How to Determine the Right Cavitation for My Mold

When beginning the process of making a mold for your manufacturing project, you may be wondering if high cavitation injection molding is a better option than a low- or single-cavity mold as if there’s a one-size-fits-all answer—but of course there isn’t. The right mold cavitation for your project depends on the particulars of what you’re manufacturing and the needs of your business: how much volume you need, what lead time you can accept, the tolerance you’re looking for.

Balancing all of these factors should help guide your decision about the mold cavitation that’s right for you. So even if there’s not a cut and dry way of figuring out if you should use high cavitation injection molding, we can help you think through all the influencing factors.

Here’s what you should keep in mind.

1. Higher Cavitation Entails Higher Upfront Costs

The higher your mold’s cavitation, the more the initial tool building process will cost you. You’ll have to pay for the design and the fabrication of your mold; unsurprisingly, the bigger the tool you need the more it will cost you to make. If you’re committed to a high-volume production, you don’t need to worry about recouping this initial expense, but for a smaller run, high cavitation injection molding is probably not worth the cost.

High cavitation molds aren’t just more expensive to make: because of their greater complexity, they also take longer to get up and running and initial test runs can be more complex for your injection molding partner. That means that if you’re looking for a short lead time, you may want to start with a lower-cavitation mold. This is particularly true if you’re making a product whose design you expect to tweak and refine, since high cavitation molds will leave you less adaptable to design changes. Later, once you’ve begun production and arrived at a design you don’t expect to change, you can then look into switching to a higher-cavitation mold if your volume needs demand the switch.

2. Don’t Forget to Factor Down-Time into Your Projections

Even the best-run manufacturing system isn’t going to be operating at 100% capacity 365 days a year. You don’t know exactly when, but you know there are going to be unexpected personnel shortages, vacations, sick days, bad weather, power outages, and other surprise disruptions to your molding partner’s operations.

And that’s without factoring in the production delays that come from your mold itself. Every so often—sometimes even every day—your mold must be disassembled and cleaned to maintain clear vents and high production quality. Further, injector pins and springs break, water lines and cooling systems need maintenance, and the system needs to be periodically lubricated. When parts are scarce, these repairs could take weeks.

Ultimately, that means you shouldn’t expect to get the hypothetical “full potential” of your mold each year, no matter the cavitation. A much more reasonable estimate is somewhere between 60% and 70%. If all of your production is resting on a single high cavitation mold, you are far more vulnerable to costly disruptions to your business.

3. High Cavitation Can Lead to Lower Tolerances

To determine the right mold cavitation for you, you need to know the tolerance you can accept. It’s a fairly straightforward tradeoff: the higher the cavitation, the lower of a tolerance can be held. In part, this is because the manufacture of products with unusual geometries demands exceptionally challenging milling, and this challenge only intensifies with higher cavitation molds.

But the tradeoff also reflects the limits of high cavitation injection molding itself: this production technique necessarily introduces variance across the cavities of the mold. It is simply impossible, for example, to make eight cavities without discrepancies among them. As a result, a single batch from a high cavitation mold can simultaneously contain units that are at the maximum of a critical dimension and other units at the minimum. This variance can tank your CPK values and, depending on your business’s needs, lead to a product that you can’t use.

To discover more about high cavitation injection molding and to talk through the right strategy for your goals, talk to one of SigmaPro’s engineers today.

No injection molding contract manufacturer in business boasts SigmaPro’s mix of technical expertise, collaborative partnership, delivery speed or quality. We pride ourselves on finding solutions to all your manufacturing challenges instead of offering excuses about what we can’t do. So let us help you bring complex plastic products to market faster than other injection molders can.

To discover more about high cavitation injection molding and to talk through the right strategy for your goals, talk to one of SigmaPro’s engineers today.

Sāfen
Medical

Manufacturing: medical tags to label IV lines in hospitals

Problem:

Current tagging system leads to high rate of clinician error Preliminary Sāfen Medical tags led to dangerous occlusion of lines

Solution:

SigmaPro collaborated with Sāfen Medical to design plastic tags that are:
• Easy to decipher
• Easy to attach to lines
• Do not lead to occlusion

Outcome

Sāfen Medical has a quality tag system that is performing well in initial tests and is ready for market months faster than they had initially anticipated would be possible.

