What is really important in the FDM 3D printing technology?

In a recent article, when I wrote about the latest updates to the Makerbot Mobile application, I indicated that one of the most important aspects of the popularization of low-cost 3D printers among the wider public is to simplify the process of the equipment’s use. While the claim is easy to support, I can not help but notice that the 3D printing technology is really about something else. Easy handling is important, as well as a number of other factors that influence the popularization of 3D printing (introduction of color, or wide range of filaments etc.), but in the end, the most important thing is that the 3D printer should be able to reproduce the spatial model as accurately as possible. Only this much – and no less…

The FDM technology 3D printers are relatively simple devices – at least in mechanical terms. That is why there are so many companies producing such devices, and why only this type of 3D printers come in the form of kits for self-assembly. What is really complicated in the FDM technology is not the construction of a 3D printer, but the software slicing an STL model into layers, generating supports in the places where they are needed, and converting the whole thing into GCode – a sequence of commands to control the printhead and the build plate of the device.

This process is so complex that only a few companies on the market equip their 3D printers with proprietary software – the vast majority uses free slicers – KISSlicer, Slic3r or Cura, or create their own software, but use one of the existing engines to slice and generate the GCode. In the end, if you buy a 3D printer which uses Slic3r engine you can be sure that 3D printing of the models with a raft (the bottom layer on which the model is constructed, from which the print is torn off) will fail (the raft will be virtually bonded with the model and it will only detach from the model by mechanical means).

Apart from the software issues, what is equally important in the FDM 3D printing is the exact reproduction of the dimensions of the model with respect to its digital version. Thermoplastics – in particular ABS, and nylon, are characterized by high shrinkage. It results from the fact that the material printed at the temperature of 240°C – 250°C needs to cool down to the room temperature and in the process starts to shrink and changes its volume, which consequently affects the geometry of the model. It may also simply crack. It works much better in the case of PLA or its composites, however, there may be shrinkage too – especially with large projects or in particular conditions of the room in which it is printed (for example, a room full of drafts).

The 3D Printer manufacturers are trying to solve this problem by closing the build chamber of their devices. Additionally, Stratasys heats it and then cools it down in a controlled manner. As a result, the material shrinkage is minimized, although by no means is it resolved. However, keep in mind that 3D printing with ABS or nylon is on a completely different level of difficulty than with PLA, and anyone who thought of using 3D printers for commercial reasons or for professional prototyping with these materials, should take it into consideration.

In the end, the issues related to whether a printout is monochrome or in color (possibly printed with two or three printheads), or whether it is made from one or another PLA composite (wood, bronze, brass etc.), and whether the 3D printer may be operated with a smartphone, or if it needs manual control, are all relatively important, but it is incomparably more important to have the model reproduced with the best possible accuracy.

In other words, when we decide to print a professional model with the dimensions of 10 x 10 x 10 cm, we should get a model with exactly these dimensions, not with a “tolerance” of a few millimeters. And that is what you should focus on when searching for a 3D printer. Unless you are looking for something to play with, where it is more important that you get anything printed at all, rather than a device which prints models with the exact same parameters as in the initial designs.