Pressure Decay Leak Testing in Automation

Pressure Decay Leak Testing in Automation

Pressure Decay Leak Testing in Automation

In automated manufacturing many assembled products require leak testing to validate product viability and quality. A leak test is used to determine if an assembled object, product, or system functions within a specified leak limit. Leaks occur when gas or liquid flow through an object via an imperfection or manufacturing defect such as holes, cracks, weak seals, etc.

The automation of leak testing generates several key challenges, such as real estate on a production line, strict quality standards, efficient productivity, as well as communication and data sharing with the rest of the automation equipment.

Proximity is Key

Square footage on a production line is valuable and costly. Leak testers are often integrated into assembly lines however they best fit. Many standard pressure decay leak testers measure over 12” wide. A common solution for integration is to extend the connection hoses between the part under test and the leak tester which can be several feet away. The longer the connection tubing, the more volume is used in a leak test, which can have a devastating effect on productivity as well as the accuracy of leak tests.

The volume of air used in a leak test includes the internal volume of the tester, the volume contained in all of the connection tubing, as well as the volume of the product under test. The farther a leak tester is from the part under test the larger the test volume. The larger the volume the longer the volume takes to pressurize which negatively effects productivity and throughput.

A higher test volume can also impede the leak testers ability to detect a leak. Think of this in terms of tires. You have a car tire which holds a large volume and a bike tire which holds a small volume. If both tires run over the same nail, what happens? The bike tire flattens almost immediately while the car tire slowly loses air over time. The smaller the test volume the faster and easier it is to detect a leak. The larger the test volume the longer it takes to identify if there is a leak, meaning extended test times with a lower accuracy of detection.

In terms of instrumentation, when running a pressure decay test, the value attributed to the pressure decay is the digital signal from the pressure sensor. When testing objects with the same size hole, such as a bike and car tire, the object with the larger test volume (car tire) will translate into a smaller signal than an object with a smaller test volume (bike tire). The pressure decay value is directly proportional to volume. Smaller signals require more time to detect a leak. Electrical, pneumatic, thermal or atmospheric effects, or noise, can mask small signals as well as influence the pressure decay value which has a negative impact on repeatability. A smaller total test volume yields a larger relative pressure decay value/signal and requires less test time. The greater the magnitude of the signal above zero, the better signal to noise ratio, which directly results in higher test accuracy and repeatability.

Moving the leak tester closer to the part under test will decrease test time and increase accuracy which raises both quality and throughput. The challenge is how to narrow that proximity when space is so limited? The answer is the iKit by Zaxis. At 1/4th the size of most pressure decay leak testers the iKit was designed specifically to fit within close proximity to the product under test on an assembly line. At only 3” wide the iKit can be mounted right on tooling saving valuable space and reducing excess test volume that is created by the use of extended hoses.

Communication

Effective automation relies on effective communication. There are many components that go into an automated production line, all of which need to be able to talk to each other. Once a leak tester runs its test it needs the ability to communicate results or trigger events such as Pass=Next, Fail=Eject or Fail=Halt Production.

There are many forms of communication commonly used in factory automation including Modbus, Ethernet TCP/IP, and EtherNet/IPTM. The most dynamic of these communication systems is EtherNet/IPTM as it combines traditional Ethernet infrastructure and hardware with both of the most commonly used collections of Ethernet standards, the Internet Protocol suite and IEEE 802.3, and integrating the Common Industrial Protocol. EtherNet/IPTM is the preferred communication system for Allen-Bradley automation equipment.

With factory automation in mind, the purpose-built design of the iKit has the option to include EtherNet/IPTM. Other communication systems such as discrete I/O, RS232 and Ethernet TCP/IP are also available.

EtherNet/IP in Factory Automation

iKit Automation Solution

Zaxis has designed the iKit to be the ideal leak tester for factory automation settings. With the smallest footprint of any pressure decay leak tester on the market combined with integrated Allen-Bradley connectivity, the iKit by Zaxis is an excellent leak test solution for factory automation.

iKit by Zaxis

Press Release: Zaxis 7i – Large Display Leak Tester

Press Release: Zaxis 7i – Large Display Leak Tester

Press Release: Zaxis has reinvented their multi-function leak tester with usability in mind, adding a large 7-inch touchscreen to the new Zaxis 7i.

