In my experience there are three parts to process validation: the Installation Qualification (IQ), an Operation Qualification (OQ), and a Process Qualification (PQ). The purpose of the IQ is to ensure that all equipment that it used in a process is installed properly and functioning as it should. Next, a OQ is run to ensure that product made at the process limits can still produce product within the critical to quality specifications. For example, if a process relies on a particular temperature (40 +/- 5 degrees C), it will be run at 35degC and 45degC to ensure that the limits are acceptable. Next is the PQ. This runs multiple lots that stretch over different operators, shifts, and supplier raw material to ensure that conforming product can be consistently produced. It is also important to continue to monitor product to ensure that product continues to reach an establish standard of quality.

The FDA explicitly defines the term: "process validation means establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications. “ The steps of process validation include:

1) Process design

2)Process validation or process qualification and 

3)Continued process validation

The steps of process validation for a process include Installation Qualification (IQ), Operational Qualification (OQ), Process Qualification (PQ), and sometimes a Process Performance Qualification (PPQ). The first step of any process validation is to run an IQ. This is basically running the set-up, checking the utilities, completing software and functional verification, and sometimes running the process once or twice just to ensure the equipment used is set up correctly and uses the parameters described in the validation. Essentially it is making sure the equipment is installed correctly for the process that it is being used for. Once and IQ is complete, the OQ can be run. The Operational Qualification is used to test a processes extreme (worst case) parameters and make sure it can still make good pieces within spec and tolerance. Normally this will include minimum and maximum settings and the number of pieces run and statistical analysis will be based on risk. After a OQ is complete a Process Qualification will be run to test a processes ability to build pieces at nominal settings. These settings are usually the normal operating settings and the number of pieces and the statistics are again based on risk and are usually larger than Operational Qualifications. Finally, a PPQ can also be run if it is deemed necessary. Usually a PPQ is executed when a new production line is set up or when a line moves to a new facility. This is essentially a PQ, but is run for the entire production line and not one test. This allows engineers to see where samples fail the most, which operations carry the most risk, and where the most inspections in a line need to be set up. That is essentially the entire process validation process.

As said by mcf29, there are many different qualifications that the manufacturer goes through to validate their processes. They usually need to also go through different steps on how they validate their systems whether that is an MSA (variable or attribute) or are justifying their process through a similar process already validated with that company (ex. anodization or coatings that are the same level of hardness and thickness). Not all validations are as specific as a tolerance on a part or a certain nominal diameter, but they all need to have the multiple operators able to produce similar parts without deviating within a certain process tolerance within their group. 

Validation during design controls is meant to provide evidence that the device inputs address the customer needs. This is vaguely captured by the following four facets of validation: planning, review, methods, and documentation. Planning essentially details all the features of the device to be tested, how the company is going to test them, and what the specific acceptance and rejection criteria are going to be. Planning is a process meant to ensure that all the customer needs and intended uses of the device are going to be evaluated. Validation review is meant to expose any gaps in the device about the customer needs. A formal review process is be the culmination of many individual people viewing the device inputs and questioning the validity of their concerns about whether the device is addressing what it needs to address. Validation methods are the methods in which you evaluate that the tolerances of the device and check whether or not the device can operate under the minimum and maximum of each standard. Although not every device needs a clinical trial, all devices need a clinical evaluation at the very least in a simulated environment. The last area of validation is validation documentation, which is the culmination of all the results of every validation activity. This is critically important to understand the history of the device and also to make sure each and every customer need and intended use is addressed inherently by the design of the device.

Validation is very important no matter which field it is encountered in due to making sure that this piece of equipment, whether it be medical devices or something as simple as a blender, The process starts with installation qualification, which basically makes sure that the device is installed according to the manual and the manufacturer's specifications. Continuing with the example of a blender, it would be important to make sure the blender is attached to the electricity as well as that it has a cap and is ready to be used. Then is the operational qualification, where the piece of equipment is then tested for conditions the equipment wouldn't encounter often, because this would indicate to the user the minimum and maximum conditions of operation. In the case of the blender, it would be to max-load the blender so it can blend lots of material at once, testing the limit of the device. Then would be the performance qualification, where the equipment would be tested in terms of what it can handle, such as through multiple trials and getting information about its use. In the case of the blender, it would be blending material and realizing that it can blend this much for this amount of time. Other things that would be different from other industries would be regulatory, clinical trials, and risk management, among other areas specific to the medical device. These other sections would also apply to the medical device because any new medical device would be tested to be safe and effective.

I've come to understand that medical device process validation plays a crucial role in ensuring the consistent production of high-quality medical devices. The steps for this validation, which I've learned about, include several key components. Firstly, there's the planning phase, where I'd identify the processes to be validated and create a validation plan that outlines objectives, scope, acceptance criteria, procedures, necessary resources, and a timeline. Following this, I'd move on to the installation qualification (IQ) stage, where I'd ensure that manufacturing equipment and facilities are correctly installed and calibrated according to the manufacturer's specifications. Then, operational qualification (OQ) would come into play to verify that equipment operates consistently in line with established procedures.

The performance qualification (PQ) phase is pivotal, as it involves testing the manufacturing process with a sample batch of devices to ensure they meet predetermined specifications and intended use. Lastly, revalidation is a recurring step to maintain quality, especially when there are changes to the manufacturing process, equipment, or materials. This comprehensive process validation is vital to uphold the safety and effectiveness of medical devices and is an integral part of the quality management system for manufacturers, a fact I've come to appreciate as a student.