Why it's Important to Know Your Tool Maker

Posted by Ken Glassen on Apr 10, 2014 8:32:00 AM

Apr 10, 2014 8:32:00 AM

Success in the injection molding business isn’t just about having the right equipment or the latest technologies. This is a good start, of course—but to completely meet the ever-evolving needs of clients who make complex products under challenging time and cost constraints, injection molders must have top tool makers in their supply chains that embrace the same vision of manufacturing excellence and customer service.

Injection molders and their tool makers must be rock-solid partners that are committed to the same beliefs about how to conduct business. Core to this philosophy is that tool makers must treat the injection molder’s clients as their own.

Over time (and hundreds of projects), a deep trust and understanding develops that establishes a partnership based on consistent performance, shared problem-solving, and trust. It is much like a quarterback and wide receiver—they have worked so closely together, with the same belief system, that they think and respond in the same way to deliver the winning play. The other important result of having a shared vision is that the injection molder and the tool maker help each other improve at what they do—sharing or developing best practices, or expanding capabilities and opportunities, to create a long, profitable relationship—and yes, even friendship.

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Topics: Tooling / Molds

Get the Injection Molding Process Right First

Posted by Al Timm on Apr 8, 2014 11:50:00 AM

Apr 8, 2014 11:50:00 AM

Injection molding is a dynamic, complex process that, simply by the nature of its many variables, requires some testing and some adjustments to get it just right, prior to production. Some manufacturers, however, choose to focus on the specifications of the mold first and then build the process around the finalized mold, thinking this saves time and money. This approach, however, typically results in production problems that slow the whole process down and reduce quality and repeatability. The best approach is developing a consistent, efficient process first, followed by fine-tuning the mold to the process.

The main steps of the process are proper melting of the plastic resin, injection at the correct rate, packing at the proper pressures, cooling with the correct temperature mold surface, and ejecting the part after the proper amount of cooling.

It’s important to get a process worked out that has the largest possible processing window—this gives the engineering team more flexibility and range in designing the mold. If the team strictly processes for dimensions only, the process may be insufficient to create the molding conditions that will yield the most consistent part.

Building the mold with critical dimensions up front is risky because there are subtleties in the process that cannot be fully predicted without testing. For example, injection speed may need to be adjusted to counteract splay created by shear stress, which can be caused by the shape of the part. Injection speed can also influence dimensional results.

The final part will have differences in shrink due to direction of material flow. Final shrink is influenced by many molding parameters. Molding within a range of acceptable parameters, cross-checked with final dimensions, allows the final processing “window” to be established. In general, the larger the processing window is, the lower the risk for problematic start-ups and inconsistent product quality.

The bottom line is that the processing window must be large enough to create a high-quality part that meets performance specifications and looks good.

This is where scientific molding comes into play. Following the principles of scientific molding is typically the best way to factor in the many variables that come into play and determine the best process. For example, with scientific molding, the proper viscosity of the material can be determined by pressure curves. When lot-to-lot material variations occur, the molding process can be adjusted to produce the same pressure curves that were generated during the initial process development—ensuring repeatability and saving time.  Take a look at our Scientific Molding Whitepaper to understand more about this.

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Topics: Injection Molding

Value Stream Mapping Brings Quick Rewards

Posted by Matt Fehrmann on Apr 3, 2014 10:04:55 AM

Apr 3, 2014 10:04:55 AM

In the manufacturing world, “lean” principles reduce inventory and work in process, improve quality, boost productivity, and ultimately lower costs. Lean originated in Japan decades ago and has been readily embraced in manufacturing sectors around the world, especially the automotive industry.

With increasing global competitiveness, lean principles have never been more important for making U.S. companies competitive. One of the most simple, yet effective, lean tools is value stream mapping. It can be implemented within days and can reap impressive results in a short period of time.

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Topics: General Manufacturing

Plastics Made from Carbon Dioxide could Slow down Global Warming

Posted by Matt Fehrmann on Mar 25, 2014 2:03:48 PM

Mar 25, 2014 2:03:48 PM

We all know that carbon dioxide (CO2)—a greenhouse gas emitted into the atmosphere through the burning fossil fuels—is a major culprit in global warming. This gas is also hugely abundant in oil shale deposits, where it is typically burned away by flaring, or sometimes captured and injected via deep wells into porous rock formations.

Companies have tried for years to incorporate CO2 into plastic, but could not make the process cost-effective. Now, however, several plastics manufacturers have found success in using CO2 in plastics—the trick was finding the right catalyst.

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Topics: Plastics / Resins

Injection-Molded Plastic Allows More Creativity than Ever Before

Posted by Al Timm on Feb 25, 2014 11:57:00 AM

Feb 25, 2014 11:57:00 AM

Design teams are always trying to come up with something better—better shapes and designs, better performance, better materials, and lower costs.  They are constantly seeking something that will give them an edge over the competition.

Cost, of course, is a huge factor. After all, there is only so much you can do to reduce costs when you use the same set of materials, designs, and processes. A one-percent gain here, a one-percent reduction there. Lean is good, but it can only go so far.

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Specialty Steels Speed up Cooling Times

Posted by Al Elger on Feb 25, 2014 11:00:00 AM

Feb 25, 2014 11:00:00 AM

One of the most important parts of the injection-molding process is cooling—it also takes the longest! In fact, more than 80 percent of the cycle time is related to cooling. You also can’t cut corners with cooling—the cooling rate must be carefully controlled to achieve tight tolerances and no defects.

However, the faster the heat transfer occurs between the part and the mold, the faster the part cools and the sooner it can be ejected from the mold. One way to enable cooling is to make the mold from specialty materials that have higher thermal conductivities compared to standard mold steel. The steel you choose depends on the properties of the selected material (engineered polymers with additives can be more challenging), production and performance expectations, and budget.

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Tonnage Calculation Is an Important Consideration for Cost Control

Posted by Al Timm on Feb 12, 2014 2:00:00 PM

Feb 12, 2014 2:00:00 PM

Injection molding is a complex, dynamic system with multiple, interacting factors—all of which impact performance, cost, and quality.

One of these factors is the tonnage calculation (also known as the clamping force). The “tonnage”  is the measure of force that is required to keep the mold closed during the injection process. This force is the main factor in determining the machine size required for producing the part.

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Hand Loads May Be the Most Cost-Effective Approach for Complex Parts

Posted by Al Elger on Feb 12, 2014 1:00:00 PM

Feb 12, 2014 1:00:00 PM

It seems old-fashioned to load anything by hand these days, especially in a high-tech operation like injection molding, which has so many high-precision process controls. However, “hand loads”—mold inserts that are physically inserted into the mold and then removed when the part is finished—are essential for the production of certain parts.

Hand loads are used to create complex geometries like undercuts and threads that can’t be formed in the line of draw. Hand loads are typically preferred for two situations:

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Outsourcing - Do You Know Your Total Cost of Ownership?

Posted by Matt Fehrmann on Jan 31, 2014 2:30:00 PM

Jan 31, 2014 2:30:00 PM

Outsourcing manufacturing work to lower-cost countries can be a tough decision for U.S. companies to make—as much as they want to keep jobs in America, they feel the higher labor costs are too much of a disadvantage to compete effectively in the global marketplace. Also, with the speed of business being what it is today, and everybody still doing more with less (the work ethic left over from the Great Recession), the decision to go off shore could be made without the proper due diligence—a possible mistake.

“Most companies make sourcing decisions based on price alone, resulting in a 20 to 30 percent miscalculation of actual offshoring costs,” says Harry Moser, president and founder of the Reshoring Initiative (www.reshorenow.org), an industry-led effort to bring manufacturing jobs back to the United States.

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Some Plastics Are Better than Others for Rugged Design

Posted by Al Timm on Jan 10, 2014 11:00:00 AM

Jan 10, 2014 11:00:00 AM

Manufacturers of rugged electronic devices (and their end users—for example, the military) count on their “rugged” devices to perform in challenging real-life conditions, and survive being dropped. Therefore impact resistance is a critical feature in product design and starts with material selection.

Common materials used for rugged housings include polycarbonate (PC), acrylonitrile butadiene tyrene (ABS), polyethylene terephthalate (PET), and nylon.  Material combinations like PC/PET and PC/ABS are often used to further increase impact resistance.  

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