Intech Power-Core Thermoplastics Engineering Blog

Cannex 2013 - Booth 934 Atlanta May1-3 2013

Cannex 2013 May 1 -3.  Intech is proudly presenting its full line of light-weight , long wearing, and self lubricating components for the can making industry. Stop by Booth 934 for more information about Intech's patented self lubricating Square Rams for Belvac Neckers, Our Patent Pending line of Cam Followers, and our full line of necker and body maker gears, Inker blades, and air selector face seals.

Following in the tradition of engineering and manufacturing light weight, self-lubricating gears and cam followers, since 1993 Intech has been developing long wearing, lubrication free machine components for the can making industry. These components, some running several times longer than the original components, reduce operating costs by eliminating lubrication, allowing increased output by lowering inertia and by reducing the amount of maintenance and down time through increased component life. Reduced energy consumption comes as a welcome bonus.

 

Eliminating lubrication while increasing machine speed and at the same time reducing wear and extending components’ life seems contradictory, yet we accomplished this goal by using new light weight materials, advanced coatings, and by improving existing design.  We also use the latest engineering software to design and calculate the structural integrity of the parts.

 

Our engineers spent time analyzing the reasons for high wear, high rejection rates and component’s premature failure. Based on the analysis, we were able to design parts to counter the forces leading to wear, failure, etc., often developing new engineering calculations to assess the useful life of the components. In the process we registered several patents. Our efforts are rewarded with parts that last beyond our initial expectations, and produce savings greatly improving the ROI. For example, many of the patented Intech square rams initially installed in the year 1999 on a 595 Belvac necker are still in operation, continuously running between 2450 and 2700 cpm without lubrication, and a measurement of  electrical consumption on the 795 line with installed Intech rams show 25% energy savings.

 

With the introduction in 2006 of Intech composite cam followers in the necking operation, we have succeeded in developing a 100% self lubricating ram. No more grease build-up on the turret and perhaps more importantly, no more cam wear. 

 

Download a whitepaper on how and why Intech designed it's patented sqare rams by following the link below:

Polymers Impellers Fight Cavitation Wear In Pumps & Hydraulic Systems

You might not think that bubbles are much of threat to solid surfaces. But engineers who have encountered cavitation wear know otherwise.

Common within pumps, valves and hydraulic components, cavitation occurs when sudden changes in liquid pressure create voids or bubbles. Typically, these bubbles form in response to and in close proximity to moving surfaces within a liquid medium.

When the bubbles eventually collapse, they generate enough energy to induce a pitting-type wear on nearby surfaces. This wear doesn’t happen instantly, since the energy released by the collapsing bubbles is relatively low. Over time, however, the collapsing bubbles do produce localized, cyclic impacts that can fatigue even the strongest of steel surfaces.

A pump impeller is a classic example of a moving component that can both cause cavitation—and suffer the consequences of cavitation wear.

Polymers resist cavitation wear. It may be counterintuitive, but polymers can actually do a better job than seemingly stronger metals when it comes to enduring cavitation wear. The reason is that inherent elasticity of polymers allows them to absorb the energy released by the collapsing bubbles.

Yet, not all polymers should be considered a good fit for applications that suffer from cavitation wear. Keep in mind that cavitation implies a continuous exposure to liquid. And many types of polymers simply will not tolerate liquid exposure for long periods of time—not without dimensional changes or degradation in physical properties.

One polymer that can tolerate the long-term exposure to many types of liquids is the polyamide that serves as the base polymer for Intech Power-Core™. We’ve theorized for years that it would be an outstanding choice for pump impellers, hydraulic valves and other components that are subject to cavitation wear.

Recently, we backed up our theories with cavitation tests that compared Power-Core to various chromium-nickel alloy steels under conditions that simulate those found in high-pressure pumps. The results show that the steel alloy loses significant weight over time, which is an indication of the pitting caused by cavitation. The Power-Core, by contrast, exhibits no weight loss, or wear, whatsoever.

To learn more about cavitation wear, download our application note, “A Polymer Solution To Cavitation Wear Problems.”