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SALT LAKE CITY, UT. (September 23, 2019) – Zaxis has focused on usability in their latest multi-function leak tester, the Zaxis 7i. The Zaxis 7i has a large built-in 7-inch touchscreen and is currently available for purchase from any Zaxis sales representative.

The Zaxis 7i is a modular, multi-function leak tester. The modular Zaxis 7i leak tester is configurable to a specific application. The Zaxis 7i is an evolution of the Isaac HD, Zaxis’ flagship leak tester, and has more room for larger valves and a capacitive 7” touch screen.

The Zaxis 7i is perfectly suited for desktop applications such as research and development but is also suitable for an automated manufacturing environment. The large touchscreen interface makes test set-up and interaction
simple. The large icons and form fields are easy to interact with and eliminate unintentional user input error.

Ideal for leak test applications with high levels of user interaction, the new 7-inch touchscreen on the Zaxis 7i increases usability and decreases human error.

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Zaxis 7i

Manufacturing Single Use Vape Cartridges

Manufacturing Single Use Vape Cartridges

Growing Vape Market

The vape market has been on the rise for several years and is projected to continue to grow at a rapid pace The global e-cigarette and vape market size was valued at USD 10,261.8 million in 2018 and is expected to grow at a CAGR (Compound Annual Growth Rate) of 24.9% from 2019 to 2025 1. Single use vape cartridges are used for both disposable and rechargeable vaporizers. Recent health concerns associated with the growing vape market will drive spur increased regulations for manufacturing vape cartridges. These increased regulations will drive demand for more accurate and reliable manufacturing equipment as seen in the Pharmaceutical manufacturing industry. Zaxis Inc. pumps are already being used to manufacture pharmaceuticals because of the eVmP’s exceptional precision and accuracy. The manufacturing of vape cartridges requires pumps that can handle highly viscous fluids while dispensing very precise doses in each cartridge. Zaxis Inc. metering pumps use positive displacement to pump fluids making them ideal for fluids with low or high viscosity. A natural progression for the vaping industry will be to convert their existing pump equipment to the Zaxis eVmP precision dispensing system.

Highly Viscous Fluids

Concentrated plant-based oils such as cannabis and hemp are known to be highly viscous fluids. Manufacturers use a number of different techniques to obtain the correct fluid viscosity for vape cartridges including distillates with thinning agents, cutting/infusing the oil with additives to thin the consistency, or infusing terpenes and strain-specific flavorings.

On a manufacturing production line all metering and dispensing pumps need to be able to overcome the backpressure the highly viscous fluids create. The Zaxis eVmP VS-Series was design specifically to deal with highly viscus fluids. The servo driven motor has nearly 4 times the torque of a traditional stepper motor and can handle flow rates near 2,000 mL/min and back pressure up to 200 psi. Meaning, the eVmP VS-Series can not only overcome the backpressure created by highly viscous fluids, is can dispense at a faster rate increasing product line throughput.

Precision Dosing

When manufacturing single use cartridges precision dosing is essential. In the Vape industry the FDA is particularly strict upon delivering exactly what is on the product label. Inconsistent dosing can upset end users if they receive a less than full product. Inconsistent dosing and overfilling can also have a damaging effect on the financial bottom-line of production.

The rising market has shined a spotlight on the Vape industry. Consumer safety is a top priority and with that comes higher quality control, including the repeatability of precision mixing ingredients. The FDA states that if you do not report your ingredients or changes to your ingredient quantities “your products may be deemed “misbranded” under federal law and therefore, subject to regulatory action, including seizure and injunction. Submission of false information is also punishable by criminal and civil law.2” If an e-liquid or “juice” mixture diverges from its label by the smallest percentage the FDA often requires destruction of the entire batch including video evidence of its destruction. Precision metering/dosing is vital to the successful and safe manufacturing of e-liquids.

