To Build In 40 Days

Maybe the aerospace industry is taking a cue from the automotive producers. Turbine engine builders want just-in-time, sequenced delivery and lower costs. Screw machine shops can no longer be content to finish up automotive components and leisurely move on to stainless steel jet engine fuel line adapters. Jet engine customers have begun to look around, now that the airlines are putting pressure on them.

It was not that supplying turbine engine builders was an easy living. But by concentrating on quality, ensuring the inspection standards paperwork was up-to-date and in order, and getting the components to the customer within a few days of schedule, life certainly wasn’t difficult.

Turbine engine builders used to think in terms of up to 1 year for manufacturing leadtime, from when the raw materials and bought-out components entered the door to when the engine was finished.

Today, many engine builders want to build and ship an engine in 40 days. Consequently, engine builders have begun to pressure their suppliers.

In one European engine plant, the management has examined the “waiting time” between machining and assembly operations. The concern is machining. The builder takes a bar, saws it, puts it through two or three setups in two-axis lathes, sends it down to the drilling section, maybe sends it back for another turning operation, then sends it on to the milling shop and the grinding bay. Between each setup, the components have to queue for inspection procedures in widespread plant locations.

This engine builder realized that more than 80 percent of manufacturing leadtime was for components waiting to be inspected between operations. The builder did a major reorganization of in-house machining into manufacturing cells and islands. In doing so, the company realized that the most modern twin-spindle turning centers can eliminate waiting time. Also, reducing multiple setups considerably reduced accumulated error.

Pressure has also gone down the supply chain to the job shop, which in the past may have had two-axis lathes, some universal mills, a few drilling machines, a grinding shop and CMMs. This no longer suffices for what the engine builders want.

One supplier of fuel line assemblies had two-axis lathes. Three years ago, the company bought its first three-axis lathe, followed almost immediately by a Mori Seiki MT series turning center. Amazed at the reduction in leadtimes, the company has since bought two of the latest Mori Seiki ZL-203 twin-spindle, twin-turret turning centers.

The fuel line supplier went into a technical partnership with the local machine tool subsidiary to gain support on programming, tooling and so on. Now the owner of that company knows that the fuel line business is staying with his shop.

It is not just engine builders that are putting on the pressure. Another company acquired its third twin-spindle, twin-turret turning center. The components are brake hubs for aircraft undercarriages. These used to be machined “piecemeal.” It took nine setups to do a hub for a large passenger airliner. It is now done in three setups in a large, twin-spindle, twin-turret turning center.

This company also entered a technical partnership with the machine tool supplier. In return for the supplier’s commitment, the supplier gets to show a few prospective customers around the user’s plant.

The message from the engine builder is that machine tool suppliers have to get even smarter. They need to be able to configure the multi-function machine tools the builder wants to reduce manufacturing leadtime and build those engines in 40 days. The machine tool supplier also has to take more care of the user, to make sure that the diagnostics cover everything, to make sure that communications are hassle-free and to express that the user’s success with the machines is of utmost importance.