Idiot's Guides: 3D Printing (2015)
What Is 3D Printing?
Every topic needs some background information, and 3D printing is no different. In this part, you learn about the history of 3D printing, including how it was invented and how it entered the consumer space. You also learn about the different kinds of 3D printing technologies available, and the pros and cons of each.
This part also covers the principles behind how 3D printing actually works. In addition to how it works, I go over how it differs from other prototyping and manufacturing methods. This includes how 3D printing can be used by businesses, and what you can use it for personally.
The Goal of 3D Printing
In This Chapter
· Why businesses invest in 3D printers
· What you can do with 3D printing
· Common misconceptions about 3D printing
It wasn’t that long ago that 3D printing was a just an obscure technology relegated to prototyping use by a handful of specific industries. But in the past couple of decades, 3D printing has become a must-have technology for engineering companies, and even more recently a useful consumer tool.
But why did 3D printing become such an indispensable tool for businesses? What advantages do 3D printers give the consumer and hobbyist? In this chapter, we look at why 3D printing is becoming so popular, what it can do for you, and what its limitations are.
I say this completely without hyperbole: 3D printing is a dream for an engineering team. A technology that would have been the stuff of fantasy just a few decades ago, today it gives companies the ability to bring an idea to life quickly, efficiently, easily, and inexpensively.
The original intent for 3D printing was to create prototypes for engineers. This allowed them to quickly test an idea before moving on to production and manufacturing. Very recently, some companies have even begun to use 3D printing for the actual manufacturing of production parts. Both uses have exploded in popularity, and both benefit businesses in a number of ways.
Rapid prototyping, simply enough, is any process that can be used to quickly create a prototype of a part. A prototype part is essentially a test part, and is useful during the development of a new product (or when revising an existing product). What the prototype is intended to test is up to the engineer, but it’s commonly used to test the following:
· How parts fit together in an assembly
· The strength of the part
· Regulation compliance
When a new product is being developed, it’s rare that a single design is kept until production. Commonly, a handful of potential designs are tested, and whichever design is chosen for production will evolve quite a bit throughout the design process. Much of the testing of these designs is done via simulation with computer-aided design (CAD) software, but it’s almost always necessary to have a real physical part to work with during this process.
Computer-aided design (CAD) software is a type of computer program used by engineers and designers to develop products using 3D models or 2D drawings. Before CAD software, drawings were hand drawn by drafters for production. Now, CAD software can export models directly to 3D printers (see Chapter 15 for more on CAD).
CAD software being used to create a 3D model.
That’s where rapid prototyping, and especially 3D printing, comes in. As the design of a product evolves, engineers can 3D print the design and test it. In the past, prototypes were costly and often required outsourcing to companies who specialized in producing these prototypes using traditional methods like machining, welding, sand casting, and other costly processes. Now, it’s commonplace for an engineering team to have a 3D printer in their office with which they can print a prototype in a matter of hours and for a relatively low cost.
Aside from the physical testing of the part, prototypes are also valuable for user testing, design proposals, and promotion. When a new product is in the early stages of development, it doesn’t always have funding secured for the entire design process. Project funding (whether internal to the company or from outside investors) often depends on a design submittal, which is essentially a proposal of the product design.
Design proposals can be anything from a simple explanation of the idea to a complete working prototype. But 3D printing has made it possible to speed up this process and has made it much cheaper. Therefore, physical prototypes have recently become a virtual necessity for securing outside funding via crowdsourcing. Backers of crowdsourcing want to see that a design is functional before they invest, and 3D printed prototypes are the cheapest way to show that.
While rapid prototyping is definitely the most common use of 3D printing, it’s starting to become a viable method of actual production manufacturing. Traditionally, injection molding is by far the most common method of manufacturing plastic parts. In mass production, injection molding can produce high-quality parts very quickly and inexpensively.
Injection molding is a fairly simple process in concept: molten plastic is shot into the cavity of a two-piece (or more) metal mold and cooled, and then the mold is pulled apart and the plastic part is removed. In a manufacturing setting, that process can happen very quickly and a new part can be made in a few seconds. It can also be very inexpensive (per part), as the plastic itself is cheap in raw form.
However, injection molding has one critical downside: the cost of tooling. Tools, in reference to injection molding, are the molds and associated part-specific machinery needed to produce a particular part. Every individual part needs its own tooling, and that can be very expensive. Molds are usually made from steel or aluminum and require precision machining. Mold making is a specialized task, and individual molds start in the thousands of dollars and often reach into the tens of thousands of dollars.
When you take into account the fact that most products are assemblies made up of many individual parts (which would each need their own tooling), it’s obvious that the costs of getting set up for injection molding can be very high. That’s okay if you’re making thousands of that part, because the cost per part gets lower as the total quantity increases. But what if you want to produce your parts in smaller quantities? The parts must be manufactured in huge quantities in order for the price per part to reasonable.
