Thordon Bearings is supplying multiple sets of grease-free bearings to completely replace old technology at the Otto Holden Generating Station on the Ottawa River in Ontario, Canada.

Andritz Hydro was contracted to undertake the mid-life refurbishment of the station’s turbines on behalf of Ontario Power Generation (OPG). Two of the 243MW station’s eight units have now been fitted with Thordon’s ThorPlas-Blue and Thorseal products, via its local distributors RMH Industries in Quebec and Millstream Engineering in Ontario.

Unit 7 was refurbished in 2022, unit 5 in 2023, and unit 8 is next with installation expected in Q4 2024. By 2029, all eight of the station’s units will have been refurbished.

Each retrofit involved 262 bearings per turbine including wicket gate bearings and seals, Thorseal linkage bearings, Thordon SXL operating ring wear pads, and servo motor bearings and seals. The bearings being installed have high-end edge loading performance and range from about 100 to 300mm (4-12in) outside diameter.

The servomotors are being made entirely by Thordon distributor RMH Industries, one of the company’s specialties honed over the last 50 years. Gaétan Dionne, RMH Industries’ General Manager, cites, for example, that the company can install Thordon’s bearings on the servomotors using liquid nitrogen in less than a minute.

Thordon’s bearing and sealing solutions were chosen for their reputation for being the highest-performance materials available on the market. A key on-going benefit is that they eliminate the need for regular greasing, thus reducing maintenance costs and avoiding contamination of rivers.

Thordon’s wicket gate, operating mechanism and linkage bearings operate wet or dry and are self-lubricating to ensure performance in limited-motion applications. There is no galling from edge loading caused by minor misalignments or gate deflections. The bearing material is ThorPlas-Blue which is a homogeneous, self-lubricating engineered thermoplastic capable of withstanding operating pressures up to 45MPa (6,527 psi).

Thordon’s Thorseals are made of a proprietary elastomer with no shelf life or degradation of properties over time. Thorseals are available in a wide range of standard sizes or can be quickly machined to custom size requirements up to 1.5m (60in) in diameter.

Greg Auger, Commercial Director at Millstream Engineering, explains that installing the wicket gate bearings requires careful attention to detail.

“It is critical to get accurate measurements of the shaft and housing dimensions before final machining of the ThorPlas-Blue bearings so that they can be sized correctly for proper fit and clearance. During installation, care must be taken to press-fit the bearings to prevent damage, and then they must be protected from risk of damage while other overhaul work continues. Careful measuring of the installed dimensions will help verify that all the large components will assemble correctly.”  

Millstream Engineering will continue to provide local support to OPG for all their facilities across Ontario. Auger says there is a big push underway for overhauling and modernizing hydropower facilities across Canada, and the Otto Holden station is one of many to be rehabilitated over the next decade.

Additionally, demand for electricity is constantly increasing, and OPG has identified significant untapped hydroelectric generation opportunities. In the northern rivers of Ontario alone, there are about 4,000MW of potential power, or enough electricity to power about 3.5 million homes.

Business Development Manager for Hydro & Industrial at Thordon Bearings, Ryan Edmonds, said: “The hydropower market is growing globally due in part to the increasing demand for renewable energy. Hydropower is a clean, secure, domestic source of electricity, and Thordon’s high-performance solutions are a perfect fit for these durable assets.”

www.thordonbearings.com

Leading water-lubricated and grease-free seals and bearings pioneer Thordon Bearings has appointed one of world’s most well-known propeller manufacturers as its new distributor for the UK and Ireland region.

Bruntons Propellers will represent Thordon Bearings across the countries from the 1st of January, 2024.

The propeller manufacturer will market, supply and service Thordon’s entire marine portfolio of propeller shaft bearings and seals. There is also provision for Bruntons to promote and service Thordon’s products in other market segments.

Neil McDonald, Thordon Bearings’ Regional Manager, Northern Europe & Africa, said: “We are delighted Bruntons has agreed to represent Thordon Bearings in this important geographical market. Bruntons is a well-known and established brand, with a prestigious heritage spanning more than 100 years. The company, part of the Langham Group, which includes Stone Marine and Tridan Engineering, also has the capability to machine and service bearings and seals on-site.”

A unique arrangement among Thordon’s global network of authorized distributors, it is anticipated that Bruntons will provide greater exposure across a number of market sectors in the UK and Ireland, leveraging Thordon products with major system integrators, systems suppliers, ship owners and shipyards.

Bruntons’ Director, Jonathan Shaw, explained that “the merchant maritime and defence sectors will be the main focus areas, but the agreement allows us to diversify into new industrial and pump markets. With our technical know-how and CNC machining technology, we can offer a wide range of professional sales and engineering services. We plan to have the Thordon inventory in place soon for quick turn-around delivery.”

While the UK’s defence sector has for decades been a significant proponent of water-lubricated bearings and seals due to their low noise and vibration signature, Thordon Bearings is seeing more and more UK-flagged merchant vessels look to the technology to meet existing and future environmental regulations.

“We hope soon to be in a position to announce the first order under this new agreement in coming weeks,” said McDonald. “There are a number of opportunities with new and existing customers throughout the region, since Bruntons can now offer complete propeller shaft lines with a Thordon seal and bearing package.”

A pioneer in the development of elastomer technology, Canada-headquartered Thordon has more 35 years’ experience designing, manufacturing, and installing robust, long-lasting marine bearings and seals that operate without the need for oil or grease.

The company’s marine portfolio includes the award-winning COMPAC seawater-lubricated propeller shaft bearing (the industry leader in zero environmental impact bearings); the award-winning TG100 shaft seal; the award-winning grease free deck and rudder bearing system ThorPlas-Blue; and the new and revolutionary sterntube-less propeller shaft system design, T-BOSS.

www.thordonbearings.com

Birmingham, UK | January 30, 2024 | The expansion of renewable energies is being driven to a great extent by wind turbines. Wind turbines are becoming larger and more powerful. The main shaft bearing system, as an integral part of the drive train, is of elementary importance, as this is where all the forces and torques exerted by the wind on the turbine add up. As a market leader and strategic development partner, Schaeffler is rising to the challenge and will contribute actively to the development of multi-megawatt wind turbines.

In Lindø, Denmark, the world’s most powerful test facility for main shaft bearings will be built at LORC (Lindø Offshore Renewables Centre). The investment is in the mid-double-digit millions and includes grants from the Danish GreenLab programme. Concrete test programmes should already be running by the end of 2025. LORC has partnered with R&D Test Systems, which is one of the leading suppliers of test benches for the wind industry, to build the new test facility. Schaeffler played a major part in defining the specifications of the test facility and will be the first customer to test its main shaft bearings for future generations of wind turbines in cooperation with OEMs.

Dr. Michael Pausch, CTO Industrial Schaeffler, stresses: “We are a key market and technology leader for bearing technologies in the wind power industry. With LORC, one of the most experienced operators of test facilities for wind turbine drivetrains, we have found a partner to help us further expand our know-how and our product performance. We now have the opportunity to shape the development of the next generations of wind turbines with suitable testing technology and method development.”

“We have been gaining valuable insights for the development of bearing solutions since 2011 with our large-size bearing test bench 'Astraios,’ the world’s most powerful test bench at the time. With the new test facility, we will now be able to advance into new and future dimensions and contribute to a more rapid development of reliable multi-megawatt turbines,” adds Bernd Endres, Vice President Business Unit Wind, Schaeffler Industrial. 

“Closed loop engineering” for wind turbine bearings
Schaeffler has been offering reliable bearing solutions for on- and offshore wind turbines for around 40 years. Rolling bearings from Schaeffler are found in every second to third wind turbine worldwide. 

Schaeffler takes a “closed loop engineering” approach for its wind turbine bearings. Besides engaging in the pure development of bearing solutions, the Schaeffler experts also support turbine development with system simulations, testing, and field measurement campaigns. The findings gained flow back into the further development of customers’ projects, design tools as well as the development of new bearing solutions. The experts from Schaeffler work closely with developers from OEMs to increase the reliability of wind turbines and make wind power more cost-effective. The new test bench will provide an important building block for the developments of the coming decades.

To maximise the life expectancy of your bearings, you need to ensure the correct models are used, and that they are correctly fitted, lubricated and maintained; failure to do so may result in early bearing failure.  Here, with SKF, we identify the most common causes of bearing failure, along with the symptoms to look out for and tips on how you can prevent premature failure.

Contamination

One of the most common causes of premature bearing failure is contamination, such as airborne dust or dirt. Contamination can occur during improper storage and handling prior to or during mounting, as well as during operation, so store bearings in their packaging in a clean environment.

The choice of bearings for heavily contaminated environments, or where contamination of the process is also an issue, is key.  In these instances, focus on the design of the housing and the seals/sealing system. Bearing seals will prevent contaminants from entering the bearing unit, whilst keeping lubricants from leaking out.  Specialist sealing solutions have also been developed for very heavily contaminated environments, such as SKF’s Three-Barrier Solution which consists of a sealed spherical roller bearing, bearing housing with seals and a biodegradable grease to act as a contamination barrier.

Excessive Load

Failure of this sort can look similar to normal bearing fatigue with the main tell-tale signs including the deterioration of running surfaces of the inner ring, outer ring or rolling elements. To function in applications where heavy loads are the norm, you want a bearing that is both hard and tough.  New heat treatment processes have made hardened steel suitable for use.

Also, consider both axial and radial loads when choosing your bearings.  Bearings are available that accommodate both.

Overheating

One of the more obvious symptoms of overheating includes the discolouration of the rings, rolling elements and cages. Overheating results in a loss in hardness, reducing the bearing capacity and leading to premature failure.

Main causes of overheating include insufficient cooling, incorrect radial internal clearance or inadequate or too much lubrication. Overheating can also be caused by the bearing being overloaded.  Where possible, consider installing adequate thermal controls and reassess the bearings being used are adequate to accommodate the application, lubricant, and load requirements.

Inadequate Lubricant

Up to 36% of bearings fail prematurely due to inadequate lubrication.

One of the main signs of lubricant failure begins with the discoloured (blue/brown) raceway and rolling elements. This will often be followed by excessive wear of rolling elements, ring and cages resulting in overheating. This type of failure is typically caused by excessive or too little of the correct lubrication, possible restricted lubricant flow and/or excessive temperatures. To combat this consider investing in a bearing that has built-in lubrication as part of its design. 

Corrosion

Corrosion can result from exposing a bearing to a corrosive fluid or atmosphere, with symptoms including discolouration on raceways, cages and rolling elements.  To ensure best practice, divert corrosive fluids away from any bearing area if possible and/or consider using a sealed or housed bearing. SKF for example can offer various corrosion resistant bearings, such as stainless steel or with special coatings along the housings made from polypropylene composites.

Misalignment

Misalignment can result in unnecessary forces being applied to machinery leading to increased wear and vibration causing premature bearing failure and costly machine downtime. Sometimes caused by a loose-fitting bearing, misalignment can be typically observed by its uneven running paths. Whilst it is important to have the bearings as accurately aligned as possible, there are several products that will accommodate some degree of misalignment: Spherical roller bearings, SKF CARB Toroidal roller bearings, self-aligning roller bearings, SKF Cooper bearing and housed bearing units. 

Incorrect fitting

Approximately 16% of bearings fail prematurely due to damage caused by the incorrect mounting technique for the application and bearing type so correct fitting and removal of bearings is vital to achieve best performance.  Firstly, it is important not to fit bearings to seatings which have been damaged by previous bearing failure.  It is equally as important to ensure seatings are of the correct specification, as this is a common cause of bearing failure. 

Rubix is Europe’s leading authorised bearings distributor. 

uk.rubix.com/supplier/skf

Egypt’s SUMED pipeline operator Arab Petroleum Pipeline Company (SUMED) has completed the tailshaft conversion to Thordon’s SXL seawater-lubricated bearing system for seven special purpose single point mooring (SPM) service boats.

The final vessel in a series of 17.5m (57.4ft) long, 1976–built service boats had its original oil-lubricated tailshaft bearings replaced with the Thordon system at Nefertiti Marine’s Yard-K, in Rosetta Nile, in December 2022. The first vessel, SUMED 10, was converted in 2019.

Referring to the first installation, Karim Abd El Karim, Engineering Manager with Nefertiti Marine, Thordon Bearings’ authorized distributor in Egypt, who has overseen the completion of all seven conversions, said: “Oil was leaking from the shafts, and the operator was looking for a longer lasting bearing solution, resistant to abrasive waterways. We proposed the SXL material as the right solution to meet all performance and environmental needs. The vessel owner agreed.”

In addition to SXL tailshaft bearings machined for shaft diameters of 95mm (3.74in), Nefertiti Marine provided classification approval drawings and advised on the installation process through to commissioning. All seven service boats received the same scope of supply.

“The success of that first installation, together with the reliability and availability of Thordon’s SXL bearings, lead times and Nefertiti Marine’s engineering expertise, gave us the confidence to convert all our special purpose service boats to seawater-lubrication. The perennial problem of worn aft seals leaking oil into the sea and canal has now been solved.”

A water-lubricated tailshaft arrangement negates the need for an aft seal, notoriously prone to failure, resulting in oil pollution, costly repairs, and downtime. Only a forward seal is required in an open system.

SUMED’s fleet of service boats assist tankers in loading shipments from the SUMED oil pipeline. The pipeline, which runs from the Ain Sokhna terminal in the Gulf of Suez to Sidi Kreir port in the Mediterranean Sea, provides an alternative to the Suez Canal for transporting oil from the Arabian Gulf region to the Mediterranean.

“We are delighted that SUMED has put its trust in our zero-pollution, low-maintenance bearings to deliver environmental and economic benefits,” said Neil McDonald, Thordon Bearings’ Regional Manager – Northern Europe & Africa.

“Based on the success of that first installation, the other vessels in the fleet spent less time in drydock, reducing vessel downtime considerably. The company is now looking at converting greased deck equipment bearings and rudder bearings to our grease-free ThorPlas-Blue bearings,” he said.

Thordon Bearing’s SXL and ThorPlas-Blue non-metallic bearings are ideal solutions for tugboat, dredger and other coastal workboat operators looking to easily convert their closed oil-polluting seal system to solutions more in-line with their Environmental, Sustainability and Governance goals.

“Compared to oil-lubricated metal bearings, SXL eliminates shaftline pollution forever,” furthered McDonald.

An open SXL water-lubricated bearing system is also less expensive than new, white-metal bearings that operate with two oil seals; however, vessel operators looking to convert should do so before existing shaft liners are too worn, as it may be possible to use existing shaft liners and simply replace the bearings with Thordon, providing additional cost advantages.

“We are seeing increased market interest for Thordon’s water-lubricated and grease-free seal and bearing products across the Middle East,” said McDonald.

“With the completion of these conversions, Thordon Bearings continues to grow its retrofit market, while increasing workboat reliability and improving the environment in the waters of the middle east.”

www.thordonbearings.com

• Over a million wind turbine bearings have already been manufactured and delivered in accordance with the Wind Power Standard
• Highest quality standards for products and processes
• Wind Power Standard has been taking into account the rising demands on reliability of wind turbines and associated components for more than ten years

Birmingham, UK | June 22, 2023 | Against the backdrop of ambitious climate goals and an ever-increasing awareness of sustainability issues in society, renewable energy generation – including wind power as a central component – is of growing importance. As market leader and strategic development partner, global automotive and industrial supplier Schaeffler has been supplying reliable bearing solutions for onshore and offshore wind turbines for around 40 years. Rolling bearings from Schaeffler can be found in every second to third wind turbine worldwide.

Schaeffler introduced a Wind Power Standard for wind turbine bearings more than 10 years ago, which takes into account the high demands on the reliability of turbines and associated components. This standard for products and processes ensures that wind turbine bearings are subject to the highest quality standards, as also implemented, for example, in the automotive industry, and in the aviation and aerospace sectors. The start of the year marked the manufacture and delivery of the one millionth bearing by Schaeffler in accordance with the Wind Power Standard.

Rolling bearings play a key role in wind turbines

The progression to multi-megawatt turbines is resulting in higher loads and torques, which place the components under even greater strain, while the costs associated with downtime and maintenance work in the event of a failure are becoming increasingly higher, particularly where offshore systems are involved.

“Our customers require reliable components that allow the increasing power density in wind turbines to be used to its full potential. With the Wind Power Standard, we have been ensuring the highest level of quality for more than ten years – and with more than a million bearings to date,” says Bernd Endres, Head of the Wind Power business unit at Schaeffler.

Processes specific to wind power applications for the entire supply chain 

In order to ensure these high standards, Schaeffler relies on coordinated and transparent processes, a defined change management system, strict quality control, and extensive documentation along the entire process chain, which is achieved in close cooperation with customers and suppliers. Targeted supplier development activities ensure that the highest quality standard is achieved from the outset.

Long-standing experience and comprehensive system expertise

Compliance with the strict quality standards that apply on a global scale to all development and design teams, and to all production facilities that design and manufacture bearings for wind turbines, is monitored by means of internal audits. In addition to the long-standing experience and comprehensive system expertise of the specialists at Schaeffler, the use of state-of-the-art calculation and simulation programmes in particular ensures that wind turbine bearings are designed to optimum effect. The calculations are supplemented and validated on powerful test rigs. Schaeffler offers extensive testing options, particularly for rotor bearings, in the form of the “Astraios” large-size bearing test rig.

Bearings that are produced in accordance with the Wind Power Standard undergo a full ultrasonic and grinding burn test in order that material defects can be identified or ruled out prior to delivery, thus preventing possible bearing damage and any detrimental effect on bearing life.

www.schaeffler.com

this article can also be found in the issue below.

• Counterfeit rolling bearings pose a danger to man and machine
• Every case of counterfeiting will be pursued
• Steel from destroyed counterfeits fed into recycling loop

Birmingham | March 23, 2023| The global automotive and industrial supplier Schaeffler takes regular and consistent action against counterfeit products. The company has now had around 30,000 counterfeits with a total weight of ten tonnes destroyed in Schweinfurt.

At the company premises of Riwald Recycling Franken GmbH in Schweinfurt-Sennfeld, the products were so heavily damaged in the first step of the destruction process that their further use is impossible. The scrap will now be compressed and subsequently melted down in a steelworks – in this way, the steel resource is returned to the recycling loop.

“Counterfeit products are a major safety risk for man and machine,” says Dr. Edgar Duschl, Senior Vice President Intellectual Property at Schaeffler. Rolling bearings and similar products play a decisive, safety-relevant role in a large number of applications – almost everywhere where there is motion of any kind.   Safe and smooth-running passenger transport with trains and cars depends just as much on reliable products from Schaeffler as the operation of various industrial facilities.

Safety aspects are decisive
Dr. Edgar Duschl explains: “A defective bearing can lead to requirements for premature maintenance, machine downtimes, and thus enormous costs for the operator – or even result in a sudden total failure or even worse, an accident with personal injuries.”

For Schaeffler, safety aspects are the most important motivation for combatting counterfeit products. “Our customers should always be able to rely on the highest quality standards, which Schaeffler has always stood for – today and in the future,” says Dr. Edgar Duschl. It is therefore important to follow up on any suspicions.

Every case of counterfeiting is always pursued by the Schaeffler Global Brand Protection Team. “Firstly, there is the threat of civil claims for cease and desist, damages, and the release of the counterfeits for destruction. Secondly, there is also the threat of criminal prosecution, which can lead to a fine or custodial sentence,” says Dr. Edgar Duschl.

Authorised distributors and app
Counterfeit bearings come from all over the world. If a distributor or customer is offered a suspect product, for example from the brands INA, LuK or FAG, the initial suspicion can be checked directly with the Schaeffler “OriginCheck” app. In this way, the product code can be scanned using a smartphone and compared with the corresponding Schaeffler product identification numbers. Photos of the suspect products can also be simply sent to the Brand Protection Team.

In addition, Schaeffler maintains an international network of authorised distributors. These are listed on the Schaeffler website and customers can be sure to always purchase original products there. “In our view, it is important to raise awareness of this issue among all participants along the entire value-added chain, including distributors, repair shops, and end customers,” says Martin Rügemer from the Schaeffler Global Brand Protection Team. He travels around the world to advise distributors and holds training courses.

After being discovered, the counterfeit rolling bearings are seized on site. They are kept as evidence until completion of the ongoing proceedings. In many cases, the counterfeit products are subsequently destroyed locally. The counterfeits that have now been destroyed in Schweinfurt mainly originated from investigations in Europe over the past two-and-a-half years.

The damage to German companies caused by product piracy is estimated by the VDMA (German Machinery and Equipment Manufacturers Association) at around 6.4 billion euros annually.

