Selection of suppliers

1. Supplier qualification

Quality management system

As a minimum requirement, WIKA expects its suppliers to prove that they have an effective quality management system meeting the requirements of the standard series ISO 9001. For suppliers whose products are used in the automotive industry, the standard requirements according to ISO/TS 16949 are applicable. A current certificate by an authorised certification body is considered to be a proof of the introduction of one of the above mentioned systems. The supplier must immediately report any change in his certification status to the responsible WIKA buyer.

Environmental management system

WIKA suppliers should be certified like WIKA according to EMAS or ISO 14001 or, at least, be able to present a documentation about regular improvement measures regarding the environment. The supplier commits to observe the legal limit values during the production of the parts and regarding the materials used for the manufacturing processes, even though those values represent only minimum requirements. Modifications of these requirements by legislation have to be taken into account, but need not be communicated to WIKA. Examination results as well as information on the supplier and environmental management must be presented without request.


2. Self-assessment

New suppliers are first evaluated on the basis of a standard self-assessment form. This form includes general questions about the company size / structure / legal form / technology / resources / QM system... The commodity team consisting of the Lead Buyer, SQE (Supplier Quality Engineer) as well as the SLE (Supplier Lead Engineer, technical support) decides on the further procedure.


3. Pre-Audit and Process Audit

Before placing an order, WIKA carries out a pre-audit for potential suppliers which is based on the WIKA checklist. The purpose of the pre-audit is to check the ability of a new supplier to fulfil WIKA requirements in order to provide one of the bases for deciding on a further cooperation with the supplier. When the audit is finished, the supplier will be informed on the audit result within one working week. If the audit result requires improvement measures, the supplier must elaborate an action plan and send it to the WIKA Lead Auditor within the agreed period of time. A second audit is not intended as a process audit will be obligatory when the order is placed. All open questions resulting from the pre-audit can then be cleared during the process audit. The pre-audit is carried out either by the commodity team or by the respective IPO (buyer responsible for the buying area in question) and quality support is provided by the respective WIKA subsidiary. Usually, this depends on the production site of the supplier.

For a final process approval, a process-audit will be conducted around the time of the first article producing.The Process audit is conducted by the Supplier Quality Engineer of the related Commodity Team. With a process audit. WIKA may also requires improvement measures. A follow-up audit is possible.
The audits include the elements 1-4 of the questionnaire according to VDA 6.3. The results of both the pre-audit and the Process Auditare rated / assessed according to VDA 6.1 (see the following point).


4. Rating and approval

A degree of compliance (in percent) is determined on the basis of the individual assessments. The supplier can be rated as follows:

  • >= 90 percentage points        -> A rating
  • >= 80 < 90 percentage points -> B rating
  • < 80 percentage points          -> C rating


5. Feasibility declaration

The feasibility assessment is made to evaluate whether a requested part can be manufactured according to the requirements (drawing / specification) under series production conditions. The supplier is responsible for the feasibility assessment which offers him the chance to contribute his experience and to make proposals for the benefit of both parties.  Ideally, this should be done in cooperation with the responsible WIKA project procurement department or engineering department. Given tolerances under statistical aspects as well as the function and load of the product must be particularly observed. Furthermore, a statement is to be made as to whether the supplier's capacity is sufficient for the delivery of the planned quantities and whether the scheduled delivery dates can be met.

Methods which can be used for feasibility assessments are for instance:

  • Design of Experiments (DoE)
  • Failure Mode and Effects Analysis (FMEA)
  • Process Capability Analysis (SPC)
  • Fault tree analysis / Ishikawa diagram


6. Supplier development

The WIKA supplier development offers the possibility of advancing existing QM systems according to the standard requirements of ISO/TS 16949. WIKA will be pleased to assist its suppliers with information, knowledge and experience. This can be done for instance by regular supplier assessments, a clear definition of the documents and procedure required for sampling inspection, training to use the WIKA-specific tools and general quality tools (e.g. FAI, 8D, Ishikawa, 5 Why), conclusion of a Quality Assurance Agreement (QAA), definition of clear goals (e.g. ppm, reliability of delivery). In addition, WIKA reserves the right to carry out a system, process and/or product audit, in order to check on site that the quality management system is effective. Furthermore, the supplier is responsible for the development of his sub-suppliers.