Accurate Force Pneumatics

Airpot Corp. announces “Accurate Force Pneumatics” for control of force, motion and displacement with unparalleled accuracy and low friction

Airpot Corp. has developed a line of products and systems, which excel in applications requiring precise, accurate control of actuation, damping, or displacement. Using high quality pneumatics in conjunction with Airpot’s precision glass cylinder and graphite piston technology, Airpot now offers designers levels of force and motion control unobtainable by other pneumatic means. Even zero friction actuation is possible, allowing for ultra precise measurement, application of minute forces, and sub-micron control of linear displacement. Ideal for uses such as high tech micro machining, polishing or grinding equipment, Airpot’s pistons and cylinders are manufactured to extremely tight tolerances and have special properties which also allow for precise volumetric displacements in the micro-liter range for sampling applications requiring the movement or measurement of a volume of air or gas.

Each of the product groups offers instrument quality pneumatic devices uniquely designed and optimized for highly accurate and repeatable force control at lower cost than other methods providing comparable functions and performance. The result is products and systems that Damp, Actuate, and Displace with superior accuracy and little or no friction. Airpot Accurate Force Pneumatics are ideal for designing or improving a product line or building specialized equipment to do research, high level testing or precision assembly.

Airpot’s “Accurate Force Pneumatics” individual component products aid the designer in the following three areas, and Airpot’s optimized systems provide the ultimate in customized force control.

Damping:

When there is the need to reduce or eliminate harmful or excessive motion Air Dashpots and Shock Absorbers use ambient air to precisely and accurately control force, velocity and impact.

Actuation:

When your mechanism needs a precise force Airpot Self aligning Actuators, Anti-Stiction and Zero-Friction air cylinders allow you to move it, hold it, or press it accurately and with amazing repeatability.

Displacement:

Precision Piston /Cylinder sets and Self-Aligning actuators make possible the precise dispensing of small volumes of air in pumping and flow applications, and can also be used for specialized bearing or driving requirements.

Optimized Systems:

Pre-selected systems components provide most of the functions needed between the air supply and the force output system to achieve your actuation objectives, and can save you research and development time. Our systems are matched to insure optimum performance and lowest cost.

Each of Airpot’s four major product groups, damping, actuation, displacement and optimized pneumatic systems offers instrument quality pneumatic devices uniquely designed and optimized for highly accurate and repeatable force control and smooth motion. Visit www.airpot.com for products and systems that exhibit superior accuracy and little or no friction. Airpot Corp. manufactures precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot Corp. is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Call or email our technical staff for application assistance and ordering information. service@airpot.com 203-846-2021, 800-848-7681.

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications: Filament & wire tensioning, positioning and manipulating optics, liquids, delicate devices, super sensitive force control, counterbalancing and safety for vertically positioned linear driven motor masses, Measuring weight, creep, tensile strength and calibration.

Airpot Tech News October 2009

An air cylinder that uses a carbon /graphite piston within a glass housing produces precise and repeatable motion during membrane switch testing. A precision low friction cylinder with a piston that slides on a cushion of air is being used to provide reciprocating motion in membrane switch test systems. An Airpel air cylinder, produced by Airpot Corp. Of Norwalk CT. generates a virtually constant level of friction at air pressures from 10 to 100 psi. As a result, the Airpel minimizes erratic movements that occur as a piston begins its travel within a cylinder.This characteristic is vital in the testing of membrane switches, a process in which the air cylinder must generate forces that are precise and repeatable. Membrane switches are part of flat panel displays such as those used to enter orders at fast food restaurants or to enter machine control data in factories Read More…

Video: Zero Friction Air Bearing Actuator

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Watch Video: Airpot introduces the first three in a series of online technical product videos which illustrate pneumatic control of unwanted motion using Airpot dashpots, snubbers and air-bearing actuators Read More…

 

 

 

Airpot Creates New Product Category

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Airpot announces its new line of adaptable piston and cylinder sets. Constructed using a graphite piston / borosilicate glass cylinder combination Read More…

Airpot introduces the first three in a series of online technical product videos which illustrate pneumatic control of unwanted motion using Airpot dashpots, snubbers and air-bearing actuators.

