Initial Foray Into 3D Printing 1 - Choosing and Building a Printer

Imagine this...

You draw an image. In that image, you draw it to scale, and show exact specifications in all three dimensions. If it helps, think of an architect's plans, or a technical drawing. Then you send that drawing to a near-magical device that turns your theoretical ideas into real world objects.

Yes, that's why I decided to get a 3D printer.

I discussed this with some people I know, and shortly thereafter, I was asked two innocuous questions:

1. "What can you do with a 3D printer?" and...
2. "Why would you want one?".

If you're wondering, let me ask you some questions that may help you to find the answer(s) that best apply to you:

• "Do you do any sort of prototyping, product testing, or marketing where a small scale model may help in your endeavours?"
• "Do you like designing things yourself, or tweaking things to suit your needs and/or tastes?"
• "Do you have any interest in technical drawing, 3D graphics, Computer Aided Design (CAD) work?"
• "Have you had a relatively simple plastic part fail on your <insert device/doodad/thingy here> and wanted a replacement part?"
• "Do you think the price for some small plastic parts are prohibitively expensive, or are the parts nearly impossible to get?"
• "Are you familiar with how to use vernier calipers?"
• "Are you willing to tinker with print settings, perhaps the design of your part in order successfully print your part?"
• "Do you have any relatively new computer powerful enough to run the various CAD/CAM/slicer software?"
• "Do you have somewhere that a printer can run continuously, overnight, or even for multiple days continuously without being disturbed by partners, children, pets, but still be observed should anything go wrong?"
• "Do you have anywhere you can run a printer for hours, perhaps even days on end, that's not going to bother the aforementioned family members and/or friends/neighbours?

... Then you're probably interested in using a 3D printer... if you aren't already considering getting one.

However, it's not as simple as using a traditional printer where you simply stick your ink and paper in and hit "print". There's a bit of a learning curve. So let me give you the broad strokes. Let's start with <drum roll please>

Choosing a 3D printer:

There are a lot of printers out there. From cheap kits with negligible instruction and cost-saving (or just cheap and nasty) parts, ordered through eBay or AliExpress, to "off the shelf" pre-built models like the DaVinci models in your local store. Going beyond that, there are the higher end consumer brands like "Lulzbot", "Ultimaker", and of course the much-praised Prusa range (which many cheap models are based on), all the way to the industrial brands like Stratasys (that I've used at previous workplaces)... but start at roughly $50,000.00 Australian when you first get set up. You have got to be serious about prototyping in order to justify that kind of expense.

Choosing a printer comes down to the usual considerations:

1. Budget.
2. Build space/volume (the maximum object size the printer can make).
3. Expected workload of the printer? Three cheap ones for a basic print farm and quantity of production? Or one expensive one for quality?
4. Intended use of printed parts... if your printer can't work with the materials you need, then obviously it's not a good choice.
5. Space. Where are you going to put this? How about all the consumables (filament, spare parts, glue stick, tape, etc)
6. Availability of consumables, replacement parts.
7. Technical skills (do you want to build a kit from scratch, upgrade a cheap printer with "improved" 3D printed parts and/or better electronics? Or skip the "hard stuff" and just plug it in and go?)
8. Are you willing to learn, tweak and make many, many mistakes but take full control of your print... or work with pre-made processes for the ease of use.. and still make many mistakes, but avoid some problems using the recommended settings and processes?

In the end I did a lot of research, I looked at things like price, and availability in Australia, however it really came down to four things for me.

1. Price: I didn't want to spend too much on my first printer... but I didn't want rubbish that would cause me a great deal of frustration... or worse. When reading about the cheap printers I came across a trend that I should at least warn you about. A disturbing number of cheaper models (particularly the Anet A8) have numerous reports of catching on fire. (Google "Anet A8 fire" if you don't believe me). However, any printer poorly maintained can set fire to your house... so please keep that in mind.
2. Community, and customer support: I can't emphasize the importance of this. Sticking to popular brands is a good choice, as there's a lot of support and guidance. I found that buying through an Australian reseller was actually cheaper than buying my printer directly from the manufacturer overseas when the reseller company took care of the import duties, and had a faster delivery window than the manufacturer. When my kit arrived, it was missing a part... (although included gummy bears) so the reseller had a part printed and sent to me within a few business days. I was up and running the following weekend.
3. General reviews, and capability: I wanted something that was well regarded, and demonstrated a reliable track record. Reviews helped me to understand the things people liked and didn't like with particular models, features that made life easier, and ways to overcome the shortfalls.
4. My objectives: I'm a technical guy, and I wanted to learn as much as possible about 3D printers. So I wanted a relatively "open source" system that would enable me to tweak things and replace things as I needed to. However, I was also considering going for the most "build volume for buck" ratio... which isn't always perfectly aligned with the open source objective.

In the end I considered this, and for me, it came down to two models... Creality 10 series, or the Prusa MK3s kit... both have substantial pros and cons, and I was honestly torn for a while. Please note that there are many brands out there, and I'm not saying that my preferences are necessarily anything like your own.

The deciding vote.... Prusa... for space limitations and domestically available support reasons... and the fact that my last workplace ordered a bunch of them and I was very impressed with the build quality. I also like the fact that you can use the existing printer to print off a bunch of spare parts should anything break, or you just want to build another printer!

Building the Prusa.... A journey of several hundred steps begins with a packet of... Gummy bears?

