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Any opinions expressed in these blog posts by non-Proto Labs employees do not necessarily reflect the views of the Company.


DMLS lugs help build the ultimate urban utility bike

San Francisco is an ideal backdrop for a bike culture to thrive. Its temperatures remain consistently mild year-round, and its landscape seamlessly blends hills, streets and shoreline. Bicyclists commute to work, run errands, transport groceries (and their kids), and climb rugged bike paths to Bay Area overlooks. And that’s just a Monday.

This fusion of task- and recreationally minded biking activities amidst the natural and man-made architecture of San Francisco was the inspiration behind Huge Design’s recent entry into Oregon Manifest’s Bike Design Project. Along with the California-based design firm, organizers of the national competition asked teams from Chicago, Portland, Seattle and New York to create an urban bike that most represented their city. Teams included both a design firm and frame builder — the San Francisco team being composed of Huge Design, bicycle fabricator Forty One Thirty Cycle Works and engineering partner PCH Lime Lab.

The EVO utility bike by Huge Design, Forty One Thirty Cycle Works and PCH Lime Lab. Photo by Gauthier Richard.

The project merged an old-world, bike-building craft with new technology and a modern design process,” explains Chris Harsacky, founder of Huge Design and lead designer on the team. Together, they began developing an urban utility bike called EVO that would allow riders to very easily attach and detach different components — baskets, racks, pannier bags, a child seat — to the front and rear of the frame depending on their activity.

To achieve the plug-and-play effect, the team designed a bike frame that combined off-the-shelf 4130 chromoly steel tubing with 17-4 PH stainless steel metal lugs that were integrated into the frame. Due to the complex geometry of the lug design, which included a unique interior mechanism for clipping accessories in and out, engineers at PCH Lime Lab had the lugs build through Proto Labs’ additive manufacturing (3D printing) process of direct metal laser sintering (DMLS).

Read the full case study on Huge Design’s development of its EVO utility bike.


Protomold Design Tip: 3D CAD Programs

Look around. Nearly everything that you interact with was likely a creation of three-dimensional computer-aided design (3D CAD) — homes, furniture, automobiles, lighting, smartphones, computers. At its most basic level, a CAD program takes a designer’s two-dimensional sketch and extrudes, or solidifies, that drawing into a three-dimensional model. Depending the industrial focus of the CAD program, and the modular extensions used to support and enhance its software, product developers and engineers are able to design extremely intricate products that can be built or manufactured. At Proto Labs, every single part submitted for manufacturing arrives as a 3D CAD model in one of several different file formats derived from different CAD programs.

There are a few major design programs that are frequently used in 3D CAD model development for prototype and production parts, and to an extent, most play well with one another when files are exchanged between platforms.

  • SolidWorks (.sldprt)
  • Autodesk Inventor (.ipt)
  • PTC ProE/Creo (.prt)
  • CATIA (.catpart)
  • SpaceClaim (.scdoc)
  • SketchUp (.skp)

Additional neutral file formats that can be imported into and exported from most programs: 

  • IGES (.igs)
  • STEP (.stp)
  • Stereolithography (.stl)

Figure 1: The 3D model shows Proto Labs’ three-part Torus assembly in SolidWorks.

The applications available in each professional design program vary slightly from one to the next, but most contain versions of basic solid modeling; plastic and mold design; weldments, sheet metal, piping and tubing design; and large assemblies. But regardless of the industry or function they’re serving, most programs have a shared set of capabilities. 

Read our entire design tip on 3D CAD programs here.


Magnesium: The Lightweight Contender for Modern Parts

Long ago in a galaxy not far from here, fuel was cheap. Vehicles were large and not particularly efficient. Devices were heavy and tended to stay in one place, and iron was king. That was then; today, all that has changed. Energy is costly, vehicles are smaller and lighter, our devices travel with us in pockets or purses, and iron is something you pump for exercise. To meet our ever-growing demands for economy and portability, we have been steadily replacing iron with aluminum and plastic, and increasingly with magnesium.

Magnesium is finding its way into a growing variety of applications, particularly those in which it helps reduce energy consumption. In aerospace applications, it’s used in engines, airframes, and internal parts. In automotive applications, it turns up in steering components, seat and sunroof tracks, and interior frames, not to mention “mag” wheels. More recently, it’s being used in roof, hood, and rear-deck lids, manifolds, cylinder head covers, and oil pans. It is even being tested for use in engine blocks. And for similar reasons, magnesium is showing up in motorcycle and bicycle parts, such as lightweight frames. In consumer applications, magnesium is often used in laptops, cell phones, digital cameras, power tools, and sporting goods. Military applications include hand-held communication devices, night-vision gear, and robotics.

This is for good reason. Magnesium is the lightest usable structural metal — widely available and easy to produce. By weight, it’s the seventh most common material in the Earth’s crust and the third most common in seawater. It is found in every cell of the human body and is an essential element in the chlorophyll in green plants. Because of its reactivity, it is one of nature’s more sociable elements and does not naturally occur in elemental form. It is, however, relatively simple to separate from its salts, and once in solid form, its surface oxidizes, producing a tenacious protective layer that resists further oxidation. Additionally, it can be coated by various means for further protection.

