Linear Motion - Motion Control Tips

How to specify motion components for cleanroom environments: Part 2

September 5, 2018 By Danielle Collins Leave a Comment

In this two-part article, we cover the products, materials, and features that designers and engineers should specify when choosing motion components for cleanroom environments.

In part 1, we looked at how to reduce particle generation due to friction between moving components. In this second part, we’ll look at another source of contamination — outgassing — and how to minimize it.

Objective #2: Minimize outgassing

Silicon wafer processing is extremely sensitive to contamination, including both particulates and outgassing.
Image credit: WaferPro

In cleanroom applications that involve the manufacture of LEDs, optics, or glass, or the processing of silicon wafers, a second type of contamination can damage the process or the product: outgassing.

Outgassing is the desorption of vapors or gasses, either from within a material or from the surface of a material. ISO standard 14644-8 addresses outgassing in cleanroom environments and specifically refers to airborne molecular contamination (AMC) as:

The presence in the atmosphere of a cleanroom or controlled environment of molecular (chemical, non-particulate) substances in the gaseous or vapor state that may have a deleterious effect on the product, process, or equipment in the cleanroom or controlled environment.

These types of airborne molecular contaminants take the form of molecular vapor. They’re smaller than particles and easily pass through HEPA and ULPA filters, making them particularly difficult to control once released.

Minimize outgassing through material selection

The first criteria when choosing motion components for cleanroom environments where outgassing is a concern is to ensure the material has a smooth surface, which makes it more difficult for airborne molecular contaminants to adhere to the surface. Stainless steel and anodized aluminum are the preferred materials, although some epoxy paints are suitable for environments where low-outgassing is required.

Fortunately, numerous motion control components, such as linear guides, motors, and gearboxes, can be made of stainless steel. When possible, plastic end caps on linear guides and screws should also be replaced with stainless steel versions to further minimize the use of plastics. And standard steel fastening hardware, such as screws or pins, should be replaced with stainless steel versions.

Although epoxy paint is sometimes suitable for motor and gearbox housings, stainless steel versions are better options.
Image credit: Wittenstein

When the required material has a high outgassing tendency, other solutions exist. For example, epoxy paint is suitable in some cleanroom environments and can be applied to the housings of linear actuators, motors, and gearboxes. And when steel is required — to maintain hardness, durability or load-carrying capacity — nickel plating can reduce the tendency of steel to outgas. (Note: Some nickel-plating formulas include a PTFE, or Teflon^®, top coat. The use of Teflon is generally advised against, so be sure to choose a nickel plating formula that does not include Teflon.)

Good: Nickel-plated steel, epoxy coated aluminum
Better: Stainless steel or anodized aluminum; minimal use of plastics
Look for: Smooth surfaces (no textured paints)

Reduce outgassing from lubricants

A wide variety of cleanroom-rated lubricants are suitable for bearings, motors, gearboxes, and other motion components.
Image credit: NSK

When it comes to outgassing, lubricants are one of the major offenders, readily spewing molecules of water and oil vapor into the atmosphere. Unfortunately, in the majority of motion systems, the use of components that require lubrication simply can’t be avoided. When lubrication is required, ensure the lubricant is suitable for cleanroom environments. Cleanroom compatible formulas that minimize outgassing while protecting bearing surfaces from rust and friction are widely available.

Good: Cleanroom-rated lubricants
Look for: Opportunities to minimize the need for lubrication through component selection

Feature image credit: Lin Engineering, Inc.

How to specify motion components for cleanroom environments: Part 1

August 29, 2018 By Danielle Collins Leave a Comment

In this two-part article, we cover the products, materials, and features that designers and engineers should specify when choosing motion components for cleanroom environments. In part 1, we look at how to reduce particle generation due to friction between moving components.

Designers of automation systems are tasked with many competing demands, such as balancing cost and performance, fitting motion components and systems into existing machine or process layouts, and designing for ease of manufacturing and assembly — to name a few. But when the system is to be used in a cleanroom, an additional layer of complexity is added, requiring designers to choose products that won’t degrade or compromise the cleanroom environment.

The level of “cleanliness” of a cleanroom is determined by the number of particles, broken down into six size ranges, that are present in a specified volume of air. In the United States, Federal Standard 209E is often used for cleanroom ratings, although it was officially canceled in 2001. This standard specifies cleanroom levels from 1 (best) to 100,000 (worst) in multiples of 10.

The current, and more universally-accepted, standard is ISO 14644-1, which defines cleanrooms on a scale from 1 (best) to 9 (worst). Each of the ISO classifications has a corresponding FS 209E level, with the exceptions of ISO classes 1 and 2, which are higher (better) than the highest FS 209E classification, and ISO class 9, which is lower (worse) than the lowest FS 209E classification.

ISO standard 14664-1 rates cleanrooms on a scale from 1 (best) to 9 (worst). Federal Standard 209E uses a scale from 1 (best) to 100,000 (worst) based on the number of allowable particles greater than or equal to 0.5 micron.
Image credit: Mecart Inc.

Objective #1: Reduce friction

One of the two primary sources of contamination, or particles, that can degrade a cleanroom environment is friction from moving components. (The other source is people.)

Virtually every motion system involves some amount of friction between sliding or rolling surfaces — whether from linear bearings, rotary bearings, or meshing gears. And when there is friction, particles are generated. Therefore, when specifying motion components for cleanroom environments, reducing friction should be the foremost objective.

Linear guides and drives

To minimize friction from linear guides, choose rolling contact rather than sliding contact and, when possible, avoid systems with high preload. For example, a non-preloaded miniature rail guide that uses two rows of recirculating balls emits significantly fewer particles than a preloaded standard guide with four rows of recirculating balls. And because there’s little chance of the bearing experiencing contamination in a cleanroom environment, use linear guides with low-friction or non-contact type seals.

Air bearings are another, although less common, method for guiding and supporting loads. In cleanroom applications, however, air bearings are often the best choice for low particle generation, since they are completely non-contact devices.

When it comes to linear drives, belts and chains should be avoided in cleanroom applications, due to the significant contact and wear they experience. Similarly, the meshing of gears in rack and pinion systems cause high friction and wear, so these should also be avoided. This means that ball screws are typically the default choice for linear drives in cleanroom applications.

However, ball screws require lubrication, and the rotation of the screw can cause lubrication to “sling” or “splatter,” contaminating the cleanroom environment. Using low-friction or non-contact seals (see above) will help keep the lubrication inside the ball nut and protect the cleanroom.

Like air bearings for linear guidance, linear motors provide a completely non-contact option for driving the load. But in their traditional setup, linear motors operate with the forcer (primary part) moving. This means the cables must move as well, and as we’ll discuss below, cables are another source of particle generation. A better configuration for cleanroom applications is to keep the forcer (primary part) and its cables stationary and allow the magnet track (secondary part) to move.

The combination of air bearing guides and a linear motor drive in this ABL 2000 stage from Aerotech provides completely non-contact movement, ideal for cleanroom applications.

Good: Rolling contact (rather than sliding contact) guides and drives
Better: Air bearing guides and linear motors
Look for: Low-friction or non-contact seals; cleanroom lubrication

Cables and cable management

Another source of friction and, therefore, particle generation, is the cable management system, including the cables themselves. Traditional round cables can generate particles when they rub against each other or against parts of the cable track. The best way to reduce particulates from cables and cable management systems is to use components and system design practices that reduce the amount of cabling required — for example, using an integrated motor-drive system instead of separate motor and drive components.

Cable carriers used in cleanrooms should have low vibration, low-abrasion fastening, and smooth interior surfaces to prevent abrasion of cables.
Image credit: igus Inc.

For the power, feedback, and data cables that are necessary in a motion control system, manufacturers offer cable designs with special low-friction coatings to minimize particulates and reduce outgassing. Similarly, several cable track manufacturers offer systems that reduce wear between chain sections through the use of abrasion-resistant joints. And for shorter lengths, so-called “trackless cables” are self-supporting flat cables that don’t require a cable track or carrier.

Trackless cables are self-supporting and don’t require cable carriers.
Image credit: W.L. Gore & Associates, Inc.

Good: Round cables with anti-friction coatings; cable carriers with abrasion-resistant joints
Better: Self-supporting flat cables
Look for: Opportunities to reduce cabling

Rotating equipment: motors and gearboxes

When it comes to rotating equipment in motion applications, the bad news is, motors and gearboxes use rotary bearings, and gearboxes require meshing teeth — all of which are sources of friction and particle generation. The good news is that these components are enclosed, so particles are less likely to “escape” and contaminate the cleanroom environment. And there is a wide range of cleanroom-compatible lubricants that can be used in the high-speed, high-load conditions found in motors and gearboxes.

To improve cleanroom compatibility, it is also possible to add a slight vacuum to the motor or gearbox housing. The vacuum serves to extract and remove particulates so they don’t have an opportunity to contaminate the cleanroom. Note that vacuum purge is also a good option for enclosed actuators that have a static (non-moving) seal. Although the enclosed design tends to keep particles inside the actuator, adding vacuum purge helps to achieve higher levels (class 100, 10, or 1) of cleanroom compatibility.

Vacuum purge is an effective way to ensure particulates from closed systems, such as this linear actuator, don’t have a chance to escape and degrade the cleanroom environment.
Image credit: THK Co., Ltd.

Good: Fully enclosed housings
Better: Vacuum purge
Look for: Cleanroom grease options

In part 2 of this article, we’ll look at another source of contamination — outgassing — and how to minimize it.

How does stiffness affect piezo output force and displacement?

August 15, 2018 By Danielle Collins Leave a Comment

Piezo actuators operate on the inverse piezoelectric effect: when voltage is applied, the actuator contracts or expands. But when the actuator is blocked from moving (by a load applied in the direction of travel), it generates a force. This relationship between displacement and force in piezo materials is an inverse relationship. In other words, the more force an actuator must generate against a load, the less travel it can produce. A “free” actuator — one that experiences no resistance to movement — will produce its maximum displacement, often referred to as “free stroke,” and generate zero force.

Conversely, when an actuator is blocked from moving, it will produce its maximum force, which is referred to as the blocked, or blocking, force. Theoretically, when the actuator is blocked, it is working against a load with infinitely high stiffness. But materials with infinite stiffness don’t occur in the real world, so the blocking force is determined by applying a voltage to the actuator, with no load applied. This “free” operation, as described above, generates the actuator’s maximum displacement, or free stroke. A force is then applied to return the actuator to its original length. This force is measured and recorded as the blocking force.

The stiffness of the actuator is the ratio of blocking force to free stroke.

k_p = stiffness of piezo actuator

F_block = blocking force

ΔL_fs = free stroke (nominal displacement) with no external load

In piezo actuators, force and displacement are inversely related. Maximum, or blocked, force (F_block) occurs when there is no displacement. Likewise, at maximum displacement, or free stroke, (ΔL_fs) no force is generated. When an external load is applied (A), the stiffness of the load (k_e) determines the displacement (ΔL_A) and force (ΔF_A) that can be produced.
Image credit: APC International, Ltd.

There are two types of load that can be applied to a piezo actuator: a spring load, which increases as the actuator moves, or a constant load, which does not vary. The actuator’s ability to produce displacement and force depends on the type of load.

Piezo output force and displacement with a non-constant (spring) load

Many piezo applications, such as valve operation, introduce loads that vary with the piezo’s stroke — in other words, spring loads. When the stiffness of the applied spring load is low compared to the piezo stiffness, the piezo output force (F_eff) is small. In other words, a spring (load) with low stiffness provides very little “blocking” for the piezo to work against in order to generate a force. Therefore, the piezo output force is greatly reduced from its maximum, or blocking, force.

F_eff = force produced with spring load

k_e = stiffness of applied load

On the other hand, the spring reduces the actuator’s displacement only slightly:

ΔL = displacement 0f actuator with spring load

Performance of a piezo actuator with no load (A) versus an actuator with a low-stiffness spring load (B). Note that the displacement (ΔL) with the spring load is slightly less than the maximum displacement, or free stroke, (ΔL_fs), but the force produced (F_eff) is much less than the maximum, or blocked, force (F_block). The stiffness of the spring load (k_e) is shown by the blue line.
Image credit: PI Ceramic GmbH

A low-stiffness spring load — typically no more than 10 percent of the piezo stiffness — is generally recommended for preloading a piezo actuator to ensure the displacement is not severely reduced.

Piezo output force and displacement with constant load

When a constant load is applied, there is an initial deflection, or compression, of the actuatordue to the load. This means the zero point of the working curve is offset, or shifted, but the actuator’s stroke is unaffected.

