Pouch Sealer Frequently Asked Questions

Nov 28, 2021 | CeraTek, Medical Pouch Sealer

How does a CeraTek pouch sealer create a seal?

A CeraTek pouch sealer is designed to seal a package made from laminated or mono-layer flexible materials, and it creates a seal by applying heat and pressure to the pouch for a set amount of time. A pouch like this is created by bringing two webs of material together and sealing them on three sides, leaving the fourth side open. The product that needs to be packaged is inserted into this opening and then the pouch is inserted into the sealing machine. The CeraTek pouch sealer applies the temperature, pressure, and time required to activate a sealing adhesive which bonds the two layers of material together, creating a seal.

What are the main process variables associated with pouch sealing using a CeraTek sealer?

The main process variables associated with pouch sealing using a CeraTek sealer are time, temperature, and pressure. All three of these process variables are required to seal a pouch effectively.

How are time, pressure, and temperature controlled and monitored?

The three process variables—time, pressure, and temperature—are controlled through the CeraTek pouch sealer’s HMI. An operator can use the setup screens to program the time, temperature, and pressure based on the desired sealing process. These parameters can be changed for different materials and/or different pouch sizes.

What is the maximum temperature that a CeraTek pouch sealer can be set to?

The maximum temperature that a CeraTek pouch sealer can be set to is 400 degrees Fahrenheit for the top and bottom heat. Some pouch sealer models only use bottom heat, while others apply heat from both the top and bottom dies. If the pouch sealer has internal sensors, then the bottom heat maximum is 200 degrees Fahrenheit. Using temperatures that exceed these maximums can accelerate the wear of parts and increase maintenance costs.

What type of pouches can be sealed on CeraTek pouch sealers?

CeraTek pouch sealers can seal pouches made from a variety of different materials, including LDPE, nylon, Tyvek, foil, and many others. Our sealers are compatible with gusseted pouches, as well as with those that have headers or ones that are made from two different types of materials. If there are any question about compatibility, the experts at CeraTek are happy to test your materials and pouch designs on our equipment at our factory. The main requirement to keep in mind is that the pouch being used must be sealed on three sides. Then, the CeraTek sealer creates the fourth and final seal on the pouch.

When is Tyvek a better choice than foil?

Tyvek is a better choice than foil for products that must undergo additional sterilization processes after packaging. Tyvek is made of 100% high density polyethylene fibers, and it is manufactured to be “breathable,” yet impervious to microbes. That means Tyvek pouches can undergo sterilization processes using EtO gas, gamma radiation, electron beams, hydrogen peroxide, and steam. For example, in the case of a medical pouch made of Tyvek, the EtO gas passes through the Tyvek material, killing any contaminating microorganisms that are inside the package. Then, the pressure is relieved, as regular air is pumped back into the chamber, dispersing the EtO gas. As long as the medical pouch remains sealed, the contents are sterile. Foil is a non-breathable material, and pouches made from foil cannot be sterilized in this way.

Are CeraTek pouch sealers able to be validated?

Yes, CeraTek pouch sealers are validatable. Sealing parameters such as time, temperature, and pressure can be validated through the output ports on the side of the machine. The operator can use these ports to plug in a calibrated test instrument and retrieve the readouts of time, temperature, and pressure and confirm that the machine is functioning properly.

Are CeraTek pouch sealers ISO 11607 compliant?

Yes, CeraTek pouch sealers are ISO 11607 compliant. This compliance means that the accuracy and repeatability of the sealing process can be verified. For example, pouch sealing parameters such as time, temperature, and pressure can each be validated through their own specific output ports on the side of the machine. Each individual thermocouple has an output port for validation of the temperature readings. Likewise, there is a pressure output port and a timer output port.

Does CeraTek perform testing on pouch samples?

CeraTek has an in-house tensile tester which collects data on the strength of the seal, and we are happy to use this for testing customer samples at no cost. We can also help customers connect with others who can perform additional assessments, such as creep, burst, and dye penetration tests.

Does CeraTek offer different width sealing dies?