SigmaPro participated in months of iterations on design, prioritizing the constant communication and back-and-forth collaborative development needed to address the various needs for the design, including those of Safen, their clients, the care-giver who would use the product, and the patient who would benefit from its final functionality. SigmaPro’s primary challenge–and innovation–was designing a channel that would allow the IV tubes, which vary widely in diameter, to pass through the tag without producing slippage or line occlusion.

Despite these complex requirements, SigmaPro was able to innovate design changes that did not threaten the cost or manufacturability of the parts, while also prioritizing the critical needs of Sāfen and their products.

Medical Equipment Supply

Client

Sāfen Medical is a manufacturer of medical tags designed to improve awareness of each patient’s IV medications. At the time of its engagement with SigmaPro, Sāfen Medical had preliminary designs for an innovative system of line labeling that needed to be prototyped and refined.

Background

The current system of IV labeling in the American hospital system is doing immense harm to patients. More than half of IV medication is administered incorrectly, and more than half of those errors result from poor labeling.

To discover more about high cavitation injection molding and to talk through the right strategy for your goals, talk to one of SigmaPro’s engineers today.

0 %

These errors can be fatal:

of clinicians have said that poor labeling has kept them from responding quickly enough to save a patient in crisis. These slow responses occur because all infusion therapy lines look alike, and no effective IV-line identification system has yet been established.

Sāfen Medical’s new tagging system will solve this problem at low cost and bring better care to patients nationwide.

Problem

Line labeling may seem like a simple problem, but ordinary hospital constraints and conditions have made a solution stubbornly difficult to find. The solution had to be low tech to account for “alarm fatigue:” so many alarms go off in hospitals that people ignore them. It needed to be easy to read at a glance but could not become illegible through frequent use and handling. It also needed to be easy to clean and to withstand the repeated application of hospital disinfectants.

Sāfen’s solution?

A series of plastic tags coded by color and shape to be attached to each IV line. The front of each tag has an image and word corresponding to the risk posed by the contents of the line: red for high risk, for example, and green for low risk.

Each tag also has a symbol and word on its front to communicate the line’s type of contents (“Opioid,” for example) and room on the back for specifics (“fentanyl”). This makes it easy for a clinician, facing an emergency, to tell immediately which line is which instead of trying to sort through a tangle of lines.

Sāfen brought this solution to three different injection molders to figure out how to manufacture these tags. Sāfen had several questions that needed to be worked out:

What material should be used?
How to design the tags so that they attached easily to the line but neither fell off nor occluded the line?
How much pressure should be required to open and close each tag?

SigmaPro’s Solution

Sāfen chose to collaborate with SigmaPro Molding. It wasn’t just that SigmaPro is an experienced, FDA-registered supplier with a proven record of successful manufacturing and excel under strict documentation and process validation conditions. It was that the SigmaPro team was responsive and collaborative from the very start.

Most importantly, SigmaPro brought a yes-we-can spirit to the work. When Sāfen showed suppliers an initial prototype that was not yet fully-functional, only SigmaPro saw how to make it work—and then proved that they could through a series of iterative, collaborative designs.

Many plastic injection molders would have gotten bogged down in the development stage, dragging the client through endless layers of red tape, reviews, and inefficient requirements that do not respect the pressure of the client’s timeline. That process can take months or years and cost the client thousands of dollars, leaving them nothing to show for their extra expense. SigmaPro’s turnaround time for each model, however, was no more than two weeks. That meant Sāfen could iterate and refine its solution in a steady process of improvement.

Sāfen found collaborating with SigmaPro to be so smooth and satisfying that Renae Franz, Chief Commercialization Officer at Sāfen, said the people at SigmaPro felt like part of her own team. “We just had to tell them what we wanted to accomplish and SigmaPro found a way to make it work,” she said. “It was so refreshing to work with a supplier who always wanted to say yes.”

Outcome

SigmaPro successfully manufactured Sāfen’s new tagging system—and did so far faster than initially expected. Ms. Franz estimated that, thanks to SigmaPro, Sāfen was able to bring the product to market six to twelve months sooner than they would have with any other supplier.

The tags SigmaPro is manufacturing are already performing well. In an initial study, clinicians were able to find the correct line twenty seconds faster than they could before—a potentially life-saving difference. In another preliminary study, clinicians were better able to identify and remedy errors in lines labeled with Sāfen tags than with existing tagging systems.

Now, thanks to SigmaPro’s speed and diligent problem-solving, Sāfen is taking the tags to market far sooner than expected. Fortunately, SigmaPro also has manufacturing capacity to dramatically scale up production at short notice as clinicians recognize the transformative power of this life-saving technology.