Functional Prototyping using Metal 3D Printing

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Functional Prototyping using Metal 3D Printing

Introduction

Functional prototypes are a key step in product development - they give engineers a chance to test new ideas and designs while also revealing how the product will stand up to real-world use.

And when it comes to functional prototypes, 3D printing is rewriting the rules of what’s possible.

One of the most important changes made possible with printing relates to speed. Where it may take weeks or months for traditional manufacturing processes like casting and forging, 3D printers can turn out parts in just days.

For manufacturers, that translates into the ability to create not just one or two prototypes of a particular part, but many. By creating multiple prototypes with subtly different geometries, it’s possible to test them simultaneously and quickly refine the design.

Printed parts can also be far more complex than their traditional counterparts, allowing designers to precisely tailor features and geometry to maximize part performance. That complexity enables the use of generative design tools to create highly-optimized, organically-inspired geometries that would be difficult - or nearly impossible - to manufacture with traditional methods.

With less material waste and no need for a dedicated, skilled operator, printing prototypes can be less expensive than traditional manufacturing.

Why doesn’t everyone print prototypes?

Despite the potential benefits that come with 3D printing, the technology still isn’t widely used for functional prototyping.

And much of the reason why has to do with how earlier-generation printers worked.

Though initially touted as a technology that would allow you to print virtually anything you need at home, parts created on early plastic printers were often plagued by poor resolution, high porosity and other defects.

While modern plastic printers can produce high-quality parts, many are still limited to producing visual prototypes, because plastic parts simply can’t stand up to the loading conditions some parts face.

Without access to affordable metal 3D printing, engineers for the past two decades had no choice but to fall back on traditional processes - like milling, grinding, casting or CNC machining - to produce functional prototypes.

Those processes, however, are expensive, time-consuming and require skilled operators - all of which act as constraints on the creation of prototypes and the efficiency of the product development cycle.

These days, though, that picture is changing.

The Power of Metal 3D Printing

Those changes began when the first metal 3D printers - which used lasers to melt thin layers of metal powder - came on the market.

But because they were both slow and expensive - $1 million or more for the systems and dedicated facilities - those systems were best suited to applications where low production and high perpart costs could be justified, like the aerospace and medical industries.

For other applications, where per-part costs must be lower or production faster, laser-based systems simply weren’t cost effective.

With the development of the Studio System™, though, Desktop Metal is addressing those issues and more - making it both easier and more economical to create functional prototypes.

The key technology behind the Studio System™ is Bound Metal Deposition™ - an FFF-style print process that heats and extrudes a rod media made of metal powder and a polymer binder, similar to the media used in metal injection molding (MIM).

Combining the ease of FFF printing with the well-established metallurgy of MIM, the system is able to quickly deliver high quality metal parts with reliable metallurgy - making it ideal for functional prototyping. In just days, users can print parts that would otherwise take weeks or even months using traditional manufacturing processes, enabling faster transitions from design to production.

The Studio System™’s office-friendly design eliminates the use of loose powders and dangerous lasers, making it an easy-to-use, end-to-end solution for printing metal parts in-house.

The system is also capable of printing using a variety of metals - including H13 tool steel, 4140 chromoly steel, 316L stainless steel and 17-4 PH stainless steel - allowing companies to create functional prototypes in the same materials they will later use for mass production.

Commonly used across a variety of industries, impellers are an essential component in pumps used to move fluid through systems. For chemical impellers, stainless steel 316L is ideal due to its chemical resistance and mechanical properties at extreme temperatures, such as those found in cryogenic, salt water, and petroleum pumps.

Impellers require complex vanes to optimize the pressure profiles in the pump. The optimum geometry of each impeller depends on the viscosity of the fluid and the specific requirements of each application.

Functional prototypes of new impeller designs would traditionally be made via CNC machining or investment casting, and would cost as much as $5,000 or more due to their complex geometry.

With the Studio System™, the same prototype can be printed for just $70. By significantly reducing the cost, designers are able to test multiple variations of the same part before selecting the optimum geometry for production, achieving the best possible result.

John Zink Hamworthy Combustion is a global authority on emissions control and a pioneer in modern Smart Combustion™ solutions. Early on, JZHC recognized the potential that additive manufacturing could have in their industry, and decided to radically redesign their fuel atomizer used in steam propulsion boilers to function in a more fuel-efficient manner.

The Studio System™ allowed JZHC to create functional prototypes at far lower cost and in far less time - days rather than weeks - than traditional methods. Stainless steel 316L was chosen for its excellent mechanical properties at high temperatures, and corrosion resistance in marine environments.

Today, the same nozzles used for prototyping are used while LNG tankers are maneuvering in port, realizing an improved fuel efficiency of almost 100% and significantly reducing the operational costs and environmental impact of the systems.

Golf club designers must consider any number of parameters - from the angle of the club base to the shape of the cavity and the weight of the club to name just a few. In addition to club features, designers consider the anatomy and preferences of each player. To explore that vast design space, testing with functional prototypes is crucial.

Traditionally, creating those prototypes starts with a blank - basically a rough club shape - which is then machined to create different features. But because each prototype starts from the same basic blank, the options for different designs are limited.

With additive manufacturing, it’s possible to access entirely new design options - for example, by altering the infill percentage in a club to fine-tune its weight distribution. The technology also opens the door to mass customization and the use of generative design tools to optimize clubs for individual golfers.

While golf clubs are typically made via casting or forging, both processes are prohibitively expensive for prototyping due to high start-up costs. Using the Studio System™, designers can create and test a number of design variants, ultimately leading to better club design and quicker time to market.

Shock absorbers are essentially hydraulic oil pumps. In the heart of every shock absorber lies a piston valve which directs the flow of oil during the compression and extension of the suspension system. The geometry of the valve is one of the main parameters that determine the response of the shock absorber under various conditions, so optimizing its design is critical.

Piston valves are traditionally manufactured via press and sinter, resulting in a number of design constraints, including on the orientation of the channels that control the flow of oil through the piston.

The Studio System™ allows engineers to fabricate a number of variations on the valve in a matter of days, expediting the design process, and enables the exploration of new geometries, like internal channels, that can only be manufactured using additive technologies.

A key component of every internal combustion engine, pistons compress the air and fuel mixture that is ignited by a spark plug, turning the crankshaft and driving the engine. From a design perspective, pistons must be both lightweight to minimize the extreme forces it experiences, yet still stiff enough to withstand the pressure generated during combustion.

To create functional prototypes of new piston designs, manufacturers typically rely on CNC machining, but the complex geometry of pistons often results in long lead times which slow the design process.

Using the Studio System™, engineers can produce functional prototypes for testing in a matter of days rather than weeks, allowing for quicker iteration before arriving at a final part. Using generative design tools, engineers can create pistons that optimize both stiffness and lightweight, but which are difficult, or even impossible, to manufacture with traditional methods.

 

This guest post was originally published on Desktop Metal blog site as a downloadable ebook. The content in this guest blog is for informational and educational purposes only and may contain copyrighted material from Desktop Metal.
Source: Desktop Metal

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