What I’ve Learned from a Month of 3D Printing
3D printing is something that I didn’t think I’d ever get in to. To be honest, I’m still not really “in to it,” but I do find it frustratingly enjoyable for reasons I can’t explain. About a month ago I picked up a used Anet E10 3D printer from someone local that had it advertised online. The Anet E10 is a fairly inexpensive but popular 3D printer, that like almost all of the affordable 3D printers, is made in and sold directly from a nameless face somewhere in China. It has a smaller brother, the A8, and a bigger brother, the E12. The E10 is an affordable and easy to work on entry in the mid-sized consumer 3D printing world, with a large 220mm (width) by 270mm (length) by 300mm (tall) printing area. Retail on a new one is just over $300, but I got mine for $200 with a few extras included.
The person I bought it from is a mechanical engineer at a company that’s actually a customer of my employer, though we’d never met before. Like most of these Chinese 3D printers, the Anet E10 has some well-known issues that need to be addressed after assembly. Though too numerous to list here, and somewhat outside the scope of this article, some of the upgrades that the previous owner added to my E10 include a X-axis belt tensioner, a 3D printed strain relief mechanism for the cables that attach to the heated printing surface, a new steel bracket for the hot end (which he machined himself), 3D printed improvements for the factory fan shrouds, and custom glass which was cut to fit the printing surface (which admittedly, I don’t use). He also upgraded the hot end with an all metal E3D V6 clone, which I’ll talk about later. Perhaps most important of all, he added a MOSFET for the extruder. From the factory, the electrical design doesn’t include one, and sometimes results in melted connectors and a failed mainboard.
He took the time to go through the unit with me and told me what he’d learned about it, which was extremely valuable. He then told me that I should look at this as more of a hobby than as a piece of consumer equipment that was guaranteed to work all the time. Other things he told me echoed what I’d heard in other research – basically that 3D printing is more of an art than anything else, that software settings (of which there are many, and all of them are extremely precise) vary from printer to printer, from filament to filament, and from environment to environment (temperature of the room, humidity, etc.) — oh, and each one can vary wildly based on changes to the others. Settings that worked for him might not work for me, but he gave me some basic settings to start with. What am I getting myself into?
The first thing I tried to print failed miserably, and several complete tear-downs and rebuilds of the print head ensued over the course of days. Extreme frustration set in, and to be honest, I almost threw the whole thing back online for sale a few times. I stuck with it though and now I’m printing semi-reliably, prints are still more likely to fail than they are to succeed. I figured that someone out there may have the same frustrations as I do starting out, so if that’s you, the following are tips that I wish I would have known before jumping in.
Understand How Your Printer Works
As I mentioned before, my printer came with an all-metal hot end. The hot end is the part of the printer that melts the filament that you’re trying to print with. The easiest and most common filament is called PLA. It melts a fairly low temperature as far as 3D printing is concerned (between 180 and 220 typically), and it’s very sticky when melted, so adhesion to the build surface doesn’t take a ton of skill to get right. It’s not as strong and resistant to heat as something like ABS, but when you’re just starting out it requires the least specialized equipment. No heated bed is required, for example – a feature that’s lacking on some cheaper 3D printers. When you’re first starting out, use PLA.
The hot end is the part of the printer that gave me the most trouble. On my printer, the PLA filament travels off the roll and through a mechanism that pushes it through a plastic tube called a bowden tube to the hot end assembly. The PLA travels through a heat sync (at this point it should still remain cool), and in to a metal tube called a heat break. The heat break has a narrow section in it which is designed to provide a narrow attachment point between the hot side of the pipe and the cool side of the pipe. The cool side is screwed in to the heat sync and the hot side is screwed in to the heat block. The break is designed to keep heat from transferring to the cool side of the heat break, which causes melting of the PLA before it gets to the nozzle, ultimately resulting in a jam. The heat sync and fan also work to help keep the PLA cool before it reaches the nozzle. The opening of the nozzle is extremely small (the one I’m using is 0.4mm) so it clogs easily, and incoming filament must be kept extremely clean and free from contaminants like dust.
I’ve marked up this diagram to provide a visual aid to the above description. You’ll become very familiar with disassembly as re-assembly of this unit, since disassembly is required whenever the hot end clogs. There are a few important things to note on this diagram. The first is that the bowden tube comes through the top of the heat sync and it and the top of the heat break have no space between them. This is required to prevent the filament from catching on the top of the heat break, which will cause feed issues. Another thing to note is that the nozzle and the bottom of the heat break meet in the heat block, and there should be no space between the two. This is vital to prevent clogs, as melted filament will pool in this area if there’s space between the nozzle and the heat break and will cause a hard clog.
