Analysis of production incompatibilities and risk level in series production of assembly elements for the automotive industry

The paper presents issues connected to risk analysis of production incompatibilities occurrence. Low-pressure cords thermoforming process analysis was presented, as well as analysis of types of incompatibilities during the phase of marking product (pad printing). The risk analysis is based on three factors: occurrence, detection, and severity of a specific incompatibility. 6 incompatibility types were defined and their various causes were determined. One critical incompatibility was determined, as well as 4 severe production problems. Presented analysis is an element of implementation of project of new products into the existing thermoforming processes.


Introduction
An important element of quality management and assessment is involving the management in the area of actions connected to detected production incompatibilities.An element of process supervision system is management involvement both during the phase of new production implementation and realisation maintenance and supervision.One of component of production preparation and supervision is production incompatibilities occurrence risk analysis.The analysis regards at first production planning, and then it is continued as supervision over production tasks fulfilment and achieved results monitoring.Utilising FMEA analyses is a system activity, the purpose of which is to ensure correct level of sureness that the product will meet assumed quality requirements [1].
One of the most important quality processes in the w automotive field companies is PPAP -Production Part Approval Process.By obtaining PPAP confirmation, the company simultaneously receives from the customer approval of competence of assembly elements provider.Processes connected to obtaining PPAP are focused on process approach, the basic element of which is focus on the customer and his expectations.PPAP requirements include the following documents: project provisions, materials composition, engineering changes documentation authorised by the customer, project FMEA, process flow chart, process FMEA, analysis of measurement systems defined by the control plan, measurement report, statistics control records, test results, appearance compatibility report, part samples, model sample [2,3].
Assembly elements producer is obliged to present full PPAP documentation only if:  a new part or product appears, which the customer has not been previously supplied with,  inaccuracies in comparison to the previous PPAP need to be rectified,  changes regarding materials or technical specification occurred in the area of provided product,  changes in the product production process itself occurred -using new or modified tool or form,  occurs a change of: supplier, control methods, production technology.Presented actions are connected to the quality management in low-pressure cords production processes.The necessity of providing full PPAP documentation was connected to structural changes in a new model of the product.Research entity prepared full documentation and assessed risk connected to the planned production processes quality.PPAP processes are realised according to the internal guidelines of the company, ant the responsibility for specific implementation phases of PPAP requirements lies within responsibilities of the Head of the Process Engineering Department.

FMEA analysis -main assumptions
Presented FMEA analysis is an element of set of documentation prepared as preparation of new production on low-pressure cords production lines.According to the requirements, a basis for beginning a cooperation with a customer (automotive corporation) is ensuring proper supervision of production processes (PPAP).An important element of the documentation is risk analysis of potential production incompatibilities, which is conducted in both FMEA process analysis and FMEA product analysis.
The presented analysis of planned production processes uses basic risk factors based on severity, occurrence, and detection values.The values were evaluated on scale 1-10, according to the guidelines of an external customer [4][5][6][7][8].Risk priority number in the FMEA analysis was assessed on the basis of the formula: where: RPN -risk priority number, SEV -severity, DET -detection, OCC -occurent.
For the needs of PPAP production parts approval process, quality tests were conducted mainly on characteristics regarded as important by the customer.Serial production implementation process analysis was conducted on the basis of low-pressure cord production.Design team is decomposing the system and preparing comparisons related to new production implementation: amounts of necessary materials, their quality, machine requirements (production devices and their wiring).
The analysis itself describes and classifies potential faults and their severity.The next phase is determining probability of fault occurrence and determining its severity for functioning of the product.the next phase is providing proper guidelines in order to decrease faults occurrence risk.

Table 1 .
Table 1 presents detailed FMEA analysis of product marking process.FMEA analyses results become a basis of creation of standard operating procedures for processes operators at specific work stations after undercure process.https://doi.org/10.1051/matecconf/201818303011QPI 2018 FMEA method in process of tampoprin-marking.