The Zaxis eVmP system achieves +/- 0.5% full scale accuracy and 0.5 CV with 0.01 µL resolution through the use of a rotating and reciprocating positive displacement design. The use of positive displacement in the eVmP design helps reduce the risk of contamination or bleed over between packages. The difference between the external diameter of the piston and the internal diameter of the liner is near perfect. This means when the piston head is drawn away from the fluid path a vacuum is created ensuring volume remains constant through the entire cycle of operation. Furthermore, the eVmP rotating and reciprocating design renders highly repeatable results. With stainless steel pump head construction and sapphire hard, alumina ceramic, internals Zaxis eVmP pumps will last for millions of maintenance free cycles.

Not only is the FDA scrupulous when it comes to ingredients and dosages, the Vape industry also has a discerning customer base that is well informed about their products and often demand high standards that preserve a plant’s unique profile, flavor, and complexity. Precisely mixing each element of a juice as a distinct individual dose can be far more exact than big batch mixing producing a very high-quality product and reducing the margin of error and potential waste.

No One Wants a Leaking Pen

Many of the first Vape pens came with a warning not to lay them down or tip them over as the oil from the tank would often leak out. Cartridge design has evolved over the last few years and with the vape market on the rise the development and refinement of cartridge design is a continual process. There are several different leak tests that can be performed to validate a cartridge design. Closing off the vents and running a pressure decay test through the mouthpiece will validate all of the seals and ensure the tank is leak tight. Then opening the vents and running a mass flow test through the cartridge is especially helpful in validating that an atomizer filter design will not leak fluid.

The Isaac HD and Zaxis 7i are multi-function leak testers that have the capability of running multiple kinds of tests in the same unit. Both leak testers come with electronic regulators and up to 100 stored programs. This mean the air pressure setting will automatically adjust from test to test saving time and removing user error. Finding a desired flow rate for a cartridge is a delicate and precise task as the flow of air should be unimpeded while the flow of liquid should not pass through the saturated filter in full drops. The intuitive user interface makes test parameters easy to adjust and customize. The ability of the Isaac HD and Zaxis 7i to set and sense the difference between such tight parameters allows designers to develop cartridges that function perfectly without leaking.

Conclusion

The Zaxis eVmP VS-Series is ideal for handling the highly viscous fluid and extreme precision required for manufacturing single-use vape cartridges. The VS-Series servo motor technology is not only powerful enough to overcome the backpressure created by highly viscous fluids, but it also has the speed and accuracy to increase quality throughput. The Zaxis line of leak testers can validate the design of any vape cartridge as well as determine if there are any cartridge leaks or defects.

  1. Grand View Research. “E-cigarette And Vape Market Size, Share & Trends Analysis Report By Distribution Channel (Online, Retail), By Product, By Component, By Region, And Segment Forecasts, 2019 – 2025” Grand View Research, July. 2019 https://www.grandviewresearch.com/industry-analysis/e-cigarette-vaping-market
  2. FDA “ How Do I Comply with FDA’s Tobacco Regulations?” FDA  27, Aug. 2019 https://www.fda.gov/tobacco-products/compliance-enforcement-training/manufacturing 
Battery Manufacturing

Battery Manufacturing

Battery manufacturing is an ever-expanding industry that is constantly adapting to new technology. The rising expectations of battery technology generates innovation at a rate seldom matched by other industries. A battery production line must be designed with flexibility in mind to deal with new and changing formats, rigorous quality testing, and produce stable and reproducible products.

Flexible Production

There are a number of battery types in production today, most of which are in a near constant state of research and development, which requires a flexible production line. Manufacturers experiment with new alloys, mixtures and slurries endeavoring to increase output and efficiency or reduce raw material consumption. The ability to adapt an existing production line to a new product or a new variation of an existing product is crucial.

