Welding Fuel Injectors
Fuel injectors are extremely precise devices that require controlled hermetic welds to ensure their operation and safety.
Excessive heat or distortion can produce fuel delivery rate or spray pattern anomalies that result in scrap. Distortion can also affect static leakage rates that are tightly controlled for environmental limits.
Using 200 – 500W Fiber Lasers and fiber optic delivery, weld times of 0.2 to 0.75 seconds are typical for most gasoline injectors. Part-to-part times for these welding and assembly machines are in the 3 – 5 second range.
Time-share multiplexing, which sends the output from one Laser to multiple workstations, can be used but high-speed assembly machines often don’t use them due to the asynchronous nature of separate machines.
More common is energy-share, which is often used on the alignment sensitive components. Two-way energy-share takes the Laser output and splits it 50:50 between two fiber optics. This results in simultaneous welds, 180 degrees apart, so the forces are equal and opposite to maintain concentricity of the assembly.
There are many different alloys used in these injectors. Ferritic stainless steels such as 405, 430, 430F, and the Chrome Core family of alloys are preferred where magnetic induction is needed for solenoid action.
For low wear components that are non-magnetic (such as guide tubes and out tubes) 305SS is used. For medium wear components that are non-magnetic (such as armature guides and seats) 416SS is a typical choice. In the manufacture of valve seats and valve seal balls, 440C is used because of its hardness.
Most Laser welding is best performed using our redPOWER CW Lasers because of the short time cycles and the metallurgy of these stainless steels.
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