Finding a Heat Sealer That Fits Your Budget

Suppliers are making top-of-the-line equipment more cost-effective, so cost-conscious device manufacturers can find a heat sealer that meets quality assurance requirements.

By Eric Swain, Senior Editor

Cost and quality assurance are often the two major factors that influence packaging engineers who are in the market for machinery, and these factors usually pull engineers in different directions. This is exactly the case with heat-sealing equipment for medical packaging.

Packworld USA's benchtop heat-seal press offers precision control.

Engineers who primarily focus on quality are taking advantage of new technology that not only provides a better seal, but also allows users to electronically capture data that show time, temperature, pressure, and other variables in the sealing process. These features give device manufacturers peace of mind and show regulators that the sealing process is consistent, repeatable, and under control.

However, smaller companies that manufacture devices may not feel they need all the data-collection features, especially since FDA has not yet formally declared how it expects device makers to validate their heat-sealing process. Keeping equipment costs down may therefore be the primary need of these smaller companies.

As a result, heat-sealing equipment manufacturers have developed a broad range of offerings, ensuring that both the big companies that demand the state of the art and the small companies that just want the basics can find what they need. And regardless of price, suppliers are improving the machines to make them easier to control.

"In a nutshell, the pieces of equipment are becoming simpler, faster, and more accurate," says Thomas A. Misik, vice president of sales and marketing for Belco Packaging Systems Inc. (Monrovia, CA).

Furthermore, many suppliers are working on ways to make top-of-the-line equipment more cost-effective, so that cost and quality assurance requirements will no longer be mutually exclusive.


The drive toward more-sophisticated data-collection features that are often found on top-of-the-line models is being fueled by the anticipation of regulations. In particular, some device makers started asking for such features upon the 1997 publication of ISO 11607: "Packaging for Terminally Sterilized Medical Devices."

"ISO 11607 mandates that all processes be documented, including sealing," explains Kent Hayward, marketing manager of Alloyd Company, Inc. (DeKalb, IL). "It encouraged people to look toward the machines to document the sealing process. The bigger medical device companies are moving forward on that pretty quickly."

Packworld USA's benchtop impulse sealer can be supplied with a data logger.

While FDA has yet to say exactly how it expects the sealing process to be validated, it has recognized ISO 11607 as a consensus standard, meaning the agency looks favorably upon any process followed according to the document.

That, plus the need to precisely control the sealing process, has encouraged QA personnel at the major device companies to get involved in machinery selection, Hayward says.

"The QA people may not be the purchasers, but they may be strongly influencing the packaging department to buy more-sophisticated sealing equipment," he says. "They are responsible for preventing faults, and if the sealing parameters can be controlled in a finite range, the likelihood of a packaging fault is a lot less. There has also been a lot more interest in measuring the sealing temperature right at the tray flange, and we can offer ways to position the thermocouples to do that."

Also sensing the need for data acquisition, O/K International Corp. (Marlborough, MA) recently introduced a new machine to facilitate it. The system runs on a programmable logic controller, but enables a user to connect it to a personal computer (PC) for data gathering. Since the user supplies the PC, the new feature is cost-effective, says Ann Marie Kellett, marketing manager.

"With PCs becoming more user-friendly, their components are more compatible with the heat-seal output, and that allowed us to upgrade the machine without a huge effect on cost," Kellett says.


Not everyone seems to need the latest technology, however. There are a vast number of small start-up device manufacturers that can't afford to spend much on packaging. They are simply looking for a heat sealer that works and for someone who can give advice in case it doesn't.

"For these companies, packaging is in the tertiary stage of product development," says Charlie Webb, medical device packaging team leader at Van der Stahl Scientific/Fuji Impulse America (Wrightwood, CA). "By the time they get to us, a lot of their revenue has already been spent on marketing and new product development. So they want to be in compliance but not blow their budget."

Validatable rotary heat sealers from Emplex Systems display sealing pressure on front control panels.

In fact, Webb says that Van der Stahl dropped its data-collection feature because of such cost factors. "The market told us that engineers wanted data collection, but at the end of the day, they didn't want to pay for it and saw it as superfluous. So we dropped it except for the alarm."

So, he says, the company decided that the better approach was to increase its after-market support to show customers how to make the machines FDA-compliant. "We help them with validation methodology by using statistical tools," he explains. "It's a proven methodology that everyone can use, and it takes the mystery out of validation."