With manufacturing flexibility in mind, the patented Zaxis eVmP (Electronic Variable Metering Pump) system allows for simple electronic adjustment. eVmP pumps are designed for high accuracy, low volume dispensing of electrolytes, slurries, and lubricants used in the manufacturing of several battery types, including lithium ion, button cell, AAA, AA, C and D. Internal pump components of the eVmP are made of chemically inert, sapphire-hard ceramics, making them ideal for dispensing corrosive KOH electrolytes, as well as viscous, abrasive slurries. eVmP pump heads are designed for millions of maintenance free cycles. Flexible production is the core of the eVmP system.

Increased Quality Requirements 

Quality assurance is an important factor in any industry but the growing dependence on electronic devices has excessively raised the expectations of battery quality by consumers. When working with electrolytes, slurries, lubricants, and other fluids, containment is critical. These abrasive and corrosive fluids can cause major damage to electronic devices through the smallest of leaks. To identify a leak on a sealed enclosure, such as a battery, a Chamber leak test is used.

A Chamber leak test is used to find leaks in sealed packaging or sealed devices without an opening to use for filling. A reference volume is filled to a pressure, after pneumatic isolation the volume is then introduced to the test chamber. A known good part will fill to the desired test pressure, while a part with a gross leak will not reach test pressure. This difference between the test pressures determines the pressure tolerance. A part that doesn’t fill to the test pressure within the pressure tolerance is a gross leak and will fail the test. If the part passes this gross test, the testing continues with a typical pressure decay test step to detect fine leaks.

The Isaac HD by Zaxis is a multi-function leak tester built for a flexible production environment. The Isaac HD can store up to 100 different programs for simple product changeover during production. The modular design of the Isaac HD allows custom configurations for highly specialized tests. To run a Chamber leak test a drawer fixture is required. The less negative space between the drawer’s chamber and the products, the faster the test can be performed. Zaxis will custom build drawer chambers to the unique specifications of the product being tested.

Stable/Repeatable Mass Production

Creating a production process that can produce dependable and repeatable products has never been more important, especially considering the dynamic requirements of battery manufacturing.

The Zaxis Dual Channel eVmP’s positive displacement pumping action maintains better than 1% accuracy and 0.5% CV(Precision) enabling highly reproducible results for mass production. The Dual Channel eVmP pump design integrates ceramic valve-less piston pump technology with Zaxis’ patented precision stepper motor control and integrated electronics, built into an IP45 rated, 316SS enclosure, which is suitable for bench top or integrated automation equipment. The dual channel configuration of the eVmP increases production output, and fully integrates power supply and communication cables. The Zaxis eVmP system has dispensing capabilities that can handle metering from microliters to 9 liters per minute.  

The Isaac HD by Zaxis contains a small, rigid internal test volume of less than 1cc. and a 24-bit analog to digital converter which enables high sensitivity and excellent reproducibility. Additionally the modular design of the Isaac HD with custom-built drawer fixtures produce a tailor-made leak tester that can achieve a resolution of 0.00001 psi with extremely repeatable results.

Conclusion

The expectations of the battery manufacturing industry are rising, and production lines must be built to meet those expectations. Creating a flexible production line that contains rigorous quality testing and precision equipment is pivotal to any battery manufacturer. Using the Zaxis eVMP for dispensing and the Zaxis leak test products for leak testing, battery manufacturers can ensure they remain flexible and productive, while maintaining high quality and reproducibility.

Patent for Integrated Safety and Motion Control Testing Device

Patent for Integrated Safety and Motion Control Testing Device

The Zaxis CamTrac

With over 30 years of experience in high precision leak testing, the engineers at Zaxis have spent a lot of time working with medical manufacturing companies. In the medical manufacturing field keeping parts clean and sterile is vital. This need inspired our engineers to create the CamTrac. The CamTrac system was developed to remove the caps from a new catheter set, perform a Pressure Decay and Occlusion test, then replace the caps all in one device. This removed any potential human error or contamination during the removal and replacement of the catheter caps.

