3D printing for dummies.

Printing a simple children's toy, a smartphone case, a prototype of a future metal product or a plastic part - all this became real with the advent of 3D printing. If you have heard about it, but do not fully understand the principles of a 3D printer or its capabilities, this article is for you.


3D printing allows you to create prototypes - prototypes and conceptual models, souvenirs and promotional items, household items. 3D products printed on a suitable printer are already used in medicine and military industry, tourism and education. What previously seemed impossible has become close and accessible to ordinary users. The simplest 3D printer today can be assembled by yourself or you can buy a ready-made printing device for your home or small business. Are you interested? Then let's start with the basics of 3D printing.


How 3D printing appeared

The "father" of 3D printing is considered Charles Hull, who in 1984 developed and patented "stereolithography" (SLA) in 1986. This term refers to the technology of additive production from liquid photopolymer resins.


Manufacturing is called additive, in which a model is created on the basis of adding materials (add is translated from English as "add"). The simplest example is sculpture modeling. Now compare additive manufacturing with other types:



creating or pouring an object from bulk or liquid materials. Usually these are serial goods, in the release of which a special form is used - a cliché. This is how most plastic parts are made, from toys to parts. For a small batch of products, this method of production will be economically disadvantageous;

cutting a new object from the workpiece. An example is the manufacture of a toy from a block of wood. The disadvantage of this method is the overspending of the source material and the need for a large amount of energy resources.

Following stereolithography with the light hand of Scott Crump, FDM technology appeared. This is what many modern 3D printers use for small batch production. The term "3D printing" itself began to be widely used only in 1995, and the students of the Massachusetts Institute of Technology made it popular. Devices for three-dimensional printing - 3D printers - got their current name after the release of the device Actua 2100 into mass production. By the way, it was released by 3D Systems, which was founded by the same Charles Hull.


Benefits of 3D printing

Accuracy and speed of product manufacturing. In SLA models, the accuracy reaches a few microns, and in comparison with other printing technologies, you can save up to 50% of the time to create the same part.

Lack of forms and blanks. All objects are made from scratch, based on a 3D computer model, which can be easily modified in a computer program.

Minimal waste of materials. You don't have to trim or recycle materials.

A wide variety of materials. Dozens of types of plastics are available, as well as metal, wood, ceramics and other exotic materials, ground to a powder.

Low influence of the human factor. Thanks to the complete automation of the process, the probability of error with the correct printer settings will be minimal.

Low cost of finished products. The cost of 3D printers is gradually decreasing, prices for thermoplastics have remained affordable for several years, and the printer consumes no more electricity than the average household appliance.


Types of 3D printing

Along with stereolithography, there are several other 3D printing technologies. Let's dwell on them in more detail.


Extrusion Printing

Behind this way of creating 3D objects lies Fused Deposition (FDM) and Multijet Printing (MJM). The principle of printing is as follows: the source material is squeezed out (this is extrusion), and a finished object is formed from the resulting mass. In this case, thermoplastics or composite materials based on them are used.


Sintering, gluing and melting

All these methods require the use of a powder material, and this can be not only plastic, but also wood or metal. Laser sintering technologies (SLS and DMLS) allow sintering to create even solid metal parts! And in SLM-type printers, not just sintering occurs, but full-fledged melting of the material - this is how monolithic and completely non-fragile products are created.


A 3D scanner can be added to a 3D printer. It analyzes the finished physical object and creates its three-dimensional model, which can then be edited in CAD or printed on the basis of a similar object on a 3D printer.


Lamination

Not the most common technology, but also worthy of your attention. Here, the finished model appears through the gradual layering of thin materials - paper, foil or plastic film. The layers are glued together and then cut along the contour of the digital 3D model with a laser or blade.


How popular FDM printers work

We will dwell on these types of 3D printers in more detail, since they provide the most affordable construction of three-dimensional models.


Materials for printing

Fused deposition in FDM printing has become popular due to the smooth cost reduction of this type of printing device. A wide group of thermoplastics is used as a consumable material, which are wound on spools in the form of thin threads. PLA-plastic can be called completely natural, since it is based on vegetable raw materials - corn or sugar cane. It is non-toxic, but also short-lived. ABS plastic, on the contrary, is pure "chemistry", but it is more wear-resistant and durable. However, when heated and exposed to direct sunlight, it releases toxic substances. By the way, you are well familiar with ABS-plastic: toys, household appliances cases and spare parts for them, plumbing accessories are made from it. Practice printing with nylon, polyethylene, polycarbonate filaments, as well as composite materials, which in appearance resemble wood, metal or stone. True, in the latter, thermoplastics are still used, but only as a binder.


3D printing has not always been used for the benefit of humanity. Several years ago, Defense Distributed developed a model of a plastic pistol that anyone could download and print. Fortunately, the US State Department quickly banned this development and demanded that all instructions and diagrams be removed from the manufacturer's website. Later, the ban on the printing, possession and distribution of firearms was enshrined at the legislative level.


