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Polishing Up on Matters of Process


Moving from a batch-and-queue operation to a one-piece flow system gave a boost to the bottom-line at aerospace supplier

By Sarah A. Webster
Editor in Chief


For more than 35 years, MPC Industrial Products (Irvine, CA) has been precisely grinding and polishing metals for airplaces, medical devices and other high-quality products. An ISO 9001/AS9100 certified organization, MPC specializes in finishing the large aluminum skins (up to 8 × 40' [2.4 × 12.2 m]) that wrap the fuselage of the Boeing 737 and other aircraft. A team of about 60 employees with a variety of skills work together to polish and, if necessary, repair the sheets, so MPC can deliver aluminum with a uniform, blemish-free and mirror finish, superseding what mills are able to produce. These sheets of metal are critical to helping Boeing produce about 30 planes a month.

“We’re in aerospace, so we have to be reliable,” said Mario Robles, now CEO of MPC, which services Tier Four suppliers. “We work to a Boeing spec, with Boeing suppliers.”

Robles joined the company as general manager in 2006. He previously worked at Steelcase and came with a long history of running kaizen events, and so he jumped in, starting work on process-improvement projects in various parts of the company.

The MPC team members and leaders atop MPC’s largest polishing machine, showing off the mirror finish on an aluminum skin.

“I had three departments, and we would run a kaizen in one department, and then we’d go over to another department and run another one,” Robles said. And while each department did ultimately become more efficient, Robles said the efforts weren’t really working together to dovetail into a larger strategy.

“What I lacked was a road map,” Robles said. “I knew what I was doing, but I didn’t know where it was going. At a strategic level, I needed to say, ‘We’ll do these 15 projects this year.’”

In 2010, MPC joined the Supplier Excellence Alliance (SEA), which helped Robles and MPC create a four-year plan, a road map, with an eye on broad, operational improvements throughout the company.At MPC, each process has an “owner” or team leader that communicates the prior day’s performance, daily goals, assignments and announcements to team members during a morning meeting.

SEA is an aerospace & defense non-profit alliance founded in 2003 by prime and Tier-One companies and led by sub-tier suppliers committed to accelerating supply-chain performance. SEA members benefit from increased performance and supply-chain transparency.  SEA provides a lean management system and a voluntary supplier certification program for enhanced visibility, performance, and collaboration. 


One-Piece Flow

Given the high level of inventory of aluminum sheets on skids in the MPC factory at any given time, a multiyear project to streamline the process of flat-sheet polishing was quickly identified as an area of opportunity.

The polishing of the aluminum skins is a critical area where polishing machines work the surface of the large aluminum skins to remove blemishes and polish the surface so imperfections can be clearly seen through the mirror finish. The polishing also enhances the strength of the aluminum by compressing the material.

For many years, MPC had used a batch-and-queue operation where skids of full orders, regardless of how large or small, were moved collectively from one operation to another until they were complete.

In this system, all the aluminum sheets that made up a single order would be completed in setup before they could move to the polish area. The sheets would be stacked high on skids and moved on to each progressive operation. When all the parts of that order were polished, the sheets would collectively be moved to the inspection area and then, if needed, to repolish or any other added steps or processes that might be necessary.

This type of process had a lot of obvious drawbacks. Large inventories would collect at every processing stage until they could be moved to another stage. Sometimes, if an order was very large, and didn’t completely fit on a skid, a piece of the order would be lost in the system when it was held back for another skid.

“We were losing track of some orders, a piece here and there that would hold back an entire order,” Robles said. “That’s typical of batch-and-queue.”

Metrics that Matter

MPC ran its plant operations almost entirely by order numbers, measuring itself on the number of orders completed in a day or week, even though orders varied in sheet size and volume.

To Robles, watching parts sit around and wait to be processed at various stages was an obvious inefficiency.

It took a full year to change over to the new one-piece flow process—training workers, getting buy-in and fine-tuning the process for their particular operations.

By moving to a one-piece flow operation—where a sheet would be processed and then immediately moved to the next stage of finishing—created instant changes on the factory floor.

Previously, for example, workers might start polishing an order at 7 am and start piling up pieces on a skid, not finishing until 4 pm, for the next process team to get started on the same order.

But with one-piece flow, “the waiting went away,” Robles explained. “We also freed up a lot of space.”

Workers weren’t waiting on skids of complete orders to arrive at their processing stage to start working. And big skids piled high with aluminum sheets were eliminated.

While the change felt more efficient, workers started getting anxious that there wasn’t as much work, even though volumes hadn’t really changed. Psychologically, workers liked seeing stacks of aluminum because it meant there was work to do. Robles had to assure them: “As long as you have one piece, you have work to do. You don’t need an entire order in queue or a whole bunch of orders in queue to have work.”

While the new system felt more efficient right away, Robles said he needed a metric to confirm it and track change going forward. “I was seeing the efficiency in my financials a couple of months into it ... I saw less labor … I was getting the gains,” Robles said. “It looked and felt more efficient, but I couldn’t verify it.”
The inspection team at MPC ensures that parts are finished to specification or whether more work on a piece may be required.
The plant’s previous method of tracking production by order no longer seemed a good fit. MPC needed a new way to measure its production and performance on a routine basis to truly see if it was as efficient as it felt. “We tried going by order. Then we went to orders by the week. We tried sheets per day. None of that felt right,” Robles explained. “It took about a year to come up with a metric that worked. We needed a measure that told a story and hit the bottom line.”
Eventually, MPC decided on square feet polished per hour.

“We tried that and that made sense,” Robles said. His team did a regression analysis with that metric and produced an average over time. “We realized we were beating our old performance by 15% … that validated our process.”

Since 2010, MPC has now increased its square feet polished per hour by 26%. MPC also tracks labor hours per 100 square feet polished and has created internal benchmarks and goals with its “Measures that Matter,” a term used by SEA. Since 2010, MPC has improved its On Time Delivery (OTD) a full 6%. As the aerospace industry ramps up and the supply chain is tested, these measures are ever so critical in remaining competitive. MPC’s RPPM, (Returned Parts Per Million) has also improved 68% since its benchmark year in 2010. As an indicator of MPC’s growth and profitability, MPC measures sales per employee. For fiscal year 2012, MPC’s sales per employee has improved by 35%.

For its process improvements, MPC has received several awards including the Stephen E. Barton Award on Leadership & Culture in 2010 and Most Improved Using SEA Metrics in 2011. In addition, MPC was nominated in 2012 for SEA awards in Operational Excellence, Workforce Development, and Leadership. ME


This article was first published as a digital exclusive feature for the October 2013 edition of Manufacturing Engineering magazine. Click here for PDF. 


Published Date : 10/1/2013

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