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.
Service and Sales in the Injection Molding Business
Knowledge of the product and process is important in any business, none more so than injection molding. The business is quite complex and a good sales or customer service person often must be able to guide a customer with little or no knowledge through the intricacies of managing the molding project.
The sales/customer service person should have knowledge not only of the quoting/costing process, but also of design, mold building and production of the molded part. He or she must either be able to answer all of the customer’s questions or know where to obtain the answers.
In addition to technical knowledge, the sales/service person must be patient and understanding, as often a customer, especially one who is under pressure can be very nervous, even “cranky.” Here the sales/service person acts as a counselor and a buffer for not only the customer, but also for the molding company.
The sales/customer service person is a person of many talents and is key for the success of not only the injection molding company but for the customer’s success as well.
Insulated Runner Molds: Old Technology, but Not Entirely Obsolete
Early in the history of injection molding, molders realized the problems inherent in producing high volume, fast cycling parts of commodity resins with cold runners, especially in high-cavitation molds. Cold runners can stick or hang in the mold and interrupt or extend the cycle; and often the cold runner being the last part of the shot to set up, can dictate the overall cycle.
It soon became obvious that “runnerless” molding was the way to go. Early hot runners were of the internally heated (torpedo) type or the externally heated manifold hot runner. Both were prone to leakage and hard to (especially the torpedo type) change colors with. Predating these systems were a type of runnerless mold called an Insulated Runner .
Insulated Runners had an oversized internal runner cut into both the top clamp plate and the “A” plate. This runner was very thick and relied on the thickness of this runner-cull to keep the plastic in a molten state as long as the molding machine was cycling. The walls of the runner were solid with only a molten center core providing melt delivery. These led to cylindrical drops (also very thick) and generally to top-center-gated parts.
This system needed fast, uninterrupted cycles to keep the gates open and even momentary interruption caused one or more gates to freeze off.
Startup was also tricky with these molds. Methods included hand injection of multiple shots into the mold before going to auto, making one big shot and going to auto, or boosting the back pressure way up and extrusion filling the runner cull.
Later the gate drops were heated with a probe which made startup easier and also made keeping the gates open easier, even allowing a brief disruption the the cycle. With very fast cycles (3 to 6 second range) the heated probe insulated runner can have a fairly small thickness and in some cases, be reground and re-used in the product.
Though sometimes a bit tricky to startup and keep running, these systems could offer advantages over not only cold runners, but hot runners as well. These include:
- Quick cycles
- Less regrind and scrap , though the thick cull wasn’t generally used back in molding
- The tool was less expensive to build and maintain
- Less chance for melt leakage.
- Color changes were very fast compared to hot runners, as the whole colored cull was pulled after the molding machine’s barrel was cleaned. Often color changes can be preformed in 5 minutes with less than 5 pounds of scrap
- Even if heated gate drops were employed, fewer and less sophisticated controllers were needed.
Yes, the insulated runner is an old technology, but if you have a multi-cavity, fast-cycling job using a commodity resin like PP or PE with frequent color changes, and want a more economical tool that is easier to maintain, then consider insulated runner tools.
Molding Robotics Have Evolved
Robots have come a long way…
I remember when I first started working with robotics on molding presses. Back then, they had to be adjusted by climbing all over the robot , and the programs were only capable of the basic “L” and “U” movements. In many cases the drop zone location on the up and down movement had to be set the same as the pick location on the up and down movement. The presses would have a mechanical stop to hold the mold in the open position and an alignment pin above the locating ring on the front half to verify that the mold was perfectly aligned each and every time it was set in the press. Even with this it was a challenge to keep everything aligned. It was also very important for the oil temp to be correct at startup. Old hydraulic presses would not open to the same distance or eject the parts correctly at the wrong oil temperature. You would need to re-adjust after running for a few hours or even days. It was an ongoing battle keeping everything lined up. The robots had pneumatic up and down movement with a servo drive existing only on the traversing and kick movements. For something designed to make a processor’s life easier they certainly brought their fair share of pain!
But like all newer technologies, issues were addressed one by one and improvements came out consistently. We now have servo movements on all three axises, with options for rotation and flip servos as well. We are able to tie the robotics directly into the process monitor on the press and automatically divert parts at startup and any time the process parameters move out of tolerance.
We continue to install alignment pins on the front half of the molds but the newer presses hold the open position / ejection forward position much better (especially newer electric presses). Now robots have evolved from the painful era of trial-and-error setup to a nearly scientific setup and operation.
I have worked with many different models and brands over the years and have been lucky to have worked with some of the best built and best supported robots on the market. Recently I attended a Flex Teach class for Yushin robots . The Flex Teach system allows the user to create motion programs for the robot using a personal computer. The same programs can also be modified using the touch panel controller. What I like best about the Flex system is that it utilizes the PC as a training tool for the robot when it is offline. This can save countless hours of down-time and allow operators that would not feel comfortable practicing on a live press to start learning the Flex Teach system. Just knowing that they won’t have to worry about damaging expensive molds or end of arm tools (or more importantly, themselves and others) opens the doors for every operator to catch up to speed.
