How does 3D printing work?

3D printing in five steps

1. The 3D file

Everything starts with a 3D file that describes the shape, usually an STL or 3MF, sometimes an OBJ. You draw such a file yourself in a 3D program, find it on a 3D model site or have it designed for you. A photo alone is not enough: the printer needs to know how deep something is and what the back looks like. Why that is so is explained under photo to 3D print.

2. Slicing: cutting the model into layers

A program called the slicer cuts the model into thin layers (with 0.20 mm layers, a print 5 centimetres high is already 250 layers) and works out, for each layer, the path the nozzle has to follow. The slicer also calculates the print time and the amount of material used. With us, every model goes through the slicer first. There we see whether the model is closed and whether it fits within the print volume, and the result is the basis of your quote. If a model does not fit within 350 x 320 x 325 mm, we print it in sections; see large 3D printing.

3. Printing, layer by layer

The printer heats the nozzle, melts the filament and lays it down in a thin track on the print bed. When a layer is done, the printer starts the next layer one layer height higher, and it bonds to the one below.

4. Removing support and checking

Parts that hung in the air during printing were temporarily supported. We remove that support material after printing. During and after printing we check every print for layer adhesion, dimensions and finish.

5. Done

Once it has cooled down, the print is ready to use. Visible layer lines are part of 3D printing; if you want a completely smooth surface, you can sand and paint the print yourself afterwards. If something goes wrong in our printing process, we reprint it free of charge.

What is FDM 3D printing?

FDM stands for fused deposition modeling, also called FFF (fused filament fabrication): literally, laying down melted material. The material is a plastic strand on a spool, the filament. The printer pushes that strand through a heated nozzle that moves back and forth above the print bed. It is the most widely used way of 3D printing, because it is affordable and produces strong prints in many colours. Our filament is PETG; why, is explained under PETG vs PLA.

Layer height: how thin are the layers?

The layer height is the thickness of a single layer. The thinner the layers, the smoother the surface, but also the longer the print time, because more layers are needed. We print with 0.20 mm layers as standard. Up close you can see the layer lines, but they are neat and even.

What is infill?

A 3D print is usually not solid inside. There is a sturdy outer wall around it, and inside that an infill pattern. The percentage tells you how much of the inside is filled. We print with 20 percent as standard; for most uses that is sturdy enough. More infill makes a print sturdier, but also heavier, and because we charge per gram, more expensive too. If something needs to be extra sturdy, tell us in your request what you will use it for; we will then look at the infill with you. What infill does to the price is explained on what 3D printing costs.

Why are supports needed?

A printer cannot print in mid-air: every layer has to rest on something. Slopes up to about 45 degrees usually work without help, but parts that stick out far, such as the brim of a hat or an outstretched arm, get temporary support material underneath. Where support has been, a faint mark often remains. That is why we decide the best position on the print bed for each model: as little support as possible, the most strength in the right direction and a visible surface without marks.

How strong is a 3D print?

That depends on three things: the material, the walls and infill, and the direction in which it was printed. A print is strongest within a layer; between two layers, where they bond, is the weakest point. A clip that has to flex is therefore placed on the print bed so that the force does not pull the layers apart. For a part that has to take force, we look at that position and at the wall thickness. The material counts too: PETG gives a little where a brittle material would break sooner.

What can go wrong? Warping, stringing and file errors

If you print yourself, you know the classics: a print that lifts off the bed at the corners and warps (warping), thin strings between separate parts (stringing), or a print that comes loose halfway. Many problems are already in the file: a model that is not closed, walls thinner than about 0.8 mm, or a model saved in centimetres or inches instead of millimetres, so it ends up far too small or too large. We spot file errors like these in the slicer beforehand, and you hear about them before the printer starts. The mistakes we come across most often are listed under having something 3D printed.

How long does a 3D print take?

That depends on the volume, the layer height, the infill and the amount of support. The slicer calculates the exact print time per model. A small part is finished sooner than a large one; a medium-sized object, such as a figure, a phone holder or an enclosure, usually takes a few hours of print time each. Large objects, such as a helmet, we often print in sections, and then the hours add up. With us you do not pay per hour: the print time is included in the price per gram. With a 3D file you receive your quote within 48 hours; from your payment it takes 2 to 4 working days until your print is ready. In a hurry? With a rush order your print can move up the schedule, if the schedule allows, at a 25 percent surcharge.

What do you need for 3D printing?

To print yourself you need three things: a 3D file, a slicer that turns that file into print instructions, and a printer with filament. If you do not have a printer, you can have it printed. Then all you need is the file or a link to a model on a 3D model site. If you only have a description with a photo or sketch, we draw the model for you when it is a simple object. How that works with us, from request to delivery, is explained under our process.

Other ways of 3D printing

FDM is not the only technique. In resin printing, liquid resin is cured layer by layer with light, which gives very fine detail. In powder printing, thin layers of powder are fused together, for example with a laser; metal is printed this way too, mainly in industry. We only print with FDM, in PETG. If you are looking for a print in resin, nylon or metal, we are not the right choice.