Summary of the Invention

The present invention relates to testing devices. In particular, some implementations of the present invention relate to a testing device that is configured to remove a cap from a sample product (such as an IV line), test the sample product for leaks or for another characteristic, and to then replace the cap on the device. While the testing device can include any suitable component that allows it to function as described, in some implementations, it includes a safety shield which acts as an anti-pinch guard, and which also includes one or more motion control cam tracks that are configured to control movement of one or more testing modules encased within the shield. Accordingly, in some such implementations, the safety shield is able to perform multiple functions, acting both as a safety apparatus and as a linear motion control apparatus.

Some implementations of the present invention provide a testing device having a base to which is mounted a sample adapter. The sample adapter is configured to receive a sample product or device for testing. The testing device further includes a mounting member which is coupled to a first and second actuator (e.g., hydraulic cylinder), wherein the second actuator (e.g., hydraulic cylinder) is further coupled to the base. The mounting member further includes a plurality of testing modules which are configured to contact the sample product and perform one or more testing functions as part of a testing procedure. Further still, the mounting member includes one or more cam followers.

The testing device further includes a safety shield having one or more motion control cam tracks comprising a groove or channel formed on an inner surface. The motion control cam tracks are configured to compatibly receive the one or more cam followers of the mounting member. The motion control cam tracks limit or control the movement of the mounting member through the interior space of the safety shield. In some instances, the first or second actuator (e.g., hydraulic cylinder) further include one or more cam followers which are configured to ride within an additional motion control cam track provided on an inner surface of the safety shield. Thus, the present invention provides a safety shield having an integrated, bi-directional system of motion control cam tracks to provide precise, repeatable, and safe movement of a mounting member as part of a sample product testing device.

These and other features and advantages of the present invention will be set forth or will become more fully apparent in the description that follows and in the appended claims. The features and advantages may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Furthermore, the features and advantages of the invention may be learned by the practice of the invention or will be obvious from the description, as set forth hereinafter.

Background of the Invention

The present invention relates to testing devices. In particular, some implementations of the present invention relate to a testing device that is configured to remove a cap from a sample product or device (such as an IV line), test the sample product for leaks or for another characteristic, and to then replace the cap on the device. While the testing device can include any suitable component that allows it to function as described, in some implementations, it includes a safety shield which acts as an anti-pinch guard, and which also includes one or more motion control cam tracks that are configured to control movement of one or more testing modules encased within the shield. Accordingly, in some such implementations, the safety shield is able to perform multiple functions, acting both as a safety apparatus and as a linear motion control apparatus.

United State Patent
Granted April 26, 2016 to
Zaxis, Inc.

-Assignee-
Patent No. US 9,322,736 b2

Integrated Safety and Motion Control Testing Device

Patent for Dynamically Adjustable Reciprocating Fluid Dispenser

Patent for Dynamically Adjustable Reciprocating Fluid Dispenser

Electronic Variable Metering Pump (eVmP)

The patented eVmP system is a precision metering and fluid dispenser combined with a detachable Touch Screen Interface (TSi) for simple programing and immediate teach and control. This pump technology combines precision ceramic pump components and an electronically controlled linear stepper actuator to make ultra-fine adjustments to angle position, thereby changing the volume of metered liquid. This allows the eVmP system to provide dynamic fluid displacement to overcome variations in viscosity and surface tension. The eVmP is the latest in fluid metering and dispense technology.

Summary of the Invention

The present invention relates to accurately and repeatably dispensing fluid. In particular, the present invention relates to systems and methods for providing a dynamically adjustable, synchronously and/or asynchronously reciprocating fluid dispenser. 

Implementation of the present invention takes place in association with a reciprocating fluid pump. A pump drive motor is coupled to the reciprocating fluid pump to actuate a pump shaft within a pump cylinder, wherein the pump shaft includes a cut out portion (duct) that allows fluid to selectively pass thereby within the pump cylinder. As the pump shaft rotates within the pump cylinder, fluid is allowed to enter into a pump bore defined by a portion of the pump cylinder through a pump ingress port. As the pump shaft rotates, it blocks the pump ingress port. Further rotation allows the duct to allow the fluid in the pump bore to be dispensed through a pump egress port. This process may be repeated for subsequently dispensing volumes of fluid using the reciprocating fluid pump. 

