How a print is built
The printer melts a plastic filament and lays it down as a thin line through a nozzle, layer by layer from the plate upwards. Each layer is a cross-section of the model: first the outer walls, a few lines thick, then a sparse pattern on the inside. That is why the layers show on sloping and curved surfaces, and why a print is stronger along the layers than across them.
The nozzle: 0.4 mm sets the limit for detail
We print with a 0.4 mm nozzle, the standard on most printers. The line comes out about that wide, and that decides what can be printed:
- A wall is built from whole lines. 0.8 mm is two lines and the thinnest wall that holds, 1.2 mm is three lines and a good size for parts that will be used.
- Details under a millimetre come out fragile or not at all. Raised text on a top face works from about 0.5 mm line width and 3 mm letter height.
- Holes come out slightly smaller than in the file, often by 0.1 to 0.3 mm. Draw a hole for a screw 0.2 to 0.4 mm larger than the screw.
Smaller nozzles give finer detail but much longer print times, and larger ones give faster, coarser prints. For almost everything, 0.4 mm is the right balance. How accurate the dimensions come out, and how to draw holes and fits, is in the guide Tolerances and fit.
Layer height: surface against time
The layer height is the thickness of each layer. We offer three:
- 0.20 mm is the standard and suits most things. The layers show if you look closely, but the surface is even.
- 0.12 mm gives a finer surface on curved and sloping areas, with less visible steps. The print takes considerably longer and costs more.
- 0.28 mm is the fastest and suits parts whose surface is not on show or does not matter.
The layer height makes little difference to strength, and vertical surfaces look much the same whatever the layer height. It is the sloping and curved surfaces, such as a head or a ball, that gain from thinner layers.
Infill: the inside sets weight and strength
The inside of a print is a pattern, not solid plastic. How much of the inside is filled is given as a percentage:
- Hollow, 0 %, for ornaments that only stand there. Light and cheap but fragile.
- Light, 8 %, for parts that carry no load.
- Standard, 15 %, is enough for figures, holders and most things around the home.
- Sturdy, 30 %, for brackets, hooks and parts that carry a load.
- Solid, 100 %, for small parts that have to be really strong or heavy. On large parts it gets expensive without giving much more.
The pattern matters less. Gyroid is our standard choice: equally strong in every direction and quick to print. Honeycomb and grid are available too.
The outer walls do more for strength than the infill. A part drawn with thicker walls and 15 % infill is often stronger than the same part with thin walls and far more infill.
Support material: when the part hangs in the air
Plastic cannot be laid on thin air. Surfaces that lean outwards by more than about 45 degrees, and anything that hangs freely, need support material underneath: a temporary scaffold that is printed at the same time and removed afterwards. We add support material automatically where it is needed and remove it before the print is sent. Where it sat, the surface can be a little rougher.
You can reduce the need by laying the model with its flattest side down, which you do right on the order page, and by leaving support material out altogether if the model can do without. Less support material means less material, a shorter print time and a lower price.
Temperature: in the printer and in everyday life
PLA is printed at around 200 to 220 °C and PETG at around 230 to 250 °C, on a heated plate that makes the plastic stick. We take care of those settings, but temperature is also why the materials behave differently afterwards. PLA starts to soften at around 55 °C, PETG at around 70 °C. Neither belongs in a dishwasher, in a car parked in the sun or next to a hob. Which material suits what is in the guide PLA or PETG.
How to choose when you order
On Order a custom 3D print online there are three quick picks that set the material, the layer height and the infill at once: Decor, Fine surface and Functional. Choose the closest one and then change what you like. The price is recalculated as you choose, so you see what each setting costs before you order. What drives the price most is in the guide What does 3D printing cost.