Large Underwater Gear Highlights Nylon's Moisture Resistance

Wear and moisture resistance are two recurring themes in the engineering problems solved by Intech Power-Core™. Oftentimes, these problems involve small components, such as gears, cam followers or rollers. Yet Power-Core’s wear and moisture resistance properties can just as easily apply to large parts. Consider, for example, the large geared ring produced in our material for underwater use in a nuclear reactor pool. Measuring 2,200 mm across and 80 mm thick, this geared ring weighs in at 100 kg. It withstands a load of 150 kN at 6 rpm.

Large Part Size, No Problem. The sheer size of the part stands stands out, but our gravity casting process actually allows us to scale up the size of our components easily. Gravity casting results in low internal stresses, even when the parts have metal structural inserts. So going “big” is not really an issue for Power-Core.

Physical Property Advantage. What was even more important in this underwater application were the physical properties of the polymer. The geared obviously needed to be produced from a material that resists continuous exposure to liquids and corrosion. Various metals fell short due to their poor corrosion performance compared to polymers such as Power-Core.

Many other polymers, however, do not tolerate long-term exposure to moisture. Power-Core does. Its ultra-low moisture uptake allows it to remain dimensionally stable even when submerged in water for long periods of time. In this nuclear application, Power-Core’s radiation resistance also weighed in its favor over other polymers. And its wear properties allow it to avoid the fretting that can occur when component surfaces rub together in the presence of water.

In this application like in most applications engineers had a selection of materials to choose from. The common conception of most engineers when it comes to wet environments is that a polyester material such as ERTALYTE or an Acetal (POM) would be the best choices. In many cases these engineers would be on the right track - both materials are excellent in many applications - however for underwater gears specifically these materials wouldn’t be able to accomplish the task. For one the size of the gear leaves only very few material options, second when using Ertalyte or Acetals you have to be very careful what type of environment you expose them to – chlorine – like that found in drinking water could destroy the polyester compound over time and Acetals don’t react well to acids such as those used in wash downs, and booth are susceptible to weakening caused by extended UV exposure. 

Most Nylons, on the other hand, perform poorly when submerged in water, so naturally engineers tend to steer away from the entire nylon family when designing underwater motion systems. Powercore has a unique place in the family of Polyamides in that its moisture absorption, even when fully submerged, is negligible.  Our site contains numerous studies and documentation showing the effects of moisture absorption on nylon and nylon 6 and nylon 12’s dimensional change when submerged. When designing your next motion system of marine or underwater use please remember to consider the environment and look of a suitable polymer for your application.  

Polymer-Steel Hybrids For Heavy-Duty Rollers For Rack Feeders

Metal or plastic? In many load transmission applications, the choice will be clear-cut based on loads, lifecycle expectations and environmental conditions. There is, however, a third choice that involves both metal and plastic. Hybrid components that use a structural metal hub with a polymer load surface can offer the best of both worlds in load transmission applications. A good example can be found on a recent feeder rack application that uses a set of rollers made by casting our Power-Core™ material over a steel hub. The rollers, which measure between 250 and 500 mm across, had to withstand high static and dynamic loads. At the same time, they also had to do operate smoothly, in part to minimize frictional heating and in part to minimize noise.

Early in the project, it became clear that a hybrid solution would be the best way to meet all the application requirements. The steel hub provides the needed structural strength, while the Power-Core bearing surfaces reduce wear, frictional heating and noise in ways that all-steel rollers could not.

The right plastic. Power-Core isn’t the only polymer that can be used in applications like this one, but it emerged as the best one for a couple of reasons:

• Power-Core is based on a nylon-12 that exhibits at least double the load capacity of polyurethane elastomers, the next-best alternative.
• Power-Core resists the flattening and flexing of elastomeric polymers, which is a key advantage in loaded rollers remain in one place for any part of the duty cycle.
• All Power-core Non Greased Cam Followers and Heavy duty rollers are calculated to last for the life of an application and exhibit excellent noise, vibration, and shock dampening while also having tremendous life expectancies and corrotion resistance. 

To learn more about Power-Core’s use in hybrid rollers, cam followers and other motion components, download our white paper “Enhancing Motion Systems With Plastics.”

 

Actuator Redesign For High-Speed Belvac 795 Can Making Machine

Though the necker on a can making line performs a very specialized task, the mechanical subsystems found on this machine offers a number of design lessons that can be applied more broadly by any engineer working to improve the performance and reliability of high-speed equipment.

