Before digging into the world of 3D printing, I’d like to make it clear that I am not an “expert”. My experiences with 3D printing are quite limited, having only printed a handful of parts at the university previously. This series of posts is not meant to be a “How to” guide, although I may create one in the future after gaining experience. Instead, this series will be a rundown on my journey so far into the world of 3D printing and the value that model railroaders may get out of this technology. In “Part 1” I’d like to give an introduction to what 3D printing is and it’s benefits to model railroaders. There are a multitude of resources available to learn about this technology and some of the resources I have been using will be listed at the end of this post. Now then, let’s get started…
What is 3D printing?
3D printing is a form of additive manufacturing and it falls under the vast umbrella of computer aided design manufacturing (CAD). This differs from subtraction manufacturing in that instead of grinding away material (CNC machining), or cutting and fastening (wood working), material is instead applied to itself to create a three dimensional part. The material used is usually a type of plastic, although other materials can be used such as metals, cement, and even food. Printers read the data stored in digital files to complete this task. The most common file type is “stl” which most printers made today can read. People who want to make something with a 3D printer either have to create the file(s) themselves or pay someone to do the task. Software like AutoCAD, Sketchup, Fusion360, and Blender can all be used to create stl files, although their complexity and usability varies by quite a bit. I spent one year in college studying CAD software exclusively but since then I haven’t focused on a single one and so I’ve only got a basic understanding of how all this software works. As of this writing, I’m still trying to decide which software to use, so we’ll have to put a pin in that and come back to it later.
Anyway, back to the 3D printing!
There are several ways to create three dimensional objects using computer programs, and so the following is a run-down on the different types of 3D printers:
Fused Deposition Modeling (FDM)
FDM printers are the most common type available to consumers. And FDM printer basically works like a computer controlled hot-glue gun, melting plastic filament and depositing the material in a series of layers. As the plastic cools, it hardens into a solid piece. Small pieces can be done in a few minutes or less. Larger pieces can take a day or more to complete! One benefit to this type of printer is that kits are available online that allow people to build printers to their own specs. These printers can also be made completely from scratch provided the builder has the necessary tools in hand. These printers can be bought cheap, sometimes even less than $100! The downside to these printers for modelers is that the detail in parts is not great. Detail is actually adequate for most applications, but miniatures that have a lot of detail needs a different type of printer.
Stereo-lithography (SLA) and Digital Light Processing (DLP)
Quite the name, huh? Stereo-lighography is just a fancy word for 3D printing using light. SLA printers use a liquid resin that is similar to what we use to make rivers and lakes on train layouts. The main difference is that SLA printer resin needs light to cure and harden rather than the chemical hardening. To get a solid object out of the resin, SLA printers use a laser to cure the resin. The laser’s beam is manipulated by a series of mirrors which reflect the laser to the proper coordinates. These printers are simple in concept, complex in design, and have only recently become affordable to the average person. The resin part needs to be washed, dried, and left to cure either in the sun (depending on the resin type) or in a UV light box. Until the resin part is cured, it will remain tacky and plyable.
Digital light processing printers work in a similar fashion to SLA printers, but the key difference is that DLP printers use a light sensor that will flash an image of each layer at the resin pool, hardening it layer by layer. These printers do fast work compared to SLA printers, but the detail is not as great. This is because the light sensor cannot create fully organic curves but instead relies on a series of pixels, which are square. On the other hand, SLA printers can move more fluidly due to the manipulation of mirrors. SLA printers therefore can achieve incredible detail that is on par, or even exceeds injection molded parts like what modelers are used to seeing in kits.
FDM, SLA, and DLP printers make up the majority of the market for consumer 3D printers. There are other types of printers out there but few are meant for the home hobbyist. The most important one of note is:
Selective Laser Sintering (SLS) and Direct Metal Laser Sintering (DMLS)
SLS and DMLS printers use a laser to melt together powdered plastic or metal into a solid object. This object is created in a large bin of powdered material and must be dug up and cleaned off once the printing process is done. This type of printing is used for industrial applications and many parts can be created all at once for prototyping. Detail can vary by quite a lot, but once parts are sanded they are solid and smooth. The biggest benefit to this type of printing is that services are available to hobbyists through companies like Shapeways. SLS and DMLS printers can be bought for home use, but prices start in the thousands instead of the hundreds.
Benefits of 3D printing
3D printers do offer a few advantages as it applies to model railroaders:
- Printing parts can often be faster than making them from scratch, saving time for modelers.
- 3D printing, or (additive manufacturing) allows anyone to create parts that are hard to make from scratch.
- Parts can be made quickly and repetitively.
- One off models that a large manufacturer would never be able to make can now be made by modelers.
- Files can be shared digitally (or sold) so others can create their own models.
- Prototypes can be used for injection molding or casting (brass steam locomotive wheels).
- FDM printers make parts quickly for any mechanical use.
- SLA and DLP printers can make detailed parts for miniatures.
- Plastic parts can simulate the metal parts found on the prototype.
- Parts can be made from a variety of plastics, some that are flexible and durable while others are brittle and detailed.
Downsides of 3D printing
While 3D printers are great, they do have limitations to consider:
- Printers take up space and are another thing that must be bought or built.
- Initial costs are high with quality printers costing as much or more than a good computer.
- Filament or resin needs to be bought in large quantities to save money.
- Improper design or curing will result in bad looking models that break easily.
- Getting the printer working properly takes some adjustment.
- Learning software can be difficult, especially for those starting out at home.
- Finding the right software takes time and experimentation.
- Like glue guns and soldering irons, hot nozzles of FDM printers can pose a fire risk.
- Making mass quantities of parts does not benefit from economies of scale and so can be expensive.
- CAD software is difficult to use in making parts that resemble wood, rock, or other organic material.
Is 3D printing worth it?
As a new technology that I’m exploring, that’s the question I hope to one day answer. My hypothesis though is that the value of 3D printing varies greatly depending on the person using it. A modeler who buys stuff off the shelf and runs equipment right out of the box probably has little need for a printer, and the costs of owning a printer would be better used for supplies to keep a railroad operating well (or more locomotives). Likewise, model train collectors and people running toy trains like post-war Lionel have limited uses for a 3D printer. Scratchbuilders, kitbashers, and people who like to experiment (*cough* myself *cough*) would most likely have some use for a 3D printer that justifies the costs and headaches of learning new techniques.
Resources to learn about 3D printing
Unfortunately, you won’t find much in the way of “how to” with my posts. Since I’m just starting out myself, it would be inappropriate to try to teach others about 3D printing. However, it is great living in the age of the Internet because there are a vast number of places online to learn about new tech. Here are some of the places I’ve been getting my info from:
- Luke Towan runs a Youtube channel where he makes impressive models and often uses 3D printing for small parts.
- Ivan Miranda is a Youtuber who has a number of videos about making and using 3D printers.
- Maker’s Muse is another Youtuber that has a lot of content related to 3D printing.
- 3D Printing Nerd is the final Youtuber that is dedicated specifically to 3D printing that I subscribe to.
- “Make: 3D Printing” by Anna K. France is a fantastic little book that I’ve been reading in my spare time. It was $20 and the ISBN is: 978-1-457-18293-8
Where to next?
The next post in this series will be a list of the different printers I am considering buying. While I won’t be able to do any reviews or hands-on printing until I buy one (or two) printers, what I can do is go over the different features listed and compare these printers to each other. I’m giving myself a limit of $500 so all the printers will be wallet-friendly and affordable enough for many model railroaders to consider for themselves.
To see the other posts in this series, click one of the links below: