MatrixLogo horizontal white

MatrixLogo horizontal white

Injection Molding and Moldmaking
with Surgical Precision

Injection Molding and Moldmaking
with Surgical Precision

Call us: (630) 595-6144

Call us: (630) 595-6144

By Paul Ziegenhorn and Anne Ziegenhorn

June 18, 2018

Back in 2003, our first significant takeover program at Matrix Plastic Products was a re-shoring transfer for a major global medical device OEM. We had only limited dealings with this customer until that time, but they contacted us when they were struggling with a very sporadic and unpredictable supply of molded product from their off-shore partner. Not only were their shipments to the U.S. delayed on a regular basis, but they were also battling numerous quality issues and high scrap rates on this program. Suffice to say, the lure of low cost tooling and production had worn thin.

By quickly building and qualifying low-cavity tooling in-house, Matrix was able run enough production to keep a stream of parts flowing, which bought time for the transfer of six tools to the States. Once these molds arrived at our facility, they were disassembled and diagnosed by our tooling staff. We repaired damage, made mold modifications to enhance performance, and ran production using these refurbished off-shore tools for the next two years.


In the meantime, the customer’s demand was increasing and production was ramping up, so we submitted proposals for high-cavitation hot runner tools. By amortizing a portion of the tool cost into each part, we helped them to justify their investment by demonstrating the payback would take less than 15 months. Two other benefits of the faster hot runner tools were a dramatic drop in part prices, and the elimination of their previous quality problems. Bottom line: with Matrix covering the tool maintenance for the life of the program, the cost to the customer was both predictable and affordable.

Helping to identify and resolve the myriad of quality issues that often accompany troubled programs has earned Matrix many new customers and has led to double-digit growth in our production molding sales. A key advantage in managing transfer programs with takeover tools is our 40+ years of in-house moldmaking expertise. Upon receiving a transferred tool, our team of engineering, tooling, processing and quality experts thoroughly analyze the mold's capabilities to diagnose and verify the issues that plague it. Sometimes it's a poor mold design, inferior materials, or a substandard tool build that's to blame; other times it’s a processing issue.

Whatever the cause, our goal in a transfer program is two-fold: Make the necessary repairs or replacement of tooling components quickly and re-qualify the tools to get them back into production with minimal disruption to our customers' delivery schedules; and Craft a game plan to provide the lowest total cost of ownership over the remaining lifetime of the program. Of course, each case is unique, but our recommendations will always have the customer’s best interest in mind. Sometimes their money is better spent to repair the existing mold, other times a new mold with our guaranteed tool life and part quality may make more economic sense, all things considered.

We know customers only transfer existing programs when unexpected circumstances force them to.  At Matrix Plastic Products, we stand behind our reputation for quality, honesty, and a commitment to help make the transition as painless and stress-free as possible. We want our customers to feel that, in the long-term, bringing their program to Matrix was the best move they could have made.

Micro Pusher

Matrix Plastic Products has been micromolding plastic parts since the mid-1990's, long before it was as prevalent as it is today. This pusher (shown) for a micro linear cutter cartridge is .031" x .040" x .040" and weighs just .0008 grams. Most of our micro projects are for the medical industry, for minimally invasive surgical applications in particular, but we also provide micro components used in the electronics industry. Weighing just fractions of a gram, some of these parts are smaller than a pellet of resin, with tolerances of five ten thousandths of an inch (0.0127 mm) or less.

I believe one of the main reasons we are not intimidated by projects like these is that we have our tooling expertise under the same roof. The close-tolerance and high precision of our molded products is rooted in our long history as a designer and builder of close-tolerance and high precision molds. Our strength in specialty tooling has proven to be a key factor in our evolution into the successful micromolder we are today.

Matrix Plastic Products builds most of our micro molds with cold runners and low cavitations (8 or fewer) because that combination makes it easier to maintain tight specifications. While mini hot runners are available, many of the resins we use in micromolding do not lend themselves to hot runner molding.

While almost any thermoplastic resin can be used in micromolding, Matrix Plastic Products commonly uses high-flow, high-temp grades such as LCP, PEEK and PEI. These materials have predictable shrink, and the high mold temps involved help flow, especially in very thin-walled parts. They also exhibit superior end use properties such as strength, stress crack resistance, thermal stability and dimensional stability.

Yes, much of our success in micromolding can be attributed to our mold construction which must be tight and precise, well supported and robust. I asked Steve, one of our experienced moldmakers at Matrix (but who was new to micro moldmaking) what the key to his first successful micro mold was.  “Trusting our equipment,” he replied.  Matrix employs only state-of-the-art CNC moldmaking technology.