Dynamic systems often produce unwanted motion and the need for control of velocity, time delay, falling mass, vibration, oscillation, over action and impact. Airpot’s glass cylinder and graphite piston technology is used to control motion by pneumatic damping, actuating with air or vacuum, applying a precise force, for pumping or pulsing air, and to sense, indicate, or relieve pressure. The videos are 3-4 minutes long and graphically illustrate cushioning impact with an Airpot snubber device, the unique properties of the Airpel –AB zero friction air bearing actuator and the differences between pull and push damping. The online video offerings are part of Airpot’s new website which includes improved functionality that now allows designers to configure 3D CAD files of non-stock products with construction requirements specially tailored to the application.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and routinely works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visit www.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information. service@airpot.com 203-846-2021, 800-848-7681.

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications: filament & wire tensioning, positioning and manipulating optics, liquids, delicate devices, super sensitive force control, counterbalancing and safety for vertically positioned linear driven motor masses, Measuring weight, creep, tensile strength and calibration.

Super-sensitive grinding and polishing operations with forces controlled to as little as 0.001 pounds or 0.45 grams are now possible and being utilized in industry by customers of Airpot’s  Airpel –AB Air Bearing actuators. Many manufacturers with the need for extremely tight control of small incremental movements along with low forces and speeds are discovering the benefits of air bearing technology used to provide zero friction actuation. Electronic components, semi-conductor processing, metrology and tensioning product manufacturers are now able to achieve levels of measurement and control previously unattainable with conventional air cylinders.  The actuators combine air cylinder-like linear actuation with zero friction air bearing technology.

The Airpel -AB provides “Force Without Friction” which is made possible by a specially shaped stainless steel piston that is precisely fitted to a borosilicate glass cylinder. The introduction of pressurized air into the air bearing’s cylinder creates a true air bearing airflow effect around the piston.

With as little as 5 PSI of air applied to the cylinder, the same air that drives the piston also produces a stiff cushion of air to support the piston and prevent it from contacting the cylinder wall.  The result is an air cylinder that delivers virtually unlimited piston life, no lubrication and clean operation. In addition, the output force of this friction-free air cylinder is reduced only infinitesimally by movement of ultra-low friction ball joints used to connect the rod. These unique qualities allow Airpot Corporation to guarantee that the Airpel -AB will exceed the life of any machine or instrument in which it is originally installed.

“The Airpel -AB air bearing actuator is designed to fill a niche in the air cylinder industry where even the slightest friction, contamination, wear, or extreme temperature vulnerability of typical air cylinders cannot be tolerated.” said Mark Gaberman, President of Airpot Corporation.

Industries include, semi-conductor, optics, medical, and test and measurement. Applications may include, counterbalancing and safety support for vertically positioned linear motor driven masses, precise tensioning, positioning mechanisms supporting delicate materials, sensitive force control for holding or clamping fragile materials, or precise laboratory test equipment.

Airpel-AB air bearing actuators are available in metric models with four bore diameters and ten standard strokes to provide precisely repeatable driving or supporting forces from 2 grams to 58 kg. Operating temperatures range from -20 C to +90 C.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added subassembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visitwww.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information.service@airpot.com 203-846-2021, 800-848-7681.

Key Markets:

Semiconductor processing, Electronics assembly, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications:

Filament & wire tensioning, positioning  and manipulating optics, liquids, delicate devices, super sensitive force control, counterbalancing and safety for vertically positioned linear driven motor masses, Measuring weight, creep, tensile strength and calibration

High performance CNC micro machining centers used to fabricate small high precision parts from plastics, metals, glass, and ceramics require extreme control of forces and speeds. Micro machining equipment manufacturers with the need for tight control of small incremental movements along with low forces, high speeds and extreme levels of repeatability and resolution are discovering the benefits of air bearing technology used to provide zero friction counterbalancing. A counterbalance removes the effect of vertical masses in the system and protects from damage in power- off situations. A counterbalance system is often used to reduce the weight and drag inherent in the linear motor driver and associated linear bearing guide systems; however mechanical counterbalance devices often exhibit more friction than is ideal.  Airpot’s Airpel –AB Air Bearing actuator used as a counterbalance device allows the use of lower cost and smaller linear motor drives which helps to reduce heat and the adverse effects of differing thermal expansion rates.  Air bearing technology enables levels of measurement and control previously unattainable with conventional air cylinders or mechanical cable counterbalance systems.  The actuators combine air cylinder-like linear actuation with zero friction air bearing technology.

