3D printed spare parts: what is possible and what is not

When printing a spare part makes sense

According to Wikipedia a spare part is an interchangeable component kept for repairs. The problem is often that the maker stops producing it, or you have to buy a whole assembly for the sake of one small broken plastic piece. That is when printing a single piece makes sense. The discussion about owners having the right to repair their things is called the right to repair.

Which parts suit and which do not

Covers, holders, knobs, small gears under light load, clips, handles or spacers come out well. Parts that endure high temperatures, UV radiation, grease or chemicals, or that safety depends on, such as brakes and load-bearing elements, are a bad fit.

We print only PLA and PETG. PLA softens at around 55 to 60 °C, so it is not suitable for a car in the sun or next to a hob. PETG holds up better. If your part was originally made of ABS, ASA, nylon or TPU, you can write to us at jakub.novak@boostello.com, but we promise nothing.

How to get a model

The simplest way is to find a ready model on a site such as Printables or Thingiverse, just enter the brand and type of the device. If it is not there, it has to be drawn from the original and measured with callipers. 3D scanning can also be used. We do not do the drawing, send a finished file, ideally STL or STEP.

Watch the licences of downloaded models, we do not check them.

So that the part fits

• Dimensions with tolerance. Plastic shrinks slightly, so count on a clearance of 0.2 to 0.3 mm in joints. More in the entry on tolerances.
• Layer direction. A part is weakest between layers. Print a broken leg lying flat instead, see model orientation.
• Stronger infill. For parts under load choose 40%.
• Test. One piece first and only then more.

For a part that slides in or snaps in, count on the first attempt not fitting exactly. It is better to print a reduced test of the most important section, for example just the connector, than the whole part. More about joints in the entry on snap-fit joints.