of the Autodesk offering is that Moldflow results can be imported into Algor where they are used to calculate material properties at each point in the FEA mesh, better representing the plastic part coming out of the mold. Different gate locations and process parameters can be simulated through both Moldflow and Algor to determine how to maximize the performance of the part in critical areas.

Moldflow Algor Interop

It’s not going to eliminate the need for empirical testing of final parts but it definitely helps in optimizing designs early in the process.

{Update February 22, 2011: Thanks to Bob Williams (@ADSKsimulation) for the link to the video}

Have your say in the forums

Injection Molded Part Tolerances


Continuing the discussion of geometric variation on mechanical components, it’s time to talk about plastic. Before getting into details of injection molded plastic part tolerances, you might want to have a look at these two posts that provide a foundation for the following discussion:
Injection Molded Plastic Parts Checklist
EDM Tolerances

Let’s have a look at the major factors that affect plastic part tolerances.

  • Part Design
    As a general rule the achievable tolerance on any given dimension is a function of feature size; roughly ±0.2% to ±0.5% depending on some other factors we will discuss below. It’s easier to hold tighter absolute tolerances on smaller parts and features than it is on larger parts.
  • Material
    All engineering thermoplastics shrink as they cool, providing a challenge for the tool designer who must create a mold at the size the part will be at the time of molding. The adjustment can be made via non-uniform scaling of design geometry based on the material specified. Since each material has a unique shrink rate it can be difficult or impossible to run a different material without significant tool modifications.
  • Tool Design and Construction
    Injection mold tools can be incredibly complex and sensitive and designing them is an art. The design must compensate for the material shrink as mentioned above, and that’s just getting started.  Tools can require mechanisms to provide transverse motion, water lines and heaters for thermal control, and geometry to accommodate the molding press. Tools with multiple cavities for the same part are quite common. Depending on how each cavity is cut and the tolerances required there can be significant variation between cavities.
    A complete description of tool design concerns is far beyond the scope of this article. Understanding the complexity and importance of the tool design and construction is the point. So give your tooling engineers a cookie next time you see them.
  • Processing
    A mold press can be quite complicated with many moving parts, sensors, heaters, fluid channels, and control systems. The process of getting all these parameters dialed in to produce a good part can be tricky. Once dialed, any deviation may cause a change in part geometry after the part cools. Like tool design, a complete description of processing is far beyond the scope of this article and simply understanding the complexity and importance of processing is the point.
  • Equipment
    Just as variations in processing result in part geometry variation, variations in equipment will also result in more variation in geometry. Expect wider tolerances on parts coming off of older, more worn equipment. The same goes for older tools; variation increases with tool-wear.
  • Cost
    Tight processes typically require longer cycle times which results in less capacity (parts-per-hour per tool) so you can expect to pay more. On the other hand, if you run the process fast you get more capacity but with higher geometric variation. Finding the sweet spot between cost and tolerance range takes time and effort. So give your tooling engineers another cookie next time you see them.
    You now know that part geometry drifts as tools wear out. Newer tools produce more consistent parts but new tools are expensive and the expense of tooling usually gets rolled into part cost.

All of these aspects will play a part in the overall geometric variation. You won’t know the actual limits of your part size until tools have been cut and T0 parts have been run and inspected. So where do you begin when you’re in the early design phase? The Form Loves Function Plastic Part Design Checklist is a good place to start.

There are several good resources available:

{image: Roberto Bouza}

Have a comment? Post in the forum.

Clean New Look

Update March 16, 2011 – less clicking while keeping it clean:
Site Screenshot


New logo, new layout, new features with more on the way. Not only is the new layout crisp on your desktop, it scales nicely for mobile devices. Give it a try on your Droid, iOS device, etc.

New content is in the queue so check back in a day or two or subscribe to the feed.

Enjoy the whitespace.

Comments are happening on the new Form Loves Function Discussion Forum.

Creo – PTC’s New Take on Product Development Tools

Looks like PTC is serious about integrating their somewhat disparate technology holdings with their new “Creo” suite which includes renamed versions of Pro/ENGINEER, CoCreate, and Product View. Using direct modeling tools on a history-based parametric model would be incredibly enabling for Pro/E users. I’m also digging their role-based approach to the offering and I’m looking forward to learning more about how they break out the apps and licensing for different user types.

The intro video:

Click here to watch the intro event.

Develop3D has a good summary of features.

Click here to tell us what you think in the discussion forum.

James Dyson on Building Innovative Culture

Dyson Ball Image

When a designer as successful as James Dyson talks about engineering and manufacturing as one of the cornerstones of innovation I tend to listen:

… Mr. Dyson is an adviser to Prime Minister David Cameron on how to accelerate Britain’s development of new technology and build up its manufacturing and export prowess.

Prominent business leaders in America have recently pointed to the same issue — that modern manufacturing, and the scientific and engineering skills that make it possible, are a crucial pillar of a healthy economy. The two most notable and outspoken on this subject have been Andrew S. Grove, the former chairman of Intel, and Jeffrey R. Immelt, chief executive of General Electric.Relying on services alone and neglecting manufacturing, they say, is short-sighted and pushes good jobs abroad.

Dyson’s Ingenious Britain, linked in the article, is also an insightful read.

Read the full article at How to Make an Engineering Culture

As always, comments are welcome in the discussion forum.

ID Resource List at Product Design Hub

I just now noticed a great list posted by Waikit over at Product Design Hub. Hit the link for details on:

  • Textures
  • Free Stock Images
  • Persona Collage Creator
  • Color Inspiration & Tools
  • Portfolio Hosting
  • Image Hosting & Sharing
  • Salary/Hour Rate Indicators
  • Invoicing Tools
  • Patents Databases
  • Material Databases
  • Anthropometric Data
  • Survey Tools

There is a pretty good discussion going in their forum.

IDES is a good materials resource I didn’t see on the list which is a great complement to MatWeb.

Comments are welcome in the Form Loves Function Discussions Forum.