What is hybrid manufacturing?

Hybrid manufacturing combines an additive process and machining in one machine and one setup. Usually that is a machining centre or mill-turn machine with a directed energy deposition head that builds up metal, typically with a laser and powder or wire, sometimes with an arc, after which the same machine mills or turns the deposit to size. There are also powder bed machines with a milling spindle that finishes the walls every few layers. More loosely, the word is used for any route that combines printing and machining; strictly, that is a process chain.

How do building up and machining work on one machine?

Deposition and machining alternate, sometimes several times: build a section, then machine the areas a tool will no longer reach later. Deposition, measured in volume per hour, is usually slower than material removal, and the heat input brings expansion and residual stress that affect size. Building and finishing are therefore often separated by cooling time and a probing cycle. The deposited material usually does not have the same structure and properties as rolled or forged material of the same alloy. Which combinations of base and deposit material work depends on alloy, process and the requirements on the bond.

How does hybrid manufacturing work in practice?

Hybrid manufacturing is used mainly for repair, such as building up a worn shaft or a damaged blade and bringing it back to size, for adding a feature to an existing part, such as a flange on a tube, and for parts in expensive alloys where machining from solid would remove a lot of material. Whether it pays depends on material price, removal volume, quantity, the rate of the hybrid machine and the extra measuring and cooling time. A repair also needs the customer's consent and agreed requirements for material and inspection.

What is hybrid manufacturing often confused with?

Hybrid manufacturing is not mill-turn: mill-turn combines two cutting processes on one machine, hybrid combines adding with removing. Nor, strictly, is it a process chain of printing and then machining on another machine: that route has a reclamp, and often a heat treatment, in between. The research literature also uses hybrid machining in a broader sense, where two mechanisms act at once, as in laser-assisted turning.