Even robotic systems from just a few years ago were no comparison. They, too, were fully programmable and also had servos with CNC type controllers, but these models required hundreds of command lines and an extensive knowledge of the programming language to run. The program itself consisted of several parts: a run program, reference program, and home program for every job. Making adjustments to a program became a trial-and-error nightmare. More importantly, valuable press time was lost in the mix. Considering today’s shortened deliveries and 24/7 production jobs, fiddling with the programs is something most molders can live without. I wish I could have done some of the work offline with a program tool like the Flex Teach system. We now have the ability to take our time (with minimal pressure) and do most of the programming offline while the press is still running.
With the old system, programming mistakes would have to be caught during the standard process of verification referred to as “stepping through the program” and tweaked accordingly. The Flex system allows us to run the program or changes through a simulator and verify that it looks good on the computer screen before being transferred to the press via a SD memory card and loaded onto the robot. For good measure we continue to step through the program to verify a second time, but there is no doubt this saves time in the process.
All of these new features have made robots perform more consistently and adds to their versatility, performing tasks like sorting, de-gating, counting, boxing, and stacking. Robots can even place small inserts and verify their placement these days.
So molders, learn to love your robots. They work tirelessly, exactly, and without a complaint or absent day. They can be a molder’s best friend (though you can still keep the dog). Yes, robots surely have come a long way!
Molding Operations Mgr.
Lack of Apprentice Training
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.
Successful Mold Building: Technology or Art?
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.
Brent G. Borgerson
Senior Process Engineer (Older Molder)
Job Losses in Manufacturing
Much is published about currency manipulation, unfair trading practices, and low cost offshore labor as primary reasons for the large loss of high paying manufacturing jobs in the USA. One thing rarely mentioned is the concept that the introduction of computer controlled machines and automation have had a significant impact on USA companies need for manual labor. Requirements for labor today are far different than in days past as manufacturers now need higher skilled people, but less of them. Special interest groups often look for easy targets when determining the reasons for job losses, but the bottom line is that in many cases, companies need fewer people to do the same amount of work as before. And as labor costs continue to climb, it’s the first place a manufacturer will look to reduce his overhead expenses.
The True Cost of Cheap Molds
A thermoplastic injection mold is like most anything you buy in life; you get what you pay for. If you want a throwaway mold with a limited life expectancy that produces simple parts and allows for generous dimensional and flash tolerances (and may require post-molding defect corrections like flash trimming), then by all means purchase inexpensive tooling from a low-cost supplier. But if factors like part consistency, uptime, conforming to quality standards, on-time delivery, low maintenance costs, long mold life, and fewer headaches are important to you, you’ll likely want to consider buying a quality mold upfront.
An injection mold is not a small purchase to be taken lightly, even for a tiny plastic part produced by a large corporation. It should be viewed as an investment, with each running cycle giving back a portion of your ROI.
For many of the molded parts of bygone years, an inexpensive mold might have been sufficient. Times have changed though and products have become more demanding. Their geometries and resins have demanded a more complex, precise and robust mold. An inexpensive mold won’t be able to give you these parts, at least not for long. What good is a cheap mold that breaks down in the middle of a production run, fails to make in-tolerance parts, or runs slower than the calculated cycle when the customer needs a steady stream of good parts promptly and consistently?
There will always be a place for simple and cheap molds in certain applications, but if there is any complexity to the part or tool, it would be foolish to build and design based on price alone. Overseas low-cost providers are an option, but that opens up potential issues with communication. Not only due to language problems, but time zones, local customs, and general business practices can add on top of that. Logistic issues and rising transportation costs should also be considered.
Reputable mold builders stake their reputations on every mold they build. They want a robust mold, built correctly with the best materials, that doesn’t come back for repair or adjustment. They want the customer to be there if at all possible for design reviews and samplings. All the teleconferencing in the world can’t take the place of personal meetings at times. These personal meetings are with the mold maker’s technical staff and design specialists, not some sales rep or consultant for a cheap offshore mold builder.
Often, time to market is critical, and control of the project timeline is not always possible with an offshore supplier. When a cheap mold is late, produces out of tolerance parts, or breaks down, its low purchase price suddenly becomes very expensive. Many times a cheap mold that doesn’t perform like it should can end up being more costly to correct than a more expensive North American mold would have been in the first place. Losses in time and productivity are often just as costly and are even harder to recoup.
When the whole picture is looked at, you can see that in the purchase of an injection mold the old adage of “you get what you pay for” holds so true.
Senior Process Engineer (Older Molder)