The importance of validation in injection moulding

It’s all too easy to look at validation as a quality control or compliance task that has to be carried out to earn a tick in the box. But a robustly validated moulding process will ensure an end product that satisfies both the customer and the validating body.

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Both the EU and the US Food and Drug Administration are placing more emphasis on validation throughout the production life cycle. Risk management is seen as a key part of the end-to-end process, and it’s hard to prove that this has been effectively implemented without a validation process to audit it. The NHS insists on this risk management process for each stage of the design of any innovative medical device to minimise risks in the final product.

The following three key validation steps will help to eliminate defects in finished products.

1. Process Design Validation

To ensure stability in production, it’s important to check that the correct size of machine is being used and that it has been accurately calibrated. Shot size and tonnage should be appropriate for the process.

2. Process Qualification

It’s important to measure the injection moulding process itself using both dimensional and statistical studies. This will enable you to define the process parameters and then identify any deviations from the acceptable process tolerances. The process isn’t valid if variations have adversely affected the final product.

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3. Continued Process Verification

Once you have validated the design and the process, the process must prove that it is stable over a production run or over a set period. During this verification, the process is tested for its repeatability, and different production runs are carried out using the same equipment so that results can be compared.

The new ISO 13485 standard specifically requires a process to be documented on an ongoing basis. So whenever machine settings are altered, revalidation should take place. Similarly, if there are issues such as distortion or pulling, or if the moulding tool needs to be replaced or repaired, these should all be documented. Firms with high quality standards, such as http://pnplastics.co.uk/, understand the importance of these validation checks in helping to design efficient production processes where re-work and product defects are minimised with resulting efficiency gains.

These three key validation stages add up to a stable and efficient production process.