High-temperature polyamide grade offers lightweighting option for blowmolded air ducts

A heat-stabilized blowmolding grade of Stanyl polyamide (PA) 4.6 from DSM Engineering Plastics (Singapore) has been developed specifically for vehicle hot charge air ducts. Components molded from Stanyl Diablo OCD 2305 BM are lighter than current solutions in metal or polyphenylene sulfide (PPS) and can handle continuous temperature up to 230°C.

The new grade is reportedly the first high-temperature PA suitable for processing by extrusion blowmolding and with a significant cost benefit compared to PPS, thanks to its lower weight and scrap rate.

The lower density of Stanyl OCD 2305 BM reduces part weight by 7% compared to PPS. Moreover, better wall thickness distribution can even raise that value to over 10% according to DSM. Stanyl Diablo OCD 2305 BM can also be viewed as an alternative to metal: it reduces both weight and costs, and has better acoustic behavior than metal solutions.

Stanyl Diablo OCD 2305 BM was developed by DSM to meet the needs of the automotive market, where new EU legislation has set stringent emission reduction targets for 2015. This has led to a trend toward smaller vehicles with downsized engines. Creating these smaller engines requires new part designs. However, current air ducts, either in metal or injection molded in plastic, do not offer the design flexibility needed to fit complex underhood geometries. This requires the next generation of hot charge air ducts be created using blowmolding techniques, which is the most cost-effective way of producing such parts.

The first company to deliver serial ducts from Stanyl Diablo OCD2305 BM is engineering technologie marketing gmbh (ETM; Saalburg-Ebersdorf, Germany). ETM was searching for an alternative blowmolding material to produce hot charge air ducts for Volkswagen.

Klaus Klockow, General Technology Manager at ETM says: "The new DSM material is clearly designed to address the challenges faced by the automotive industry. We are happy to be the company which brings to market the first blow molded ducts made in Stanyl Diablo OCD 2305 BM, approved by Volkswagen."

With its Stanyl Diablo OCD 2100 and OCD 2300 injection molding grades of polyamide 4.6, DSM pioneered the development of polyamides with high resistance to long-term heat aging. The company's Turbo System Team has built up considerable experience in air management applications over many years. "With this new grade, we are completing the portfolio for air management solutions," says Kurt Maschke, global segment manager, Turbo System. "We now offer solutions for all temperatures required, with both injection molding and blow molding grades."

Maschke also points out that Stanyl Diablo has very good impact resistance: "It is not unknown for PPS air ducts to crack during handling." he says. "As a broken part is only checked after assembly; costs can be reduced easily with Stanyl Diablo OCD 2305 BM. It will reduce scrap rate and—even more importantly—reduce the risk of having a broken part fitted to an engine."