Aleph Objects, a 3D printer manufacturer based in Loveland, Colorado, uses its own 3D printers to manufacture some of the parts to build new printers. This “cluster” of 3D printers used for manufacturing is the largest in the world, consisting of 135 individual 3D printers.
That’s where 3D printing has started to enter the manufacturing world. With 3D printing, there is no high tooling cost up front—your printers can produce whichever part you need them to at a given time. You can print one part or a hundred, and your price per part will be the same. This means you can manufacture in low quantities without incurring huge tooling costs. Possibly even more valuable is the ability to change designs on the fly. You can redesign a part and immediately start manufacturing the new design without having to purchase a new mold, which means your product can evolve in real time as you improve the design.
The cluster of 135 3D printers used for manufacturing at Aleph Objects.
(Photo courtesy of Aleph Objects)
Of course, 3D printing in a manufacturing setting does have its downsides, which have kept it from gaining widespread adoption. If a part is going to be manufactured in large quantities, it’s still cheaper to have it injection molded (despite the cost of the molds). That’s because the raw material is much cheaper for injection molding than it is for 3D printing. Possibly even more importantly in mass production is time—an injection-molded part might only take a few seconds to make, while a 3D-printed equivalent can easily take hours.
To be able to keep up with an injection molding machine, many 3D printers would have to be run simultaneously. So injection molding is still the best option when parts need to be produced in mass quantities. But for small quantities or designs which need to be updated often, 3D printing is becoming an attractive alternative.
For the Hobbyist
Engineering 3D printing prototypes for corporations is all well and good, but what’s really exciting is 3D printing for the average person at home! In just a couple of decades, 3D printers have gone from being too expensive for most companies to buy to being cheap enough that you can realistically purchase one just to tinker with at home. But why would you want one in your home? What could you even do with it?
The Maker Culture
The idea of making stuff for fun and self-fulfillment has gained tremendous popularity recently, but the basic motivation is an inseparable part of human nature. The same urge to invent that put man on the moon is also what motivated your father to build that birdhouse when you were a kid, and it’s the same thing that has you interested in 3D printing. We all have this urge to create (to varying degrees, of course), and the maker culture is just a modern branding of that—a way to identify like-minded people and form a community.
3D printing has been a huge factor in the growing maker community, and for good reason. Traditional maker activities include things like wood working and metal working. Those are skills which take a great deal of practice, patience, time, and money. But 3D printing allows you to create similar physical objects quickly and relatively easily. It’s become a fairly simple task to take the ideas from your head and make them real.
At its heart, maker culture is about creating things. It’s using whatever tools you have available creatively to invent and construct things that interest you. In the same way that your father may have used a hand saw, a hammer, and nails to build that birdhouse, you can use a 3D printer to make whatever you can imagine. Robots, electronics enclosures, and artistic creations are all possible, along with anything else that interests you.
A Tool in Your Arsenal
By definition, a 3D printer is just a tool, and that’s how you should think of it. If you want to hammer nails, you use a hammer. If you want to cut a piece of wood, you use a saw. And if you want to make a part out of plastic, you use a 3D printer. It’s important to think of a 3D printer like any other tool—a very versatile tool, but still a tool.
Make sure to utilize 3D printing in the right context. It’s impractical to try to 3D print an entire coffee table, but you can certainly use your 3D printer to make brackets, drawer handles, tracks, and other parts. Like any other tool, a 3D printer has uses for which it’s well suited, and some things which would be better handled by another tool.
As always, it’s best to use the right tool for the job. It might be possible to cut a metal pipe with a wood saw, but it’s not a good idea. 3D printers are no exception—they can do a lot, but they’re not the right tool for every job. When you first start 3D printing, you’ll be tempted to try and use it for everything. Birdhouse? 3D print it! A coffee table? Print the pieces and glue them together! But you’ll quickly learn that 3D printers aren’t the solution to every problem.
With that said, 3D printers are incredibly versatile. That’s why they’re such a revolutionary tool. You can use them to print everything from things like pencil holders to replacement parts for your car. This is what makes 3D printing so exciting: if it fits on the printer and it’s made of plastic, you can make it! Sure, 3D printers aren’t the solution to every problem, but they’re one of the most widely useful tools ever invented.
In essence, the goal of 3D printing (whether for business or consumer use) is to be able to quickly and easily create objects with a single device. To an extent, 3D printers today do accomplish that feat.
But 3D printing presents a kind of perfect storm of misunderstanding that many fall victim to. It’s a technology that is very new to consumers, it’s complex, and it’s still fairly experimental. It’s somewhat reminiscent of the early days of the internet, when most people still didn’t quite know what to make of it. There are some real-world drawbacks which keep them from being the miracle devices envisioned in popular science fiction and media.
Materials You Can Use
Probably the most common of these misconceptions concerns materials. 3D printing technology has come a long way, and there are a variety of materials available to print with. But, for consumer printers at least, all of these materials are still some type of plastic. Printing metal is out of the question for a consumer printer. Metals, ceramics, and other more exotic materials are possible on extremely expensive professional 3D printers, but don’t expect to be printing them at home anytime soon.
