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As of August 2026
The short answer
A 3D printer builds up a component layer by layer from a digital 3D file. Software breaks down the 3D model into hundreds of thin cross-sections (slicing), and the printer applies material – usually melted plastic, liquid resin or powder – layer by layer until the finished object is created. This additive build-up fundamentally distinguishes 3D printing from milling or injection moulding.
How a 3D printer works – briefly explained
3D printing always follows the same basic principle: additive manufacturing. Instead of removing material as in milling, material is added precisely. A slicer translates the 3D model into directions for the print head (known as G-code). The printer follows these paths and produces each layer individually. After the final layer, the component is finished – often followed by post-processing such as removing support structures or smoothing the surface.
The 3 steps: from 3D model to finished component
Every 3D print goes through three phases: the digital model, slicing, and the actual print. Anyone who understands the process can design components so that they can be manufactured cleanly and cost-effectively.
1. The 3D model (CAD)
At the beginning stands a three-dimensional model, usually as an STL or STEP file from a CAD program. The model describes the geometry of the component completely. Even at this stage, it is decided how well a part can be printed – wall thicknesses, overhangs and details should match the process. Principles on this are summarised in our guide to DFM design for 3D printing together.
2. Slicing
Slicer software slices the model into horizontal layers – typically between 0.05 and 0.3 millimetres thick. The thinner the layer, the smoother the surface, but the longer the printing time. The slicer also determines the infill density, support structures and print speed, and exports everything as G-code.
3. Layer-by-layer printing
The printer now builds up the component layer by layer. In the most common process (FDM), a nozzle melts plastic filament at around 200 °C and deposits it along the calculated paths. Each new layer fuses with the one below it. Printing is followed by post-processing – removing supports, sanding and, if necessary, painting.
What 3D printing processes are there?
Not every 3D printer works the same way. The three most important processes are FDM (molten plastic), SLA (liquid resin cured by light) and SLS (powder fused by laser). They differ in accuracy, materials and costs.
| Procedure | Material | Strength | Typical application |
|---|---|---|---|
| FDM | Plastic filament (PLA, PETG, ABS) | cost-effective, robust, large components | Prototypes, jigs and fixtures, large-format parts |
| Service Level Agreement | Liquid resin | very fine details, smooth surface | Fine models, fitting parts, design |
| SLS | Plastic powder (PA/nylon) | without supports, stable functional parts | Small-batch production, parts subject to mechanical stress |
We explain in detail, in a comparison, which process is best suited to your component FDM, SLA & SLS as well as in our overview of the 3D printing technologies.
How accurate is a 3D printer?
Accuracy depends on the process. FDM typically achieves tolerances in the range of ±0.2 to ±0.5 millimetres, whilst SLA and SLS are significantly more precise. The layer height determines how visible the individual layers are: 0.1 mm produces smooth surfaces, whilst 0.3 mm prints faster but shows grooves. For functional fits, process-induced warpage is factored into the design from the outset.
From hobbyist printer to industrial production
The basic principle is the same for a 200-euro device and an industrial system – the difference lies in the build volume, repeatability and materials. Industrial systems print larger parts with greater dimensional accuracy and using technical materials. For large components, we rely on large-scale 3D printing, which allows parts to be manufactured in one piece instead of from many segments. As a 3D printing service provider, we take care of the complete Manufacturing – from file to ready-to-install component.
To give a sense of scale: a hobby device typically prints 220 × 220 × 250 mm and reaches nozzle temperatures of around 260 °C. An industrial machine like the SAM from Mach-3D builds 900 × 900 × 1000 mm in one piece, travels at up to 500 mm/s and reaches 500 °C at the hotend – which also allows engineering materials such as PA-CF or PPS-CF to be processed, which a hobby printer cannot melt.
How much does a 3D-printed component cost?
The price depends on the size, material, fill level and production method. Instead of making an estimate, you can upload your file directly and get a guide price: With our 3D Print Price Calculator you can see what your component costs in just a few clicks – or send a manufacturing enquiry straight away.
Frequently Asked Questions about 3D printing
How does a 3D printer work – explained simply?
A 3D printer builds an object up from many thin layers. Software breaks the digital 3D model down into cross-sections, and the printer applies material layer by layer until the component is complete. This is known as additive manufacturing.
What material does a 3D printer use?
Depending on the process, plastic filament (FDM), liquid resin (SLA) or plastic powder (SLS). Common materials are PLA, PETG, ABS and nylon. For technical applications, there are reinforced and high-temperature-resistant plastics.
How long does a 3D print take?
From a few minutes for small parts to several days for large or very delicate components. The decisive factors are size, layer height and fill density. Thinner layers improve quality but increase printing time.
Do you have a specific component? Upload your 3D file and get a guide price – or send us one directly Manufacturing enquiry. We’ll get back to you with a quote within 24 hours.
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Want to print your own part? The calculator shows you the price after uploading your file – no registration required.
Conclusion: How a 3D printer works
A 3D printer builds components layer by layer from a digital 3D file in three steps: CAD model, slicing, and printing. The processes differ in the material used (molten plastic, liquid resin, or powder), price, and accuracy. A hobby device is sufficient to get started; as soon as dimensional accuracy, engineering materials, or large components are required, the path leads to an industrial machine or a service provider. The price for a specific component is shown by the 3D printing calculator immediately.
