In order to meet the requirements of its automotive customers, ZF PWK Mécacentre inspects the quality of the friction characteristics guaranteed by the screwed connections of its stamped spherical joints.
ZF PWK Mécacentre manufactures approximately 160 million safety parts in its Saint-Étienne facility that are designed for automobile steering and suspension components. The company works for the leading automobile manufacturers in Europe such as Mercedes, BMW, PSA and Renault to name a few.
A coating is applied to certain threaded spherical joints made from stamped steel in order to improve the friction at the screwed connection. The proper performance of this treatment must be inspected and validated on a regular basis so that it can meet all the quality requirements of the instructing parties. Accordingly, a characterisation test of the torque and the tension of the screwed connection helps to ensure total product compliance.
Guaranteed responsiveness
As part of its continued inspection approach, the company takes regular samples from the batches of parts coated by its subcontractors and entrusts them to Cetim. Cetim's experts then inspect the friction coefficient of the threading on one of its tightening benches and ensure that the characteristics measured are suited to the specific expectations of the customer.
"We call on Cetim on a regular basis to check our training or inspection means, explains Hélène Morel, technical engineer at ZF PWK Mécacentre. For us, this is a guarantee of responsiveness and our customers have the assurance of an inspection carried out by an independent and recognised expert."
The capacities provided by the two benches installed at the Cetim Saint-Étienne facility are unique in France. By subcontracting the inspection of its parts, ZF PWK Mécacentre saves on a costly investment that would have been difficult to amortise.
Cetim is the only independent laboratory in France that possesses test benches to measure and check friction coefficients.