Yes, CeraTek offers sealing dies of different widths. The most common width is three-eighths inch, but we also offer standard one-eighth, one-fourth, one-half, and one inch sealing dies. We can also custom-make dies for requirements outside of our standard widths. Each sealing process has its own die requirements and validation parameters, so it is critical to make sure the die being used is the correct width.

When is it important to vacuum air out of a pouch prior to sealing it?

There are a few different reasons why it may be important to vacuum air out of a pouch before sealing. One of the most common reasons is to accommodate altitude changes for packaged products that are going to be shipped by air. If the pouch is sealed with too much air in it, and the altitude increases, the pouch could potentially burst. Another common reason to remove air from a pouch is to reduce its bulkiness so that it fits better into secondary packaging. CeraTek sealers can vacuum out air from a pouch through a nozzle that extends from the machine. The operator simply loads the pouch around the nozzle, initiates the cycle, and the nozzle vacuums out the air. Once the vacuum cycle is complete, the nozzle retracts and the sealing cycle begins.

How much compressed air needs to be supplied to a CeraTek pouch sealer?

For optimal pouch sealing, CeraTek recommends supplying 15 PSI above the desired pressure set point, up to a maximum of 125 PSI. For example, if the desired pressure set point is 50 PSI, we recommend supplying at least 65 PSI to the CeraTek pouch sealer. There are onboard air accumulator tanks within the CeraTek machine that reduce the risk of any pressure drops during the sealing cycle.

How is compressed air used on a CeraTek sealer?

The manufacturing facility supplies air to the CeraTek sealer’s onboard air accumulator tanks, and a pressure regulator on the machine ensures that the pressure supplied is accurate (i.e., it is not under- or overpowering). The air accumulator tanks initiate and perform the sealing cycle, driving the cylinders up and down to create the pressure applied to the seal. Incorporating these tanks into the sealer’s design helps mitigate the risk of fluctuation in the air supply. For instance, if the manufacturing facility has multiple machines on the same airline, the pressure flow across that line could vary. The CeraTek sealer’s air accumulator tanks significantly mitigate that risk.

What is Process Capability (Cpk)?

Nov 19, 2021 | CeraTek, CPK

What is Process Capability (Cpk)?

Cpk is shorthand for the term “process capability index.” It is a statistical measure of process capability that engineers use as a tool to determine how accurately a target is met.

Why is Cpk such an important parameter with sealer heating technology?  

Cpk is used throughout the sealing process as a way to measure how accurately and repeatably seals are being applied. Heat sealers apply temperature, pressure, and time to create seals of a specified, targeted seal strength. Cpk is used to determine how accurately that seal strength is reached and how consistently it is reached over time.

What type of industries are focused on Cpk?  

Since Cpk is a statistical measure of process capability, it can have application in any industry where defined processes are used repeatedly. Cpk is particularly useful in packaging because it can be used to measure how accurately and repeatedly a sealing machine applies a seal.

Why type of medical products are packaged with pouch sealers and why is Cpk important in those packaging processes?

Pouch sealers are used to package high value medical products that need to be kept sterile. These products run the gamut from single-use, disposable medical devices, such as catheters and stents, to devices that ultimately become a permanent part of a patient’s anatomy, such as the components used for hip replacements and the screws and rods that can be used to repair bone fractures. Pouch sealers are also used to package certain surgical instruments, although in these cases, the instruments are cleaned, sterilized, and packaged in pouches more than once.

When packaging medical products that must remain sterile, it is critical to consider Cpk. That is because Cpk helps determine how accurately and repeatedly a heat sealer has applied the seal that will maintain sterility. It is vital to know that the packaging seal has been applied according to specifications; otherwise, there is little assurance that the product will remain sterile, and the lives of end users could be at risk.

 What type of machines are used to seal medical device pouches?

 Medical device pouches can be sealed in a variety of different ways, depending on the type of pouch material being used, the sealing temperatures needed, and other factors. Broadly speaking, these medical grade heat sealers are either constant heat sealers or impulse heat sealers.

