Choosing a 3D printer is simpler than it looks. There a large number of options, and understanding all the different specs can be daunting. This page will break it down to a few popular printers to meet your budget and requirements. This page will be updated to stay up to date with changes in the printer market. Before discussing particular models, we will break down the basic options available to you.
Types of Printers:
There are a number of 3D printing technologies, only two of them are predominant on the consumer market, resin printers and filament printers. other technologies are less available and more expensive. Both of these systems print plastic parts, metal printing is extremally expensive and not covered here. You would be better off pursuing investment casting if your set on making metal parts.
Resin printers use a UV curable resin as the raw material, the resin is exposed to light one layer at a time to build the part up. The process is messy and the final parts tend to have poor structural integrity.
Filament printer use a plastic filament as the raw material, the filament is extruded through a heated nozzle and forms lines of plastic, these lines build the part up one layer at a time. Filament printing is the most popular form of Fused Deposition Modeling, and often referred to as FDM printing. The process is relatively easy and produces strong functional parts in a variety of polymers. FDM printing is the process of choice for 3D printed weapons.
Extruders:
The extruder is the heart of the FDM 3D printer. It feeds the filament, melts the filament, and extrudes it out of the nozzle onto the previous layer. There are countless extruder designs, but three features are particularly important, these features will effect what materials you will be able to use.
The first is how the filament is guided to the heated nozzle, or hot end. The lower cost option is to use a plastic PTFE tube to guide the filament directly to the nozzle. The issue with this method is that the temperature of the nozzle is limited to the decomposition temperature of PTFE tubing, which is 260 C MAX. Many high performance filaments require more than this. The alternative is often referred to as an all metal hot end. A precision metal tube guides the filament to the nozzle, and the nozzle may be heated to a much greater temperature without issue. Now, there are some other pros and cons to these, but they are not important here. When you are getting started and printing with low temperature filaments, the PTFE style will be fine, but the all metal hot end give you more material options for the future. The best way to see what hot end a printer has is to look at the max nozzle temperature. 260 C max means it’s a PTFE style, 300 C or greater indicates an all metal hot end. All metal will cost you a bit more, but has become the predominate hot end in the industry.
The second is how the filament is pushed into the hot end, particularly where the extruder motor and drive gears are placed. The drive gears are what forces the filament into the hot end. There are two options, direct drive and bowden. Direct drive places the motor and drive gears as close to the hot end as possible, normally directly above it on the print head. This limits the distance the filament has to be pushed, allowing you to print with softer filaments, even soft rubbers. Bowden systems place the extruder motor and drive gears away from the print head and push the filament through a long PTFE tube to the hot end. This results in a much longer feed path and makes printing with soft filaments difficult or impossible. For printing most weapons parts, either will work, but if you want to print soft parts direct drive is recommended. Most modern printers use a direct drive system.
The third is the nozzle itself. This is normally the easiest part to change and upgrade if required. Standard nozzles are made from brass. Brass conducts heat well and works great for unfilled materials. However, if you want to print with higher performance carbon or glass fiber filled materials, the brass nozzle will quickly wear out. Hardened steel nozzles are a good alternative. When buying a printer it will probably come with a soft nozzle, but it’s an easy part to upgrade. This is also a good place to touch on the extruder gears mentioned above. These can also be made from brass on low cost printers, and they will wear out quickly with fiber filled materials. Starting out you should be printing with lower cost unfilled materials and the brass parts will be fine, but hardened parts will give you more material options.
Motion Systems:
The motion system is what actually moves the print head around in relation to the part being printed. There are a few different types, but two of them predominate.
Mendel style printers have a print head which moves on two axes, up and down, and right to left. The third axis is achieved by moving the entire print bed, with the part being printed, forward and backwards under the print head. Because of this motion it is often referred to as a bed slinger style printer. This is a very popular system due to the simplicity and low cost. Because of the heavy bed the print speed is more limited, and tall parts can be prone to falling over if the bed is moved too quickly. This is not a huge disadvantage as speed is not a large concern when printing weapons parts.
Core XY is the current state of the art system available. It uses a system of belts to move the print head on two axes, forward and back, and right to left. In most systems the Z axis is achieved by moving the entire print bed up and down, but in some cases the core XY carriage may move instead. Core XY does not have the disadvantages of the mendel style, and it can be easier to enclose the printer, which helps with some materials. Core XY printers tend to cost more.
There are other systems such as Delta printers or belt printers, but these should be avoided due to higher cost with little advantage.
Bed Leveling:
The print bed on 3D printers must be on a known plane, perpendicular to the rest of the motion system. This is often referred to as “level”, even though it has nothing to do with being perpendicular to the force of gravity. Different printers have different systems of bed leveling.
Manuel bed leveling is found on most low cost printers, it consists of threaded jack screws on each corner of the bed that must be manually tuned by the user to achieve a level bed. This process is a bit painstaking, but works well.
BLTouch auto bed leveling is a system found on many upgraded low cost machines. It is available as an upgrade to existing manual leveling machines. This system is often only partly automated, as the printers still use the manual jack screws for the first round of leveling. BLTouch does serve the useful of mesh bed leveling , which is where the printer compensates for a slightly warped print bed. In general this system is not much better then manual bed leveling. It should be noted that some higher end printers use the BLTouch probe for true auto bed leveling, so be sure to continue reading.
Auto bed leveling is where the leveling process is fully automated. Most higher end printers use this system. It may be implemented using a number of systems, including a BLTouch probe. The best way to tell if a printer is fully automatic is to look for the manual jack screws. If it has none, chances are it features true automatic leveling. Auto bed leveling is more convenient and easier to use then manual systems.
Build Volume:
The printers motion system is limited in movement by the length of the rails, it can only print an object that is so large. This limit is enumerated in the printers build volume. If the build volume is too small you won’t be able to print some parts. We design all of our weapons systems to be printed on the most commonly available sizes of printers. Because of this bigger is not better, it will cost you more with no real advantage unless you specifically have very large parts in mind. The diagonal size of the bed is the best way to judge how long of a part you can print, at least 310 mm is recommended, use Pythagoreans equation to calculate the diagonal. For the Z height at least 210 mm is recommended. All of the recommended printers are at least this size.
Recommended Printers:
This section has changed as the available printers on the market have improved.
The Creality Ender 3 has been the go to budget printer for years. It is about as basic as you can get, and the price reflects that at under $200. You can even get these printers on sale for under $100! This is an incredibly basic printer, manual bed leveling, bowden drive with a low temp hot end, bed slinger, and lots of tinkering to keep it running. If time is more valuable than money, this is probably a poor option.
At under $600 the Bambu P1P is probably the best option for the cost available on the market today. It does not come stock with hardened extruder, but the upgrade parts are available for low cost from Bambu, and are easy to install. There is an issue with the Bambu printers, and it is not related to the printers quality. Due to the closed source nature of their hardware and firmware, and their similarity to DJI, they are the one company that has the ability to control what you print if they desired to implement such a system. It is important to note that as of now they have not done this, and there is no indicator that they will. However, it is something to keep strongly in mind. As a precaution, you should avoid connecting your Bambu printer to the internet, and do not upgrade the firmware until you know that it is safe.
The Prusa Core One is a more costly machine at just under $1000 for the kit, but it has none of the Bambu security concerns, and is a fantastic printer. If price is not a significant concern, this is one of the best options.
Which of the above printers you choose depends on your budget and goals. If you have the money, buy a Bambu or Prusa, you will not have to tinker with the machine and can get right to printing. If your budget is smaller or you want to gain a more in depth understanding of how printing works, the Enders are a great option. Just be sure to understand the tradeoffs.