Process-FMEA

For example, the characteristic dimension A on the cover support leg was critical to the success of the automated assembly process, the potential failure mode being a major disruption to the production line. An FMEA Severity Rating (S) = 8 is allocated. See a Process FMEA Severity Ratings table as provided in Chrysler Corporation et al. (1995) for guidance on process orientated failures. The component cost, Pc = 5.93 and the number planned to be produced per annum, N = 50000. 

There is one technique widely used in the automotive industry for detecting and analyzing potential nonconformities Failure Modes and Effects Analysis (FMEA). There are Design FMEAs and Process FMEAs. The technique is the same - it is only the focus that is different. As clause 4.14 addresses potential nonconformities, the subject of FMEAs is treated in Part 2 Chapter 14. 

In both cases the Design FMEA and Process FMEA should be analyzed to reveal features that present a certain risk which can be contained by redesign with mistake-proofing features. 

Understanding production process FMEA, Pareto analysis, flow charts [2]... 

A Design FMEA focuses on the interface of a new product, service, or solution with customers. A Process FMEA focuses on the behind-the-scenes steps that produce the product or enable the service provided. However, both FMEAs share a common format, approach, and interpretation. 

In constructing a Design FMEA, the language differs in a few key spots from a Process FMEA. For example, in a Process FMEA, the first column usually lists the process step under analysis. The first column of the Design FMEA, however, is a list of product or service components and the functions they re supposed to perform. 

Another area where a Design FMEA differs from a Process FMEA is in the controls and detection sections. In a Process FMEA, controls are production controls in a Design FMEA, controls are design controls. 

An excellent reference for both Design and Process FMEAs is ... 

Use a Process or Value Stream Map (Technique 46) in conjunction with a process FMEA to discover potential mistakes related to how you produce or deliver your innovation. 

Conceptual design Process flow diagram Process FMEA/HAZAN... 

The design vahdation plan follows requirements and actions dictated from the design and process FMEAs. Without the FMEA in hand, it could be argued that the vahdation is, at best, incomplete since it is unlikely that the component specification team has unambiguously established what had to be tested (unless of course another process that achieves this result had been used). 

Potential Failure Mode and Effects Analysis in Design (Design FMEA) and Potential Failure Mode and Effects Analysis in Manufacturing and assembly Processes (Process FMEA) Reference Manual. Society of Automotive Engineers, 2000. 

A Process FMEA (refer Table 5.7) or Human Error Mode and Effects Analysis (refer SCF/ SYS/A/108/4523) can highlight the detectability and consequence of the human triggered Event following the classic bottom-up logic of the EMEA. It is typically applied to each step in a task (or process), with failure modes which include ... 

Prioritisation of the safety significance of hnman errors, bearing in mind the potential for detection and recovery of errors. The process FMEA (refer Step 3d and Table 5.7) is usefnl in this regard. 

Different FMEA types are discussed in the literature [51], and can be classified as system FMEA, construction FMEA, and process FMEA. In the context of fuel-cell systems development, the system FMEA will be considered here. Such an analysis deals with the proper interaction between system components and also their interfaces. However, it should be noted that all FM EA types follow almost the same procedure. It is possible to define the following phases for a system FMEA [51] ... 

The basic objective of FMEA/FMECA is early identification of catastrophic, critical and other potential failures so that these can be eliminated or mitigated through design and manufacturing process at the earliest possible time. There are three kinds of FMEA/FMECA, namely, functional FMEA/FMECA, design FMEA/FMECA (DFMEA/DFMECA), and process FMEA/FMECA (PFMEA/PFMECA) (see Clause... 

SAE J1739 Potential failure mode and effects analysis in design (design FMEA) and potential failure mode and effects analysis in manufacturing and assembly processes (process FMEA) and effects analysis for machinery (machinery FMEA) ... 

PFMEA and relationship with DFMEA. (A) Process FMEA, (B) PFMEA relationship with design FMEA. 

Occurrence classification/severity classification—from the discussions in Chapter I, it is seen that occurrence is a ranking number associated with the likelihood that the failure mode and/or associated causes of failure will occur. DEMEA/DFMECA looks for occurrence during the design phase of the product, whereas in PFMEA/PFMECA, the same is applicable during the production process. FMEA identifies failure modes in terms of probability of occurrence. These are actually relative values rather than absolute values, because they are measured in a defined scale. The probability of occurrence of each failure is grouped into discrete levels ... 

The B-sample (design phase) is often the sample with which the design is verified and validated (DV). This means that all characteristics should already be secured. As a result, all requirements should be verified and available and the architecture and the design also need to be analyzed and verified. Production concepts should be detailed enough, that Process-FMEAs and safety-related activities during production can be identified. All safety features or safety mechanisms and related characteristics shall be correctly implemented, tested and verified. 

The original standard for FMEA is MIL-STD-1629A, Procedures for Performing a Failure Mode, Effects and Criticality Analysis, 1980. A more recent standard is SAE/ARP-5580, Recommended FMEA Practices for Non-Automobile Applications, July 2001. Another more recent standard is SAE Standard J-1739, Potential Failure Mode and Effects Analysis in Design (Design FMEA) and Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA) and Effects Analysis for Machinery (Machinery FMEA), August 2002. 

FMEA was originally developed by the US department of defence for military purposes today it is one of the first choices for performing a system safety analysis. It shall be mentioned that, apart from this System FMEA, there are also variants for process improvement called Process FMEA. According to the system structure, all components are analysed with respect to possible failures, and - similar to the HAZOP study - causes, consequences, and detection as well as risk mitigation measures are analysed and improvements proposed. Unlike the HAZOP, however, FMEA uses neither parameters nor guidewords but relies on the expertise and creativity of the analysis team to discover all potential failure modes of the system components. 

Process analysis A prerequisite for other processes (FMEA/FMECA, PRA, HACCP) in order to describe an activity that brings together all the functional constraints (flows, resources etc.) in order to identify critical points and improve the steps in its functions, particularly with regard to interfaces between services Requires a knowledge of the need that has to be met in relation to the available resources... 

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