Motion Engineering Corner

The Future of 3D CAD: Online?

2008-07-11T04:57:00.000-07:00

At right is a screen shot of a "room" in Google's 3D Virtual World. The name of the room: Superhero's HQ.

Now, if you're like me, you probably find the whole Secondlife phenomenon to be somewhat...disconcerting, if not outright cringe-inducing. The level of dorkdom on such sites must be mind-numbing. The probability that the designer of Superhero's HQ has ever had a date with an actual girl is infinitesimally small, and just by looking at the image, a small zit has probably started forming in the middle of your forehead.

However, the SolidWorks blog SolidSmack points out the potential usefulness of a 3D virtual reality world: This could allow engineers to design within a browser, and it could be a huge step forward in collaboration, telecommuting, etc. They predict that SolidWorks 2010 might include some sort of Virtual Reality functionality. You can picture how this would work: You would have your own room (or lair, as the case may be), with various models lying around like furniture; you could invite someone into your room, where you could actually assemble parts into assemblies, etc.

This seems like an optimistic assessment of the motivations behind Virtual Reality to me. While gaming systems graphics cards can be used to run CAD, and advances in these graphics cards have been driven by gaming, the benefit to the CAD community has been peripheral and accidental. Actually incorporating CAD into Virtual Reality, and VR into CAD, would require a conscious effort and a lot of money, and I just don't see it happening. I can see the developers of this technology putting much, much more effort into the appearance of character's virtual breasts than they will into the interface between SolidWorks and VR.

But I could be wrong; so you might want to start working on your Viking Warrior avatar now.

Babbage's 1822 Design for a Mechanical Computer Actually Built, for the First Time

2008-07-07T10:12:00.000-07:00

In 1822, Charles Babbage designed a computer that was entirely mechanical. He never actually constructed it, but here's a video of someone who did -- the video actually shows him using the computer to find the solution to a polynomial.

Jewel Bearings: Not as Expensive as You Might Think

2008-06-23T13:27:00.000-07:00

Jewel bearings have always been relegated to use in things like watches and instruments, where their remarkable properties (very low stick-slip, virtually no thermal expansion, low wear) have distinct advantages.

But these bearings have other advantages: They run dry (no lube) and clean (generate virtually no particles), and their cost makes them competitive with ABEC-5 instrument bearings. Recent advances in synthesizing crystals, including sapphire, have made them more economical than they've been in the past.

Perhaps these pretty little bearings should be considered for general applications too.

A Remarkable Flexible Shaft Coupling

2008-06-23T12:36:00.000-07:00

OEP Couplings offers a shaft coupling that is unique and remarkable: Their type UI coupling has all of the flexibility of an Oldham coupling, with smooth angular misalignment accomodation of up to 6 degrees.

This has been done before, but to my knowledge, never so well or so robustly: The hubs are a single piece, machined from bar, and so is the plastic midsection. The hubs can be machined from aluminum, and then anodized (for low friction), or stainless steel. Midsections are available in either Delrin, or a remarkable 30% carbon-fiber-filled PEEK. Quality is outstanding -- all subcomponents are machined in the US, with an eye toward detail.

The axes of the two cylindrical fins actually intersect one another -- they lie in one plane, instead of being offset. The result is a remarkably efficient and smooth flexion -- there's a flash video of one of these couplings rotating at the website.

A Gyroscopic Joint

2008-06-17T10:32:00.000-07:00

The Wolfram Demonstrations Project has several interesting flash depictions of mathematical phenomena, but they also have quite a few interesting abstractions of simple machines.

The gyroscopic joint is an interesting concept -- essentially a double-universal joint with the joints nested within one another. This clearly wouldn't be a very strong shaft coupling, but for certain low-torque applications where axial space is at a premium, where a large angular misalignment must be accomodated, and where a constant-velocity (homokinetic) joint is necessary, this concept might find a niche.

Building a Scanner out of LEGOs

2008-06-17T09:53:00.000-07:00

Here's a project for a rainy day (or more like a week, for me, at least): A working color scanner made mostly out of LEGOs.

There are other interesting projects at this site, including a LEGO rover and a candy machine.

Lubricated by their own squeak

2008-05-28T07:43:00.000-07:00


Germany during WWII was a remarkable hotbed of engineering. Almost all of their innovation during this time was, of course, in weapons; and most of this innovation was not as readily transferable to peacetime applications as other nations' wartime advances (like Great Britain's work in computers and radar, for example; or the US's work in atomic fission).

But many of their innovations were decades ahead of their time. Look at the Tiger tank, for example -- and how dissimilar it was from other tanks of the day, and how remarkably similar it is to tanks like the Abrams, still online today. Look at the Me262 fighter, and compare it to other planes of the day, and even to jets that came later (like early Sabres and MiGs). Even in small arms development, the Germans led the way with the first legitimate assault rifle.

But one of the more interesting advancements by the Germans wasn't so much a result of their technical ability as it was pure serendipity, and their inability to produce a sealed bearing that would survive the harsh environment of a tank tread. I've only ever found one reference to this anecdote, so it might well be spurious; but it has the ring of truth to it.

Apparently, the Germans had an issue with squeaky bearings in the Panzer tank tread. This wasn't a big problem, since the sound of the squeak was usually accompanied by the sound of the tank's massive diesel engine; but the Germans were concerned about bearing wear. When they looked into this, they found that they'd stumbled upon a bearing that didn't need lubrication -- the squeak was just the right frequency to cause physical separation between the two surfaces for a substantial amount of time, and when the two surfaces weren't in contact, coefficient of friction and wear both went to zero.

But again, like many of the German innovations of WWII, I'm not aware of any applications of this phenomenon in more constructive endeavors. If any readers know of any other uses of this acoustic lubrication, let me know.

Welcome

2008-05-28T07:39:00.000-07:00

Welcome to the Motion Engineer Corner. I'm hoping that this blog will become a useful resource for design engineers in the motion control industry, and in other similar industries.

The focus, at least initially, will be on solutions to technical problems commonly encountered in our industry. I'll keep an eye open for new products that seem particularly novel or promising, either as materials for components, as components in assemblies, or as design tools. I'll also look for clever new design ideas that readers might be able to apply to their own assemblies; and I'll occasionally dredge up old ideas that might otherwise be forgotten.

But, to a certain degree, I'll let the conversation go in whatever direction it naturally leads, and I'm hoping for some constructive input from readers in the comments…should we actually have readers, eventually. Please let me know what interests you.

Some constructive suggestions for topics might include:

	A new product that you recently found, that you think might be particularly useful;

	An issue that affects design engineers professionally, like H1B visa issues, or salary, or job availability;

	A story or anectdote related to design engineering.

Suggestions that I'd consider less constructive and would not want to incorporate into our discussion might include:

	Who's going to win American Idol this time;

	Why Motorhead is underappreciated for their musicianship;

	Anything related to Kim Kardashian's butt.

…While this last verboten topic might actually have some interesting engineering issues associated with it (how does she actually avoid falling over backward?), these technical issues would be outweighed by the more prurient aspects of the topic; and while I'll try to make this blog entertaining, I'll also try to make it sfw.

Thanks for reading and commenting.