Matrix Tooling, Inc.

In addition to building injection molds for medical applications, Matrix specializes in injection molding with a wide range of medical grade polymers. Among these materials are bioabsorbable resins for surgical implants which we process in our ISO -8 / Class 100,000 cleanroom. Examples include PLA, PLG, PLC, PDO, PDLG, and PG. These dissolving resins have very unique (and sometimes challenging) requirements, and several years of experience have taught us how to process them successfully. These bioabsorbable materials represent the majority of our cleanroom production at Matrix.

Recently we were awarded a medical program that involved processing an implantable-grade PEEK polymer . Due to its high-strength, biocompatibility, and high temperature & chemical resistance, PEEK is being specified for an increasing variety of long-term implantable medical device applications. While Matrix has been building PEEK tooling and molding PEEK in production for many years, this was the first time we would be processing PEEK in our cleanroom.

Over the years, we have designed our PEEK tooling to utilize either hot oil circulation or electric cartridge heat. In our experience we have found that hot oil provides more consistent heating than electric heaters; and while some PEEK parts can be processed using either heat source, many critical parts definitely require hot oil. In the past, we always had the flexibility to pick and choose where to run these jobs: on our main floor or in the cleanroom. Now, however, we had an implant that, due to customer requirements, had to be processed in the cleanroom. At the same time, it required hot oil heating. We had a dilemma: “how do we use hot oil in our cleanroom?”

Those responsible for overseeing our cleanroom operations would not consider using oil in the room, so we began our search for temperature control alternatives. The solution was the purchase of a Single Temperature Controls high-pressure hot water thermolator capable of reaching 430° F. We're in the process of making a few design tweaks to strengthen the final part which is still being qualified, but the thermolator has been tested several times in samplings and we are prepared for the production phase of this project.

For anyone in manufacturing today, we have had the luxury of being handed a rich tradition in how to make things.  For over 125-years, the United States has honed its skills as a manufacturing destination for making products sold world wide.  Add in the knowledge gained by being thrown into two World Wars, where many businesses were asked to support the military effort.  These wars required a rapid response and high volume production from our existing manufacturing plants, it was truly a national effort to support our military.

Today, we are faced with global competition that has a younger work force, one willing to work at greatly lower wages, and they are using the same equipment and software that we use.  While this seems to be a competitive threat that would be tough to beat, we have one huge advantage over them.  Our legacy of making world class products here is something significant, and not to be squandered.  Much of China's manufacturing base in high end products is less than twenty years old.  Having the latest and greatest equipment gets you just so far.  The ability to win an endurance race such as the Indy 500 is more about the best and brightest technicians building an engine that not only performs well, but does it under the most grueling circumstances.  While a stock engine might make it thru the race, someone committed to winning will only accept the best.  And the fact remains that the best tooling comes from countries with long traditions of making things.  Not the most populous regions with large groups of young people using the latest technology.  

We have a duty to continue the legacy of manufacturing that was handed to us.  What was passed on to us must be passed on to the next generation.  We absolutely must invest in our youth, in our infrastructure and equipment.  If not, the one huge advantage we currently enjoy will be gone.  And once it's gone, playing catch up will be tougher than anything we've faced in the way of competition thus far.

As an ISO 13485 certified manufacturer, managing risk is always a priority. And the most basic concept of that management process is first understanding what those risks are.

Recently, the question was raised: "Can any trace mold corrosion be transferred to the final molded product?" This opened a spirited discussion because, while we've been building injection molds for over thirty years, nobody here had a definitive answer.

After consulting with others in the industry, as well as a metallurgist at our steel supplier, we came to the conclusion that while it's theoretically possible to transfer any contaminant from one surface to another, having a problem with bio-burden testing or introducing a contaminant into a product during plastic injection molding production is highly unlikely.

We are involved in a program that overmolds stainless steel with plastic. A stamped steel piece and a metal injected piece are both loaded into a tool steel mold, then overmolded with a high temperature nylon. The stamped piece is passivated; the MIM piece is as-molded and sintered. In speaking with our metallurgist, we learned that the main sources of corrosion on the mold cavities would be degraded resin coupled with high mold temperatures. Fortunately, as we are the molder on this program, we have control over both of these issues. Our processing and mold temperatures are both within manufacturers' specifications, so that helps control a major source of any corrosion. The metallurgist also explained that any corrosion sufficient enough to create a transfer problem would be visible to the naked eye.

The material we chose for this program was a high hardness, general purpose tool steel. We did this due to the fact that two metal inserts are being inserted into the mold cavity for overmolding . There are other grades with similar hardness and stainless properties available, but based on what we learned we do not feel it is necessary to change steel grades at this time. However, we have decided to add a visual check to our regular preventive maintenance plan for this job, a solution we now feel is sufficient to catch a problem before it occurs.