This is primarily because the technology needed to print in metal or ceramics is far more complex than what is needed for a consumer 3D printer. Consumer 3D printers use fused deposition modeling (FDM) or fused filament fabrication (FFF) technology, which is inexpensive (see Chapter 2). But to print in metal, for example, an expensive and complex process like selective laser sintering (SLS) is required. SLS 3D printers use high-powered lasers to actually melt metal powder, and, as you can imagine, those aren’t cheap. So for now, consumer printers are relegated to just printing plastic.
A Replicator in Every Home
A popular theme in news articles about 3D printing is the idea of a replicator in every home. It’s the picturesque future from the popular culture of the ’60s and ’70s: a device that instantly produces anything you need at the touch of a button.
The replicator was first introduced in Star Trek: The Original Series (and officially named in Star Trek: The Next Generation) as a device that could recycle garbage and waste and synthesize food and other useful things. The idea is so similar to 3D printing that a popular line of 3D printers made by MakerBot even uses the replicator name for some of their models.
The setup is simple: there you are in your kitchen cooking dinner, when suddenly your spatula breaks. Your dinner is starting to burn, and you don’t have time to drive up to the store and buy a new spatula. Not to worry though, you have your trusty 3D printer! You run over, push a button or two, and in a matter of minutes you have a new spatula. Problem solved! This is the kind of thing imagined by the media and those unfamiliar with the realities of 3D printing.
Unfortunately, reality doesn’t quite meet the expectations set by these kinds of stories. 3D printer developers would certainly love to be able to produce such a product, but it’s just not the case (and probably won’t be for a very long time).
Your dinner fiasco would be quite a bit different in real life today: your spatula breaks, and dinner is about to start burning. You turn to your 3D printer for help. But before you can start printing that new spatula, you’ve first got to find a 3D file to print from. After searching for a few minutes online, you’re lucky and find one (saving yourself from having to 3D model one). Now all you have to do is load the file, heat up the printer, start it printing, and wait an hour or two for it to print. Of course, by that point, your dinner is already burned.
As you can see, as amazing and versatile as 3D printers are, they do have their limits (of which there are many). Eventually, you may have that sci-fi replicator in your house, but we’re not quite there yet.
The Time It Takes
The time involved to print something is also a highly misunderstood topic. 3D printing is often referred to as being very fast (I’ve even said so earlier in this chapter). But it’s important to note that that’s only in relation to traditional manufacturing methods. Even the smallest prints are going to take a few minutes at best. Larger prints on consumer 3D printers can take the better part of a day, and it’s possible for a single print to take days (even on an average-size consumer printer). So don’t expect to be printing out parts instantly; it’s usually a fairly long wait.
3D printers have very hot parts and can be a significant fire hazard. Only leave a 3D printer unattended at your own risk, and be sure to follow appropriate fire safety precautions when printing with it.
What It Can Print
3D printers carry with them the promise of being able to print anything. But there are some caveats when it comes to what geometry you can actually print. Overhangs are the biggest enemy here. Overhangs are geometry which have no supporting material directly underneath, which is troublesome for obvious reasons. This can be overcome with support material, which I’ll go over in more depth in later chapters, but you should be aware of the fact that 3D printing does have design challenges of its own.
Another area where 3D printers (especially consumer 3D printers) have difficulty is with printing small features with fine details. They’re limited by the size of the filament being extruded (or pushed out) from the nozzle, and fine detail tends to get washed out when common nozzle sizes are used. Professional 3D printers that use more expensive technology are capable of astounding detail, but consumer 3D printers are still pretty limited.
The finish of the printed object is one of the most glaring limitations of 3D printing. Because of the nature of the process (essentially stacking layers of plastic), the surface finish of vertical surfaces is usually quite poor. Even on the highest-quality settings, you’ll still be left with a series of small ridges. It’s virtually impossible to get a truly smooth finish straight from a consumer 3D printer. People expend a great deal of effort trying to minimize this and improve surface finish, and there are some postprint techniques you can use to smooth it out. But don’t expect to get a nice, smooth part hot off the printer.
Even with high-quality settings, layer ridges are evident on this owl model.
You shouldn’t be too disheartened by all of this, though. These are all fairly minor limitations, and are just part of 3D printing. There are ways to deal with most of them, and a lot of work is being done to overcome these challenges. It’s important to keep your expectations for 3D printing realistic, but don’t let these downsides trouble you too much.
The Least You Need to Know
· 3D printers initially gained popularity for rapid prototyping, which remains their most common use today.
· Manufacturing with 3D printers is a viable option for small-scale production but is still impractical for mass production.
· The maker culture has been fueled by 3D printing and the creative outlet it provides.
· Being able to produce anything in your own home is an exciting idea, but it’s far from being a reality.