ΔL_N = offset of the zero point with constant load

F = applied load

Some force is generated when the load is applied, causing the initial deflection, but once the actuator responds to the application of the load, its remaining work goes into generating the displacement. The zero point of the blocking force (maximum force) is also shifted, but is magnitude is not affected.

When a constant load is applied, the zero point of the actuator’s displacement is shifted, but its total displacement, or free stroke, is not affected: ΔL’_fs = ΔL_fs
Image credit: PI Ceramic GmbH

Feature image credit: Noliac

How do rotary voice coil actuators work?

July 17, 2018 By Danielle Collins Leave a Comment

Most linear motion devices have a rotary equivalent, and voice coil actuators are no exception. While the versions depicted in most product images and videos are linear, rotary voice coil actuators fill a need for smooth, arc-shaped motion and torque production with fast response times. But unlike the design relationship between rotary and linear motors, developing a rotary voice coil actuator isn’t simply a matter of taking the linear version and rolling it into a cylinder. While their components are the same, the configurations of linear and rotary voice coil actuators are quite different.

Voice coil actuators work on the principle of the Lorentz force, which is the force generated when a current-carrying conductor is placed in a magnetic field. In the case of a voice coil actuator, the magnetic field is created by permanent magnets and the conductor is a coil of wire. When current is applied to the coil, a force is generated, and the magnitude of the force is proportional to the applied current. (All other variables in the force production, such as magnetic flux and length of wire, are fixed for a given voice coil design.)

F = k*B*L*I*N

F = force (N)

k = force constant

B = magnetic flux density (tesla)

L = length of wire (m)

I = current (amps)

N = number of conductors

The most common linear voice coil actuator design features a moving coil, although the actuator can be constructed so that either the coil or the magnet is the moving part. In the moving coil design, a stationary cylindrical permanent magnet produces a radial magnetic field. Housed inside the permanent magnet cylinder is a coil that is wrapped around a non-conducting structure, or holder. The permanent magnet is housed in a ferromagnetic cylinder that is open at one end and has a “core” through its middle, which is necessary for completing the magnetic circuit. The coil assembly rides in the air gap between this core and the interior surfaces of the permanent magnet. Although it sounds complicated, the construction is actually quite simple, as shown below.

The construction of a linear voice coil actuator is relatively simple. In this example, the magnet is stationary and the coil moves.

A rotary voice coil actuator is sometimes referred to as a “flattened” version of the linear design described above. In other words, to transform a linear voice coil actuator into a rotary version, place the linear voice coil actuator lengthwise on a table (as it would sit if it were operating horizontally) and flatten it into an essentially 2-D object. Then bend the ends so that it forms an arc (like a piece of macaroni). Now you have a rotary voice coil actuator.

In this rotary voice coil actuator, the permanent magnet segments are on the top and bottom (white) and the coil (gold) rides in the air gap between them.
Image credit: BEI Kimco

Rotary versions provide torque rather than force. Similar to their linear counterparts, the amount of torque generated is proportional to the applied current, and the direction of the current determines the direction of motion. Excursion angles are typically less than 180 degrees, and commonly fall between 15 and 60 degrees.

Voice coil actuators are, technically, non-commutated DC motors. The term “voice coil” is often used because one of their first applications was to vibrate the paper cones in loudspeakers. Rotary voice coil actuators are also referred to as “arc segment” actuators or “limited angle torque motors” because they produce arc-shaped motion.

One of the strengths of voice coil actuators is their extremely smooth, cog-free motion with no torque ripple. This makes rotary versions ideal for applications that require high torque and quick response, such as gimbal positioners. They are also well-suited for moving optics and for controlling stabilization devices.

This gimbal assembly design uses two rotary voice coil actuators. The inner axis moves 40 degrees in 32 milliseconds, and the outer axis moves 20 degrees in 140 milliseconds.
Image credit: BEI Kimco

Feature image credit: H2W Technologies, Inc.

Electric motors: Trends in stepper, battery-powered, and integrated motion designs

March 2, 2018 By Lisa Eitel Leave a Comment

From induction motors in electric vehicles to tiny coreless dc motors in drug-delivery equipment, electric motors continue to proliferate. Last year we saw consumer products, implantable medical devices, and automation of previously manual tasks spur the most innovation in motor design and use. This year those trends continue — and now we see increased use of servo and stepper motors in robotics.

maxon precision motors EC 4 brushless dc motors (which can be fitted with GP 4 planetary gearheads) are 4 mm in diameter with an ironless winding; ISO 13485 certified; and suitable for use in laboratory robots, micropumps, and diagnostic devices. Two lengths deliver power to 0.5 and 1 W. “We also want to offer more value-add services, as more companies than ever in the U.S. want finished motor and motion systems — so-called drop-in designs,” said McGrath of maxon. “So to that end, our expanding U.S. factory will have the capacity to supply custom assemblies and PCBs.”