The heat block has two things not shown in the above diagram which are vital to its operation – a heating element and a thermistor. A thermistor is a resistor whose resistance is dependent on temperature. This is the component that tells the 3D printer’s logic board how hot the heat block is. The heating element is used to heat the heat block and nozzle, which allows the filament to flow. The insides of all of these components need to be kept extremely clean. It’s not a bad idea to have quite a few extra nozzles and heat breaks on hand, as those components typically require cleaning when a clog occurs, and spares are the fastest way to get up and running again in case of a clog. These components are fairly cheap. I got a set of 20 0.4mm nozzles on Amazon for around $10, shipped.
I would also recommend having a few extra thermistors on hand. They’re very cheap, and if you break your thermistor it’s not safe to use your 3D printer. Since the logic board can’t tell how hot the heat block is, it could heat the heating element too much and cause a fire. Rather than be down for a few days with a broken thermistor, keeping some on hand “just in case” isn’t a bad idea. The tips are very small and made of glass. After being heated and cooled numerous times they get very fragile and are easy to break if you aren’t careful. I broke one and was out for 4 days until replacements came. I got 6 compatible thermistors on Amazon for $8.88.
Experiment, And Use What Works
When reading about my particular model before picking it up, the “all metal hot end” was something that a lot of people swore by. I was stoked to see that the previous owner had done that upgrade, but wasn’t stoked when heat kept constantly creeping further and further up the heat break during prints, which resulted in jams due to filament retraction – a required setting to prevent stringing when 3d printing. Retraction is when the filament is pulled out of the hot end slightly as the print head moves from one location on the print to another during printing, which reduces stringing melted filament all over the print. This is annoying, but it’s not deal-breaking.
I later found out from experience that the “all metal” heat break isn’t the greatest thing to use when printing PLA because (drum roll please…) it clogs a lot. At the point that I found this out, I was able to complete successful simple prints, where the print head didn’t need to jump around a lot, but as soon as I tried to print something more complicated than a basic geometric shape, I’d get a hard clog and have to tear my entire hot end apart. It turns out that my hot end was clogging due to the retraction that is required in detailed prints. Why was this happening? It was because I was printing PLA with necessary retraction combined with heat creep in my all metal hot end were resulting in serious clogs.
There are two types of heat brakes that are supported in a hot end like the one from the diagram above. The first is all metal, and the meaning of that is exactly how it sounds – the heat break is a solid piece of metal. A second type of heat break exists, which contains less metal on the hot side of the heat break, which is lined with a piece of PVC tube.
1.75 mm is a very common size for PLA filament, and is the size I’m working with, so check out the left-most heat break and compare it to the one that’s three in from the left. This image shows the hot side openings of the heat breaks. Notice there’s a lot less metal in the version with the PVC tube, and so it transfers much less heat to the heat break itself. Since there’s less metal, it retains less heat as well. The PVC provides a more slippery route through which the PLA travels, and unlike an all metal heat break the actual inner walls of the heat break are required to be less smooth and perfect than that of an all metal unit. This means that you can more reliably use cheaper PVC units with much less jamming versus cheap all metal units. If something happens to mess up the inside of the PVC tube you can just pull the tube out and replace it and don’t have to worry about soaking the entire heat break in acetone and polishing it back out again, which is required for an all metal unit.
There are down sides to the PVC units though. The PVC breaks down at around 260 degrees C, so if you want to print ABS you’ll have to use an all metal unit. For lower temp filaments like PLA though, the PVC unit works just fine. My point in describing this is that when I was doing research in to the unit before buying it, and when trying to figure out why I was constantly having clogs when printing anything more than the simplest of shapes, I didn’t think to try a PVC unit since so many people were saying that the PVC units were junk and that all metal was the way to go. Thus the title of this section, “Experiment, And Use What Works.”
Make it Stick – First Layer Adhesion
First layer adhesion is something that is hotly debated, and is very important for a successful 3D print. If whatever you’re printing breaks free from the bed of your 3D printer during a print, your entire print will be ruined. Everyone has their own tricks to getting that first layer to stick. Some people attach a thin layer of glass on top of their bed, and print directly on glass. Other people swear by covering their bed surface with masking tape and printing directly on to the masking tape. I’ve read stories about people spraying their bed with Aquanet brand hairspray or using Elmer’s Glue Stick, though it seems like either of those would be a mess.
Looking back at the previous section, another successful “but you’re not supposed to do it that way” setting I found was my heated bed setting. Many posts I read suggest that you don’t need to run a bed heater while printing PLA, because it doesn’t help with PLA adhesion, and that you should never run a bed heater when you use masking tape on the bed. Despite all of this, I found that heating the bed to 50 degrees C in conjunction with using 3M blue masking tape gives me great adhesion, and I’ve never had an adhesion problem with this combination. I find that this helps me remove the printed object once printing has finished, since I can just pull up the masking tape and the object comes with it.