The Airpel -AB provides “Force Without Friction” which is made possible by a specially shaped stainless steel piston that is precisely fitted to a borosilicate glass cylinder. The introduction of pressurized air into the air bearing’s cylinder creates a true air bearing airflow effect around the piston.

With as little as 5 PSI of air applied to the cylinder, the same air that drives the piston also produces a stiff cushion of air to support the piston and prevent it from contacting the cylinder wall.  The result is an air cylinder that delivers virtually unlimited piston life, no lubrication and clean operation. In addition, the output force of this friction-free air cylinder is reduced only infinitesimally by movement of ultra-low friction ball joints used to connect the rod. These unique qualities allow Airpot Corporation to guarantee that the Airpel -AB will exceed the life of any machine or instrument in which it is originally installed and operated in accordance with specifications.

“The Airpel -AB air bearing actuator is designed to fill a niche in the air cylinder industry where even the slightest friction, contamination, wear, or extreme temperature vulnerability of typical air cylinders cannot be tolerated.” said Mark Gaberman, President of Airpot Corporation.

Industries include, semi-conductor, optics, medical, and test and measurement. Applications may include, counterbalancing and safety support for vertically positioned linear motor driven masses, precise tensioning, positioning mechanisms supporting delicate materials, sensitive force control for holding or clamping fragile materials, or precise laboratory test equipment.

Airpel-AB air bearing actuators are available in metric models with four bore diameters and ten standard strokes to provide precisely repeatable driving or supporting forces from 2 grams to 58 kg. Operating temperatures range from -20 C to +90 C.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added subassembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visitwww.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information.service@airpot.com 203-846-2021, 800-848-7681.

Key Markets:

Semiconductor processing, Electronics assembly, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications:

Counterbalancing and safety for vertically positioned linear driven motor masses, filament & wire tensioning, positioning  and manipulating optics, liquids, delicate devices, super sensitive force control, , Measuring weight, creep, tensile strength and calibration.

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abactuator

Tension control in high performance industrial winding equipment used to wind filaments, ultra-thin wire, tape, textiles and cords for many kinds of products achieves new levels of performance in speed and force with the use of zero stiction and friction air bearing technology tensioning devices.  For years mechanical systems for tension control such as dancer arms, take ups and similar devices have limited the sensitivity and control of winding operations possible due to the inherent friction and drag in the mechanical interface.  Airpot Airpel –AB air bearing actuators used as tensioning devices, overcome these limitations and allow super -sensitive measurement and control of winding  speed and force assuring consistent product quality and lower manufacturing costs.  The actuators used as tensioners, combine air cylinder-like linear actuation with zero friction air bearing technology.

The Airpel -AB provides “Force Without Friction” which is made possible by a specially shaped stainless steel piston that is precisely fitted to a borosilicate glass cylinder. The introduction of pressurized air into the air bearing’s cylinder creates a true air bearing airflow effect around the piston.

With as little as 5 PSI of air applied to the cylinder, the same air that drives the piston also produces a stiff cushion of air to support the piston and prevent it from contacting the cylinder wall.  The result is an air cylinder that delivers virtually unlimited piston life, no lubrication and clean operation. In addition, the output force of this friction-free air cylinder is reduced only infinitesimally by movement of ultra-low friction ball joints used to connect the rod. These unique qualities allow Airpot Corporation to guarantee that the Airpel -AB will exceed the life of any machine or instrument in which it is originally installed and operated in accordance with specifications.

“The Airpel -AB air bearing actuator is designed to fill a niche in the air cylinder industry where even the slightest friction, contamination, wear, or extreme temperature vulnerability of typical air cylinders cannot be tolerated.” said Mark Gaberman, President of Airpot Corporation.

Industries include, semi-conductor, optics, medical, and test and measurement. In addition to tension control,  applications may include counterbalancing and safety support for vertically positioned linear motor driven masses, precise tensioning, positioning mechanisms supporting delicate materials, sensitive force control for holding or clamping fragile materials, or precise laboratory test equipment.

Airpel-AB air bearing actuators are available in metric models with four bore diameters and ten standard strokes to provide precisely repeatable driving or supporting forces from 2 grams to 58 kg. Operating temperatures range from -20 C to +90 C.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added subassembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visitwww.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information.service@airpot.com 203-846-2021, 800-848-7681.

Key Markets:

Semiconductor processing, Electronics assembly, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications:

Counterbalancing and safety for vertically positioned linear driven motor masses, filament & wire tensioning, positioning  and manipulating optics, liquids, delicate devices, super sensitive force control, , Measuring weight, creep, tensile strength and calibration.

abactuator

AirpelAB1

Airpot® Corporation announces its family of filter/regulator (FFR) products designed specifically for use with their low friction line of Airpel® air cylinders and Airpel –AB® air bearing controlled actuators. Airpot FFR systems offer engineers, designers and manufacturing professionals the precise control, optimal air quality and properly sized components needed to get the most from Airpot’s unique Anti-Stiction® and low friction technology. Each Airpot FFR system is a complete modular air preparation system composed of components selected by Airpot engineers, based on years of application experience with low friction pneumatic motion control products. These systems are especially suited for use with Airpot actuators and Airpel cylinders where low friction/low hysteresis, sensitive response, long life, clean operation, and extreme temperatures are critical requirements. Offered in both compact and standard configurations for moderate and high flow, Airpot FFR systems are available with standard or precision regulators for precise control and sensitivity for the most demanding applications, even those in which very low speed, and or pressure requirements exist.

All Airpot FFR systems are composed of lightweight aluminum/resin hybrid material which is 50% lighter than traditional systems built into a compact and modular 40mm x 40mm envelope per component (compact series). A simple two fastener attachment bracket system allows easy upgrading, maintenance and rearrangement of the modules. Standard and Precision series (with increased low pressure sensitivity) regulators are available; all with hand adjustability and single push lock operation. The precision series offers a pressure range of 0.005 to 0.4 MPa and sensitivity within 0.1% of the full scale. Port connections are available with NPT or G metric threads. Each system is equipped with dual filtration modules that remove particles, dust, oil, moisture and mist down to 0.01 micron assuring that the recommended quality of clean, dry compressed air is delivered to the actuators and cylinders.

This two stage filtration system is comprised of a 5 micron dust and moisture filter augmented by a 0.01 micron coalescing filter. The long life media transitions from a coarse outer surface to a fine interior structure to reduce clogging prolong life and prevent rust formation. All filters boast a standard corrosion resistant filter bowl guard, one quarter turn filter element removal and a unique O ring slip prevention design. FFR gauges offer highly visible color zone indicators, field adjustable limit marks, flat face design with a non- protruding (standard series, compact and high flow types) gauge embedded in the module made to JIS3 grade with either MPa or PSI readings.

Airpot® Corporation manufactures instrument quality, precision air dashpots, snubbers, pneumatic actuators, Airpel® Anti-Stiction air cylinders and Airpel-AB® air bearing actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot® Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visit www.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information. service@airpot.com 203-846-2021, 800-848-7681.

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications: Filament & Wire Tensioning, Positioning and Manipulating Optics, Liquids, Delicate Devices, Super Sensitive Force Control, Counterbalancing And Safety For Vertically Positioned Linear Driven Motor Masses, Measuring Weight, Creep, Tensile Strength and Calibration

“If someone has already worked out all the problems in a particular component and it is now available off the shelf at a reasonable cost, why spend time designing it all over again? Why absorb the cost of setting up to manufacture it yourself? “These questions arose when the members of the engineering team at Phillips Medical System of Shelton CT were designing a radiographic / fluoroscopic (R/F) system. Their subsequent decision to buy rather than build, the necessary part reaffirmed the validity of the basic axiom: “Don’t reinvent the wheel.”

The component in question, a snubber, was purchased from Airpot Corporation. As a matter of fact, not one but six of the model 160 snubbers were installed on each machine; each snubber in conjunction with a limit switch. Together they govern the travel of three trays as they are shuttled back and forth in the film plane to provide just right framing of the X-Ray photo. Called the ECG trays- Esophagus, Cone, and Grid- they must move quickly from side to side to cover all or part of the X-ray film, as desired and to provide the proper scatter protection. Travel of the trays is provided by toothed belts, driven by miniature motors. Because of their small mass, these motors provide no drag when turned off. Therefore, most of the kinetic energy (3/4 ounce-inch) developed by the trays, travelling at 2 ½ ips, must somehow be absorbed at the end of their travel, just before they strike the small limit switches too hard and damage them The snubbers accomplish this energy dissipation. These dashpots have often proven their usefulness where vibration must damped out, velocity must be controlled , shock must be absorbed, in short, whenever mechanical motion must be precise, free to respond yet under total control and undisturbed by spurious inputs. Because of their precision construction and compatible materials, these dashpots offer multimillion cycle capabilities. A particular advantage of the typical pneumatic dashpot is that it does no depend on liquids for its action, thus requiring no seals that can dry out or begin to leak after a while. Air is the damping medium, whose supply is plentiful, and whose infinite heat sink capability instantly dissipates the heat of compression generated by the dashpots action. Another benefit accruing from specifying this type of dashpot is that starting and running friction are almost identical. There are no humps to overcome, no bouncing, no vibratory forces introduced by the dashpot itself. Friction between the carefully matched glass cylinder and graphite-carbon piston is so low, that galling is avoided and no lubrication is ever necessary.