However, we also subscribe to scientific molding practices. With a part that you can barely see, it is next to impossible to fill to 95% before transferring; but many other aspects of systematic/scientific molding are rigorously applied here at Matrix. I will discuss “Scientific Micromolding” in a subsequent blog.

Matrix Plastic Products operates both hydraulic and electric presses in the smaller size ranges, and it is essential that the molding machine be sized according to the job at hand. But for micromolding, we prefer the electric machines with their inherent precision and repeatability.

On jobs where the actual finished part is barely much more than an add-on to the sprue and runner, not only is the tooling critical, but the quality assurance can also be very demanding. Here again, Matrix meets the challenge. Our OGP metrology systems are multi-sensor, so we can perform vision, touch probe, and laser inspections on the tiniest of parts. Additionally, our increased usage of CT scanning technology enables us to perform comprehensive First Article Inspections in a fraction of the time they used to take. And our Vision Engineering video microscopes are a common sight not only in our QA lab, but in the molding, cleanroom and tooling areas as well!

We don’t “sweat the small stuff.”  Matrix Plastic Products has the equipment, know-how and experience to successfully handle any micromolded project. We’re always happy to offer our insight into yours.

By:  Brent Borgerson (Senior Process Engineer)
Published: January 25, 2012

Back in the early days of moldmaking, the product was the result more of craftsmanship than technology. A crusty old moldmaker with thick glasses, clad in a denim apron would take the project from a block of steel all the way to a finely-fit, fully-functional injection mold. The mold was his masterpiece. He took his time hand-fitting the components, and each mold, even for similar products, was often unique. Some tools took the moldmaker the better part of a year to produce.

Times have changed though, and the necessity of quick time to market and short product lives have shrunk lead time, while demanding resins and complex part geometries have dictated that robust and precise molds be built in much less time than in the past.

These shortened lead times are where technology has really stepped in to help. The crusty moldmaker has been replaced by a technologically savvy leadman, and each stage of the mold building operation is done under the control of specialized operators who are completely versed in the technology of their stage of the operation.

All steps of the mold building operation (design, steel milling, electrode cutting, wire and sinker EDM operation, turning, and grinding) are Computer Numerically Controlled and connected via a local area network. Many of these operations are palletized and robot attended, enabling lights-out operation to further reduce time to delivery of the finished mold. Direct access to 3D design models is available to every operator at every phase of operation. Time-tested standards like prints and setup worksheets are becoming a thing of the past. Even the progress of jobs and tracking records are maintained electronically.

Matrix Tooling, Inc. is now thirty years old. Having seen the mold shops of even twenty years ago, it would have been hard to imagine that today’s machining centers with their brightly colored computer displays, robotic arms, and servo motors have any relationship with the mold shops of the “old days” where craftsmanship was king.

But there’s no doubt craftsmanship still has its place. We’ve spent the last thirty years blending the best aspects of traditional mold making with state-of-the-art technology to produce a precise, top quality and robust injection mold as quickly and economically as possible. The first paragraph of the Matrix Tooling quality policy reflects this: “Matrix Tooling, Inc.’s mission is to combine traditional craftsmanship with state-of-the-art technology in designing and producing the highest quality injection tooling and molded products.”

Our team members have found the key to successful mold building and we take great pride in combining the latest technology with old-time craftsmanship into every build. Though the mold building business has evolved each team member takes the same pride in our end product as the crusty old mold maker with the denim apron.

Written by:

Brent G. Borgerson
Senior Process Engineer (Older Molder)

By Brent Borgerson

December 17, 2009

Of great interest to buyers, accountants, quality managers, toolmakers as well to, of course, molders, is the projected service life of an injection mold for thermoplastics.  Many people in the injection mold industry use the SPI Mold Classifications as guides for estimating the expected life of a mold. The common classifications are:

  • Class 101

For a life in excess of a million cycles, with a hardened mold base (minimum of 28 R/C), hard molding surfaces (minimum of 48 R/C) with other details of hardened steel. Guided ejection is mandated as are other features such as wear plates for slides. Parting line locks are mandated, and corrosion resistance is suggested for cooling channels. This is the highest quality of the SPI classifications, usually accompanied by the highest price.

  • Class 102

This is specified for a lifetime not to exceed 1 million cycles. This features the mold base hardness of class 101, molding surfaces (cavities and cores) also feature the hardness specified in 101, and functional details are heat treated. Parting line locks are recommended. Guided ejection, wear plates, and corrosion resistance of water passages are not mandatory, but dependent on expected total production quantities. If expected cycles approach the maximum, then these features should be specified.

