December 2009 | Focus: Transportation

Polycarbonate dash dial in VW Golf saves materials and labor

New materials and technologies make the manufacturing process for automotive dials more cost-effective and give designers greater creative freedom.

By utilizing a patented new “high pressure forming” method, the dash dial in the VW Golf is now made of polycarbonate film, eliminating the need for a decorative aluminum ring. Integrated into the dial is a matte metallic outer ring, which previously would have been a separate metalized molded part.
The integration of the dial into a single component eliminated several steps in the component assembly process, resulting in savings in materials and logistics, and removing the need for a complex electroplating step. In addition, the formed film looks more homogeneous than an equivalent component with a mounted ring.

The dash dial is made of printable polycarbonate film. The 375 millimeter thick film is printed on both sides with more than 10 layers of ink using the screen printing method. The translucent symbols are gray and are backlit by colored LEDs (backlit effect for nighttime use). Read more.

This article was written by Sheffield Plastics, Inc., A Bayer MaterialScience LLC Business

Clearing the way: engineering plastics in automotive windshield wiper systems

Mercedes Benz single-arm windshield wiper system. Drive and wiper arm covers are injection molded from Ticona’s impact-modified, weather-resistant, UV-stable Hostaform® acetal copolymer.

Windshield wipers have come a long way since the first U.S. wiper patent was issued in 1903. The original manual device has evolved into a complex unit that must function perfectly for 15 years or more under all conditions. Today’s wiper systems must be lightweight, strong and durable and able to withstand sunlight and the harsh substances they encounter in use.

In meeting such stringent requirements, automakers have increasingly turned to engineering thermoplastics to gain the design freedom, performance and reduced weight and cost they need in exterior and underhood wiper components. Through the mid-1990s, plastics were mainly used in wiper covers, clips, fasteners and other exterior wiper elements. As engineering polymers grew more sophisticated and were economically able to provide greater stiffness, better UV re­sistance, lower wear, better surface appearance and other essential properties, their use in wiper systems expanded rapidly. Today, auto designers use these materials in applications ranging from wiper arms and airfoils to motor bearings and gear housings.

Plastics often used in wiper systems include acetal copolymer, polyester (both polybutylene and polyethylene terephthalate, PBT and PET) and long fiber-reinforced thermoplastics (LFRT). In addition to high stiffness and strength, these materials offer good fatigue resistance and low moisture absorption, so parts are dimensionally stable whether exposed to desert dryness or tropical humidity. They also are unaffected by windshield washer fluid, often containing methanol, the detergents used in car washes and road salts. Read more.

This article was written by Tom Miller and Jason Lipke, Ticona

UHMW – transporting the heavy-duty materials

Röchling Engineering Plastics’ MegaSheet™ significantly reduces weld seams. MegaSheet™ is a compression-molded UHMW sheet that measures an incredible 8 feet by 20 feet.

When it comes to transporting heavy-duty, abrasive materials such as coal, limestone, gravel, sand, asphalt, phosphates, salt and even quarry materials — UHMW (ultra high molecular weight polyethylene) bedliners have proven their worth and durability for years. UHMW lining systems significantly outlast aluminum and steel floors in most applications, protecting them at the same time. Wet, sticky and even frozen materials dump easier and with a lower dump height. These advantages provide safer and more productive hauling with more fully dumped loads per day, translating into increased revenue for the owner.

Today’s dump truck liners have evolved considerably with the availability of new sheet sizes, special grades and improved fastening systems. Generally, 4 feet x 10 feet sheets are fusion welded into a one-piece, drop-in liner that can be rolled into a manageable coil for easy shipment. The most common thicknesses used are 3/8" and 1/2", with 1/4" chosen for the less abrasive materials. The sheets are butt-fusion welded and fabricated to fit the exact dimensions of the bed — whether 16 feet or 40 feet in length. Liners for the sidewalls and bulkhead are usually optional. The biggest and most recent development in this industry is the availability of a new compression-molded UHMW sheet that measures an incredible 8 feet by 20 feet. These large sheets greatly re­duce, or even eliminate the weld seams. The overall cost to fabricate the liner is improved by reducing the labor time, and with fewer weld seams there is less risk of a break or crack. Read more.

This article was written by Tim Brown, Röchling Engineering Plastics

Polyethylene roll-up door panels

A roll-up door built with polyethylene custom run in the Penske yellow color.

Quality conscious companies in the truck and trailer industry had a problem. Over time, they were seeing peeling, warping, cracking and overall degradation of the face of the roll-up doors. These doors were a painted plywood structure that typically carried no warranty as far as the aesthetics on the face of the boards.

Laminators, Inc. was asked to quote a solution to the problem. Laminators was a very active supplier to the trailer industry. Since they had many years of past experience in this field, they decided to develop a solution. Laminators proposed a laminate panel manufactured with outer polyethylene skins, which was a special proprietary UV grade of polyethylene (PE). The core center is furniture grade plywood selected to be lighter and stronger than traditional materials. S & L Plastics, Inc. worked with Laminators to develop the proprietary polyethylene face material, assure color, test for color fastness and shifting and process the resin. S & L has worked with Laminators for years and is known for their reputation in producing a superb flatness grade of thin polyolefin sheet. Flatness is critical to the quality output of the lamination process.

The UV grade of polyethylene is formulated to help protect the compound from degradation caused by the ultraviolet rays of the sun. It is also formulated to keep the product color fast so there is little or no fade or chalking. The initial sheet at the production stage is quality checked using a Gretag Macbeth Spectrophotometer, comparing it to a metal chip supplied by the customer painted the same hue as the truck body. The benefits of the polyethylene were that it is easily cleaned, relatively resistant to scratches and graffiti, gives even color dispersion throughout the thickness of the poly skin, won’t peel, is very durable, and can be custom run in any color to match the truck. In comparison to substitute products, it is also very economical. Laminators offers a 10-year warranty on their products; however, they have customers who have still been using the same panels for close to 20 years. Read more.

This article was written by S & L Plastics, Inc.

Test Your Knowledge

What do you know about plastics in transportation applications? (Answers are at www.iapd.org/popquiz.html.)

1. UHMW-PE falls into what category of plastics?

a. polyethersulfones
b. polyamides
c. polyolefins
d. cellulosics

2.  The most common additive used to prevent/reduce ultraviolet light degradation is:

a. talc
b. salt
c. glass
d. carbon black

Sponsored by

Kydex LLC

In this issue

Polycarbonate dash dial in VW Golf saves materials and labor

Polycarbonate film eliminates need for additional metal ring and extra fabrication time.

Clearing the way: engineering plastics in automotive windshield wiper systems
Windshield wipers have come a long way, thanks to plastics.

UHMW – transporting the heavy-duty materials
UHMW lining systems provide safer and more productive hauling.

Polyethylene roll-up door panels
Plastics open doors for trucking company.

Test your knowledge
What do you know about plastic materials used in transportation applications?

About IAPD
The International Association of Plastics Distribution, founded in 1956, is an international trade association comprised of companies engaged in the distribution and manufacture of plastics materials.

Members include plastics distributors, processors, manufacturers, resin manufacturers, manufacturers’ representatives and associated products and services, all of whom are dedicated to the distribution channel. Visit www.iapd.org for more information.
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Designing with Plastics is published by the International Association of Plastics Distribution. While every effort has been made for accuracy, IAPD encourages you to verify information with a plastics distributor to ensure you select the correct plastic products to meet your needs.
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