Meeting Regulatory Standards in Injection Molding: A Step-by-Step Approach

You have done it. You have spent days and nights in the lab, drawing on white boards, and running on coffee, but finally the design of your new medical device is emerging. It’s brilliant. It’s innovative. It can actually transform patient outcomes. Between your CAD model and the real world there is only this one, small, but nagging thing: the regulatory gauntlet.

Come on, as an R&D engineer, regulatory compliance and quality standards are more like guardrails to trip over and a maze created by a committee out to get you. You went into this business to construct something, to create something, to solve problems – not to spend your life in a mountain of paper. However, here is the point: the regulations are not the problem in medical injection molding, but the road map towards safety and success. Making your product available to the market is not a matter of loopholes. It is about creating a process which is so strong, so well documented, that compliance is the natural consequence of good engineering.

And how do you do that without going crazy? How do you get to down that mountain of standards into a manageable step-by-step path? It does not sound as intimidating as it may seem. All you require is a chart. This is your roadmap to the tricky, yet all-important world of medical injection molding, to make sure that your stroke of genius gets out of the screen, and into the hands of people who need it.

First Things First: Your Destiny is Your Design

One is tempted to consider manufacturing and regulations as downstream issues. I design the part, then I will find out how to manufacture it and how to get it approved. This is perhaps the one biggest and most expensive mistake you can make. The regulatory compliance starts when you open your design software. Each design decision you make, whether it is a material you use, or the radius of a corner, affects quality, safety and manufacturability.

That is where Design for Manufacturability (DFM) will be your best friend. In our world it is truly DFM with a high regulatory inflection. You are not saying, how can this be shaped? You are saying, can this be molded in a consistent manner, with a validated process, with the biocompatible materials, and documented to the n th degree?

Consider the issue of materials. It is not only a matter of getting a polymer of the correct tensile strength or chemical resistance. In the case of a medical device, you are promptly introduced to the land of ISO 10993 and USP Class VI biocompatibility testing. Is your material proven to be used as intended? Does the FDA have a Drug Master File (DMF)? Selecting a low-profile, untested material based on a single, desirable attribute may appear to be a clever move in the laboratory, but it may turn into pure hell in terms of testing and justification later. Frequently it is easier to begin with a familiar medical-grade polymer and design to its characteristics.

Then there is part geometry itself. Even thickness of walls is not only a molding rule, but it is a standard of quality. It avoids sinks and voids that may act as points of structural failures or worse still harbor bacteria. Draft angles do not only make it easy to eject a part out of the mold, but they also avoid scrapes and drags that may jeopardize surface finish and integrity. This information, all the decisions and their rationale must be in your Design History File (DHF). The fact that DHF is not a binder that gathers dust but the history of your device. It is your evidence to auditors and to yourself that you made quality a part of the foundation.

Finding the Right Partner: It Is not a Transaction Only

When your design is good enough, you have to locate a party to build the thing. Selecting a contract manufacturer in medical injection molding is somewhat similar to selecting a surgeon. Would you go with the lowest price you could find on the internet? You would want someone who has a good track record, who is experienced and whose facility is one that you would be confident of.

The first filter you should use is certifications. Does the molder have ISO 13485? This is non-negotiable. It is the international standard of a quality management system (QMS) of medical devices. An ISO 13485 certified molder understands you. They know the risks, the records, and the extreme significance of process control. When you mention validation protocols and traceability, they will not laugh at you.

Then, visit their facility. Are they cleanroom capable? Molding and assembly may be required in a certified ISO 7 or ISO 8 cleanroom depending on the type of device, and how it is being used. This avoids any contamination by particulates and microorganisms which is obviously essential to anything that will come in contact with a patient. Request a tour. A good partner will be happy to demonstrate you their operations, their quality lab and their controlled environments. When they are reluctant, it is a red flag.

But there is more to the certificates and the square footage you have to measure their culture. Are they joint partners or are they a job shop? An excellent medical molder will become a part of your R&D department. They will look at your DFM, make recommendations and point out possible problems before a scrap of steel is cut to make a mold. They will have their own engineers who are able to communicate to you in your language. You desire a partner that is equally interested in the success and safety of the product as you are.

The Validation Mountain: Your IQ, OQ, PQ Guide

Okay, you got your design and you got your partner. This is followed by the stage that makes many an engineer twitch his eye, process validation. It is usually introduced as a three-headed, inflexible monster named IQ/OQ/PQ. I realize, it is more alphabet soup by the quality people, but let us analyze it. Consider it as the scientific method of production.