For those who don't want to spend the money on new equipment, there are ways to outfit older machines with data-collection features.

Donald Barcan, principal of consulting firm Donbar Industries Inc. (DBI; Long Valley, NJ), helped develop a data acquisition system that includes both the hardware and the software. The package is composed of independent sensors, the acquisition hardware and software, and the PC. The software provides a feature for setting the individual parameter tolerances. An alarm will sound, and a visual display will appear on the computer screen when the process varies from the preset windows.

"These sensors are individually calibrated and provide the most unbiased, up-to-date information about the process, including sealing and forming temperatures, dwell, sealing and forming pressures, voltages, and coolant temperature," Barcan says. "And as an add-on feature, the system is affordable and ideal for quality system regulation compliance. It can be adapted for form-fill-seal or other sealing processes."


Regardless of how much a company is willing to spend on heat-sealing-equipment, it still must demonstrate control over the sealing process to ensure complete seals. Such control means monitoring the temperature: both the heating temperature and the temperature of the seal at the time of release. Heat sealer suppliers offering models at all prices are helping packagers gain and maintain such control.

Control isn't always easy, however. "Temperature is most difficult to manage because as heat energy is applied to the sealing process, it is concurrently being drained away by the material to be sealed, by the metal jaws of the machine, and by cooling water if it is being used," explains Charles Trillich, president of Packworld USA (Nazareth, PA). "Only a high-response precision temperature controller can measure and respond consistently when the duration of the complete sealing cycle is less than one or two seconds."

The OK Medical Supersealer from O/K International can connect to a PC.

Further complicating matters, he says, is that "the creation of new and superior plastic films has increased the demand for precision control because the temperature window has, in many cases, become smaller."

Therefore, he says, high-response temperature controllers are essential, and Packworld's machines use digital ones that are consistent, repeatable, and accurate to 2°C.

One way to ensure that the process runs correctly is through bar code scanning. "That allows the operator to do a number of things," Hayward says. "The three main options for bar code scanning are operator security, recipe management, and recordkeeping."

Misik of Belco says several advances to eliminate operator error have been made, including password protection that allows only supervisors to make changes in settings, memory systems that set up the correct parameters when a package identification number is typed in, and graphical interfaces that use color to indicate when things are and aren't correct.

A safeguard that Doyen Medipharm Inc. (Lakeland, FL) set up in its new electronic four-side-seal machine is modular computer control. Each of the main four modules (infeed, side seal, cross seal, and cutoff) is controlled by independent software modules within the machine controller to ensure that any potential changes in one module do not invalidate others, the company says. The system also allows 50 different package and printing configurations to be stored, enabling one-touch product recall and quick changeover.

Another recent development, Trillich says, is a new means of evacuating air from flexible packages before sealing. The traditional method is to insert a nozzle, draw a vacuum, then withdraw the nozzle quickly before sealing. "But this method is inconsistent and somewhat unreliable because the walls of the flexible package are drawn down upon the nozzle, thereby blinding the nozzle and interfering with the ability of the system to withdraw the air," he says. A new Packworld machine, he says, concurrently evacuates and seals the package to prevent that problem.


While the past year or two may not have brought along the major leaps in development that the 1990s saw, they have been spent honing the technology and making it applicable to specific customers' needs. That can mean scaling it up for the major manufacturers, scaling it back for the smaller ones, or just making it more user-friendly and efficient for all.

"There is a lot of fine-tuning going on right now," says Kent Hevenor, product manager–laboratory machinery, Sencorp Systems Inc. (Hyannis, MA), a member of DT Industries Plastics Group. "You can't be ready to make the next leap until you get a handle on the growth from the last one. Everyone went through tremendous strides, and now we have to catch up with ourselves."

John Lewitt, vice president of sales for Emplex Systems Inc. (Toronto), agrees, noting that "we have been able to focus on the functionality of the equipment, such as eliminating downtime as much as we can and upgrading to a urethane timing belt so that the belt is not a part that wears out anymore."

When will the next great leap in technology come, and what will it be? It is too early to tell for sure, but experiments are taking place using heat-producing light to make peelable seals. "This technology is truly in its infancy, and as a whole other form of energy, it has its distinct advantages," says Donbar's Barcan. "The equipment manufacturers haven't begun to look at it, but it is a technology waiting to be applied."

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