Injection Molding Innovations
Lear Injects a Dash of Ingenuity
Lear Corp.s Iowa facility specializes in injection molded instrument panels and rotationally molded armrests for Daimler Chrysler and General Motors vehicles.
By Karen M. Koenig
|At Lears Iowa facility, instrument panels used in Daimler Chrysler and GM cars are molded on the companys 28 injection molders.
Lear Corp. is world renown as a top automotive component manufacturer. A full-service, Tier One supplier, the companys 300-plus worldwide facilities specialize in the manufacture of instrument panels, armrests, seating and seat systems, door systems, electronic and electrical distribution systems, consoles, etc.
Lears customer base reads like a Whos Who of automakers. The list includes: DaimlerChrysler, GM, Ford, Mercedes Benz, Porsche, BMW, Jaguar, Fiat, Rolls Royce, Honda, Isuzu, Volvo, Volkswagon and Mazda.
Innovations at the Iowa Facility
DaimlerChrysler and GM are the primary customers serviced by Lears Iowa City, IA, facility. Sales by DaimlerChrysler account for approximately 73 percent of Lears Iowa City business, while 25 percent of the plants sales are to GM. Instrument panels and armrests account for the majority of purchases by these two automakers.
Quality control on these items is a high priority at the almost 400,000-square-foot Iowa City facility. In addition to having quality control engineers circulating throughout each of the plants 11 manufacturing cells, Lear also implements the Six Sigma philosophy for increasing production efficiency and reducing scrap waste, thus ensuring profitability, says Brian Pedrick, plant manager.
For example, Pedrick explains, we had a problem at one of our rotocast machines. It was generating high scrap amounts and resulting in a lot of overtime. When we put one of the companys six Six Sigma black belts on the shop floor he was able to prove that the problem was not with the equipment, but rather the material; there was a compound that was missing from the formulation. We were then able to correct the problem and get back on schedule.
Real-time monitoring of all machines and processes also ensures that the facility is running at its peak ability. The company uses Mitutoyo Measurlink software and wireless
transmitters for real-time data collection.
|Armrests account for 33 percent of Lears Iowa City facilitys business. The armrests are rotationally molded on either Ferry or older model machines. After the molding process is complete, the skins are trimmed, prepped, injected with a high pressure foam and then cured.
We not only can chart production, but also downtime, scrap and rework. The system also identifies the top three defects in the processes, Pedrick adds. Bar code labels provide SPC data tracking of parts. According to Pedrick, each cycles SPC data and processing parameters are stored indefinitely in the system.
As added insurance against defects, the company implements poka-yoke process monitoring systems throughout the plant. If a part does not match its specifications, the machining process stops and the part cannot advance to the next level of production, Pedrick explains.
Process monitoring also occurs within the molding operation. At the Iowa City facility, a RJG DARTVision system provides cavity pressure monitoring and control. According to Lear, the system also: verifies the shot-to-shot dimensional repeatability, establishes a molding template for dimensionally correct parts, captures a cycle-by-cycle pressure map of what is happening within the mold and monitors the changes in injection pressure from one grade of material to the next.
Manufacturing Instrument Panels
A PC/ABS material is typically used in the instrument panels that are injection molded and assembled at Lears Iowa City facility. The instrument panels account for roughly 65 percent of the plants product sales, with the remainder of its sales coming from armrests (33 percent) and consoles and other small parts (2 percent). DaimlerChryslers Dodge Stratus sedans, Chrysler Sebring convertibles and sedans, Dodge and Plymouth Neons, the Dodge AB Ram wagon/van as well as GMs Chevrolet Camaro are among the vehicles which utilize Lears instrument panels.
Lear has streamlined the production process to the point that it can produce an instrument panel every 45 seconds. This is probably one of the most important and complicated parts we make, says Cal Lilienthal, engineering manager. Everything has to be perfect for the (insertion) of the electrical components.
Instrument panels are molded on the companys 28 Milacron injection molders. To help speed production, Lear devised a quick tool system that enables it to change molds faster and easier, says Lilienthal. We sometimes average 10 or more tool changes a day. This system makes it quicker, which, in the long run, helps us control our inventory better.