Installation Qualification (IQ): This is the simple one. It is more or less the question, did we get the right stuff and is it installed properly? You are verifying that the molding press, the mold and any auxiliary equipment (dryers or robots) are in accordance with the purchase order specifications and are installed as per the manufacturer recommendations. You write down the serial numbers, the connections of the utilities, the versions of the software, everything. It is its basis. You can not establish a strong process with flimsy equipment.

Operational Qualification (OQ): Time to have fun. This is where you give the process its paces. The OQ determines the window of processing. It is not just attempting to make a good part, but it is an attempt to make good parts at the extreme limits of your processing parameters. What is the maximum and minimum melt temperature with which it is still possible to operate? The quickest and slowest rate of injection? The hold pressure maximum and minimum? You will perform some designed experiments (DOE) to specify this window. Why? Since you must demonstrate that your process is strong. A process that can be finicky only when every variable is set to the T is a fragile process, and is destined to fail in the real world of production. The OQ shows that your process is capable of the small, unavoidable variations of daily production.

Performance Qualification (PQ): This is the test of time. The OQ demonstrated the capabilities of the process. The PQ demonstrates what it will consistently do, in the long run. In this case you adjust the machine to a nominal value in the window you created in the OQ and you allow it to run. And run. And run. You will normally perform three distinct production scale runs to indicate repeatability. You will run some parts at the beginning, middle and end of every run and measure them. You want to find statistical evidence that the production is consistent and that it fulfils all requirements. The PQ is your very last evidence that will speak, Yes, we can produce this part to specification, safely and reliably, every time. It is your passport to full production.

The Material World: Traceability is All

Let us go back to the materials just a second, as they cannot be overestimated in their significance. You may have an ideal design and a proven process, but when your material is wrong, you have nothing. In the medical world, right does not simply refer to the right properties, it refers to the same thing, of the same source, each time.

It is the notion of material traceability. You have to be able to trace the individual lot of raw polymer resin in which your parts were manufactured back to the original manufacturer. All your shipments of raw material should be accompanied by a Certificate of Conformance (CoC) or a Certificate of Analysis (CoA). The material has its birth certificate in this document, which certifies its identity and properties.

It is also the reason why it is very important to have a locked process. When you know that your process is good with a certain grade of a certain supplier of polymer, such as Makrolon Rx1805 of Covestro, then you are done. You can not simply replace it with some similar polycarbonate as it is a couple of cents cheaper. The other supplier may employ a slightly different catalyst. Another grade can contain a different mold-release agent. The biocompatibility can be affected even by a change of colorant. Even a slight change will entail re-consideration and, in most instances, re-validation. This sounds very strict, but this strictness is what will save you and the patient. It makes sure that the product you release is the same product you are selling five years after.

The Job Is Not Done: The Vigilance After Launch

You are there! Your machine is cleared, your procedure is verified and initial production orders are being sent out. So it is time to relax, isn t it? Not exactly, though. Compliance with regulations is not something that happens once but rather an ongoing condition.

The Quality Management System of your molder is the one that is in the driver seat. They will be carrying out quality control checks on each production run. This may involve dimensional inspection using calipers or CMM, operational testing and inspection of defects. All this information is captured and is associated with a particular lot number, and that chain of traceability we discussed. In the event that there is a problem somewhere in the field, you will be able to put on hold any suspect inventory and trace the problem to a particular batch of material or a particular production run.

This is also the place where post-market surveillance appears. You require a feedback gathering system in the field- the doctors, the nurses and the patients. When you receive feedback on a persistent problem, such information is priceless. It goes back to your risk management files and may generate a corrective and preventive action (CAPA). Perhaps it might be a small improvement to the procedure, but perhaps it is a more drastic design modification of the next generation of the device. Such a feedback loop is what facilitates continual improvement and, eventually, leads to safer and more effective medical products.

Finally, it is not a matter of marking the boxes when it comes to operating regulatory standards of medical injection molding. It is an attitude. It is about understanding that each and every step, starting with the initial sketch and leading to the final packaging, is the chance to incorporate quality and patient safety. It takes hard work, teamwork, and proper respect to the process. However, at the moment you can observe your device in the world, functioning as it should, and making the life of a person a little bit better, you will realize that all of this is worth it.