In fact, whether it’s basic tin-can motors for low-cost custom actuation or integrated motors that output servo-like performance, overall use of stepper motors is growing. On the latter, a study by P&S Market Research projects a CAGR of 6.3% through 2023 for the global closed-loop stepper motor market. P&S cites the well-known benefits of control-feedback signals and power-adjusted current control as key reasons for the technology’s steady adoption.

Low-current dc motors from ISL Products Intl. Ltd. come in myriad mechanical and electrical configurations. Sometimes gearmotor modifications help the dc motors meet exacting OEM application specifications. In other cases, the motor must have special construction to avoid inducing EMI and RFI interference (Here, raw materials in the motor components are a main consideration, said to Kawaller of ISL.) Designs with reduced power consumption benefit from motors with specialized internal construction and nontraditional component materials.

Warren Osak, CEO of Toronto-based distributor Electromate Inc., sees this trend for integrated stepper motors, even while the middle of the stepper-motor market (actuated by standalone 1.8° hybrid stepper motors) recedes. Technology is either migrating upward (and taking the form of integrated motors or smart motors) or migrating downward — to lower-cost motors with less sophisticated structures, according to Osak.

“The use of traditional hybrid stepper motors has been yielding to integrated products … while in lower-end applications, we see more use of less-sophisticated motors with customer-provided integrated chips (ICs) to drive them,” he added.

Full interview with Osak: Motion-control trends distributor insight

Some closed-loop stepper manufacturers we surveyed for the Design World Trends issue include Schneider Electric Motion USA, Applied Motion Products Inc., Lin Engineering, MICROMO of Faulhaber, Oriental Motor Co., and Nippon Pulse America Inc. — with commentary from the latter in our actuator trends coverage. All detail pre-integrated or application-specific motor offerings. Case in point: Automation in the oil and gas industry has created numerous opportunities for motion control products, but stringent requirements for hazardous location ratings rule out most standard motor and drive solutions.

Use of tin-can stepper motors is on the rise, and now some new tools let engineers check their programming on the little motors more easily. Consider the Motion Checker 5 controller from Nippon Pulse America Inc. — a standalone handheld controller with an integrated driver circuit. Using it is as simple as plugging it into a normal outlet and connecting a stepper motor to run through motion sequences.

“To serve engineers in this industry, we’ve released the world’s only ATEX-rated stepper drive for hazardous locations … and this year we’ll introduce our first explosion-proof step motor to pair with it,” said Eric Rice of Applied Motion Products. “The drive is already being used on rigs in the oil field for applications where accurate braking and speed control of drill strings are required.”

Motors in (proliferating) battery-powered designs

Battery-powered designs such as ATVs, mobile robotics (including AGVs), scooters, ebikes, and drones present unique motion-system challenges. Motors that integrate into these designs might need to accept 48, 24, or 12-V input, and nearly all of them must meet tough efficiency requirements … NEXT PAGE →

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Engineered materials and upfront design work (are leading trends for mechanical components)

February 28, 2018 By Lisa Eitel Leave a Comment

Seals, chains, cable carriers, springs, retaining rings, and general power-transmission (PT) components continue to see new materials at critical surfaces; proliferation of application-specific versions (especially for compression and wave springs); and increasingly practical online purchasing for both off-the-shelf components and customized orders. Here we explore some of these trends.

Online B2B ordering of very specific components — increasingly common

Forrester Research projects that by 2021, about 13% of all B2B sales in the U.S. will take place through ecommerce. Rather staggering is that (according to other research from Statista Inc.) last year B2B ecommerce activity generated $7.7 trillion in sales globally — triple that of B2C sales. Even very specific engineered components are coming to be sold this way.

