Pre-assembly is a part of the production process. Here, an initial assembly of certain component groups is carried out even before delivery. This saves time during final assembly which usually takes place on the site. A pre-assembly also reduces the potential for errors.

Pre-assembly is popular in numerous industrial sectors. These include mechanical engineering, the construction industry, the automotive sector and aviation. If the assembly of technically demanding parts is carried out in advance, larger assemblies, such as engines, can be installed quicker.

In many cases, various assemblies are pre-assembled for a complex product, further accelerating the final assembly. With the increasing complexity of electronic devices and machines, pre-assemblies are also becoming more specific and specialized.

A pre-assembly can be supported by a modular system, in which, for example, different designs are based on a common platform or use a big number of identical parts.