BMW covers these testing requirements with an AllroundLine 20 kN testing machine from ZwickRoell of Ulm (Germany). This four-column, floor-standing testing machine features hard-chromed guide-columns and precision ball-screw with ball-nuts adjusted for zero backlash, guaranteeing high accuracy. AllroundLine also offers variable crosshead installation, giving the option of a second test area.
For use at BMW an additional upper fixed crosshead has been incorporated into the testing machine. A 6-channel measurement platform with mechanical overload protection is mounted on the lower fixed crosshead. To enable precise determination of upper intersection points, the moving crosshead is equipped with a 2-channel measurement platform. Measurement and control operations are handled by in-house ZwickRoell product testControl, allowing time-synchronous acquisition of measured values from all measurement channels at high resolution and measurement frequency, plus real-time processing. The measured values obtained provide information on quality-determining properties such as spring characteristic values and intersection points of resultant forces, together with transverse forces occurring in helical compression springs, delivering an important contribution to quality assurance.