While it can be used in essentially pure form, magnesium typically is found in lightweight alloys, most commonly with aluminum, zinc, or manganese. It’s nearly as strong as aluminum and about one-third lighter, giving it a significant strength-to-weight advantage. It has excellent electrical characteristics, excellent thermal conductivity, is reasonable in cost, and is easily recyclable. For these reasons, it’s a very desirable material, and we can expect to see magnesium in a growing range of applications as technology for its use and fabrication continues to develop.

Besides machining, which is typically used when small numbers of parts are needed, the primary fabrication methods for magnesium are:

  • Extrusion: typically used for simple forms;
  • Lost wax casting: a complex process of about a dozen steps that produces near-net parts and can be used for prototyping of complex designs; and
  • Die casting and thixomolding: net-shape processes typically used for larger runs of complex magnesium parts.

Read the full article on die casting, thixomolding and other magnesium prototyping and production applications at Designfax.


Started From the Bottom Now We're Here: The Rise of 3D Printing

It’s nearly impossible to have a conversation about the current state of manufacturing without mention of 3D printing, an additive process that uses digital CAD models to build physical, real-life objects, layer by layer. While additive manufacturing has existed for more than 30 years, it wasn’t until the last few that 3D printing, led by increased accessibility, has become the poster child for progressive technology within the industry — NASA prints telescope! Designers print runway pumps! Scientists bio-print human organs!

It’s undoubtedly an exciting time in manufacturing that has many eager to see what the future brings, but can the promise of a printed world withstand the heat? We deconstruct the layers of 3D printing to find the substance beneath the style.

The relationship between 3D printing and additive manufacturing is akin to Google and Web search or iPod and mp3 player. They’re essentially interchangeable with the former used much more frequently as an umbrella term that describes the latter. Technically, 3D printing refers to the process of building layered objects with an actual inkjet printer head; Z Corporation cleverly trademarked a process in the early 1990s called 3D printing (3DP), where a printer head solidifies powder layers with a liquid binder. However, a decade earlier, engineer Chuck Hull developed stereolithography (SL), which truly marked the dawn of 3D printing. Along with SL, which uses a fine laser to solidify layers of liquid thermoplastic resin, many other 3D printing technologies fall within additive manufacturing, namely:

  • Fused deposition modeling (FDM): spool of plastic filament or metal wire extruded from a nozzle into successive cross-sectional layers that form three-dimensional shapes
  • Selective laser sintering (SLS): thermoplastic nylon powder fused in layers to create solid objects
  • Direct metal laser sintering (DMLS): layers of atomized metal power fused to form fully dense metal objects
  • PolyJet (PJET): UV-curable photopolymers jetted by inkjet head, layer by layer, into final objects
  • Laminated object manufacturing (LOM): thin sheets of material cut and adhered together to form desired shapes
Read our complete cover story on 3D printing at protolabs.com/journal.

Medical Device Prototyping With A Manufacturing Hand From Proto Labs

Modern science has allowed surgeons to fix the human body amazingly fast, yet leave behind only small traces that repairs were performed. One of the more commonly used methods to achieve this is by a minimally invasive technique called laparoscopic surgery, where small incisions are made into a patient’s skin, a laparoscope is inserted to provide a magnified view of the patient’s organs, the procedure is performed, and the incision is closed by stitching or surgical staples. You can have your gallbladder removed before breakfast and be binge-watching Netflix from the comfort of your couch by dinner.

Typically, the small openings created during laparoscopic surgery are closed in one of two ways: manually stitching subcutaneously (beneath the skin) with a bio-absorbable, thread-like material and a curved needle that moves from one side of the hole to the other to close it tight, or with a surgical stapler that inserts metal staples into the skin to close the wound. The first technique is more time consuming, but leaves less surgical evidence. The latter method is faster, but can cause scarring and infection. Chuck Rogers, Ph.D., and Kenneth Danielson, M.D. of Massachusetts-based Opus KSD are nearing the launch of a device that combines the best of both worlds: the ease of a stapler with proprietary bio-absorbable subcutaneous fasteners.

“General surgeons are finding themselves under pressure because the user-friendly metal staplers that became very popular in the 1990s are not cost effective,” explains Rogers, CEO of Opus and longtime biomedical engineer. “When people really began doing cost analysis, the five minutes that a surgeon saved in the operating room did not compensate for the fact that their patient still had to come back to have the staples removed.”

Danielson approached Rogers with a concept for a new stapler and shortly thereafter the two began development on the SubQ It! skin closure system — a disposable, handheld surgical stapler that delivers bio-absorbable fasteners beneath the skin with one click of the device.

Check out our full case study on Opus’ SubQ It! stapler, and see how they used machined and injection-molded parts from Proto Labs to prototype the device’s entire thermoplastic assembly.