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October 1, 2001

4 Min Read
WEB EXCLUSIVE:Materials Update

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A secondary air pump for automotive engines required not only the properties of nylon, but also a global coordination effort among molder, OEM, and resin supplier.

Nylon takes on underhood pump in global project 
Underhood applications such as air intake manifolds (see image below) have long relied on nylon in one form or another to withstand the high heat and harsh chemical environment of the engine. Resin supplier DSM Engineering Plastics recently participated in a project to bring a secondary air pump (see image at right) molded from Akulon K224 HG6 BK (a 30 percent glass-reinforced and heat-stabilized nylon 6) to market. This part not only required the properties of nylon, but also some major cross-continental coordination. 

Pierburg is a Tier One automotive supplier located in Neuss, Germany that focuses on fuel and air management systems. It developed the pump design for several major international OEMs. The mechanism reduces emissions by pumping ambient air into exhaust gases following a cold startup. The catalytic converter, which turns pollutants into harmless gases, is not yet operating at startup, so the secondary pump reduces the harmful emissions until the catalytic converter takes over. 

DSM EP application development engineers in Germany participated in some of the application development tasks. The specific grade of nylon 6 was selected not only for its heat and chemical resistance, but also because the pump would be ultrasonically welded and laser printed during assembly. Dimensions of the 1-lb pump are approximately 9 inches tall by 6 inches wide by 6 inches deep. 

While glass-filled nylon doesn't exhibit as much dimensional change as neat resin in humid environments, designers still took potential changes into account. Molded portions of the pump consist of impeller parts, a top, and a housing. Standard underhood temperature resistance is required in the application. It is critical that the parts maintain stiffness at these elevated temperatures. 

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In another underhood Akulon nylon 6 application, Briggs & Stratton chose to mold an intake manifold for its Intek V-Twin line of engines from a 33 percent glass-fiber-reinforced grade to replace a sand-cast aluminum version for cost and weight savings.

Once the design was set, tools were produced at Mikron Corp. in Italy. DSM EP Europe assisted with tooling recommendations and flow analysis. Gate locations as well as part interface dimensions were areas of concern. Once Mikron Corp. completed the tools, they were tested and transferred to its facility in Anderson, SC for production. DSM EP Americas became involved in assisting with a smooth startup on this side of the Atlantic. 

According to Mike Cherry, senior account manager for DSM EP, this project highlighted the global nature of automotive manufacturing. "With design in Germany, production in the U.S., and global OEM customers, this could have been a logistical nightmare," says Cherry. "But its smooth execution points out that resin suppliers need to be able to serve customers anywhere in the world, and to coordinate between locations." To that end, DSM EP focuses on global accounts participating in automotive and E/E markets.—Michelle Maniscalco



Table: Properties for Akulon K224-HG6U

MECHANICAL PROPERTIES*

 

Unit

DAM

Conditioned

Tensile strength

23C (73F)

MPa (psi)

180 (26,100)

115 (16,700)

 

80C (194F) 

MPa (psi) 

102 (14,700) 

74 (10,700)

 

121C (250F) 

MPa (psi) 

78 (11,400) 

55 (8000)

 

-40C (-40F) 

MPa (psi) 

235 (34,000) 

235 (34,000)

Tensile elongation, break 

% 

3.5 

6.0

 

Flexural modulus

23 °C (73F) 

MPa (psi) 

8,500 (1,220,000)

4820 (700,000)

 

65 °C (149F)

MPa (psi) 

3740 (542,000)

--

 

-90°C (194F) 

MPa (psi) 

3530 (512,000) 

--

 

-121°C (250F) 

MPa (psi) 

3123 (453,000) 

--

 

40 °C ( -40F) 

MPa (psi) 

9250 (1,340,000) 

9630 (1,400,000)

Izod impact strength 

23C (73F)

kJ/m2 (ft-lb/in)

14.0 (2.1) 

21.0 (3.1)

 

-40C (-40F)

kJ/m2 (ft-lb/in)

9.0 (1.35) 

9.0 (1.35)

PHYSICAL PROPERTIES*

Density

 

gm/cm3

1.38

 

Water absorption, 24 hours 

%

1.3

 

Water absorption, equilibrated at 50% RH

%

1.8

 

Mold shrinkage, 2 mm thickness
 Parallel to flow/Transverse to flow 

% 

.5/1.0

 

THERMAL PROPERTIES*

Heat deflection temperature @ 1.82 MPa

C (F) 

200 (392)

 

Coefficient of linear thermal expansion,
 (parallel to flow/perpendicular to flow)

-30 to 150C

E-5/C

2.0 / 10.0

*DAM = Dry-as-molded. Conditioned = Conditioned to equilibrium in a 50% relative humidity atmosphere



DSM Engineering Plastics
Evansville, IN
Paula Wolfe
(812) 435-7500
www.dsmep.com 
[email protected]

1001i60b.jpgResins add durability to laptop 
In an attempt to combine performance and portability with durability, IBM turned to GE Plastics for two eco-label-conforming resins to use in the ThinkPad A Series Notebook. IBM chose Cycoloy C6600 and Cycoloy JK500 resins for their durability, aesthetics, and good flow properties that allow thin walls and optimum size. The C6600 resin, a blend of polycarbonate and ABS, was used in the rear cover and keyboard bezel on the laptop. This resin reportedly provides a good balance of heat resistance, high flow, impact strength, and flame resistance. The base of the computer is formulated of JK500, a 10 percent glass-fiber-reinforced, high-impact PC/ABS compounded by GE Plastics' Custom Engineered Products group. Developed for IBM to provide strength, durability, and impact resistance, it's said to provide the flexibility to expand design options while maintaining product strength. Both resins conform to many eco labels, helping IBM address the demands of the global marketplace. 

GE Plastics, Pittsfield, MA
(413) 448-4690
www.geplastics.com 

 

 

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