Case in point: Now the fastener, spring, and shim manufacturer SPIROL offers engineers a new ecommerce platform at shop.spirol.com for purchasing coiled spring pins — and plans to eventually offer all its engineered components at the site. Engineers can purchase pins in several materials and finishes (in light, standard, and heavy duties) from 0.8 to 20 mm in diameter — and get certifications or search by specification at the site. Designers can also get 2D and 3D models there. More after the jump.

Online procurement and purchasing portals — such as this one from SPIROL — are increasingly common for an array of power-transmission components.

In a similar move, Klüber Lubrication (a Freudenberg Group company) will soon supply its specialty lubricants and tribological formulations to OEMs and end users through an Cloud-based portal as well. Management company JAGGAER will build the digital-procurement platform to serve engineers. The tool will be implemented in modules for digital-complaint processing based on QDX standards; integration of SAP contracts; and electronic RFXs. All will integrate into existing IT and ERP systems for automatic documents and information exchange (to manual data entry). Connection of ERP systems will create a platform to give purchasers a uniform lubricant database.

Other industrial-lubricant suppliers have taken a different tack to solve mechanical challenges with tribological product design. Over the last several years, Nye Lubricants has cultivated technical competency for better integration of R&D and product development. “We focus on … understanding fundamentals of applied tribology and combining this with simulations of customer applications,” said Jason Galary, engineering development and applications manager at Nye Lubricants. More after the jump.

Klübersynth LEG 4 75 90 W is specifically for gearboxes in railway applications and works in oil-sump temperatures from -50 ° to 100° C with no change in effectiveness performance. Soon, Klüber Lubrication will supply lubricants to meet specific OEM and operator requirements through a digital procurement platform.

Usually, a lubricant supplier develops formulations and then ships samples of it out to the OEM or end user for testing (in turn based on quantitative data and sales engineers’ experience. But this arrangement burdening users with testing — which is why Nye established its applications development and validation testing (ADVT) team. So today, this ADVT executes applied mechanics as well as component testing and simulation.

Bearings continue to inspire material science for oils and greases capable of extreme pressure survival, sound damping, seal-life extension, and more exotic ends. “Materials used for bearing lubrication in particular have advanced considerably — even allowing safe operation in food applications with high-performance characteristics,” said Steven Feketa of LinMot USA. “In the past one got one or the other characteristic … but not both.”

Materials for PT performance characteristics

Motion-component manufacturers are leveraging advanced materials to improve designs — in lubricant formulations (as just mentioned) as well as forgiving linear-rail materials; composite disc-packs for couplings; alternative rare-earth magnet formulations in motors; engineered sleeve-bearing formulations; new plating and coating options; and performance-grade 3D printed parts for PT components.

One example of the latter from Haydon Kerk (of AMETEK Advanced Motion Solutions) is a 3D-printed leadscrew-nut insert prototype service called 3DP. Read more about this in our leadscrew trends coverage; the 3DP service gives machine builders a way to verify linear-motion design iterations quickly and more accurately.

Others also see the value in boosting the performance of parts generated through additive manufacturing. “We currently offer a variety of tribo-filament materials for 3D printing,” said Nicole Lang, iglide product manager at igus.

“These materials are tested and offer excellent wear rates … and service life exceeding those materials commonly used in 3D printing.” In fact, the manufacturer also offers high-temperature materials and materials that offer high chemical resistance to work in challenging applications.

Engineered plastics excel in an array of warehousing and logistics applications. Shown here are examples of engineered plastic motion components and power-transmission systems from igus -including cable carriers, cables and energy chain, linear slides, rotary bearings and robot joints, and compete conveyor installations. Click to enlarge.

Aerotech Inc. also uses additive-manufactured components in certain designs to increase design freedom, reduce weight, and boost dynamic stiffness. “Because we service the high-performance automation space, new materials and methods are often needed to meet exacting design parameters,” said Brian O’Connor, director of product and market development at Aerotech.

Emphasis (for now at least) is on the use of 3D printing for preliminary design builds. “Most of the new materials we’ve been using are for prototyping,” said Laura May of Thomson Industries. “Thanks to advances in 3D printing and laser forming, we produce prototypes much faster and less expensively than before.” May also points out that besides freeing time for product innovation, having more (and better-performing) prototypes facilitates the product-development process.

Of course, traditional power-transmission (and electric motor) components leverage the most advanced materials. Consider NORD Drivesystems’ relatively recent alternative offering to stainless steel for gearmotor resistance to harsh washdown environments. Called NSD TupH, the coating is a molecular conversion of aluminum-alloy housing bodies to resist blistering (to ASTM D714) and corrosion (to ASTM D610-08).

Prevention of corrosion is also essential to exposed motion components. Manufacturer U.S. Tsubaki Power Transmission sells several variations of chain, including power-transmission chain with its proprietary NEPTUNE surface treatment (to resist corrosion when outdoors or subject to seawater) and nickel-plated chain (for moderately corrosive environments). In contrast, its AS Series chain made of 304 and hardened 600 stainless steel delivers high load capacity and adherence to FDA regulation. Still other chain for situations requiring nonmagnetic power transmission and conveying components use other materials — including polyacetal stainless steel.

Elsewhere, ceramics are an advanced material used in gearing, motor shafts, linear components, and stage bases. Aerotech makes use of silicon carbide in some of its planar air-bearing stages. “We’re always looking at ways to employ newer materials, coatings, and construction methods in our designs to improve performance and reduce cost,” said O’Connor of Aerotech. “Various composites and ceramic structures in our designs increase stiffness and reduce weight, which means higher accuracy and throughput of the motion system. We also employ engineered coatings to reduce wear and friction in mechanisms for standard and customized products.”

SERAPID supplies Meridian Lift for XXIII Olympic Winter games opening ceremony

February 9, 2018 By Miles Budimir Leave a Comment

The SERAPID solution has once again been chosen to provide dynamic stage action for the opening ceremony of the 2018 Olympic Winter Games in Pyeongchang, South Korea. SERAPID had previously provided an extensive stage lift system for the 2008 Summer Games in Beijing, China.

The opening ceremony took place in the Pyeongchang Olympic main stadium, and was broadcast globally with pre-show estimates of nearly 400 million viewers, 35,000 of which watched live in the stadium.

Center-stage at the ceremony was the SERAPID Meridian Lift, an impressive circular lifting platform, totally supported by the robust and reliable SERAPID LinkLift actuators. “We are proud to provide the Olympic games opening ceremony a system resistant to harsh climate (-20°C approximate with wind) and safe for moving people“, said Eric Michaut, Project Manager at SERAPID Group. “We used 15 LinkLift 100 telescopic actuators rising up to 5.5 m in height to lift two different platforms, one with a diameter of 24 m and another in its center with a diameter of 9 m.“

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About SERAPID
SERAPID produces customised solutions for moving heavy loads by use of our Rigid Chain Technology (RCT). This durable, low maintenance, eco-friendly technology has found applications in diverse industries including architecture, nuclear, medical, defense, automation, manufacturing, theatre and entertainment. SERAPID has a longstanding commitment to continued innovation in product design as well as to providing leadership in the advancement of engineering applications worldwide.

For more information, visit www.serapid.com.

SERAPID Group (lift and transfer-system supplier) launches new website

January 20, 2018 By Lisa Eitel Leave a Comment

SERAPID Group — a leading supplier of lifts, quick die change, and horizontal transfer systems — has launched its new website at www.serapid.com.

“We are proud to provide customers with a new and improved website,” said SERAPID Group Chief Operating Officer Guillaume Davies. “With this new site we aim to create an exciting experience for visitors … so that in discovering products and original designs, they’re [inspired to contact our team] …”

Davies continued, saying that the team is excited about the important release, and will continue to strive for perfection through a continuous improvement project — “taking into account comments and suggestions.”

SERAPID produces customized setups for moving heavy loads by use of Rigid Chain Technology (RCT). This durable, low maintenance, eco-friendly technology has found applications in diverse industries including architecture, nuclear, medical, defense, automation, engineering, manufacturing, theater, and entertainment. SERAPID has a longstanding commitment to continued innovation in product design as well as to providing leadership in the advancement of engineering practices worldwide.

Video illustrates smart linear actuator benefits for automation applications

December 11, 2017 By Paul Heney Leave a Comment

Thomson Industries Inc. has released an educational video (below) that summarizes the benefits of smart actuators, which feature integrated electronics. The five-minute video explores how smart electromechanical actuators are meeting demands for greater connectivity, application flexibility and cost efficiency, and illustrates their use in factories, on- and off-highway vehicles, and structural automation.

In discussing the benefits of smart actuators, Häkan Persson, Thomson Global Product Line Director – Actuators, said: “Smart actuators help OEM design engineers build smarter machines with smarter components. Their onboard electronics perform traditionally external control functions such as switching, position feedback, system diagnostics and communications. Embedding these into the actuator housing reduces component cost, installation cost and design labor that might otherwise be needed. This, coupled with concurrent advances in power density and environmental protection, allows design engineers to electrify more axes of motion than previously thought possible, putting actuators on the frontlines of Industry 4.0.”

Smart actuation benefits

The video details the following benefits of the Electrak Modular Control System (EMCS), which is built into every Electrak HD actuator, and the features that make them possible:

• Option to receive either absolute or incremental position feedback from embedded potentiometer or encoders

• End-of-stroke indication, which signals when the actuator has reached either end of the stroke

• Ability to control the actuator from the outside with lower level power switching through embedded H-bridge switching functionality

• High position accuracy and coasting control through dynamic braking

• Network communications for condition monitoring, diagnostics and other applications through J1939 CAN bus connectivity

• Sharing of the load among up to four actuators via advanced synchronization functionality

• Improved performance across actuator lifecycle through real-time monitoring of voltage and temperature and ability to shut down the actuator on overload.

Applications for smart actuators

In addition to describing the basics of smart actuation, the video demonstrates how such benefits are achieved within the following application areas:

• Factory automation, where lift trucks, conveyor systems and automated guided vehicles benefit from smart features such as controllability and connectivity

• On- and off-highway vehicles, where users in markets such as agriculture, construction, and marine and public transportation can benefit from improved efficiency and simplified wiring

• Structural automation, such as louver control, stair lifts and medical mobility devices, where users enjoy features such as increased control and built-in safety functionality.

Thomson delivers smart actuation through the Electrak HD, Electrak Throttle and WhisperTrak product families, which all have high ingress protection (IP) ratings, making them suitable for operation in demanding environments.

Thomson Industries
www.thomsonlinear.com/smart

Belt drive axes can reduce automation costs

October 26, 2017 By Paul Heney Leave a Comment

Cost-effective alternative for mechanical engineering: The self-lubricating and maintenance-free toothed belt axis, drylin ZLW eco from igus, executes simple positioning and adjustment tasks.

Mechanical engineers often need a basic, space-saving linear guide when designing technology that performs simple tasks, such as vending machines. Since such technology does not handle high loads, high speeds or high positioning accuracy, intricate linear guides are not necessary. However, most solutions on the market are very advanced, leaving manufacturers forced to either pay for features they do not need or develop their own linear guide.

Solution from igus: Toothed belt drive axis starting at $150
igus is now offering the drylin ZLW eco, a ready-to-install entry-level series that is making simple positioning and adjustment tasks extremely efficient and, above all, cost-effective. “A toothed belt axis of this entry-level series with a stroke length of 100 millimeters starts as low as 150 dollars,” said Stefan Niermann, head of igus’ drylin linear and drive technology division. “In comparison, a toothed belt axis from the standard series, which has high-performance features and is therefore unnecessary to use for simple operations, costs almost three times more.” The carriage and shaft end supports are produced by injection molding, which is more cost-effective than mechanical filling used for metal component production. “This also reduces the number of components and thus the installation efforts for every eco linear axis, which in the end is reflected in the low prices of this entry-level series,” explained Niermann. A further cost-saving element of the drylin ZLW eco is the plain bearings used in the sliding carriage, which are made of iglide high-performance plastics. “iglide bearings are forty percent more cost-effective than conventional rolling bearings and 100 percent maintenance-free in operation,” Niermann said. Without compromising the smooth-running operation and durability of the standard series, users can simply install the eco axes and save time and money with the maintenance-free, dry-running triboplastic bearings.

Entry-level series in two sizes
The entry-level drylin ZLW eco has two installation sizes: 0630 and 1040. The base is an anodized drylin W profile made of clear anodized aluminum. At the ends of the profile are plastic shaft end supports for drive technology. A neoprene toothed belt is tensioned between the shaft end supports, which pushes and pulls a solid plastic carriage with a positioning accuracy of 0.3 millimeters. The stroke lengths can be individually adjusted by the user. Due to its lightweight construction, the toothed belt axes weigh only 0.3 kg and 0.7 kg, and can move loads up to 3 kg or 10 kg respectively. Matching motor kits also are available.

igus Inc.
www.igus.com