Learn Everything You Can About Your Slicing Software
Slicing software takes a 3D model and slices it up into layers. It generates a set of instructions for the 3D printer to tell it where to place melted filament for each layer in order to re-create the three dimensional object, physically, using the printer. 3D models for printing are typically distributed in .STL format, and the slicing software will generate printer instructions in the form of a .gcode file. The .gecode file is the file that you’ll likely transfer to a micro SD card, which will then be placed in to your 3D printer to create the print. Choosing a high quality SD card is vital here, as I’ve seen all sorts of strange issues on forums and Reddit posts about people who have issues with their prints when using cheap Chinese SD cards that they bought online. Stick with something like Sandisk or Samsung and save yourself a headache.
The slicing software that I use is called Cura. It’s free and available on Windows, Linux and MacOS. It’s very widely used and most people are very familiar with it so it’s easy to get help with if you run in to issues. I’ve seen many posts in my troubleshooting research where people were running in to strange printing issues using some not very well known slicing software, and switching to Cura to slice their models fixed their problems.
Having a deep knowledge of the settings in your slicing software is extremely important to successful 3D printing. There is not a perfect configuration that will work for every 3D printer in every environment. Every printer is different. There are a couple of general “rules of thumb” that I’ve run in to when it comes to some of the settings, and following those rules of thumb have proven very successful for me. Layer Height determines how thick each printed layer will be. With my 0.4mm nozzle and 1.75mm filament, I have my layer height set to 0.2mm. I was told that having a layer thickness (in millimeters) that’s half of your nozzle size (in millimeters) is a great starting point. Keep in mind that if you change nozzle size you’ll also have to change your layer thickness.
Retraction is another important setting. Retraction is when the printer pulls the filament back slightly when moving the print nozzle from one area of a print to another in the instance where should be no filament in between those two locations. This helps to reduce “stringing” on the print. The amount of filament that’s pulled back is called the Retraction Distance. By default, in Cura, the Retraction Distance is set to 6.5mm, but I lowered this to 4mm. That seemed to help reliability when I was running the all metal hot end, but I kept the setting when I switched to the PVC hot end and it still works fine. I also pulled the Retraction Speed up to 40 from the default of 25.
It’s important that you find settings that work for your printer and your choice of filament and stick with those settings and filament brand and type if you want consistency. A lot of people swear by the quality of Hatchbox brand filament, and after switching to it from the generic filament that was given to me by the guy who sold me my 3D printer, I’ve found that the Hatchbox filament is extremely good in terms of consistency and quality and is very predictable and reliable. It’s available in a variety of colors and starts at around $20/1kg spool on Amazon. This is one of those instances where you can find cheaper no-name alternatives, but the resulting headaches will make you wish that you spent a few dollars more on the quality stuff.
Find (Or Make) Something to Print
Before you can even start messing around with Cura, you’ll need something to print. Here, you’ve got two options – make your own 3D models, or download 3D models that other people have created.
The best resource I’ve found for 3D models created by others is Thingiverse. This is a free website where users submit their own 3D models for others to download. Models range from useless trinkets and shapes to useful tools that can be used every day. Thingiverse has everything from puzzle cubes to key chains to brackets to hang tools on the wall. It’s easy to get lost in this site for hours, and there’s a lot of cool stuff to be found.
If you want to make your own 3D models, you can start with Tinkercad. Tinkercad is from AutoDesk (the company that makes AutoCAD, 3DS Max, etc.), and is a free 3D modeling software that runs in a browser. You have to sign up for an account using an email address, but you can then save your 3D creations directly on the Tinkercad site for access from anywhere. You can also share your 3D models with other Tinkercad users. There are a ton of YouTube tutorials on how to use the software, and it’s actually quite powerful for making useful objects that translate well to use in the real world since Tinkercad’s measurements are in real-world units and print out at the correct size.
If you want something more powerful, FreeCAD is another free option and is available for Linux, Windows, and MacOS.
Conclusion
I’ve learned a lot over the past month with my 3D printer, and I’m just now to the point where I’m able to start printing reliably and consistently. When first starting out, I spent more time tearing my printer apart and fixing clogs than I did printing. I also threw more failed prints away than I was actually completing at a rate of around 10:1. It was a discouraging start, but every time I figured out why an issue was happening that caused a failure of one form or another, it was a very rewarding experience.
3D printers are cheaper and more reliable now than they ever were, but if you decide to take the jump in to the 3D printing world, I highly recommend you go in to it thinking of it as something that takes skill to master and not as something you’ll pull out of the box and be excellent at right away. You don’t just go to the store and buy a guitar thinking that when you get it home you’ll plug it in and be able to play whatever you want. 3D printing is much the same. If you understand from the beginning that there is going to be a lot of trial and error, a lot of tweaking, and a lot of experimentation, then you’ll be in a more realistic mindset and will have a much more rewarding experience with every battle you win.
Overcoming challenges is half the fun with 3D printing, and the cool things you print are like little trophies that you’re rewarded with for besting those challenges. I hope you found this information useful, and good luck with your prints!