Finishing Touches

With most materials, molding gives you the highest degree of control over the finish of your parts. Direct machining, on the other hand can leave tool marks, and 3D printing processes like SLA or FDM will almost certainly leave signs of their production as well. These imperfections can be minimized or eliminated completely with secondary processes, and there are plenty of service providers who can perform those secondary processes quickly and efficiently. In a previous position I specialized in last-minute finishing and damage control for prototypers facing deadlines and needing help finishing up (occasionally while the client waited in the boardroom).  In this environment I learned a surprising variety of techniques for refinishing machined and 3D-printed parts. For obvious reasons, these are best suited to one-offs or extremely small numbers of parts when you are squeezed for time or money or both.

Abrasives

The most obvious way of removing roughness or providing a uniform surface is abrasion. Sandpaper can be used to smooth both plastic and machined metal. It will leave uniformly scratched or matte finish and requires careful application to get into tight spaces and avoid swirls, deep scratches, and other obvious marks. Hand polishing with a rag and rubbing compound is an option if you would like to take that finish further. The final result depends on the grit of the compound; for a very smooth or polished finish on a rough piece you’ll want to work in steps using increasingly fine compound or rouge. The results of this process can be quite impressive with final product being as shiny and polished as its injection molded counterpart. It can take a long time but it is a fairly straightforward method if you have patience—lots of patience. (You might want to throw on that audio book you’ve been meaning to get to or put on your favorite radio station).

Heat

Flame smoothing or polishing, as the name implies, is a simple matter of applying heat to a rough plastic surface to soften it, then allowing it to self-level and cool. Depending on the size of the piece, you can use a heat gun, propane torch, or even a butane lighter or match. (Indirect application of a cleaner burning flame will produce a better finish, while matches and lighters can leave a smoke residue that needs to be cleaned off.) This technique works particularly well on clear thermoplastics, allowing you to regain internal clarity in just a few seconds. For obvious reasons be careful of how much heat you apply; the last thing you want is your hard work going up in flames, literally.

Solvent

Among many solvent options, acetone dissolves many plastics including ABS and polycarbonate and can be used to soften and level rough surfaces. Dipping is the most aggressive way of applying acetone and should only be used on larger parts with larger features that are not likely to creep or droop after immersion in the solvent. Brushing allows more targeted application; however, it can be messy and is likely leave brush strokes. An acetone spray or Vapor bath can produce excellent results and, if carefully monitored, is the most controllable application method. The vapor bath method involves heating a small amount of acetone in an open, heatproof vessel in which the part is either hung or raised above the liquid. A gentle heat source—a heating pad, for example; not an open flame—is placed beneath the vessel to vaporize the acetone, which slowly softens and levels the plastic surface. The required time for the process varies and should be carefully monitored. When the desired finish is achieved, the part is removed from the vessel and allowed to harden in its new polished state. Check out this video and detailed description of the vapor bath process.

Note: solvents like acetone are both toxic and flammable and should be used only in well ventilated areas. This is particularly true of heated/vaporized acetone.

Painting

Paint, typically sprayed, can change the finish of both plastic and metal. A matte finish is best at hiding blemishes and inconsistencies. In my experience, one of the best spray paints for adhesion to plastic is Krylon Fusion; I have yet to find anything that is as readily available and works as well. Certain floor waxes and linoleum finishes can be applied by rubbing and can fill the marks caused by machining, and lacquer can be sprayed on for a smooth, clear final finish. Both work on plastic and on metal, given the right choice in paint and application.

Rubberized Coating Compound

A variety of rubber-like coatings can be applied by dipping, brushing or spraying to mimic overmolding. You can control placement by masking, and most of the products will air-dry to a shiny and durable surface fit for any board room presentation, though probably not for functional testing.

Adam Poetter is a Proto Labs Customer Service Engineer.

COOL STUFF: SOLOSHOT IS MAKING WAVES

Sports enthusiasts around the globe have long been accustomed to enlisting friends, family and even strangers to serve as amateur videographers. But even if you’re able to convince someone to invest the time and energy to help out, usable footage is never a guarantee. Now athletes ranging from professional surfers to little league soccer players can capture high quality video of themselves on their own, from a distance, thanks to SOLOSHOT.

Check it out.

SOLOSHOT joins a growing list of cutting-edge products that have received the Cool Idea! Award. Now in its third year, Cool Idea! is an award program offered by Proto Labs that gives product designers the opportunity to bring innovative products to life.

