Metal Replacement in Hot Coolant
- Thermostat housing for VW: Ultramid HRX in production
Since February 2012, thermostathousings molded from Ultramid® A3WG6 HRX are in use at VW. The new polyamide specialty from BASF which is now available worldwide has been developed specifically for applications requiring high hydrolysis resistance in conjunction with high strength. Production takes place at Veritas AG, headquartered in Gelnhausen, for the VW engine factory in Salzgitter (both in Germany).
The coolant control module’s cover, which is molded from the new material, must withstand demanding conditions – a pressure of several bars at a peak temperature of up to 130°C – and exhibit minimal deformation, as this would reduce the module’s efficiency.
Weight and cost benefits
Compared to its all-aluminum predecessors, the housingcover molded from thepolyamide specialty offers benefits in terms of both weight and cost: In contrast to the metal component, the molded plastic component does not need to be finish-machined, and the desired dimensional accuracy, especially of sealing surfaces, is easier to achieve. Supports, holders, valve seats and other functions can be integrated into the molded component without effort. In addition, the high surface quality of the plastic is important, since it counteracts abrasion by the coolant.
CAE design competence
As with other challenging plastic components molded from Ultramid, the CAE experts at BASF provided assistance to the customer during design. Great attention was devoted to optimal positioning of the gates. This made it possible to shift the unavoidable weld lines with their reduced strength to regions of thehousingthat are subject to lower loads. Ensuring long-term tightnessof the component under the seal and thermostat loads as well as the internal coolant pressures presented Veritas with an additional challenge. With the aid of BASF’s universal simulation tool ULTRASIM®it was possible to analyze the creep behavior of the component in advance and optimize design accordingly.
Additional information on Ultramid® (PA) is available at or by calling: +49(0)6216078780.
Press photo: at the heading ”Plastics” or by entering the search term ”Ultramid”. Text and photo will also be available in BASF’s Plastics press archive: