Intech Power-Core Thermoplastics Engineering Blog

Explore The Ways Our Large Diameter Gear Integrated Bearings Shine in Difficult Environments

Posted by Georg Bartosch on Jan 13, 2021 4:49:23 PM

When the design calls for a large bearing—for example, to support a large outer diameter (OD) ring gear—choosing a sturdy yet lightweight mechanism with the properties and stability for reliable performance can be tough. Finding an appropriate bearing that can operate in cleanroom, food processing or vacuum environments, with all their hygienic requirements, can be an even greater challenge.

The list of bearing considerations is lengthy. It includes accuracy and rotational tolerances, load handling capabilities, maintenance and cost—just to name just a few. One factor that’s central to all of these considerations is the construction of the bearing and its constituent components. Not only must the bearing support accurate, efficient motion, but it has to satisfy the need for lighter designs, which has been a constant trend across many industries and applications. And if the bearing’s intended environment is a vacuum, it can’t disperse any contaminants. At the same time, lubrication isn’t an option, making your material selection critical.

Unique Design and Materials Excel in Special-Duty Applications

At Intech, we have expertise in designing and manufacturing self-lubricating, lightweight machine components that can operate in difficult conditions. Drawing on decades of experience with designing gears, guide rollers and cam followers using polymer materials, we recently developed a versatile, large gear-bearing unit that is well-suited for hygienic or difficult environments, as well as for other applications where precise rotary motion and lightweight designs are essential. This bearing features a novel design that combines two components into one unit: a large aluminum ring gear driven by a pinion and supported by several, individually mounted guide rollers. The large ring gear is typically made from aluminum, and the pinion and supporting guide rollers are made from our Power-Core™ polyamide-based thermoplastic material. When the unit has to operate in vacuum, the gear is made from stainless steel.

The large ring may have an internal gear, or the teeth can be machined outside the ring, and the drive gear is a Power-Core pinion with integral metal core. Spaced around the perimeter of the ring gear are the supporting cam followers that both locate the gear in place, axially and radially, and enable the rotating motion. (Picture 1) By using an engineered polymer as the bearing surface, these cam followers can withstand large forces, have a long wear-life and offer many additional advantages.

Intech Large Gear Bearing

Picture 1: Design principle of an iCam® support of a rotating gear ring with internal gear teeth.

Hybrid Construction Provides Many Advantages

The Power-Core engineered polymer offers several advantages versus other materials. It can handle high mechanical loads that are prohibitive to other plastics, and it even exhibits higher strength than similar injection-molded polymers. In fact, some of the larger structural parts we’ve designed have been able to withstand continuous forces of several metric tons. Despite our advanced polymer’s high strength, it’s also very lightweight.

When the unit’s weight and inertia is a concern, the ring gear is made from aluminum. Together in this unique design, the aluminum and polymer materials create a lighter gear/bearing unit and deliver a host of benefits for many applications:

  • Precision rotation. The precision machined outer guide rollers have a maximum OD tolerance of 0.004 inches and closely match the pitch diameter tolerances on the large ring gear. Additionally, any slag can be tightened up with selectively placed eccentric guide rollers.
  • No backlash. Besides the traditional methods to reduce or eliminate backlash in gears, our engineers developed several tooth mesh modifications for reducing or eliminating backlash, specifically designed to take advantage of the Power-Core’s elastic properties. Additionally, the Power-Core pinion features a cast-in metal core, which allows a secure attachment to a shaft and reduces up to 50% of the thermal expansion of the plastic portion of the gears. The polymer remains dimensionally stable under varying process conditions, including moisture, contributing to backlash-free rotation.
  • No need for lubrication. The polymer material we use for the gears and cam followers is maintenance-free, eliminating the need for lubrication even when running on aluminum, carbon or stainless steel.
  • No metal particulate contamination. Our Power-Core gears, cam followers or guide rollers do not wear out metal. As a result, they do not generate metal particles—which is an important feature in many industries and processes.
  • Reduced noise. Because of its shock absorbing properties and precision machined surfaces, Power-Core polymer reduces noise in gears by up to 6 dBa and up to 10 dBa compared to metal cam followers.
  • Lower cost. Using individual polymer cam followers to support a large ring gear eliminates the cost of, typically custom designed, large metal bearing. Further, Power-Core pinion and cam followers save money in the long term over metal parts because they don’t wear, corrode or require lubrication.