Crowdfunding: Money and More

Since its inception the Internet has impacted virtually every aspect of business. It has extended retail from bricks-and-mortar to online venues as large as Amazon and small as a kitchen table. It has challenged the power of major music labels with online downloads and social media self-promotion. It has empowered startups, allowing outsourcing of “corporate” functions. And it has turned our homes and coffee shops into offices. Product developers can turn CAD models into 3D printed, machined, and injection molded prototypes overnight and get feedback on their products as quickly as they can put them in the hands of users. Until recently, however, financing remained the province of venture capital firms and investment banks.

Now, however, the Internet has given rise to crowdfunding, the aggregation of funds in increments large and small, for creative, cause-related, and entrepreneurial ventures. Crowdfunding generated an estimated $2.8 billion in 2012 in transactions ranging from donation to equity investment. Kickstarter, for example, allows individuals to “back” projects but not to invest. In other words, they can provide funds in exchange for recognition, for sample products or for other “tokens,” but not for monetary profit.

Investment is another story. Crowdfunded investment literally required an act of Congress to become legal. It achieved that as part of the Jumpstart Our Business Startups (JOBS) Act signed by President Obama in 2012. The act incorporates a “startup exemption” from the strict rules previously applied to business funding. The change was spearheaded by a three-person lobbying group (www.startupexemption.com) set up specifically to change federal law and legalize crowdfunding, a goal they achieved in 460 days at an out-of-pocket cost of just over $50,000.

The group’s site offers a concise summary of the new law at http://www.startupexemption.com/crowdfunding-101#axzz2IpemsPh2. The JOBS Act defines three levels of crowdfunding:

1. Token crowdfunding raises non-equity capital in exchange for recognition or access to a product but does not convey securities. It is widely used for charitable and creative projects as well as some product and service startups.
2. Crowdfund investing as defined in the act is exempt from certain registration requirements of the Securities Act, but must be done through an SEC-registered crowdfunding platform. Investors under this section of the act do not have to be “accredited.”
3. Regulation D crowdfunding  bypasses the SEC-registered crowdfunding platform and allows companies to raise money using publicity and other media, but only from “accredited investors” as defined in Regulation D under the U.S. Securities Act.

Today there are literally hundreds of crowdfunding sites supporting hundreds of thousands of projects. They encompass an enormous range of services and goals. Some specialize in business, non-profits or the arts, while others are open to all. Funding targets range from hundreds of dollars to millions. But the secondary benefit of concept may be just as important as the money. In a very real sense crowdfunding provides invaluable market feedback before you’ve launched your product or service, perhaps even before you’ve designed it. It gives real people a chance to “vote” for your offering with real dollars, and that’s market research that money can’t buy.

Greg Kagan is an independent writer specializing in technology marketing, and is author of his own blog, www.techammer.com.

Globo-Proto

From the UK and Japan, Chris Brown and Shirley Brown (no relation) report on “backwards” cars, small living spaces, and life in the office overseas. Proto Labs headquarters may be rooted in the American Midwest, but with facilities in Europe and Asia, and customers worldwide, we’ve got cultural feelers all over the place. Take Business Development Rep, Chris Brown and Sales Manager, Shirley Brown, both recently spent months working alongside our sales teams in England and Japan. But beyond knowledge sharing, customer satisfaction, and supporting Real Parts Really Fast on a global basis, Chris and Shirley also give those of us back in the States a look at what it’s like to live and work in another culture. 

What is the biggest difference between working abroad and working in the US?

Chris taking in the local scenery, near Bath, England.CB: Holidays!! At least once, if not twice a month, you get a day off of work… thank you Queen!!

SB: In Japan, people tend to work very long hours. It is not uncommon to see employees still working at their desk until 8 or 9 pm every day. The last one to leave the office is viewed as the most valuable employee of the company. I’m obviously not it.

 How did you get along with the British English? Favorite new word(s)?

CB: ‘Bits’… In the UK engineers don’t make plastic parts, they make plastic ‘bits’; the only problem is no one back here in the US understands what I mean when I say it and I just can’t stop.

What cool gadgets do you see in Japan that we don’t have in the US? 

SB: Multi-functional toilets with heated seats. The modern toilets in Japan are pretty amazing and have a number of buttons on the side that I’m pretty sure offer a variety of functions to the user. Unfortunately, the labels and instructions are all in Japanese, so I haven’t figured out how it all works just yet. But I’m sure there will be many future opportunities before I leave. Shirley and a Buddha statue, Japan.