  • Class 103

Aimed at molds intended for under 500,000 cycles. These are molds for low to medium production needs, and corresponding price ranges. Mold bases are at least 8 R/C and cavities and cores in excess of 28 R/C. Any extras must be agreed upon.

  • Class 104

For less than 100,000 cycles and limited production. These are lower priced molds. The base can be aluminum or mild steel. Cavities and cores can be of the same or a metal agreed upon.

  • Class 105

These are for cycles less than 500 (prototyping only) and are very inexpensive. They can be of cast metal or epoxy.

These SPI, or Society of the Plastics Industry (, classifications should and do take much of the guesswork out of estimating the useful life of an injection mold, but not every class 101 mold is the same, and this is true in all the mold classifications. Classifications indicate, but don’t guarantee quality.

No matter the class of mold, how the molder treats the mold can determine the life of the tool. I have seen and heard of aluminum molds that have lasted for years, indeed decades, and conversely witnessed class 101 tools rapidly turned into junk.  Much of what the molder does, or how he treats the tool will determine the life of the mold.

Never over-clamp (use more than required clamp force) the mold not only will you wear, stress, or deform the steel prematurely, you will peen closed the vents, leading to a viscous circle of more injection pressure being dictated and then even more clamp force.

Don’t neglect preventive maintenance on the tool, devise a schedule or consult generic schedules, or better yet consult a reputable mold builder. Taking the mold down for a day or two for PM can add years of life to a mold. If you don’t have in-house tooling capabilities for this you can contact a mold builder such as Matrix Tooling Inc. A great part of mold PM is disassembly and cleaning and replacing components such as springs, o-rings, and pins. Many molding shops designate a person for these relatively simple but extremely important tasks.

Don’t skimp on mold protection, sometimes called low clamp pressure. You want to be set “fat” enough to stop the mold from clamping well before a possible stuck part is crushed by the mold faces. Your press maker can train you in this if there are any doubts. Many mold protection settings can be defeated by closing the mold too fast. Never slam a mold closed. Where there are slides or other actions and angle pins, you should slow the movement before they engage. The possibility of saving a half second on the cycle here could cost days of lost production while repairing the damage that a defeated mold protection could produce.

Daily cleaning of mold faces and lubing components such as pins and slides will extend the life of any class mold. Use the right lube for the job: FDA and medical grease where required and high temp grease for hot running tools such as those running PEEK, PEI, PPS and PSU, where mold temps can exceed 400°F. Remember it is the film of grease a few thousands of an inch thick that does the job, so don’t goop the grease on. It is counterproductive and can attract dirt.

Again the SPI classifications can give the molder a good idea of the potential lifetime of an injection mold, but not all molds in any one classification are made equally. One should always have their molds designed and built by a reputable mold builder. A mold builder such as Matrix Tooling Inc. will stand behind and care for every mold the build over its extended lifetime.

I’ve been involved in high school career education programs for much of the last 15 years. A good portion of that time was spent talking to educators and parents about careers in precision manufacturing being a viable alternative to the typical 4-year college program being pushed on our kids. Colleges have done a very good job of convincing us (and especially the parents) that the only way to a successful and rewarding career is to get a degree. I, for one, don’t agree. An apprenticeship can offer a young person another option; and the fact is that college is not necessarily the best choice for many high school students. Most teachers will agree with this logic. They know first hand which of their students are good candidates for advanced degrees and which are more likely to struggle. Most apprentice programs are struggling to attract talented young people, who by that time have had 12+ years of people telling them that they will need to get a degree in order to get a good job.

I know that the U.S. is not the only country with this problem. Much of Western Europe suffers from the same shortages. Many look down on those who work with their hands, but eventually, someone will need to learn and become the next batch of journeyman plumbers, electricians, toolmakers, etc. If not, homeowners better get ready to learn these skills or be ready to open up the checkbook.

I read an interesting article back in the mid 1990’s. In Germany (where an apprenticeship in a trade is still considered a viable career choice), the graduating number of architects outnumbered the number of apprentices from all skilled building trades combined. Think of how many architects it takes to build a home versus the number of workers needed from the various trades, and you’ll realize that something is seriously out of whack. Apparently the Germans, too, have spread the word that working behind a desk versus working with your hands is the way to go.

Hitting closer to home, we’ve struggled with finding quality candidates. Toolmakers today require skills far different than what was needed prior to the computer age, and the fact that few are training today makes for an unsustainable labor situation.

Written by:

Paul Ziegenhorn


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