FDM or Fused deposition modeling (as well as FFF or Fused Filament Fabrication) is a method of additive "growing" of objects on the basis of which almost all modern "household" 3D printers are built. The method implies layer-by-layer "cultivation" of an object from molten plastic, which is supplied in the form of a rod.
The idea was originally patented, but the patent expired and after that inexpensive 3D printers of various manufacturers poured into the market – from eminent Americans to nameless Chinese – For every taste and purse. Someone chooses by brand – but if you have knowledge of electronics and the desire to solve problems yourself (without the technical support of the manufacturer), you can save by purchasing a kit kit or even collecting a printer from scratch for one of hundreds of published models.
A barrel of honey
FDM technology is really impressive. Today it is no longer just a matter of rapid prototyping for designers and architects. In fact, having a three-dimensional model of the object, we can reproduce it at home, if necessary changing the scale or slightly modifying it in the editor. For example, you can download the attachment model for the phone in the car and scale it to your own device. Or from scratch to draw any household detail – from the lampshade to the lamp to the door handle, not to mention all the little things like homemade bindings to GoPro, elements of children's designers, etc.
Of course, 3D printing can not replace the conveyor with Mass production – the speed of layered forming of parts from plastic is not high, therefore one "standard" printer can serve at best only the requests of its owner. But it is not worth the task of skipping the existing production technologies. 3D printing rules where it needs maximum customization and serial production would be completely unprofitable. Therefore, she was very fond of DIY fans in various fields, etc. In fact, a 3D printer is a DIY tool.
Household 3D printing is now experiencing explosive growth. FDM technology is quite simple, and the enthusiastic community has already developed several typical designs of such printers, differing in the methods of feeding the rod and kinematics. Based on these standard designs, both branded printers and dozens, if not hundreds of homemade articles, individual parts or even complete kit-kits to which one can buy on Ebay or AliExpress are created.
Fly … also a barrel?
It would seem that the technology is rolling in, cheaper, while it already has a serious demand. Is not this a pledge of an early grandiose success in the mass market (as it already happened with mobile phones, digital cameras, and a little earlier – and computers)? Is not it time to buy?
It seems to us that we should not hurry. FDM technology is pretty capricious, and while it is far from becoming a kind of "digital camera" or "washing machine" in the hands of an ignorant user. Almost every corner here has to apply engineering thought. For the sake of justice it is worth noting that if you are all right with engineering, then the possibilities of 3D printing are really huge. But it is better to know in advance what you are "subscribing to."
Processing of table and model
The layer-by-layer application of something requires special preparation of models and the surface on which printing is carried out, plus the post-processing of the parts will be necessary.
The printer comes with a glass or a table made of metal – not any material will stick to them without additional tweaks (and not any then will be stuck without violating the geometry of the model). PLA-plastic can be printed on a table without heating, using a blue-scotch tape – a very strong paint tape from 3M, which now has been re-qualified as an enterprising user in an "adhesive tape for 3D printing." The overwhelming majority of thermoplastics need at least table heating, and sometimes additional glue coatings (varnish, glue, beer, syrup from acetone, etc. – there are lots of options tested by users). Finding the right coating for this printer (and plastic) is the way of experiments and mistakes. It is necessary to spoil more than one model before there is the most optimal option.
But the seal of the first layer of the problem is not limited. The filament from the molten plastic can not hang in the air, therefore, on the strongly protruding parts (for example, details with a reverse bias), support is necessary, which at the end of the printing will have to be cut off, somehow processing the cut site so that there are no sharp edges. It should be noted that the most ordinary vertical wall after the 3D printer will not be perfectly smooth (at least the boundaries of layers, and maybe other defects will be noticeable). So postprocessing is required for almost all parts for which surface quality matters.
Not all plastics are well suited for post-processing. For those who print a lot and different materials, a whole set of solvents, hand tools, etc. will have to be built at home. (As well as those who actively entertain DIY). By the way, some plastics are also toxic at the time of printing – so you need closed cases, hoods, etc.
Features of consumables
Depend on consumables
Quality problems can be determined not only by factory marriage, but also by the "regular" features of the material used: for example, some types of plastic are hygroscopic (absorb water from the environment). If you do not store such plastic in tightly closed packages with silica gel, the rod becomes brittle, it can break when fed, produce strange sounds when printing, it is bad to lie down on the model, etc.
