Joining involves permanently joining two or more workpieces together. In some cases, a "formless material" (e.g., adhesive) is used. The cohesion of the joined parts is achieved by:

  • Non-positive connections (screw connections, press fits),
  • Material connections (welded, soldered, and bonded connections),
  • Positive connections (e.g., tongue and groove connection, feather key, connecting fitting).

Connections can be detachable, conditionally detachable and non-detachable. Screw connections, for example, are detachable. Conditionally detachable connections include riveted connections. To separate these, the rivets must be destroyed, but not the joined components. Soldered connections can also usually be detached by desoldering. Undetachable connections are welded joints. These cannot be separated without destroying the components.

Joining techniques in the metalworking industry