The snubbers in the Phillips system are a standard item, except for the length of the cylinder, which was determined by the application. Extending from the piston is a semi-flexible polyurethane rod which helps to absorb some of the impact and bends sufficiently to accommodate any slight misalignment between the tray and the snubber mounting.

Although the engineering department had originally considered designing its own special snubber to slow down the ECG trays, this approach was abandoned when it was found that off-the-shelf dashpots would be able to handle the task. The designer of the ECG trays, commented the following about the basic concept that was used. “When you’re out to build a new piece of equipment, unhampered by subliminal influences of the earlier models, you have a wonderful opportunity to try new ideas. In your eagerness to create something ‘brand new’, however, you should not ignore the time tested, successful results of others. The Airpot dashpots are a typical case of ‘something borrowed that has worked to our advantage.”

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visit www.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information. service@airpot.com 203-846-2021, 800-848-7681.

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications: Filament & Wire Tensioning, Positioning and Manipulating Optics, Liquids, Delicate Devices, Super Sensitive Force Control, Counterbalancing And Safety For Vertically Positioned Linear Driven Motor Masses, Measuring Weight, Creep, Tensile Strength and Calibration

Marketing Contact: Edward Keane edkeane@airpot.com

Technical Contact: Tom Lee tlee@airpot.com

203 846 2021 www.airpot.com

2KS325S

An Air cylinder that uses a carbon /graphite piston within a glass housing produces precise and repeatable motion during membrane switch testing.

A precision low friction cylinder with a piston that slides on a cushion of air is being used to provide reciprocating motion in membrane switch test systems. An Airpel air cylinder, produced by Airpot Corp. Of Norwalk CT. generates a virtually constant level of friction at air pressures from 10 to 100 psi. As a result, the Airpel minimizes erratic movements that occur as a piston begins its travel within a cylinder.

This characteristic is vital in the testing of membrane switches, a process in which the air cylinder must generate forces that are precise and repeatable. Membrane switches are part of flat panel displays such as those used to enter orders at fast food restaurants or to enter machine control data in factories. A key is pushed on the flat panel display, resulting in the deflection of a polymer layer with silk screened ink traces. The deflecting layer then contacts another polymer layer that is also patterned with ink. When the ink patterns contact each other, the switch closes. As a result, an electrical circuit is closed and a signal is sent to a computer controller. To verify the quality of these membrane switches the testing company designs and manufactures computer controlled test systems. For quality control a keypad manufacturer pulls a few switches at random from the production line. They are electrically connected to the test system and positioned under an actuator probe that continuously monitors and logs switch resistance values.

To gather data about a switch’s performance a typical test might involve 5 million on/off cycles. The life test system measures the electrical resistance of switches and sends the data to a computer controller. In the controller, the resistance measurements are compared with the maximum allowable measurement for a switch which has already been entered by the system operator. A failed cycle occurs when the resistance reading exceeds allowable limits. To reproduce the action of activating the switch, a device is needed to automatically simulate the movement of a finger. To achieve this engineers developed silicone fingers and connected them to the piston rod of an Airpel cylinder. Depending on the design of the display panel the air cylinder is required to provide a load from 4 to 40 ounces, These loads are required with panel displays that have flat keys or dome shaped stainless steel buttons that return to their original shape after the load is removed. In the case of flat panel switches the air cylinder is required to hold the mechanical finger 1/32 inch. With the dome shaped tactile displays the Airpel typically holds the silicone finger 1/32” above the button and then deflects the button 1/16”.