Consider, for example, the necker’s cam-driven ram actuators. Mounted on a rotating turret and moving at speeds up to 250 strokes per minute, these rams push the round can shell onto a series of shaping dies that gradually reduce the diameter of the can to form its neck.

Traditionally, these Belvac rams have consisted of a round moving pin that translates axially within a barrel-like steel housing, with a machined keyway to keep the pin from rotating. The ram was driven directly via a pair of metal cam followers that mount on the rear end of the pin and engage a stationary cam.

That design, however, suffered from three problems in the field. For one, it required an aggressive lubrication regimen to combat ram and cam wear. For another, it allowed the pin to lift and twist in the barrel, causing premature wear that extends all the way back to the can. And lastly, the traditional design limited the operating speed of the necker.

We eliminated all three problems with a radical redesign of the ram that:

• Eliminated the need for lubrication. The redesign replaced lubrication-hungry metals with lube-free polymers wherever possible. The redesign completely does away with the metal-on-metal wear between the cam and cam followers, which had been the primary failure mode with the traditional ram design.

• Optimized the geometry of the ram. The redesign features a square ram, rather than round. The square ram does a far better job at managing the actuator’s on- and off-axis forces. It also guides the pin more effectively, reducing wear.

• Removed moving mass. Thanks to the use of polymer components and structural aluminum, the redesigned ram weighs in at less than half the weight of the traditional round ram design. Total reduction of moving mass on a 10-stage line is nearly one metric ton.

Now in use by can makers around the world, the redesigned ram has offered a compelling payback. It has resulted in reduced maintenance costs, including the elimination of expensive automated lubrication systems. It has also contributed to reduced defect rates and faster line speeds.

Learn more about the redesign in our latest design case study, Redesign Improves High-Speed Can Making Machine. The case study offers a deeper look at our design process, including a glimpse at the finite element analysis (FEA) work that guided some of our decisions. The case study also highlights the side-benefits of designing for lubrication elimination.

 

Powercore Offers Unique Balance Of Properties

From cheap plastics to the world’s most expensive composites, many types of polymers have been machined, molded or cast into power transmission components.  We’ve focused our development efforts on the use of a proprietary, gravity cast Polymer called Power-Core®.

Thanks to the interplay of its intrinsic physical properties and low-stress casting process, Powercore represents the ideal material choice for power transmission applications. Here’s why:

Remains Stable and Dampens Vibrations.  Power-Core has an unparalleled ability to maintain its physical properties under a broad range of operating conditions. This stability allows us to make highly accurate predictions of the material’s behavior and lifecycle even when the application has variations in moisture, temperature and chemical exposure.

In particular, Power-Core’s stability in persistent high-humidity or total-immersion conditions makes it uniquely well-suited to power transmission applications and sets it apart from other polymers. Unlike Power-Core, most high-performance polymers absorb moisture. As they do, they lose their tensile strength and swell. Power transmission components made from moisture absorbing, or “hygroscopic,” polymers can end up too weak to carry the loads they were designed for and too swollen to work with mating components.

For an idea of how severe the moisture problem can be, consider the difference between Power-Core and the much more common nylon 6. While both are nominally “polyamides,” powercore outperforms other nylon 6 and nylon 12's dramatically as moisture content increases.

Power-Core also exhibits excellent vibration damping characteristics, which contributes to its ability to reduce noise and absorb the shock loads commonly seen by power transmission components.

 

Eliminates Internal Stresses. Power-Core isn’t just a material but also a manufacturing approach that encompasses gravity casting and precision machining. We gravity cast the Power-core over metal hubs or thermally install it over rollers bearings to produce the beginnings of a cam follower, roller or gear. We then precision machine these blanks to form a finished component.

With engineering polymer applications, the interplay between manufacturing methods and the inherent polymer properties matters as much as the choice of the polymer itself.

Power-Core is no exception. In this case, the gravity casting contributes to low internal stress state that gives the polymer an inherently uniform crystalline structure. As a result, Power-Core components have a consistent machining resistance that improves overall machining precision–and allows the material to retain that precision over time. And under external load, the dense crystalline structure helps thwart the stress-induced cracks or swelling that sometimes force molded plastic components to fail prematurely.

 

Lube-Free Rotary Positioning for Cleanrooms and More

Intech’s Power-Core® rollers have found uses in applications ranging from industrial machines to transportation. Most of them have seen use in linear motion systems of one kind or another, but there’s no reason that these gravity cast nylon 12 rollers cannot be incorporated into rotary motion systems such as our new rotary index table.

Designed for integration into third-party servo systems, this new rotary index table makes extensive use of rollers and gearing made from Power-Core gravity cast nylon 12. The table’s drive mechanism consists of a pinion-driven ring gear whose helix tooth profile eliminates wear and backlash. The gravity cast nylon 12 gear is machined from a polymer blank that has been cast around an aluminum ring. This ring serves as a circular rail and as the mounting surface for the payload.The Power-Core nylon 12 rollers, which mount on the unit’s base plate, support the rotating gear and integrated mounting surface. They feature enclosed stainless steel bearings, making the unit suitable for washdown and other corrosive environments.

The use of gravity cast nylon 12 for the drive and bearing elements helps this rotary table outperform all-metal designs in several ways:

•  Low wear without lubrication. This design avoids the metal-on-metal contact that can shorten the working life of motion systems. The only contact is between two Power- Core nylon components in the case of the drive mechanism and between Power-Core and aluminum in the case of the supporting rails. Power-Core nylon is formulated with an internal lubricant, so no external lubricant is needed. The metal bearings are lubed for life too.
• Backlash free. Power-Core gravity cast nylon 12 gears offer a couple of intrinsic advantages when it comes to reducing backlash. For one, their dimensional stability eliminates the need for the backlash compensation required by moisture-sensitive plastics. For another, the uniform crystalline structure of Power-Core nylon 12 and our gravity casting production methods produce gear blanks with very low internal stresses and uniform machining resistance. These characteristics allow very precision machining of tooth profiles that have been optimized for backlash reduction–and would be difficult to achieve in metal. 
• Fast and smooth. The low-inertia of the gearing and
  the rollers helps the table operate at higher speeds. By producing a tighter inertia ratio between the motor and driven load, the low inertia of the Power-Core drive components also makes it easier to tune the controls for a smooth, precise motion profile, particularly when moving light payloads. 
• Washes down, resists chemicals. Power-Core nylon 12’s dimensional stability in the presence of moisture and its thermal stability make this rotary table a good fit for washdown, high-humidity and high-temperature applications that would prohibit the use of less capable polymers. Nylon 6, for example, can exhibit a dramatic loss in tensile properties and undergo dimensional changes when exposed to moisture and high heat levels. Power-Core nylon 12 also offers excellent chemical resistance compared to nylon 6 and other polymers used in power transmission applications. 
• Cleanroom friendly. Because Power-Core nylon 12 resists wear and does not throw off the particulate associated with externally lubricated metal power transmission components, clean room use is a natural fit for this rotary table design. 
• Scaleable. By manipulating the size of the gear and roller components, the table design can be scaled to handle payloads ranging from ounces to tons.
  

Plastics Improve Roller and Cam Follower Performance

When designing motion systems that require rollers or cam followers, many engineers still believe that only all-metal components will fit the bill. Yet rollers and cam followers with polymer bearing surfaces have emerged as a high-performance alternative to traditional metal components. 

In heavily loaded applications, polymers can withstand enormous forces if designed properly. For example, we’ve engineered and delivered polymer rollers that can withstand continuous forces up to 8 tons.

Most applications, however, are not so heavily loaded. The primary role of the roller or cam follower is to transmit motion, rather than support hefty loads. In these applications, off-the-shelf rollers and cam followers will do a good job without the need for custom engineering.

And increasingly, these off-the-shelf products are not made entirely from metal. Instead, they are hybrid designs that consists a polymer load bearing surface over a metal roller bearing or structural hub. Sized as drop-in replacements for standard sized metal rollers, the hybrid rollers offer some compelling technical advantages thanks to their use of polymers. 

These advantages include:

• Self-lubrication. The engineering polymers best used for rollers, most notably gravity cast nylon 12, exhibit an internal lubricity that lasts for the life of the component. Bearing surfaces made from these polymers require no external lubrication between the roller and the rail, eliminating on-going maintenance costs and reducing the risk of failure.