It's been said that training is the lifeblood of an organization.  Yet over the last few years, finding money for training and educational purposes has been a challenge.  As our economy struggles to its feet, it's high time we realize that the only way an American manufacturer is going to thrive (or even survive) is to throw every available resource towards ensuring that his employees are better coached than the competition's.  We can't wait for our government to level the playing field when it comes to free (and fair) trade.  The core of the free market concept is rooted in competition driving us to improve

quality and innovation, lower prices, and thus be able to sell more and grow.   Our competitors in low cost manufacturing locations are using the same equipment that we do.  In many cases, their workforce

is younger, more hungry, and certainly more plentiful.  How do you compete with that?  By making sure your employee is thoroughly trained, in both the latest technology, and old world craftsmanship that can be

passed down from the senior toolmakers and designers who built tooling prior to the age of computers.  Old world craftsmanship is often not available in these low cost manufacturing countries.

The opportunity to get involved at the ground floor is an opportunity not to be missed.  Apprenticeship programs are struggling, and if they are allowed to fail, we have failed.  Opportunities abound in local vocational and career training programs for mentoring, donating time and resources, and ensuring that there is an influx of future talent for hire.  Our company is active in numerous trade associations, including the Tooling and Manufacturing Association (TMA), the American Mold Builders Association (AMBA), Society of the Plastics Industry (SPI), Society of Plastics Engineers (SPE), Illinois Manufacturing Association (IMA), the American Society for Quality (ASQ) and the Manufacturers Association for Plastics Processors (MAPP), to name a few.

So as manufacturers, we are left to our own devices to stay in the game.  But without training, we are certain to have a more difficult time competing in the future than we currently do today.

At Matrix Tooling, we design and build injection molds for a wide variety of advanced materials and processes, including metal injection molding (MIM.)  While it is possible to build a very accurate injection mold, getting the actual molded part to meet the print specifications often requires more.

Resins with predictable shrinkage rates allow you to confidently machine details to a specific size without having to invest additional time "sneaking up" on them after processing.  However, when working with MIM tools, not only are the shrinkage rates significantly higher (often representing a large percentage of the part size) but they are also less predictable.  Subjecting the molded MIM pieces to the next required stage of heat treating further complicates things.  Re-compounding the feedstock to adjust the "green" part is a common method used to achieve the required shrinkage and physical properties.  But because each round of sampling entails the secondary processes of debinding and sintering, qualifying a MIM part can be time consuming.

While our industry's conscious efforts to reduce lead times have benefited the development of medical devices, certain parts are proving more difficult to qualify quickly.  MIM parts seem to be among them.  In order to address this challenge, Matrix has worked with our customers to develop "breadboard" parts: small quantities of machined finished parts, made to the database using conventional machining technologies, and made from the same raw material.  This approach has numerous benefits.  Since the initial test launch of a device may require as few as 3-6 units, machining breadboard parts is a more timely way to sample components that are destined to be produced using MIM.  Any problems that crop up during the testing of the breadboard prototypes can be remedied prior to cutting any steel in the MIM tool, saving both time and money.  Being able to prove out the concept more quickly and inexpensively with breadboard parts results in a faster release of MIM tooling for production and a smoother debugging and qualification process.

Written By:

Paul Ziegenhorn
President

Since we've added web conferencing several years ago, it becomes more and more evident how this tool significantly improves the design / build process as costs are scrutinized and deliveries compressed. One recent program stands out, a stapling device with numerous metal and plastic parts that were activated by a series of gears and pulleys. Our initial design review with the customer using our web conferencing program allowed us to review the entire assembly get an overview of the device with a diverse group of Matrix personnel. Representatives from our design, manufacturing and quality areas all reviewed the device from their own point of view. And with the convenience of a voip phone call, our marketing manager attended the meeting remotely. During the review, suggestions were made to the customer that allowed them to eliminate several parts by redesign of the current assembly. Parts were combined, reducing the part count in the assembly. Slightly more complicated tooling, but far less costly in the long run. The customer immediately embraced those suggestions, as their COGS target for the device was going to be difficult to achieve. The savings our suggestions allowed gave them an immediate benefit. And, during the review, a fundamental design flaw was flushed out when this group of a dozen technical people got into a spirited discussion on the mechanics of the device, which was corrected within days. And as our mold design work was firming up, we held a concurrent review of both tool and product design, which saved significant time. Mold design (ours) and device design (theirs) were being toggled back and forth, with mods to both being made as the meeting continued. A very fast and productive use of time, for sure.

- Paul Ziegenhorn