After injection molding, robots are used to remove large components, such as cavity base panels an
d top covers, and place them into a degating machine. Welding of clips or other small parts is done within the production cell. At each step, Lear uses the poka-yoke method for ensuring that quality and part specifications are maintained.
A Look At Lear
Headquartered in Southfield, MI, Lear Corp. first began operations in 1917 in Detroit by producing seat frames under the American Metal Products name. The company soon rose through the ranks as a full-service, Tier One automotive supplier, offering, research, design, engineering, testing and manufacturing services.
The companys acquisition of Automotive Industries in 1995 and Masland Corp. in 1996 reportedly helped it become the worlds largest independent supplier of fully-integrated automotive interior systems and components. It cemented its position in 1999 with the acquisition of United Technologies Automotive and its plants, including the Iowa City, IA, facility. This acquisition also gave Lear added electronics and electrical distribution systems capabilities.
Today, Lears key components and systems include: acoustic components; airbag-equipped seats, instrument panels and headliners; articulating seats; car kits for portable phones; closed container products; consoles; dashboard and floor insulators; door trim panels; door systems; electronic and electrical distribution systems; floor systems, fully-trimmed seats, hard trim systems; headrests and armrests; HVAC ducts; instrument panels; junction boxes; manual seat recliners and seat track adjusters; mobile multimedia products; on-board computing systems; overhead audio systems; package trays; power seat recliners and seat track adjusters; self-aligning head restraints; shelves and trunk storage systems; soft surface interior trim; underhood systems; and visors.
Currently, Lear has operations at more than 300 facilities worldwide. The company reported sales of $12.4 billion in 1999 and is listed in the Fortune 500. It is also publicly traded on the New York Stock Exchange (NYSE:LEA).
Bar coding is used to track the injection molded parts throughout all phases of production, including additional molding processes. On Chryslers Stratus, for example, Lear vacuum forms a PVC skin onto the injection molded part. The panels manufactured for Chevrolets Camaro also feature an injection molded SMA carrier with a foam-in-place PVC skin.
Rotationally Molded Armrests
Armrests are also tracked throughout their production cycle.These rotationally molded products account for one-third of the plants business.
Armrests manufactured at the Iowa City facility are used in nine GM models the GMS Safari, Sierra and Yukon, Cadillac Escalade, Chevrolet Silverado and Tahoe, the CK Truck, Astro minivan and GMC and Chevrolet Suburbans. They used in the Chrysler Town and Country car, Dodge Caravan and Plymouth Voyager minivans.
To manufacture the armrests, newer Ferry molders along with older rotational molders are used to mold material which Lear compounds on site. According to Lilienthal, the molds are filled, then cycled for approximately 15 minutes, which includes the heating, cooling and removal of the skins. The skins are hand trimmed, prepped and filled with a urethane foam prior to finishing.
Finishing is the final step prior to assembly. Armrests and instrument panels are finished in one of two ways: with either a single-component water-based lacquer or a two-component water-based material for a soft-touch finish. According to Lilienthal, the company has used water-based finishes for a number of years due to their environmental benefits, in particular the reduction of VOCs released into the air.
As an added measure, HVLP spray guns are used in finishing booths for spraying single-component finishes onto instrument panels, armrests and other items manufactured at the facility. Application of the soft touch finish, a more complicated process, is done in a specially designated area of the plant. There, a robotically-controlled sprayer with a Graco conventional spray gun attached, is used to apply the water-based two-component finish onto selected instrument panels, such as those found in the Neon.
In addition to finishing, the Iowa City facility offers a variety of additional services. These services run the gamut, from insertion of small items, such as metal clips into the instrument panels, to ultrasonic and vibration welding of added components, up through the installation of air bags.
Eventually, we want to be able to offer a complete package including all of the electrical, the radio, the instruments. That is our goal, says Lilienthal.
Click here to go back to the PMF feature articles.
Plastics Machining & Fabricating
|P: (847) 634-4347
F: (847) 634-4379
|P.O. BOX 1400