 Impulse heat sealers

The heating element in an impulse heat sealer is a very thin wire that can heat up and cool down quickly. It generates an “impulse” of heat, allowing the die to rapidly reach temperature and then cool down, all while under pressure. Impulse heat sealers are typically used for either the high temperature sealing or welding of mono-layer materials. They are usually not used for sealing pouches made from multi-layer materials because when the temperature fluctuates between heating and cooling every cycle, it is difficult to maintain accurate temperature control.

 Constant heat sealers

A constant heat sealer has a heater embedded into its aluminum ceiling die. The operator sets this heater to a certain temperature and turns it on. After a few minutes, the heat is evenly distributed across the ceiling die, and the die will remain at this temperature until the sealer is turned off. Because they maintain one, consistent temperature, constant heat sealers are the easiest heat sealers to validate. They also provide the most stable, repeatable sealing process and require less ongoing maintenance than other types of sealers. Most of the seals used in sterile medical pouches are produced by constant heat sealers.

A continuous band or rotary band heat sealer is a type of constant heat sealer that uses opposing bands to carry pouches through the heat sealing process. The operator feeds the leading edge of the pouch into the sealer, where it is captured by the bands and pulled through to the section where heat is applied. The heat brings the materials to the melt point and seals them together, and then the bands continues to pull the pouch through the sealer to an unheated section where cooling occurs. The cooled pouch then emerges from the machine. Interestingly, a continuous band or a rotary band heat sealer offers the benefits of both constant and impulse heat. The actual pouch sealing is done with constant heat, which is a very stable temperature, but then the pouch is pulled along to an area where there is no heat, enabling it to cool under pressure.

What is the difference between a weld seal and a peelable seal?

Medical pouches are sealed using either a weld seal or a peelable seal. For a weld seal, the two layers of pouch material are annealed, or welded, together. This creates a seal that is quite strong. While a weld seal is optimal for certain applications, it can introduce problems when the pouch needs to be opened. At times, opening a weld seal can result in tearing the pouch, creating fibers or very small particles that could compromise the sterility of the product, the pouch, or the environment where the pouch is being opened. A peelable seal is different because it is strong enough to withstand handling and shipping, but not so strong that it presents problems when the pouch needs to be opened. As the name implies, a peelable seal can be easily peeled open. It must be tested for both strength and peelability, and then the heat sealer must be set for those parameters of temperature, pressure, and time. The sealing process must be very accurate and repeatable to ensure that each pouch maintains sterility and can be easily peeled open at the time of use.

What sealing parameter has the most impact on Cpk?

The sealing parameter that has the most impact on Cpk is heat, whether that is the temperature set point or the duration of time that that pouch is exposed to the heat. The temperature must be consistent and repeatable at the defined set point. Any variation widens the average and lowers the Cpk. Ideally, the Cpk is as high as it can be with a very tight average. That is why it is critical to reduce variation in all heat sealer set points, especially temperature. Temperature can be difficult to control because of fluctuations related to factors such as air movement, heat sinks, and pouch materials.

How do the upper and lower dies on a heat sealer vary with regard to heat loss and gain?

The upper die on a constant heat sealer is constantly battling heat loss. During the sealing cycle, each time a (heated) upper die makes contact with an (unheated) lower die, it loses some heat. That means it is essential for the upper die to have a very tight heating profile and constantly adjust to maintain temperature over time. By contrast, an unheated lower die will continually gain heat throughout a sealing run. That means, as the run progresses, the pouches toward the end of the run could be exposed to different sealing conditions than those at the start of the run. Differences like these can be accentuated by the speed and attention of the operators using the sealers. Using a heat sealer with a lower heated die that is fully controlled and alarmed can eliminate much of this variability and improve Cpk.

 How can a heat sealer with a lower heated die help the integrity of the sealing process and improve Cpk?

 Cpk improves as variables are eliminated. Adding temperature regulation to the lower die gives the operator control over yet another variable in the entire sealing process. Our pouch sealer with a lower heating die is becoming increasingly popular because customers are finding that having a controllable, heated lower die allows them to improve Cpk.

