What is 3D printing and how the 3D printed parts are made?

Many people talk about 3D printing technology, but unfortunatelly most are aware only of its basics. So what exactly is this „3D printing”? Those who do not have contact with it perceive it as something exceptionally spectacular, unusual and magical in its own way. Well, in fact as a whole concept it’s quite an easy stuff.

Let’s start with basic definition:

• 3D printing is a manufacturing method, where a device called 3D printer, is applying layers of material, bonding them selectively
• there are many different varieties of this method, divided according to the material used and the way it is bonded.

For example:

• we can use plastick in form of a wire, melt it in special nozzle, and apply it on a plate – called printbed; with melted plactic we can draw a flat shape in X and Y axis, making the first layer of the object we want to create
• then we either move the nozzle up or lower the printbed down and draw another shape – apply another layer of material
• the melted plastic cools down on the surface of the printbed and on the surface of the already printed layer, making a solid structure
• when all the layers are applied, we have our object completed.

This technology is called FDM or FFF, and right now is the most popular additive technique. However there are others:

• when it comes to material, instead of plastic, we can use a light-curing resin
• we pour the resin into the container and photopolymerize it selectively, using a laser beam or by displaying an image from a DLP or LCD projector
• depending on light source, this method is called SLA (for stereolitography) or DLP or UV LCD.

We can also use powdered plastic or metal that are sintered with laser, or use alternative techniques involving chemical agents and heating. We can print things with gypsum powder in full color. We can apply hydrogels, ceramic masses and many other materials.

In other words: we call 3D printing every manufacturing process, where we make an object by applying layers of materials one on another. That’s it. No magic in it…

3D printing have been brought to life as an alternative way of making prototypes. The advantages of this method over others are:

• short production time
• low production costs
• ability to make quick changes to given design and correct the product
• ability to make very complex geometries, that cannot be done with any other technique
• and easy and cheap personalization.

To sum up, as a rule – from which are exceptions!, 3D printing:

• is the fastest
• is the cheapest
• is to create the most complex geometries.

At the same time, it has disadvantages… The biggest are the quality of the model’s surface, which for now is not able to match injection molding, casting or CNC milling. I’m talking about the layers, which in different techniques are more or less visible. Of course you can polish the surface, paint it etc., but additional time, equipment and skills are required.

Another disadvantage is the lack of effectivity in high volume production. As long as we are manufacturing a few to several dozen of details, the advantage is on the 3D printing side. When we enter in numbers of hundreds – thousands – millions of pieces, traditional production methods are unrivaled in this respect.

So in terms of industrial manufacturing, the thing to remember is:

• ADDITIVE MANUFACTURING = single items or low production series
• TRADITIONAL MANUFACTURING METHODS = mass production.

The process of creating things using additive technologies can be divided into four stages:

• 3D MODEL – first the designer designs the thing in a 3D modeling program. It can be any program – all it has to do is create a thing in three dimensions and save it in one of the extensions used in 3D printing: STL, OBJ, or 3MF. THING TO REMEMBER: An experienced and advanced designer will already know at this point what 3D printing technology will be used for manufacturing and what material it will be made of.
• PREPARE THE 3D MODEL FOR 3D PRINTING – the model must be prepared for 3D printing, with particular emphasis on the technology in which it will be made, the material from which it will be printed and the 3D printer model. The model should be properly oriented in the working chamber and support structures should be generated (a 3D printer cannot print things in the air). Supports are usually generated automatically, but we can edit them – add or remove them.
• 3D PRINT THE MODEL
• POST-PROCESSING – depending on the manufacturing method, post-processing looks different. We need to clean the printed part from supports, material remnants and possibly sand it in the places where the supports meet the model. In some cases, in FDM / FFF technology, post-processing is completely unnecessary – the 3D model is ready for use immediately after being removed from the 3D printer, but in other methods it is more complex and complicated.

What’s important, working in the 3D printing industry, we can deal with all four stages or specialize in only one of them.

If you want to know how to start 3D printing business – read one of our articles on this subject:

• What 3D printing business worth to start and which better to avoid?
• What does the job in 3D printing business looks like?
• Who uses 3D printing?