They’ve published videos that show both the fabrication techniques and some success at flying. While they don’t appear to have great flying technique, yet, they’re well on their way.

This fabrication technique certainly has applications much broader than robotics. I look forward to seeing a breadth of creative micro-scale components in the micromanufacturing realm. Has anyone seen other examples of novel micromanufacturing techniques?

Layer built processes create a single part by building up  a series of 2D cross-sections. Different methods require different layer heights and have different means of supporting the layers that are hollow underneath. Of course, one advantage of this process is that parts can be made that could never be fabricated by traditional production methods, such as hollow spheres or even an assembly of multiple integrated parts in a single build that come out of the machine assembled (such as the links of a chain).

SLA (Stereolithography) – Liquid photopolymer (resin) is cured with a laser in layers. After each layer is laid down, the platform lowers further into the resin by the layer thickness, and the laser cures the next layer of material. The part is then post cured with UV light. SLA was one of the first additive rapid prototyping technologies and is still the gold standard.  It is good for general pupose form and fit protoypes and when parts require high resolution, smooth surface finish, or optical clarity.

A part manufactured by SLA (Photo Credit: Key Tech)

SLS (Selective Laser Sintering) – SLS builds layers similar to SLA, except instead of using UV light and a liquid photopolymer, a powdered material (real plastic or metal) is heated and fused together by a laser as a series of 2D cross-sections. SLS is a good choice for functional testing with real materials when smooth surface finish and fine resolution are not required.

A part manufactured through SLS (Photo Credit: Key Tech)

FDM (Fused Deposition Modeling) – Similar to a precision hot glue gun, long strands of real plastic material (ABS, PC, and others) are fed into the nozzle, melted, and deposited in a series of 2D cross-section layers. FDM layers are generally the thickest of the various processes, which limits feature size, but it usually provides better strength and robustness in comparison. FDM is good for prototyping functional parts without small features where surface finish is not important.

A part manufactured through FDM (Photo Credit: Key Tech)

Polyjet – Using inkjet printing technologies, UV-curable materials are effectively “printed” on top of the previous layer to create a 3-dimensional part. Polyjet can produce high resolution parts with decent surface finish, is generally cheaper and faster than most other processes, and is one of the only additive prototyping processes that can produce flexible parts.  It is a good process for small parts requiring good resolution and a decent surface finish, or when flexible parts need to be prototyped.

A part manufactured through Polyjet (Photo Credit: Key Tech)

• Uniform wall thickness
• Radii on the corners
• Sufficient draft
• Bosses
• Ribs
• Choice of parting lines
• And many more

Learning how to design a perfect injection molded part can take a long time and could require years of learning lessons the hard way. There are many books on the subject, but sometimes a great resource is the downstream vendors themselves. I’ve said it before, and I’ll say it again, it never hurts to work closely and early with vendors when designing custom parts. They’ll be designing the tooling and controlling the process parameters, so they can help you understand what works best.

ProtoMold is a rapid injection molder – they turn soft-tools and injection molded parts around quickly. To help designers make the most out of their services, they’ve provided a Design for Moldability reference with a few of the most fundamental concepts discussed. While their capabilities are slightly limited to provide such quick turn-around, their guidelines provide several sound ways to improve an injection molded part, resulting in less expensive tooling and a better performing component. (Registration required to view the document)

Disclaimer: Key Tech is not connected in any way with ProtoLabs or their affiliates and was not compensated in any way for pointing out this guide to you. We just like their work.

Read more about the symbiosis of modeling and prototyping (PDF) for designing microscale parts in an article I wrote that was published in MICROmanufacturing Magazine this month, page 33 (Jan/Feb 2010, Volume 3, Issue 1).

You can read the article in the Summer 2009 printed publication or catch it in the online version, Meeting the challenges of micropart design.

To me, “rapid prototyping” refers to any fabrication method that can approximate the production part while shaving weeks or months off the delivery time. Three-dimensional printing processes like SLA, Polyjet, and SLS are just part of the product designer’s toolbox. I’ve used processes such as cast urethane, wood tooling (thermoforming), or even machined plastic to quickly create parts that I can hold in my hands, check the fit, and even test depending on the circumstance. In most instances, prototyped parts cannot be subjected to the full spectrum of real world conditions, such as drop-tests or thermal cycles, but it can happen. I’d consider any of these processes to be rapid compared to the production process.

I was recently interviewed for an article regarding the state of rapid prototyping as it pertains to micro-scale manufacturing and product development. From what I’ve seen, the prototyping processes are just not down to the micro-scale, yet. Granted, the micromanufacturing industry is still pretty young, and it’s been growing so quickly in size and capabilities that I expect to see more rapid prototyping solutions soon.

You can find the article and my comments online at MicroManufacturing Magazine.