What are the factors that affect Cpk for medical pouch sealing?

Cpk for medical pouch sealing is affected by a wide variety of factors, ranging from how much temperature, time, and pressure is applied during the sealing process to which materials are used to create the pouch. In addition, Cpk can be affected by how the desired seal strength is initially determined and tested over time. After all, it is important that any seal strength testing is repeatable and accurate, as well. Weighing all of these different factors can be daunting. That is why it is so important to work closely with the manufacturer of your heat sealer. They can help you develop a full understanding of the heat sealing process and the most effective ways for you to improve Cpk.

The Role Automation Plays in Medical Device Packaging Risk Mitigation

Nov 8, 2021 | Blog, CeraTek, Risk Mitiagtion

What role does automation play in risk mitigation for medical device packaging?

Automation provides unique opportunities for the medical device industry. First and foremost, automating a packaging process removes the operator from the process, eliminating the risk of human error, which is the greatest risk. When a packaging process is automated, the machine is programmed to complete a particular set of steps in a particular order. That process can be validated, ensuring a repeatable and reliable process.

The downside of automation is it is significantly more challenging to validate. Validating a piece of automation takes repeated testing and trial and error, as engineers introduce variables to impact the process in different ways. By contrast, a human operator is able to look at a package and decide that it doesn’t look quite right (without knowing the reason why). In other words, they can assess variables that may have not been tested.

Risk mitigation is very frequently just trying to engineer out the distractions that we know operators experience and where there might be gaps in that process where a distracted operator might make a mistake. This makes automation a good fit for longer runs, longer lifecycle products, where there would be a return on the upfront investment needed to validate the process.

Likewise, automation may be optimal for a high value product that has a very complex packaging process with many risk factors. In this case, the validation process associated with automation may be worthwhile to ensure that the high value product does not have the opportunity for risks related to a human process.

Why is automation such a good fit for rotary band sealers, continuous sealers, and pouch filling devices?

Using automation with rotary band sealers, continuous sealers, and pouch filling devices is becoming increasingly commonplace because it can increase throughput and mitigate risks caused by human error.

Automation can be used for packaging, for inspection and counting of the finished packages, and for segregating of finished packages by whatever parameter is required. With automation, operators do not have to worry about making mistakes. The entire process is handled automatically. If errors occur, they can be detected by sensors, and the incorrect packages are diverted to a reject bin. Alarms notify operators if any of the automated processes fail.

What are the future trends in medical device packaging risk mitigation?

CeraTek is committed to identifying areas for improvement and then implementing these improvements to benefit our customers. To that end, we are currently working on integrating our heat sealers with load cells that measure the amount of force being delivered to the seal area. This will ensure that the sealing die is closing fully and has delivered the correct amount of force. It could also offer an opportunity to start and end the dwell time off of a force window that is saved in the recipe.

These features will allow the heat sealer to maintain the desired seal pressure and risk mitigation features, while still controlling and alarming for the correct input pressure. We are also actively pursuing an automated seal inspection for our pouch sealer. This would be a system through which the sealed pouches automatically index for inline nondestructive seal inspection and it would satisfy the medical device industry requirement for Container Closure Integrity Testing (CCIT).

More and more medical device manufacturers are requiring CCIT systems in their sealing equipment to ensure that every package that comes out of the heat sealer is inspected according to a programmed set of inspection pass-fail requirements. In automated environments, it is not subject to manual inspection by an operator, who may or may not make the correct judgment call, or who may or may not get distracted.

What’s important to look for in a heat sealer manufacturer?

When evaluating heat sealer manufacturers, it is essential to find one that fully understands your particular project and has experience solving similar challenges. CeraTek focuses on solving problems, not simply selling machines. We partner with our customers and work together for shared success. Our goal is to provide our customers with the packaging solutions they need to get their products safely, reliably, and efficiently to the people who need them.

Features to Review When Evaluating Heat Sealers

Nov 1, 2021 | Blog, CeraTek, Risk Mitiagtion

What Features Are Important to Review When Evaluating Heat Sealers?