Ok so while I've used multiple 3D printers before for work purposes. My understanding of them has been rather superficial. I know how to load files, and print them using a high-end industrial printer. However, things are quite a bit different for the home user when the device is substantially stripped down... (at least from the perspective of a $50K printer). There's often a great deal of educational merit to using cheap-end equipment in any field. You not only learn about the problems that aren't automatically solved for you, you also learn techniques to work around the limitations of your hardware. This increased skill set can only improve things further when you eventually use better equipment.

Who should build the kit themselves?

To save you some time reading through my tale, I thought I'd summarize it here:

The Prusa MK3S was my first 3D printer that I've owned, and while it is not the most difficult build I've ever done, it's certainly quite involved. I honestly wouldn't recommend the Prusa to beginners and non-technical people if you're buying it in kit form. If you're spending the extra cash to have it made for you, then that's an entirely different matter. Tech heads, electronics people, and people used to carefully reading instructions, and following them precisely will have no problems assembling this kit. If assembling Ikea furniture is difficult for you, get it pre-made, get help from a friend, (a beer is not enough compensation for a build that might well take days the first time).. alternatively, you could simply buy a different printer. 

Back to my construction tale....

Reading the instructions, I noticed that they include a bag of gummy bears as a reward system for going through the hours of construction. I particularly liked the reward system... however, I can imagine that the bears are often consumed before anyone reads the instructions on how to ration them on a section by section basis. Upon opening the box, you are indeed greeted by a bag of gummy bears on top.

Gummy bears aside, once you've opened the nested cardboard boxes, you'll find that the kit is packaged in resealable plastic bags, each clearly labelled for each section of the assembly. Whether it's the initial frame, the Y-axis, the heat bed, the Z-axis, the X-axis, the extruder, the power supply, the control circuitry, and the wiring. There's usually two bags for each section, with one bag for the screws and various odds and ends, and another bag with the corresponding printed parts. Each bag has a "to scale" image of all the parts, so you can quickly identify which screws are what. This is particularly handy when you have both 18mm and 20mm M3 screws, and they have to go in the right places.

I can't stress this enough. Read the instructions for each step entirely before you so much as gather the parts in question. When I mean entirely, look at the pictures closely. The book is good, but the online assembly instructions are better. You can zoom in and read the various comments and experiences that other builders have gone through. Learn from other people's mistakes, they've shared their pain so you don't have to experience it yourself!

Starting the build:

I had already read the entire online assembly manual twice while the kit was being shipped to me. I didn't expect to remember much, but I feel that seeing what each stage brought to the printer, what it looked like, and the most concerning comments at each stage came in handy when I had moments like "Hey this might be the bit where over-tightening might cause a problem". or "Some poor guy managed to push out the bearings when installing the rods here"... "This Y-axis drive belt is exactly the right length, don't trim it like the guy who thought this belt was the X-axis one". 

A note on tools:

The tools included in this kit involved several allen/hex keys (one with a ball head), a standard #2 sized philips/cross type screwdriver, and a pair of needle nose pliers. I found that a pair of scissors, tweezers, a pair of side cutters, and small socket driver (for certain nuts) made things easier along the way. However, it is entirely possible to do this with just the included tools.

Getting off to a good start....

Assembling the frame is simple, yet surprisingly finnicky. The parts are aluminium extrusion, and a precision cut sheet of metal for the upright frame. Despite the fact that this simply involves installing screws and tightening the parts together you should do this slowly and carefully.

The order that the screws are tightened, as well as the extent of the tightening on each and every screw can have a significant impact on the final accuracy of the printer. If you tighten things too much, that may cause warping in the frame. If you don't line up all your parts very carefully before tightening, you can have a rock in your printer, which will increase vibrations, noise, loosen screws more frequently, and cause all sorts of other problems.

The system can compensate for a small amount of warp... but go beyond 2mm out on any dimension, and the first calibration will tell you to go back and build it again!

Ok, so I got a little carried away with this, I was tightening screws by 1/8th turns, on a precision ground flat cast iron worktable, that (depending on the temperature at the time) will be out from complete flatness somewhere between 3-5 microns (1/1000th millimetre). However, if you have a granite benchtop, or table saw, that's going to be more than flat enough. I spent hours doing, and re-doing this until my dial gauge said that there was less than 5 microns when pushed in numerous locations on the frame... but the screws were sufficiently tight. Often I'd tighten one, and the precision would drop substantially.

Moving beyond the frame:

In a very real way, once you have the frame done, you generally start from the ground up and add bits as you go. So you start by assembling the Y axis, the heat bed, and add the Z axis, then Extruder and X axis, do the electronics and wiring, then the preflight check. However, due to a Y belt holder part that was actually missing, I did things somewhat out of order while I waited for the part to arrive.

Some parts like the heat bed and the X and Z axis assembly was pretty darn easy. However, the extruder took me quite some time... somewhere around 5 hours. Mostly because there are around 60 steps in the assembly, and each can be quite particular in how it is done. Since the extruder really is "where the magic happens" I made sure it was done as carefully as possible.

I'm not going to go through the whole assembly, that is easily seen by visiting the Prusa web site. However, the instructions are very detailed and refined, but it's a long road. I can see why people charge $300 or more dollars for assembly. I'm sure they're faster due to practice, but it's certainly not making them much money if they're starting out.

However, I believe the assembly for me was the right choice, and I've got a very good understanding of it's structure, and how it works. However, please don't let me deceive you into thinking that I know everything. There's a lot I don't know, and there's a lot of skills needed to actually print well.

For that, have a look at my next article... Initial prints and beyond...

Stay safe, and have fun!

Ham.