Did you have you had an embarrassing cultural faux pas?

CB: Every time I filled up with ‘petrol’ I got in the wrong side of the car afterwords. I don’t know why that one task fooled me, however it got me every time. One time I got in and sat down and I must have had a great look of defeat on my face. The lady filling her car next to me simply asked ‘American?’

SB: I don’t think so yet, but then again maybe the Japanese are too kind to point them out to me. I do still struggle when we go anywhere in the car. Cars here are built backwards from US models, so I continually try to get in on the right side, which is the wrong side (behind the steering wheel, which is a place I really never want to be anyway).  Many of the roads are very narrow; so narrow, in fact, that 2 cars coming from opposite directions can’t pass one another.  One of them usually has to back up.

If we stepped inside your home there, what would tell us we’re no longer in America?

CB: The size… 425 sq. ft. of living space was considered a lot by the friends I had in the UK; many of their flats were less than 300 sq. ft. It took a lot of getting used and a lot of cleaning to keep it presentable. Also, the size of the refrigerator; I’ve seen larger in college dorm rooms!!!

SB: No oven, no dishwasher, no clothes dryer, no furnace. The only room that’s heated (or cooled in the summertime) is the main living room with a unit that hangs on the wall up near the ceiling. There are doors to shut off every other room so as not to waste the heat. You turn the heat off when you leave in the morning, and you turn it back on when you return home at night.

Overall, what was/is your favorite experience living abroad?

CB: Learning a new culture was my favorite part of the trip. Living in a building that was older than the US and living in a town where Darwin was raised as a child gives you a perspective on age and time like no other experience can.

SB: Sushi on the merry-go-round. I’m pretty sure that’s not what it’s called, but it’s a little restaurant not far from the office where we often go for lunch. A long conveyor belt wraps in and around all the booths carrying small plates of sushi. There’s usually 2 pieces on every plate, and if you see something you like, you just take the plate off the conveyor belt as it passes by your table. When you’ve had all you want, you press a button on the table and the waitress comes over, counts the plates and hands you your bill. It’s quick, it’s fun, and there’s lots of interesting choices.

Any interesting overseas habit(s) you’ll bring back to the US? 

SB: Lots and lots of walking!  Most people ride the trains to major stations, then walk or bike everywhere else — even in the rain — to the grocery store, to the train station, to work, to lunch, to the gym. Every age, old and young are walking. This was somewhat foreign to the girl who always drove round and round the Cub parking lot vying for the closest parking spot. I figure I must walk a million steps a day, and I’m actually surviving. And feeling great! 

Bridging the Gap Between Prototypes and Production

In the traditional approach to product development, there is a sharp line between development and production. Development begins with a light bulb over someone’s head, proceeds through napkin sketches and CAD models, and ends, ultimately, with prototypes. At one or more points in the development process there may be input from the market, be it someone’s best guesses, one or more focus groups, or actual market tests. And from start to finish there is always pressure to “get on with it,” either because you need to catch up with a market leader or because you are the leader and someone may be catching up with you. But then, when you have reached your goal—a fully developed, marketable product—everything comes to a screeching halt and the drawings and/or models disappear into the “production machine,” from which, weeks or months later, a whole lot of deliverable product appearsand the rush begins again as it heads off to market. 

In plastic molding, as in most other technologies, some aspects of this transition are unavoidable. Production molds are costly, and they take time to manufacture. It would be risky to begin producing them before the design had been fully proven in development, when even a small change could turn tens of thousands of dollars’ worth of molds into doorstops and boat anchors. Traditionally this has always presented manufacturers with a dilemma. They could keep development and manufacturing sequential and live with the resulting delay. Or they could treat them in parallel, starting on production molds before the end of development, cutting their time to market but running the risk of having to go back and start tool-making over again. It was a painful choice, because today’s competitive global markets reward both speed and low cost. Manufacturers already recognize that rapid injection molding as a prototyping method can reduce both cost and delay in the design of plastic parts. They are now beginning to see that it can also help reduce the post-development delay in bringing a product to market.

While rapid injection molding is not identical to traditional production tooling, it is similar enough in process and technology to solve several problems and help speed up production. Read more about bridging the gap between prototypes and production, in this month’s Protomold Design Tip for Injection Molding.

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