Why you should use Com.IPM
1) Because valid measurement results are essential
Valid measurement results actually speak for themselves. Because any further assessment of facts, statistical evaluations with calculation of capability indices or conformity assessments are ad absurdum if the measurement uncertainty is not known. ISO 14253ff (see illustration on the right) provides clarity with the requirement to calculate the expanded measurement uncertainty.
ISO 14253 also regulates how to deal with specification limits for both suppliers and customers. The requirements of ISO 14253 relate primarily to GPS (Geometrical Product Specification) dimensions, but can be applied to other measurands.
The figure on the left shows relevant standards and guidelines for calculating measurement uncertainty.
The GUM (Guide to the Expression of Uncertainty in Measurement) describes a measuring system or the measurement process using a mathematical model. Although GUM is the measure of all things, measurement uncertainty according to GUM is difficult to apply in practice due to the large number of influence quantities and is therefore primarily used by Dakks test laboratories (see ISO 17025).
In order to be able to determine the measurement uncertainty for practical applications, ISO 22514-7 was published with simplified procedures for calculating the measurement uncertainty of measuring systems and measurement and inspection processes. This procedure has been adopted 1:1 in VDA Volume 5 because it enables users to calculate measurement uncertainty for inspection processes in the automotive industry. These methods have established themselves in practice over the years and are considered to be GUM-compliant measurement uncertainty evaluations.
2) Because there is a difference between measuring system and measurement process
A distinction is made between measurement system analysis and measurement and inspection process capability, as illustrated in the figure below. You calculate the measuring equipment capability and the process capability.
The influencing quantities shown in the lower area (blue) are primarily part of the measuring system. The resulting standard measurement uncertainty is referred to as uMS. This can be an MPE value (Maximum Permissible Error) or result from tests carried out. The tests are usually conducted under ideal conditions in the laboratory by suitably qualified persons. Such tests can be carried out by the manufacturer itself for new appliances. They state the result in the product specification of the measuring equipment. In a company, these tests are normally conducted in an internal or external test laboratory (e.g. Dakks) for existing measuring equipment.
The uncertainty of a measurement process consists of the standard uncertainty of the measuring system and the standard uncertainty resulting from the other influence quantities (green).
The statistic uMP specifies the standard measurement uncertainty of the measurement process. The tests described in ISO 22514-7 and VDA 5 help you calculate this uncertainty and later derive further relevant statistics. See the examples on the right illustrating the calculation of measurement uncertainties according to VDA 5.
Once the statistics are known, you start the required conformity assessment. The illustration opposite shows the conformity assessment in accordance with ISO 14253 and VDA Volume 5.
This is how to prove inspection process capability in accordance with VDA 5 and ISO 22514-7. Com.IPM supports users with these diverse tasks.
3) Because Com.IPM fulfils all tasks of inspection process management according to VDA Volume 5
Due to the large number of possible influences in the real environment, it is difficult for users to determine the resulting standard measurement uncertainty using complex mathematical models. It is therefore advisable to first carry out a risk assessment to determine whether the proof of capability described above needs to be conducted at all. You should also consider the transferability of known results from similar or comparable measurement and inspection processes. The time-consuming proof of measurement and inspection process capability might no longer be necessary. It is also important to maintain an overview of which measurement and inspection processes are currently in use and their current status (stability) in order to be able to intervene, if required. These tasks are part of an inspection process management system.
What does inspection process management mean according to VDA 5?
In terms of VDA 5, an inspection process management system covers the following areas of responsibility:
- The starting point is the characteristics specified in a drawing or CAD model and the limits as the basis for an inspection plan (control plan).
- The test process is assigned to a risk class on the basis of a risk assessment. The assigned risk class “high”, “medium” or “low” is based on the probability of occurrence of a wrong decision (in relation to the risks of the measurement process) and the consequence of a wrong decision (e.g. using a P-FMEA) depending on the area of application (production, development, …). The risk class is used to determine whether and how inspection process capability must be established in accordance with VDA Volume 5 and ISO 22514-7.
- As these assessments are generally time-consuming, we recommend you consider whether suitable measuring and inspection equipment, measuring systems or measurement processes are available in the company-specific inspection equipment management system to evaluate the transferability for the respective application. Validation can be designed efficiently through possible transferability:
- Transferability of uncertainty components (e.g. measuring system based on calibration and existing capability analysis).
- Transferability of capability analyses (e.g. comparable measurement processes for similar components and characteristic specifications under the same boundary conditions).
- If the assessment is negative, a proof of capability is required. It may be necessary to purchase new measuring equipment for a measurement process that is suitable as a measuring system. The selected measuring system is then used to prove the capability of the measurement or inspection process.
- If the measurement process is capable, the conformity assessment is conducted in accordance with ISO 14253.
- If the measurement process is applied in practice, its stability over the period of use must be verified. This is the only way to determine that the stability of the measurement process uMP has not changed significantly and can therefore still be considered suitable for the measurement task. This is referred to as stability check.
Com.IPM, the software for inspection process management accoridng to VDA 5, supports you with all these diverse tasks. With Com.IPM you maintain an overview at all times, show the transparency of your system in audits and generate the relevant reports for customers.
Why is VDA Volume 5 important?
VDA Volume 5 is a guideline published by the German Association of the Automotive Industry (VDA). It describes how companies can ensure that their inspection processes are suitable for assessing the quality of their products.
In industrial manufacturing, particularly in the automotive industry, product quality depends heavily on how well and reliably measurements are taken. If an inspection process is not able to fulfil the intended task properly, defective parts may be classified as ‘good’ and good parts may be unnecessarily rejected. This leads to quality problems for the customer, unnecessary costs and a loss of trust.
In addition to inspection process capability, calibration and traceability, as well as statistical methods, the procedures contained therein focus on determining measurement uncertainty. The VDA 5 practical guide, published in parallel, provides numerous examples illustrating typical applications, from the use of specific measuring devices to concrete analyses. Many of these can be found as sample data sets in the Com.IPM software for VDA 5-compliant inspection process management.
Who must comply with VDA 5 specifications?
Implementation of VDA Volume 5 is not legally binding, but in the automotive industry it is effectively unavoidable for suppliers and OEMs and is part of IATF 16949 certification. For companies outside the automotive industry, the guideline is considered a recommendation and is applied as best practice in many industries. Anyone who supplies products that need to be tested on the basis of customer requirements must prove inspection process capability in industrial quality management. VDA 5 has proven itself in practice for this purpose.
Com.IPM for VDA 5-compliant production
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