One of the main features to review when evaluating heat sealers is process control capability for temperature, seal dwell time/speed and pressure as well as the ability to interface with the heat sealer for data acquisition, operator identification and recipe control.

Capabilities for controlling process parameters such as temperature, pressure and time

When evaluating heat sealers, it is critical to review each machine’s capabilities for controlling process parameters such as temperature, pressure and dwell time. For packaging medical devices, temperature is one of the most critical process parameters to control, but it can also be the most challenging. Constant heat sealers heat to a specific setpoint, which then must be maintained within the validated window. Impulse heat sealers heat up and cool down for each seal, and the entire cycle must occur within the validated window.

The amount of pressure applied to the seal must also be carefully controlled. If too little pressure is applied, there is not intimate contact of materials in the interface layer and the seal will be spotty or too narrow or weak. If too much pressure is applied, the adhesive in the interface layer may squeeze out or the packaging materials could be thinned.

One of the best ways to ensure a repeatable pressure process is to use seal bars that apply direct force versus a cantilever design. It is also beneficial to have a protected air reservoir such as an air accumulator tank within the regulated side of the pneumatic system of the heat sealer. This ensures that the sealing process is not subject to other equipment that might be cycling in the plant between the machine and the air compressor. Having a protected air reservoir inside the heat sealer helps guarantee that the sealing process is protected and the risk of other equipment cycling at the same time is mitigated.

Capabilities for HMI, the interface with the heat sealer, and data storage

It is also essential to review each heat sealer’s capabilities for communicating with operators when functions fall outside of the validation window. Alarms help operators ensure that they are not putting incorrectly or improperly sealed product into the good disposition area. CeraTek tray sealers have a light tower, and the HMI is mounted on the swing arm. That way, regardless of where the operator is standing, they can always see the messaging that is on the HMI.

The light tower also includes a green light that, if illuminated, notifies the operator that at least from a time, temperature, and pressure process standpoint, the seal cycle was completed without encountering any alarms. Of course, that doesn’t necessarily mean that there is a good seal. The lid could have been put on upside down, the product may not be fully seated into the tray, etc.  Errors like these can be mitigated with cameras and sensors that can detect that a lid is oriented correctly, that the tray is fully seated into the tool, and that the product is fully inserted into the tray.

What other features are important to review when evaluating a tray sealer?

It is critical that the tray sealer deliver consistent heat across the entire usable seal area. CeraTek uses a blanket style heater that is wired in series so that one line comes into the heater, makes a closed-circuit pattern throughout the entire heater, and then exits out of the heater. The custom heater pattern ensures a very even temperature profile across the entire usable seal area. Other tray sealer manufacturers use cartridge style heaters. These heaters use rods that run parallel through the heated dye so that, theoretically, the heat will migrate from the rod to the areas in between the rods.

However, what actually happens is that there are hotter areas underneath the rods and cooler areas between them. That means there could be one tray flange underneath the rods that could be getting good heat exposure and another tray flange that is in-between the rods that could be at a lower temperature exposure and so not able to create a good hermetic seal.

Cartridge style heaters also introduce a risk that a failed heater rod could go undetected during a run. This cannot happen with CeraTek’s blanket style heaters because they are wired in series, and if one zone fails, then the entire heater fails. CeraTek has been selling heat sealers since 1996 and has never sold a replacement heater due to a failure in the field. Our heat sealers are known for their reliability and durability, which are especially critical for medical device manufacturers.

For tray sealers, it is also important to review platen orientation and which platen moves in a tray sealer. CeraTek tray sealers have a stationary top platen. During the sealing process, this platen heats up and the tool is moved up to it. That enables extremely precise parallelism between the top heated die plate and the bottom tool area. In fact, CeraTek’s four post guided press maintains parallelism within five thousandths of an inch for the life of the machine. This extremely precise parallelism makes it possible to deliver an even amount of pressure across the entire tool area.

Identify And Close Medical Device Packaging Process Gaps

Oct 25, 2021 | Blog, CeraTek, Risk Mitiagtion

What processes are effective for identifying and closing gaps in the medical device packaging process?