A separate use of the air cylinder involves the testing of membrane switches that are part of touch screen display systems such as those used in automated bank tellers. In this example loads on the display buttons are from 2 to 4 ounces. The air cylinder does not apply direct pressure but lowers a weight on to the screen to activate the switch.

The air cylinder is microprocessor controlled to perform within test limits and tolerances during the test system’s development. “Electrically powered linear actuators are not an option,” according to the engineer. “They cannot achieve the precise control of force that is required in this application.” Design engineers considered using conventional air cylinders with rubber seals but they realized that due to erratic piston movement these would not provide the required control over force either.

A common load requirement for membrane keypads is 10 ounces. A conventional air cylinder produces a range of forces that generate loads that vary between 7.5 and 13 ounces, According to the engineers. By contrast the range of the Airpel cylinder varies by only plus or minus 0.2 ounces from .8 to 10.2 ounces.

The primary cause of erratic piston movement in conventional air cylinders is contact between the elastomer seals and air cylinder surfaces. A gradual increase in air pressure leads to a breakaway motion by the piston as it overcomes friction. However, it is extremely difficult to consistently control the movement of the piston during this breakaway phase. Membrane switch testing requires tight control not only over the piston rod’s linear movement but also over its lateral movement. It is important that the piston rod return consistently to the same location. Moreover, the Airpel and silicone rubber fingers are required to operate in an environment chamber at temperatures that cycle between -40 and 105 degrees C. Two conventional cylinders of different deigns were needed to span the range of temperatures.

The Airpel has two air chambers, one behind the piston and another in front of it. It consists of a carbon graphite piston custom fitted inside a glass cylinder. The gap between the piston and the cylinder is only 0.0005” and the roundness specification for the cylinder and piston is 0.0001” When the cylinder is pressurized, the piston rides on an air cushion formed between the piston and the glass wall. The piston rod slides on a carbon graphite seal and low friction bushing.

Design engineers at Airpot selected a pivot pin as the connecting component between the piston and its rod. The pivot pin allows the piston to realign itself in the cylinder should the cylinder be subjected to lateral forces. In this case the pivot pin allows the piston to float radially to realign itself. The resulting design produces extremely low friction along the length of the piston’s travel.

To make the cylinder rugged, the engineering team at Airpot designed a steel tube to encase the cylinder and piston assembly. The air gap between the glass cylinder and the steel tube allows the cylinder to continue to operate even if it is dented. During development tests the Airpel cylinder withstood the striking impact of a 10 pound weight and continued to function as required. The air cylinder operates for more than 25 million cycles. It requires no lubrication, which eliminates the potential for oil contamination. Such a characteristic is useful in industries such as food processing and semiconductor manufacturing, where cleanliness is key. Moreover, the Airpel cylinder eliminates the potential of fires fueled by oil.

In comparison tests, piston motion in the Airpel cylinder is smoother than piston motion in a comparable conventional air cylinder. According to Airpot, at 10 psi it takes 25% of the air pressure to overcome static friction in the conventional cylinder. Only 1 psi of air pressure is required to overcome the static friction in the Airpel cylinder.

The Airpel cylinder works best with loads that are between a few ounces and 30 pounds. The air cylinder is particularly suited for use in applications that require smooth motion at extremely low pressures and for moving lightweight objects at either low or high speeds.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visit www.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information. service@airpot.com 203-846-2021, 800-848-7681.

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

Key Applications: Filament & Wire Tensioning, Positioning and Manipulating Optics, Liquids, Delicate Devices, Super Sensitive Force Control, Counterbalancing and Safety For Vertically Positioned Linear Driven Motor Masses, Measuring Weight, Creep, Tensile Strength and Calibration

Marketing Contact: Edward Keane edkeane@airpot.com

Technical Contact: Tom Lee tlee@airpot.com

203 846 2021 www.airpot.com

800-848-7681

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An important high technology manufacturer builds processing equipment used in the fabricating of semiconductor integrated circuits. One operation in their chemical / mechanical polisher (CMP) involves lowering a cassette of silicon wafers into a rinse tank, then raising it. This sounds simple enough but a cassette can contain as many as 25 wafers etched with patterning for advanced- memory or microprocessor components. A full cassette of wafers can be worth more than $1 million, so smooth, precise and reliable elevator motion is important – for both operating and aesthetic reasons.