• Improved Wear. Even with some lubrication, metal-on-metal contact can result in excessive wear and galling. Plastic rollers eliminate this wear mechanism altogether. 

• Contamination Reduction. Self-lubricated polymers eliminate two potential sources of contamination—stray lubricant and particulate from metal-on-metal contact. 

• Smooth and Quiet Operation. Unlike metals, polymers such as gravity cast nylon 12 have the ability to dampen shock and vibration. 

• Speed and Efficiency. Because they weigh about 40% less than similarly-sized metal rollers and cam followers, polymer products facilitate high-speed, energy-efficient motion.

• Environmental Tolerance. Rollers made from gravity cast nylon 12 do not swell in moisture and also tolerate chemical exposures and temperature fluctuations. 

• Cost Reduction. The true cost of cam followers and rollers has very little to do with their purchase price and everything to do with their lifecycle cost. Polymers save money over the long haul by eliminating the need for lubrication, extending maintenance intervals and eliminating metal-on-metal wear.

Our latest white paper delves into the technical advantages of gravity cast nylon-12 rollers and cam followers. It includes detailed comparisons nylon 12 with both metals and other plastics. Download it now.

Anti backlash gear design at the heart of clear tomography imaging

 

Special gear design is at the heart of clear image in multi-axis tomography device.

For the rotational machines used to gather dental X-ray images, motion chatter can produce a fuzzy image, which is not suitable for diagnostic purposes.

Panoramic radiography is a branch of rotational tomography where the creation of images are through the movement of a source and receptor in such a way as to cause the foreground and background structures to blur, leaving a defined focal trough.

As a panoramic radiographic device, the Vantage Panoramic X-ray System, designed and manufactured by Progeny, Lincolnshire, IL, incorporates a DC X-ray source, CCD digital receptor, distributed processing circuitry, and an LCD touchscreen control panel for ease of use. What makes the Vantage system unique is that it is adjustable to the patient’s height via a motorized, 3-speed, telescoping column. The use of multiple lasers is to locate the patient and configure the device to the patient’s morphology. In addition, a workstation coordinates the individual processors.

The system incorporates an overhead, swing arm (lateral Y-axis) that supports a C-arm, which is the rotating member that moves around the patient’s head. The C-arm includes a tube-head, which produces the X-ray beam, and a removable CCD sensor, which is the digital image receptor. If this arm does not operate smoothly, a distorted image results.

The swing arm pivots on bearings located in the mounting casting fastened at the top of the column. Producing its motion is a ball screw drive, one end of which connects to the mounting casting and the other end to the swing arm. A step motor mounts at the column end. Both mechanical connections of the drive assembly are through ball bearing assemblies.

Suspension of the C-arm is on a pair of bearings mounted to the underside of the X-axis translation plate. The C-arm casting incorporates a 10" ID internal tooth ring gear that meshes with a pinion gear on a step motor mounted on the stationary X-axis translation plate. The motor is spring-mounted to maintain positive mesh and to minimize slop. The internal ring gear and pinion are sized and shaped to engage on the inside surface of the C-arm. With activation of the motor, the stationary pinion engages the teeth in the internal ring gear causing rotation of the C-arm.

The engineering team at Progeny worked with Intech to help design the C-arm casting and its interface with the gear drive for the C-arm’s rotation. Design of the company’s Power-Core products is specifically to reduce noise and vibration and run without lubrication, an important factor (a must) for medical equipment designers. Intech components are far lighter in weight than metal parts and offer longer life (less wear) and lower maintenance costs. Intech engineers used a proprietary gear load/life calculation to verify that the gears designed into the dimensionally restricted place would last at least 8,000 hours of operation or about 15 years in field use.

The challenge was to design a backlash free gear to produce a steady rotational movement of the image producing components. There was no room to employ the traditional split gear design. To eliminate backlash, installation of a spring, on slight angle relative to the axis connecting the gear centers attached to the pinion, pulls the pinion toward the 10" ID internal ring gear. The spring arrangement did eliminate the backlash, but caused the gear teeth to bottom out, resulting in chatter. The chatter registered on the X-ray image.