In addition, our Power-Core large gear-bearing design is especially suited for harsh environments, including vacuum conditions and environments subject to washdown.

Optimize Components to Fulfill Your Needs

If you need a large bearing that must meet strict requirements, achieve a long operating life or run without lubrication, chances are a large metal bearing isn't an option. And if you’ve never worked with an integrated-type bearing or one that’s made with our Power-Core material, you likely have questions.

We’re ready to assist you with designing your large diameter gear-bearing and can help you make predictable life-cycle calculations on both plastic or metal components. Our gear life calculator, for instance, uses an algorithm specific to Power-Core gears that lets you estimate the number of hours the gear will last in your application, based on torque, RPM, shock load and other operating parameters. The design of our cam followers and guide rollers is based on similar calculations.

For more information about our Power-Core large diameter integrated gear-bearing technology, or to get started with our wear life calculation, contact an engineer.

 

Contact an Engineer.

Greaseless Cam Follower With Hybrid Design Excels in Washdown Applications

Posted by Alexander Bartosch on Nov 11, 2020 3:59:03 PM

The wrong type of cam follower or roller can lead to contamination issues, frequent maintenance and reduced service life—especially in washdown applications. This is an especially important concern now that washdown chemicals have become more caustic under the FDA Food Safety Modernization Act (FSMA). In these environments, even traditional all-metal stainless steel cam followers are subject to corrosion and accelerated metal-to-metal wear, leading to premature failure.

Fortunately, you have another option in the form of a hybrid design. This maintenance-free cam follower combines a polymer load-bearing surface with stainless steel, ceramic or hybrid-ceramic ball bearings, enabling the cam follower to withstand even the harshest conditions.

Capped_iCams

The Power of Power-Core™ iCams®

Bear in mind, not all plastics will be equally suited for use in cam followers and guide rollers in washdown environments. With over 35 years of design experience, our engineers have selected polymers for washdown applications that can be precision machined, are dimensionally stable and don’t swell in moisture. These polymers are also highly resistant to chemicals and temperature fluctuations and exhibit excellent wear properties. Whereas traditional cam followers are subject to corrosion and wear, our Power-Core iCams® don’t corrode at all, making them a good fit for washdown applications, outdoor exposure and other harsh environments.

Eliminate Contamination From Grease and Metal Particulates

Fitted with sealed bearings, iCams’® self-lubricating, highly wear-resistant bearing surface eliminates two potential sources of contamination: stray lubricant and particulates from metal-on-metal wear, both of which could contaminate your product.

Because washdown liquids can wash off the grease, needle bearings in metal cam followers and the metal bearing surface, as well as the rail or cam that the cam followers are running on, require frequent lubrication. Lack of lubrication can significantly reduce the cam followers’ wear life. To eliminate this need for lubrication, Intech polymer cam followers feature sealed ball bearings, which are pre-lubricated for life. And the metal surface the iCams® are running on doesn’t have to be lubricated either. Thanks to this design, you can start your machine immediately after washdown, saving regreasing time.

In addition, the wear-resistant polymer outer racer doesn’t wear the metal surface it’s running on, preventing the generation of metal particulates. This is a frequent and highly undesirable source of particulates contamination with metal cam followers—especially in food and beverage and pharmaceutical applications. For these reasons, iCam® polymer cam followers and guide rollers are an excellent choice for food and beverage machines, as well as pharmaceutical, food processing, electronics assembly and other hygienic environments.

Save on Maintenance and Downtime

Besides saving on lubrication and avoiding product contamination, Intech iCams® offer additional savings by eliminating the need to replace worn metal components in contact with metal cam followers due to metal-to-metal wear. Insufficient lubrication between washdown sessions often accelerates this wear process.

For example, replacing a cam in a food processing or packaging machine—especially outside the scheduled maintenance window—can lead to prolonged downtime and production losses, not to mention all the maintenance overtime to minimize the lost production time. iCams® don’t wear out the metal surfaces on the machine components they’re running on, saving all the costs associated with replacing them and extending maintenance intervals.

Remember Your Bearings

And don’t forget, your choice of bearing matters too. iCams® with sealed stainless-steel bearings and shafts are the traditional, go-to choice whenever corrosion is likely. You also have ceramic options, which are preferred by customers who use more aggressive washdown solutions. These ceramic bearings reduce friction, feature a high static load capacity and don’t rust, which is especially appealing for hygienic environments. Two types are available, all-ceramic or hybrid ceramic bearings, the latter of which combines ceramic ball bearings with a steel race. The hybrid type can also withstand some shock load. Despite their many benefits, however, ceramic bearings tend to come with a hefty price tag compared to stainless steel.

Reap the Benefits of Higher ROI

The precision ball bearings used in iCams® exhibit low rolling resistance compared to externally greased needle bearings in metal cam followers. Over-greasing leads to more rolling resistance and often skidding—another cause of wear. In machines with several dozens of cam followers, low rolling resistance will result in lower drive power requirements and energy savings. iCams® also weigh about 40-percent less than traditional cam followers. The lower weight and rolling resistance enable our customers to increase their line speeds and line output. Higher line speeds, combined with all the other savings iCams® offer, deliver higher ROI to our customers.

Intech Corrosion and Wear-Resistant iCams®—Designing for New or Existing Machines

At Intech, whether we work with design engineers on new equipment or maintenance engineers on existing production machines, we’ve found that we can design our way around the problems associated with washdown, moisture and other environmental factors by picking the right type of polymer and bearing combination. If our standard cam followers aren’t a good fit for your application, we can design one that will. For example, we designed a capped iCam® that can handle high-pressure washdown.

To learn more about your cam follower options, please contact our engineering team. We’re also happy to verify the iCam's® load capacity and estimated lifespan in your application—free of charge. Ask us about samples for testing.


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5 Advantages of Plastic Rack and Pinions in Motion Applications

Posted by Alexander Bartosch on May 21, 2014 4:00:00 PM

 Polymer Eliminates Contamination in Linear Motion Systems 

In an ideal world, linear motion systems would run only in squeaky clean operating environments. In the real world, linear motion systems usually have to run in plants with varying degrees of contamination, chemical exposures or moisture. These less-than-ideal conditions can shorten the lifespan of linear motion systems that rely solely on metal drive components—particularly rack-and-pinions.

KLEENLine conveyor with Intech Gear self lubricating rack and pinion

(Pictured Above: Intech Power-Core™ Gear and Stainless Steel Rack in a High Speed Retractable Bakery conveyor - Read More Here )

To meet the challenges posed by real-world operating conditions, we have designed and delivered many rack-and-pinion systems based on our Power-Core™ polymer.  Typically these consist of an Intech Power-Core™ gear with a stainless steel core and a stainless steel rack, though some applications have been best served by a Power-Core rack and a stainless steel pinion. 

Either way, we’ve found that use of polymers has five key advantages in rack-and-pinion applications:

  1. Eliminates lubrication. As a self-lubricating polymer, Power-Core™ does away with the need to apply lubricants over the life of the rack and pinion. The elimination of lubricant eliminates a key source of contamination in sensitive applications such as packaging, pharmaceutical, semiconductor or food processing. 
  2. Extends wear life. Power-Core and stainless-steel together offer an extended wear life and typically last for several years longer than all-metal designs. The user of Power-Core has also allowed us to create some design features that further extend wear life—such as pitch line control feature prevents pinions from bottoming out.
  3. Prevents corrosion. Traditional rack and pinion designs with metal gearing are subject to rust and corrosion, particularly in washdown applications. As a polymer, Power-Core does not corrode at all.
  4. Remains dimensionally stable.  Thanks to the physical properties of its base polymer, Power-Core does not suffer from dimensional and tensile property changes that affect conventional polymers when exposed to moisture, chemicals or elevated temperatures. Power-Core's base polymer has one of the lowest moisture absorption rates of any engineering plastic. Power-Core stands up to a wide range of industrial chemicals.  And Power-Core exhibits about 50% better high-temperature performance than comparable engineering polymers. 
  5. Improves motion control. Power-Core can produce rack-and-pinions that operate both smoothly and quietly as the rack moves back and forth, reducing noise by about 6 dBa compared to all meal components. The reason is that polymer has intrinsic vibration and shock load damping properties.  Power-Core components also weigh about 85% less than a comparable metal component. In motion applications, this weight reduction translates directly to reductions in moving mass and inertia.

Rack-and-pinions based on plastics components do have to overcome the perception that they won’t be as durable or carry the same loads as the all-metal designs familiar to motion control engineers. However, we’ve proven that perception false time and time again. 

Our experience with gear design and predictive analysis has allowed us to design polymer rack-and-pinion systems that can and do outlast all-metal designs in highly-loaded applications. To learn more, give us a call.

Contact an Engineer

Tags: rack and pinion system, self-lubricating gears, gear design, r gear life calculation, custom gear design

Power-Core Plastic Components Take On Metals

Posted by Alexander Bartosch on Feb 27, 2014 8:17:00 AM

Even with all the advances in engineering polymers and processing methods, metal alloys still dominate the production of large parts used in power transmission and structural applications. And that dominance makes sense. Metals not only have the strength to withstand heavy loads over time but also have the advantage of familiarity. Most engineers know how to design with metals and how metals fail. Plastic properties can seem obscure in comparison.

It’s time, however, to shed some light on the capabilities of plastics in large part applications. Plastics can outperform metals in these some of these applications—but only under a very specific set of conditions:

  • Mechanical Properties Are Within Reach. To be sure, some large part applications have extremely high mechanical and thermal loads, which can rule out plastics of any kind. But don’t count out plastics prematurely. We have delivered larger polymer structural parts and power transmission components that withstand continuous forces of several metric tons. The key to these heavily loaded applications is picking the right material and manufacturing method. Our approach to large parts relies on a proprietary nylon material that we gravity cast. It has significantly different—and higher—strength properties than seemingly similar injection molded or cast polymers

  • The Application Requires Special Properties. No engineer in his right mind will replace a proven metal component with a plastic one—unless he has a good reason. Premature failure due to wear or corrosion represent two of the most common reasons to replace metal components with a high-performance plastic. The right plastic can eliminate wear altogether and resist corrosive environments in ways that metals cannot. Weight reduction is another good reason, since polymers like our Powercore (TM) weigh about 7x less than steel. The weight reduction comes in handy in many transportation applications where every ounce counts or in high-speed machines that have difficulties with inertia mismatches. Still other special properties revolve around the electrically and thermally insulatative properties of polymers.

  • Plastics Have To Cost Less. Plastics components often cost less than their metal counterparts, though their cost advantage is not always straightforward. Our Power-Core nylon material, for example, does not always offer an immediate cost reduction compared to metals. In fact, sometimes it costs more to produce the plastic component if it’s replacing a simple machined steel part. But the cost advantage will tip in favor of polymers over time whenever metal components fail prematurely due to wear or corrosion. Polymers also gain an advantage whenever they produce significant process advantage—such as higher speed or unit cost savings.The polymer component may also cost less because it eliminates the expensive lubrication needed to keep metal components running. When polymer components replace more complex metal parts, as opposed to a simple part, the cost reduction can be immediate. The reason boils down to a manufacturing edge. Polymer components can often be produced net-shape or near-net-shape, so they can cost less to produce then complex metal components that require multiple fabrication steps. A single casting can often replace multiple metal parts, producing more savings.

  • Polymer Properties Must Scale Up. A polymer’s physical properties won’t typically change with the size of the part. For example, a polymer that resists moisture will do regardless of part size. The inherent physical properties, however, paint only half the picture. Some polymer properties will change with size due to the influence of the processing method. Our gravity casting process, for example, can produce large parts without the internal stresses you would find in a high-pressure processing method such as injection molding. This low stress state is largely due to the resulting dense crystalline structure in the cast part as well as the gradual cooling in the mold. The low stress state allows the cast parts to remain dimensionally stable regardless of size. Indeed, we have produced parts that measure several meters across that have essentially the same dimensional stability parts measuring a few centimeters.

     Contact an Engineer

     

Tags: PA12GC, cast nylon 6, nylon 66, delrin alternative, gluing delrin, plastic welding, Nylon 6 Alternative, Cast Nylon Alternative, PA12G alternative, PA12C Alterative

Large Cast Power-Core (TM) Propeller Dives Into Paper Pulp Mixing

Posted by Alexander Bartosch on Feb 20, 2014 8:00:00 AM

Most engineering polymers won’t stand up to the harsh conditions found inside the mixing tanks used in pulp and paper processes. High shear forces, elevated temperatures, aggressive chemicals and continuous wear can mean an early death for ordinary polymer pumps and impellers. And in fact, internal mixer components are typically made from expensive stainless steel grades or platings, not plastics.

Our Power-Core(tm) PA12GC Gravity Cast monomer, however, is different than other engineering plastics, and it has emerged as a emerged as a cost effective alternative to composites and metals in tank propeller applications. This ability to withstand the challenging conditions found in pulp and paper processing also makes Power-Core(tm) a natural fit for other types of mixers and processing machines.

 

Power-Core(tm) has four key characteristics that allow its use in these propeller applications:

  • Resists Aggressive Chemicals. Power-Core resists the strong acids and bases found in pulp and paper processing. As a result, the material avoids the environmental stress cracking and brittle failure that would put an end to propellers made from less capable plastics.

  • Fights Wear. Because of their continuous contact with viscous liquids, mixer propellers tend to suffer from hydroabrasion. Power-Core has an innate resistance to this wear mechanism.

  • Scales Up. The propellers measure 1,500 mm across. So none of Power-Core’s chemical and wear resistance would make much of a difference in this application if the material didn’t lend itself to large structural parts. Regarding size, Power-Core’s proprietary gravity casting process can produce stress-free parts that measure more than 3 meters across. What’s more, the Power-Core gravity casting process allows the polymer to be cast over structural steel parts. The propellers, for example, have a structural steel hub to optimize the power transmission from the shaft to the blades.

Costs Less. No one would replace steel propellers unless there was a clear advantage to polymers. Power-Core has just such an advantage in the form of a longer life than steel, which tends to give into hydroabrasion prematurely. Power-Core also has a manufacturing advantage in that it can be cast net shape, eliminating expensive machining and finishing operations required by stainless propellers.

 

Contact an Engineer

Tags: PA12GC, paper pulp mixer, plastic for paper pulp, Voith plastic parts, cast nylon 6, PA12G alternative, PA12C Alterative

Modified Plastic Gears For Electronic Power Steering (EPS) Systems

Posted by Alexander Bartosch on Feb 13, 2014 8:00:00 AM

At the beginning of the 1990s Electronic power steering was just beginning to hit the main stream. Delphi - since bankrupt was on the forefront of the R&D. During a ten year period numerous tests were made with plastic gears as a choice for EPS systems. Power-Core(tm) PA12 Cast Nylon plastic gears were among the top finalists.

The polymer properties of Power-Core(tm), in particular the ability to cast and mechanically bond the polymer around a metal core - aluminum, steel or brass - and insure optimum power transmission with minimum creep. The shock dampening qualities of the material allow the gears to withstand both curb shocks and obstacle ride overs. The natural tendency of the material to  return to its natural position also adds to the quality of driver feel as noticed in cornering and general steering response.

In recent months we have had a number conversations on the topic of electronic steering, the core problems seems to be the same now as they were in 1990. Unfortunately, with more performance automobiles, namely the Porsche 911 and electric cars, moving to electronic steering we are excited to have a renewed interest in our power-core plastic gears and as car people look forward to one day driving a car that we can be certain has the best electronic steering possible.

Tags: EPS, Electronic steering gear, Column Steering Gear, Electronic rack and pinion steering gear

Power-Core Withstands Pulsed High Voltages

Posted by Alexander Bartosch on Feb 6, 2014 8:57:00 AM

The development of high-voltage pulsed power systems for both research and commercial applications has created a tricky design problem related to electrical insulation. Ceramics would be the traditional choice for bushings that insulate the metal electrodes in these systems, but ceramics are bulky and expensive to manufacture.

Intech Power-Core™ has emerged as compact, cost-effective alternative to ceramics. This gravity-cast nylon 12 polymer offers a combination of electrical and physical properties that make it uniquely suited to high-voltage pulsed power applications. These include:

When used in a recent experimental design for a pulsed electron accelerator, the Power-Core insulation was cast over the system’s stainless steel electrode to form an insulating bushing. Often these bushings will have to separate different insulating media—for example, vacuum on one side and transformer oil on another. So both low-outgassing and chemical resistance can come into play simultaneously.

One advantage of casting in this application has to do with the interface between the polymer insulation and steel electrode. Casting the polymer over a knurled surface on the electrode creates a seamless mechanical interface that helps produce a stable vacuum around the electrode and prevents any leak paths between the different insulating media.

To date, we’ve helped design and test insulation for pulsed electron sources up to 400 kV with pulse durations from 20 to 30 nanoseconds in vacuum, oil and gas environments. However, our experimental data suggests that Power-Core insulation bushings could withstand pulsed voltages to 1 MV. With more development work, Power-Core bushings could go even further—to voltages in the 5 to 10 MV range.

For more detailed information about our work insulating our pulsed power supplies:Contact an Engineer

Tags: cast nylon 12, electrically insulated, PA12GC, PA12C, PA12G, Cast Nylon, Nylon 6 vs Nylon12, Nylon Vs Delrin

Intech Gears Could Eliminate Noise From Your Segway Gearbox

Posted by Alexander Bartosch on Jan 30, 2014 8:56:00 AM

Does your segway make too much noise? Have you ever wondered where it is coming from? Segway drive gears in the segway gear box are all metal (figure 1)

Segway Helical gear Gearbox

The metal on metal movement, in this beautifully constructed helical drive gearbox, creates noise. This noise can become worse with time as the gears wear.  See the video below for an example of the noise we are talking about.

Intech has conceptualized a segway replacement gear box to dampen vibration and reduce the noise of the segway metal on metal wear. Our simple bolt on attachment benefits from our  PA12GC Power-Core Cast Nylon (polyamide) which doesn't absorb moisture and won't crack in subzero conditions. The self-lubricating material allows our gears to run quietly and oil free. Removing another annoyance from the maintenance of your segway and its gearbox.

Using plastics to design high load, high shock, and highly critical applications is our specialty here at intech and being engineers the segway was always a toy we've wanted to tinker with. Making plastic gears for an application of this type was not without challenges. The first of which is the tooth root stress, you see metal gears can be much thinner and carry far more load than any plastic. The second is power transmission, very few - if any plastics can evenly and continuously transmit the power needed to drive a segway in the way its meant to operate. Imagine a right gear box transmitting less efficiently than the left and the circles or compensation a rider would need to make. Luckily, Intech's Power-core PA12GC material and its unique gravity casting process allows it to chemically bond to a metal core allowing it to transmit power evenly and continuously while perserving the benefit of a self lubricating gearing.

The retrofit is not inexpensive but if noise or vibration are causing you problems a new intech gearbox might be the solution to give you the quite and smooth riding personal movement device you've always wanted.

 Contact an Engineer

 

Photocredit: http://segwaynz.files.wordpress.com/2012/08/gearbox.jpg

Tags: Power-Core gears, cast nylon 12, gear box, gear backlash, gear design, plastic gears, Power Train Design, Plastic gear box, plastic helical gears

Vacuum Conditions Pose No Problems For Power-Core

Posted by Alexander Bartosch on Jan 23, 2014 9:52:00 AM

Of all the physical properties required of engineering polymers, vacuum stability does not come up all that often. Yet some high-tech aerospace, industrial and medical applications absolutely require polymers that won't degrade or outgas under vacuum. One such polymer is our Power-Core™ gravity cast nylon 12.

Power-Core has demonstrated its vacuum readiness not just in the field but also in testing conducted at NASA's George C. Marshall Space Flight Center. The test (SP-R-0022A) subjected Power-Core samples to a powerful vacuum of 6.0E-7 Torr at elevated temperatures of 125 C. After 24 hours, the samples were measured for total mass loss (TML) and for volatile condensable materials (VCM).  To pass the NASA test, a material must have a TML under 1% of the original specimen mass. The maximum VCM of 0.1% of the original specimen mass.

With a TML of 0.54% and a VCM of 0.01%, Power-Core passed the NASA outgassing test by a wide margin, making the material suitable for use in high-tech systems that require vacuum rated components and materials.  Power-Core's low outgassing performance under vacuum won't make a big difference in most earthbound applications. But think of its vacuum stability as yet another indicator of Power-Core overall stability under challenging environmental conditions.

The need for vacuum stability usually arises in applications that have other types of demanding materials requirements.  So keep in mind that Power-Core's biggest advantage is the ability to combine vacuum performance with other properties such as its insensitivity to moisture, corrosion and chemicals. Many vacuum application also require very high electrical insulation capabilities, which is yet another Power-Core property.

 

Learn more about vacuum applications

Tags: Clean Room rollers, Clean room cam followers, Clean room approved plastic, Vacuum safe plastic, Vacuum rollers

Cast Nylons Replace Structural Aluminum and Gluing Delrin Parts

Posted by Alexander Bartosch on Jan 16, 2014 10:23:00 AM

P 500 System resized 600

Robotic arms for e-coat systems have traditionally been made from aluminum, whose strength-to-weight ratio made it seem like a good choice for this application. Aluminum, however, has a downside.

Its electrical conductivity allows the arm to attract paint particles whenever the painting system experiences voltage fluctuations. The resulting paint losses quickly build up—typically to more than $300,000 per paint line annually.

To eliminate those losses, a leading paint robot manufacturer and Intech teamed up to engineer an electrically-insulating plastic arm. That engineering proved to be easier said than done for three reasons.

For one, any plastic used in the arm had to offer high-end structural properties and be capable of insulating against 100 kV charges. For another, the part is big—too big to be cost-effectively injection molded in this application. Finally, the part has a challenging geometry.

When looking for a plastic with the right balance of properties, we quickly ruled out common reinforced plastics. Both fiberglass and carbon-fiber reinforced materials would easily have met the structural requirements, but both were too conductive.

Delrin, another possibility, was a suitable insulator, but it was only available in small chunks. The robot manufacturer had also ruled out the possibility of gluing delrin to form the arm.

Ultimately, Intech's knowhow and innovation allowed for a suitable arm to be cast from  Power-Core™ cast nylon 12 and for the last 3 generations of robots has proved to be the best choice for the job. Because Power-core™ met the structural and electrical requirements and could also be cost-effectively cast into large, complex shapes, the manufacturer has been able to successfully file and receive patent protection on 5 aspects of the arm that would not have been possible were it not for Intech engineers.

Plastic Requires Design Changes

Switching from aluminum to plastics did require a rethinking of the arm design to account for differences in tensile strength. With a 40,000 psi tensile strength, aluminum could carry the robot payloads with a 100 x 100 mm cross section. The cast nylon has a tensile strength of 8,800 psi, so the cross section had to be increased and a minimum wall thickness of 15 mm had to be maintained throughout the part.

The finished arm ended up at 120 x 30 x 18 cm at its widest point. It weighs 45 kg and is capable of carrying a 150 kg.

Result: because of the uniqueness of our engineering approach and our ability to push the boundaries of our material supply beyond where other material suppliers could Intech was proud to be rated a sole supplier to the automotive paint robot supplier.

For more details on the design and manufacturing challenges using polymers, please contact us using the form to your left.

 

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Tags: washdown application, cast nylon 12, electrically insulated, Intech Corporation, forming nylon, non-hygroscopic, PA12C, PA12G, Cast Nylon, Power-Core material, Nylon 6 vs Nylon12, Nylon engineering, fanuc p700, Fanuc P500, Fanuc p1000, Fanuc P-20ia