Older machines used a servomotor and precision ball-screw to raise and lower the cassette in incremental steps. When a new design eliminated the need for steps and called only for top- to- bottom travel, the lead senior design engineer, decided to investigate the use of air cylinders for this movement to reduce the cost.

The cylinders had to stroke 12 in. to immerse the cassette fully in the rinse tank and then to raise it to interface with a handling robot. Because this machine operates in a clean-room environment, no lubricants or particle-generating mechanisms can be present. In addition, the cylinder is exposed to harsh chemicals- for example; polishing slurries are present that can have ph’s that range from a very basic 1.5 to highly acidic 13.

From experience, the engineer knew that their inherent stiction would prevent most air cylinders from starting and stroking with the high degree of smoothness required in this application. He also knew that typical elastomeric seals could not meet the cleanliness specifications, nor could other materials used in typical air cylinders survive in the chemical environment. These limitations led him to Airpel pneumatic cylinders, built by Airpot Corp.

Airpel cylinders have no elastomeric seals between the piston and cylinder walls or between the rod and cylinder head. Instead, the Airpel design places a precision carbon/graphite piston inside a Pyrex glass cylinder-with a 0.0005 in. air gap surrounding the piston. The piston floats inside the barrel using air bearings principles. Instead of a rigid connection between piston and piston rod, a biaxially pivoting arrangement allows the piston to maintain its orientation despite lateral loading. These techniques dramatically reduce both static and dynamic friction, without lubrication.  As little as 0.1 PSI can initiate movement in unloaded Airpels.

Rated for 100-PSI pressures, with an operating temperature range from -65 degrees to 150 degrees C, Airpels are well suited for applications that call for very smooth motion, low speeds, or short strokes, or where only low pressure is available. But they also will produce the same range of motions as conventional small air cylinders. To make the cylinder more rugged, Airpot adds a stainless-steel, impact- protection sleeve over the glass barrel, with a gap between the two. This protection lets the cylinder withstand impact testing with a 10 lb. load and continue to function.

While Airpel cylinders performed well during the initial tests, the elevator assembly did not quite meet the stringent motion requirements. Friction in the linear-guide mechanism and the variation in loads between full and empty cassettes resulted in motion that still was too irregular. The designer decided to see if he could actuate the CMP cylinders with water and capitalize on its incompressibility to achieve the smooth motion he wanted. This decision presented another problem. To meet the cleanliness requirements of the CMP machine, pressurized de-ionized water had to be used to drive the cylinder. And de-ionized water tends to corrode many materials. In particular it eats aluminum pretty quickly. To circumvent the corrosive effects of the de-ionized water, Airpot made some design modifications on the standard Airpel, These amounted to replacing the nickel plated aluminum piston couplings and cylinder heads with stainless steel components.

To test the modified cylinder, the designer used a 5 lb load and canted it at a 4” angle adding side loading to exaggerate the wear potential. With the raise-lower speed set at 6 in/sec. the modified water-powered Airpel was cycled more than a million times with no degradation in travel rate. (A small amount of demonized water leaked past the gap around the piston and was collected in a drain pan for disposal.) Testing on the actual elevator assembly followed, and the water actuated cylinder met all design and performance specifications.

Airpot Corporation manufactures instrument quality, precision Air Dashpots, Snubbers, Pneumatic Actuators, Airpel Anti-Stiction Air Cylinders and -AB Air Bearing Actuators. Airpot welcomes custom requirements and works with customers to adapt products to suit their individual application needs. Value added sub-assembly services are also a specialty. Airpot Corporation is a trusted supplier to many of the world’s most prestigious original equipment manufacturers. Visitwww.airpot.com for detailed specifications. Call or email our technical staff for application assistance and ordering information.service@airpot.com 203-846-2021, 800-848-7681.

 

Key Markets: Semiconductor, Electronics, Medical Devices, Metrology, Test & Measurement, Laboratory Diagnostics.

 

Key Applications: Filament & Wire Tensioning, Positioning and Manipulating Optics, Liquids, Delicate Devices, Super Sensitive Force Control, Counterbalancing and Safety For Vertically Positioned Linear Driven Motor Masses, Measuring Weight, Creep, Tensile Strength and Calibration

Marketing Contact: Edward Keane edkeane@airpot.com

Technical Contact: Tom Lee tlee@airpot.com

203 846 2021 www.airpot.com

800-848-7681

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