Implementation of the present invention further includes an adjustment motor (e.g., a linear actuator, etc.) that is coupled to an adjustment mechanism, which selectively adjusts the volume of the pump bore. In at least one implementation, the volume of the pump bore is adjusted as the angle of the pump shaft is modified. A modification of the angle changes the stroke of the pump shaft. In another implementation, the volume of the pump bore is adjusted through a system of gears to selectively change the stroke of the pump shaft. Further, at least some implementations allow for synchronous and/or asynchronous reciprocation. 

Further implementation includes a controller coupled to the adjustment motor to dynamically control the adjustment motor to cause the adjustment mechanism to be precisely and repeatably modified. As such, the volume of fluid dispensed is extremely accurate, repeatable, and dynamic. Moreover, a controller may be used to provide control over the particular waveform of a synchronously and/or asynchronously reciprocating fluid dispenser. 

As the methods and processes of the present invention have proven to be useful in the area of dynamically dispensing fluid, those skilled in the art can appreciate that the methods and processes can be used in a variety of different applications, in a variety of different areas of manufacture to yield, and embrace a variety of different kinds of fluids. Examples of such industries include the medical industry, the industrial industry, the electronics industry, the food industry, the dairy industry, the precision cleaning industry, the cosmetic industry, the hygene industry, etc. Examples of such fluids include adhesives, lubricants, chemicals, drugs, paints, pigments, resins, solvents, epoxies, inks, ceramic slurries, solutions, candy coatings, polishes, flavorings, food preservations, cleaning agents, pigments, fragrances, gases, liquids, ets. 

These and other features and advantages of the present invention will be set forth or will become more fully apparent in the description that follows and in the appended claims. The features and advantages may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Furthermore, the features and advantages of the invention may be learned by the practice of the invention or will be obvious from the description, as set forth hereinafter. 

Background of the Invention

The present invention relates to accurately and repeatably dispensing fluid. In particular, the present invention relates to systems and methods for providing a dynamically adjustable, synchronously and/or asynchronously reciprocating fluid dispenser. 

A variety of industries require a safe, accurate handling of fluid. One such industry is the medical industry. By way of example, in the medical industry an assay testing procedure is typically employed to determine whether an infectious disease (e.g., hepatitis or another infectious disease) is present in a particular blood serum. As part of the testing procedure, a biological sample is disposed into a testing receptacle. A reagent is added to the biological sample. In performing the test, it is important that the amount of the biological sample and the amount of the reagent are accurate. In particular, the amount of the reagent added to the biological sample may be in the range of 50 .mu.L-100 .mu.L, with a required accuracy of .+-.0.5 .mu.L. 

The assay testing procedure may further include a variety of separate test receptacles to perform a variety of assay tests to confirm and/or compare results. Some assay testing procedures may include disposing a series of specific reagents. 

Valveless, positive displacement pumps have been used in applications that require a safe, accurate handling of fluid. An example of a valveless, positive displacement pump is disclosed in U.S. Pat. No. 4,008,003. While the pump disclosed in U.S. Pat. No. 4,008,003 is an available technique, the pump does not provide an accurate calibration for metering and dispensing fluids. For example, the piston stroke of the pump is not easily adjusted and the angular displacement of the ports cannot be readily calibrated. 

Further problems with techniques used in industries that require a safe, accurate handling of fluid include the fact that complex pump designs increase the likelihood for error in manufacturing and assembling the pumps. And, pump designs with moving parts contribute to field failure and maintenance costs. 

Thus, while techniques currently exist that are used in industries requiring a safe, accurate handling of fluid, challenges still exist with such techniques, including a requirement for calibration of the fluid-handling device for each surrounding condition, an inability to provide accurate calibration, an increased likelihood for error, an increased likelihood for field failure, increased maintenance costs, and other such challenges. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques. 

United State Patent
Granted May 4, 2010 to
Zaxis, Inc.

-Assignee-
Patent No. US7,708,535 b2

Systems and methods for providing a dynamically adjustable reciprocating fluid dispenser