The precision gearing for the Vantage Panoramic X-ray System uses Intech’s Power-Core nylon materials for reduced chatter, resulting in clearer images from the system.

Drawing on its expertise in gear design, Intech engineers designed and precision-machined the pinion and the internal gear to incorporate a special contact surface, which allowed the components to control the center-to-center distance between the inner tooth gear and the motor pinion. Adding the center-to-center distance management element presented a method for precise gear positioning in the mesh, and drastically reduced system vibration generated by the spring force and the resulting bottoming out of the gear teeth in the earlier design.

This configuration provides precise control over gear mesh vibration and backlash, resulting in high image quality in both a clockwise and counterclockwise rotation of the C-arm. It also adds a robust design element, which helps to increase product life so that image quality does not degrade with component wear and tear. With no fuzzy imaging due to chatter, dentists can make better diagnosis and provide better service to their customers.

Shown is the Vantage Panoramic X-ray system with the C-Arm that holds the lasers as well as the removable CCD receptor..

 

This article was featured in Today's Medical Developments magazine and can be viewed at http://www.onlinetmd.com/TMD-0912-motion.aspx

How to avoid design compromises when the equipment function calls for cam followers

 

How to avoid design compromises when the equipment function calls for cam followers

Engineering design is an art of compromise. To achieve a design goal — for example, a certain machine function — engineers select components based on several criteria such as functionality, reliability, component’s availability, cost, and lead times. Pro and cons are analyzed and final selection made.

In the case of cam followers, in the past engineers did not have a choice other than selecting the manufacturer. With few options available, the engineers were forced to accept a host of costly requirements and operational limitations.

Whether the application calls for high or low load capacity, the design has to provide for lubrication either manually or through a central lubrication system. Rail or cam surfaces have to be hardened. In operation, lack of lubrication of the bearing or the rail surface can lead to a catastrophic failure. Over-greasing can lead to the cam follower’s skidding, causing wear, and excess grease can contaminate the product being processed.

In addition, shock and vibration can cause metal to metal impact that has to be considered. Metal particles and grease contamination often prevent equipment manufacturers from entering the growing clean room market. The relatively low rotating speed of needle bearings, their high rolling resistance, and inertia may be limiting factors in high speed equipment design.

When selecting Intech iCamFollowers® the designer can eliminate most of the disadvantages of metal cam followers. This is especially the case in designs where the cam follower’s primary function is to transmit motion and not its high load carrying capacity.

Today the trend is toward high speed, light weight, and light duty machines in processing, packaging, medical, and semi-conductor machines, which account for about 40 percent of applications. In these applications, Intech iCamFollowers® can easily carry the load, help simplify design, and better achieve the design goal.

Considering the cost associated with design and operation of metal cam followers, it pays to better understand the actual load carried by the cam followers in the application. With load data, including radial and axial forces, load duty cycle, and desired linear speed, Intech engineers can use a unique plastic roller life calculation to quickly assess whether an iCamFollower can be used.

The load capacity of Intech standard iCamFollowers® is listed on Intech’s web site and represents the maximum load the cam followers can safely carry for 100 million cycles, under both static and dynamic loads, without developing a flat or excessive wear. A consultation with Intech engineers may lead to an alternative designs, opening the way to eliminating wear and lubrication as well as the number of modifications in the machine’s design.

If iCamFollowers® can be used, the advantages, compared to metal followers are many:

For New Equipment:
* Simplified design- cost savings
* No need for surface hardening- can run on aluminum rails
* No rail or cam wear
* No need for lubrication- manual or automatic
* Reliability
* Higher machine speed- Lower inertia, low rolling resistance
* Shock absorption
* Wash Down- stainless steel bearings and shafts, sealed design
* Sub-zero temperatures
* Elimination of lubrication and metal particles can open new markets

In plant Operations:
* Eliminating Lubrication
* Eliminating rail and cam wear
* Cost savings on maintenance
* Cost savings on production shortfall
* Longer maintenance cycles
* Noise reduction
* Low cost to try if iCams work

 

 

 

Credits: As featured in Design World May 9 2011. http://www.designworldonline.com/how-to-avoid-design-compromises-when-the-equipment-function-calls-for-cam-followers/#_