How a 3D printer works

The main element is a print head, an extruder. It is into it that the very thread from the coil is fed and melted. The diameter of the molten filament directly depends on the diameter of the nozzle through which the material exits. The operator needs to achieve the optimum melting point using a thermistor. Temperature affects the quality of all work: if you overheat the material, the plastic will begin to decompose, if you heat it badly, it will not be plastic enough.


One printer can have one or more extruders. If you need to print a complex part with a large number of cavities, use a water-soluble polyvinyl PVA plastic, which fills the very cavities when printed. This plastic is fed from an auxiliary extruder and then the finished product is washed with water.


FDM printers cannot print objects without a support, so the finished product will necessarily have a flat base that fits on a platform with a removable table. This makes it much easier to clean the work surface and remove the model from the platform - there is less chance of damaging it.


How to operate a 3D printer

How does a printer know what and how to print? For this, electronic controllers are used. They regulate the temperature of the material, are responsible for the easy heating of the platform, the speed of filing and all other operations. Usually controllers run on the popular open architecture Arduino platform, which means that anyone can create control components. The list of commands for the printer is set using the G-Code program code. In this case, some printers require only "native" software, while others can use the development of third-party companies.


If you have the simplest 3D printer in front of you, then most likely it only has a USB port for connecting to a computer. Advanced models, on the contrary, are completely autonomous, complete with everything you need to control the work.


A little about SLA printers

At the beginning of the article, it was mentioned that the discovery of SLA technology preceded the emergence of three-dimensional printing, but it remains in demand to this day! Laser stereolithography is the second most popular method for creating 3D objects. Its main advantage is the high, up to several microns, accuracy of the finished product . In software terms, SLA and FDM printing are very similar, but the principles of building models are still different.


To begin with, SLA devices do not use lasers at all (although sometimes they do too), but more affordable and reliable UV LED projectors. A consumable material is a photopolymer resin, an analogue of epoxy. The resin is sequentially poured in thin layers and smoothly immersed in a cuvette - a special container - with a photopolymer. Final hardening occurs with laser or projector irradiation. Then the model is removed from the bath and illuminated again. Some printers have a reverse protocol: the object is not immersed in the cuvette, but gradually pulled out of it.


Materials for SLA printers are very expensive, although varied. Therefore, the cost of printing can hardly be called affordable. Why is this technology so important then? It is highly likely that you will have to deal with the results of SLA printing personally. For example, you want to make a custom-made piece of jewelry - and the master will make a prototype on just such a printer. Or if you want to install a dental implant, the dentist will print the exact model of the tooth on the SLA device.


An interesting feature of some 3D printers is their reproducibility. This means that it is easy to print some of their own details on them. The first such product - RedRap - could reproduce more than 50% of the parts required to assemble it!


Where to get models for a 3D printer

You can find ready-made 3D models on specialized sites.


Thingiverse is the site of MakerBot Industries, a manufacturer of Replicator 3D printers. The smart system will study your interests in order to offer the most relevant 3D models for download over time.

3dshook - a large selection of 3D models of cars and buildings, as well as spare parts for 3D printers;

YouMagine is a site with models for Cube series consumer printers. There are fewer free models here than on the previous two, but there are interesting categories in which models for children are presented. ...

Cults3d is a French community (but English is also supported) where free 3D models are often posted.

Instructables is another community where users often exchange ready-made projects and make detailed manuals.

If you want to quickly find a specific 3D model, use a specialized search engine: yeggi.com , yobi3d.com or stlfinder.com . All three search engines only support English-language queries.


Top 5 misconceptions about 3D printing at home

Anything can be printed on a 3D printer.


Actually, no - the print resolution, the size of the printable area and the diameter of the printer nozzle impose restrictions on the size of the parts. Also, the part must have a flat base, otherwise it will quickly peel off the surface of the work platform.


Easy to seal prefabs.


A nut that is screwed onto a bolt can actually be printed, but not on a home printer. This requires a higher precision that only expensive equipment provides.


You can create a multi-colored object on the printer.Manufacturers are working on this, but this has not yet been implemented on budget printers. Multi-color (two or more colors) printing requires multiple printheads.


3D-printed models are very fragile.


Yes, they will be more malleable than cast ones, but strong enough for everyday use. It all depends on where the force will be applied: along or across the fibers (as in wood).


Printing is easy - plug in the printer and go!


Wait, first you have to calibrate it, adjust the settings and figure out the controls. Even after that, it may take several weeks before you learn to print neat models.


If you want to buy a 3D printer for your home, you will have to find the right model, learn how to set it up, understand the software, and find quality printing materials. But, we are sure, the result will please you: you can print plastic dishes and other household utensils, hair accessories, various storage containers, baby and stationery - almost anything that can be made of plastic. Or you can go even further and learn how 3D printers are used in the military and space industries, in research and education, in the production of electronics and the arts. But that's a completely different story.

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