Achieving Predictable Production Rates
By Scott Walker
Mitsui Seiki USA Inc.
Franklin Lakes, NJ
There’s a compelling part production trend occurring in the aerospace industry. The aerospace OEMs and their top tier suppliers are realizing that the days of taking a part from the machine to buffing to measuring to final assembly are coming to an end.
Now, you might be thinking, “Scott, this is not a news flash,” and you are right. We’ve been reading about these automated systems for years in the trade journals and many industries—such as automotive—have not only led the trend, but have been instrumental in advancing the technology to stay competitive in their global markets. However, what is new is that the aerospace industry is now embracing and applying these automated systems in their factories.
The comment I often hear when visiting an aerospace OEM is: “I don’t need parts faster; I need them at a consistent production rate, and I need them just-in-time to reduce the cost of WIP on the balance sheet.” For example, IBRs (integrally bladed rotors) typically are machined and then “benched” for surface finish adjustments and tolerance conformation. It takes excellent manual skills to make these parts. The IBR manufacturers want to automate this process from the turned blank to the ready-to-assemble IBR without any human intervention. This allows the engine builder to know that they will get a certain number of IBRs a day. Based on that daily number, they know they can build x number of engines per day and assemble them like, well, car engines.
The auto industry has almost perfected this technique. Just the right parts are delivered to the assembly plants at just the right time. Further, car manufacturers have a supply chain that has compressed significantly over the last 15 years. Likewise, as much as 40% of jet engine machining is outsourced to a supply chain that has been quietly consolidating in recent years. Large Tier 1 public companies have acquired second tier shops, placing them in a position to “do it all” for an aero OEM—supply the castings, materials, perform the machining, and even ship subassemblies with all the tools needed to complete the final product assembly at the OEM’s plant.
The increased level of outsourcing to keep up with the demand for new commercial jets has enabled the OEMs themselves to research new manufacturing technologies for hard metals and composites. Once the optimal equipment, processes and cell configurations are established, the OEM conveys the best practices to their suppliers. Throughout the network, the suppliers can replicate the manufacturing solution and provide the OEMs with parts and subassemblies that are consistently correct, produced in a repeatable process, and delivered predictably “just in time,” along with the cost savings JIT provides.
Going forward, you will see at least a dozen machines lined up on the factory floor with a robot loading and unloading parts. The process will be virtually hands-off during machining, finishing and inspecting, and the parts will be placed in a transport bin ready for assembly. As a case in point, we at Mitsui Seiki have recently converted a production line to a fully automated flexible manufacturing system (FMS) cell that provides complete machining and inspection of 63 new part numbers along with magnesium or aluminum castings for the new 737 MAX gearboxes.
As impressive as these automation systems are, the heart of any FMS is the machine tool itself. To that end, current machine tool developments specifically for the aerospace industry are aimed at providing solutions for jet engine, structural parts, and gearbox machining for consistent Six Sigma process control standards, as seen in automotive component manufacturing. In particular, there is significant investment in developing machine tools dedicated for machining the blisks for the new jet engine programs powering the fresh, fuel-efficient Boeing 737 and Airbus 320 fleets. The machining processes of these blisks demand a much better surface finish and improved production rates to meet the new protocols being adopted by the industry. As such, Mitsui Seiki is focusing on advancements in direct-drive motor based machines that allow for better agility to drive a very thin tool around the blade profiles of IBRs and blisks. The result: markings and poor surface finishes are eliminated. Parts come off the machine ready for assembly.
It’s a revitalizing time to be serving the aerospace industry, as it transforms its end product with all new components, new designs, and new fuel efficiencies in operation, and as it also evolves the way in which these components are made. Sort of like...cars. ✈
This article was first published in the 2013 edition of the Aerospace & Defense Manufacturing Yearbook.
Published Date : 12/4/2013