In general, even if the material quality at height (There are no obvious problems), for printing certain plastic does not fit any model. Some materials are fragile and do not allow printing thin walls, others – on the contrary, are well stratified in volume.
Each plastic has its optimum printing temperature. If it is exceeded, the details become worse and surface defects appear. In the reverse situation layers are badly sintered. Likewise, there are optimal layer thicknesses, retract parameters (reverse thread motion), and other similar parameters.
Many print imperfections can be "compensated" by reducing speed. But correctly say that the main problem is not to print the object, but to do it in a reasonable time. Therefore, for objects, more matchbox will have to deal with the optimal settings for each plastic.
The difficulties are added by the fact that the detailed settings are not prompted by "colleagues" on the forum – the optimal parameters are largely determined by the printer: how well the sensor calibrated it Temperature; Whether remote filing is used, or the like. Plus, the final figures may differ for the same plastic of different manufacturers, as well as for coils of different colors from one manufacturer.
"Foci" of the printer
Capable and the printer himself knows how. Each of the existing designs on the market has its drawbacks. Somewhere the motors that need to be perfectly synchronized work a little differently; Somewhere – the table fluctuates during printing at high speed; Somewhere, too much input is given by the weight of the print head. Similarly, there are "sore spots" that come out regardless of whether it is a self-assembled printer, whale or bought in the form of a "black box from the manufacturer." In the first two cases, the probability of getting glitches is somewhat higher, but the company's origin does not relieve the device of "typical" diseases.
There are quite a lot of moving parts in the average 3D printer, and the mechanic has its own resource of work. In some devices, plastic gears are worn out, in others the Teflon tube is snug with a fitting, etc. Sooner or later such minor flaws begin to affect the result of printing. Alas, but the universal FAQ, which helps to catch the problem on the final result, no. Here, as in old cars – we must look for colleagues in misfortune, study the forums and hope that someone has already come across this problem. Or – as an option – to find out which node is to blame for the problem, and completely shake it. But this is more like building your own printer from scratch.
Before the tens of meters of the rod turn into a viable object, the model must undergo a procedure of slipping – cutting into layers taking into account the printer's specifications – nozzle size, layer thickness, etc. The Slicer can "break wood" if the original model is not closed (it happens that in the simplest model holes are obtained – in the most direct sense). To "cure" models there are online services and tools in specialized software, but not always they cope with the task. In this case, they themselves can "lose" some details.
Frankly, the slicer can be mistaken, even if the model is completely normal, and the reason for that is rounding. If the pitch of the shaft thread along any axis is not proportional to the thickness of the layer, a rounding error will accumulate during the slicing, which in the model appears in the form of a corrugated surface.
If to speak more globally, the main problem of consumer 3D printing in the existing Option – no feedback when growing the model: the printer simply does not see what it is printing. There are temperature sensors, jamming threads and other tools, but the appearance of the model is not evaluated in any way. The only feedback goes through the user, in his own way, treating what is happening.
As a result, a 3D printer today is not quite a home appliance. It can not be compared to a conventional printer and all the more so with a washing machine. Can you imagine if for the successful washing of clothes you needed during the experiments to select the frequency of rotation of the drum of the machine, changing it through the firmware? Yes, for some it was really interesting, but unlikely for most.
The 3D printer is closest to the power tool. This is an excellent tool for creating objects, but they need to be able to use. Unfortunately, at the moment this idea is not quite clear in the advertising of some 3D printers – as a result, there appears to be quite a noticeable share of disillusioned buyers expecting miracles from science fiction, and having received an unused stand under the house's junk.
In my opinion, in the future, 3D printing technology still has a chance to become a truly domestic one. First, FDM is rapidly developing: the firmware is being improved, new sensors are added, and so on. At the same time, volumes of Russian-language documentation are growing exponentially, which is quite understandable for non-specialists.
Secondly, printers working on a different technology – the laser sintering method (SLS) – began to enter the consumer market in the past two years, and the patent restrictions on SLS ended in 2014. However, while the cost of devices exceeds 5 thousand US dollars. So while speaking of consumer 3D printing, we still mean FDM with all the attendant problems.