One of the most effective methodologies for identifying gaps is the Failure Mode and Effects Analysis (FMEA). Engineers use this method to identify were there may be failures in the package itself or in the assembly. Another popular method for identifying gaps is the Process Failure Mode and Effects Analysis (PFMEA). This method focuses more on the actual packaging process. Engineers use a PFMEA to confirm the specific actions that operators should take to properly package the medical device.

What is the difference between multi-piece and single-piece flow?

Operators using multi-piece flow process multiple pieces together, at the same time. This is similar to multi-tasking and although it may sound efficient, it usually is not because of the number of potential errors that are introduced. Operators using single-piece flow handle and package one product at a time and are disallowed from starting the next one until the first package is completely finished. Much of the medical device industry is shifting from multi-piece flow to single-piece flow as a way to reduce packaging risk. A PFMEA can determine whether multi-piece flow or single-piece flow is optimal for any given packaging process.

Are there other examples where PFMEA is used?

A PFMEA can also help determine the best way for operators to orient a pouch for the most effective seal. If a pouch is comprised of dissimilar materials, the operator must know which side needs to be placed in the machine facing the operator and which side needs to be placed in the machine facing away from the operator. They also need to orient the pouch correctly so the seal is made in the right place. Historically, operators have been asked to check their work by simply holding the pouch upside down to confirm the seal (if the product drops out, the seal is not good). However, newer machines have sensors that can alert the operators if they did not place the package into the sealer correctly. Orienting the lid correctly on a tray is just as critical.

What are the areas to focus on to mitigate sealing risk and ensure a good hermetic seal?

To mitigate sealing risk and ensure a good hermetic seal, the heat sealer used must be maintained to factory specifications, validatable and have alarm capabilities for all process parameters associated with the validated window. A validatable heat sealer with alarm capability can alert the operator and terminate the seal cycle when there is a detectable variance beyond the validated window.

What is validation and what parameters are reviewed for a validatable window?

For any kind of heat-sealing process, the validated parameters are time (or speed when using a rotary band pouch sealer), temperature, and pressure. To create a hermetic seal for a pouch or tray, the heat sealer needs to be able to deliver a repeatable and even temperature over repeatable time (or speed), and at a repeatable pressure. Validation provides information about how stable the sealer performs at the required times/speeds, temperatures, and pressures. The validatable window allows for a small amount of deviation from these defined parameters. Then, if the sealer performs outside of that window, the machine alerts the operator to the deviation. This is a fundamental part of risk mitigation for the seal process. If the validated window is not protected, the operator could unknowingly process the pouch or tray resulting in a poor seal. That, in turn, would allow the improperly sealed package to go out into the field. By the time that medical device is needed, the seal could be broken or have voids in it that allowed microbes into package, creating an infection risk for the end user.

How is a validatable window established with the three variables of time, temperature, and pressure?

A validatable window is established using a process called a design of experiment (DOE). The engineers input different times, temperatures, and pressures and then test the packaging at these various combinations. They create a 3D mathematical/testing model of the results, which helps them determine the most repeatable recipe for creating the barrier seal for that package. For lightweight medical devices, the goal might be a minimum of a one-pound peel strength. Heavier products require a stronger peel strength. Ultimately, the goal is to achieve a hermetic seal that can: 1) maintain sterility throughout the shelf life of the medical device and 2) be easily opened in a controlled manner by medical professionals in a sterile setting.

Beyond validation, what other areas are important for seal risk mitigation review?

In addition to establishing a validatable processing window, it is also important to ensure that the medical device being packaged does not interfere with the seal area. If there is product in the seal area, it is not possible to create a hermetic seal. Ensuring that the product is away from the seal area might involve reducing the opening height of the guarding, ensuring that the product can’t migrate into the seal area, or using height indicators that produce an alarm to notify the operator that the product is too close to the seal area. Risk mitigation review should also include the labeling process. All labels must be applied correctly so that they do not encroach upon the seal area and interfere with the creation of a hermetic seal.