Security via scan: The Schaeffler “OriginCheck” app is available for iOS and Android and can be downloaded at:
www.schaeffler.com/apps

Nowadays it is widely recognised that modern relatively low cost vibration analysers are capable of detecting bearing faults in their early stages. They generally do this by measuring the high frequency bearing noise present in the vibration signal. Allowing the user to trend the bearing noise readings over time, typically via automatic upload to PC based software, enables the user to predict when a bearing will need to be changed.

In days gone by, judging the extent of bearing wearwould have been done by an experienced technician holding a screwdriver to their ear and listening to the tinkling sound of the bearing. The problem was this was highly qualitative, relying heavily on individual experience. Vibration analysershowever, allow thebearing noise to be quantified, giving repeatable measurements.Bearing noise, generally measured as vibration acceleration in units of Earth’s gravity (g), is typically presented in some more meaningful way. A typical example being Bearing Damage Units (BDU), where 100 BDU equates to 1g RMS high frequency vibration. This allows the BDU reading to be considered as an approximate “percentage” of bearing wear. In other words, a reading of 200 BDU indicates the bearing is approx. 200% worn and should be replaced!

However, that is not the end of the story. Whilst we can accurately measure high frequency vibration, in some instances not all of it is due to bearing wear. For example, pump cavitation can produce vibration that looks like bearing noise. Both are of concern of course,but how do we distinguish between them and know when the bearing needs changing? This is where temperature comes in. When a bearing starts to wear out or is in need of lubrication, it usually gets hot. This allows us to be confident that if a bearing is both noisy and hot, then it really is a bearing issue and not cavitation.

Vibration sensors with built-in temperature sensing are nothing new of course, but theseneed to be left on the bearing for a long period of time (at least several minutes) for the temperature reading to stabilise. This poses no problem for permanently installed sensors, butwould be a big issue for portable vibration analysers used as bearing checkers. With its 9085 vibration analyser, Test Products International (TPI) has overcome thislimitation by embedding a platinum resistance temperature sensor (PRT) in the sensor’s magnet mount. This allows the PRT to be in direct contact with the bearing block when the sensor is attached, capturing anearinstantaneous temperature reading while thevibration measurement is carried out.

TPI believes it has madea verysignificant contribution to affordable Condition Based Maintenance (CBM) with this low cost, easy to use, high functionalityvibration analyser/data collector. With its full colour OLED display, instantaneous temperature and vibration measurement, the TPI 9085setsanother benchmark forCBM equipment with high-speed data capture.

The 9085, with wireless battery charging,offers on-meter, easy to decipher CBM analysis for thedetection of unbalance, misalignment, looseness and bearing wear. The inclusion of instantaneous temperature capture means that worn bearings and lubrication issues can be identified beforethey become a problem. With colour-coded alarms and on screen zoom and cursors, the TPI 9085 can store up to 10,000 separate readings,all withtemperature,vibration waveform and frequency spectrum (FFT). 

The 9085includes aroute-based mode, where a list of machines can be downloaded for ease of measurementpoint identification and data collectionusingthe includedFREE, Subscription FREE, C-Trend PC software.C-Trend’s basic functions such as vibration and temperature trending and alarm reporting are totally intuitive, ensuring the software can very easilybe usedby both novice andexpert users to implement an effective CBM strategy.  

For more information, please contact TPI Europeon +44 1293 530196 orwww.tpieurope.com or email This email address is being protected from spambots. You need JavaScript enabled to view it.

This article can also be found in the issue below.

NSK has developed a new type of ball screw that exhibits reduced motion errors to deliver higher surface finish quality for machine tools used in mould and die machining and other surface-critical applications. By eliminating or reducing the time needed for secondary burnishing or polishing applications, the new ball screw also contributes to higher productivity, while simultaneously reducing the amount of drive torque to save energy.

In recent years, builders of machine tools such as five-axis milling machines have been demanding increased accuracy to produce higher quality mould and die surfaces, where the ball screws used in these machines must further improve motion accuracy.

When a ball screw reverses direction, sudden fluctuations in friction cause ‘quadrant glitch’ motion errors with two peaks, leaving streak marks on the machined surface and reducing surface quality. Numerous studies conducted on quadrant glitches show that it is possible to correct the first peak through numerical control (software-based servo controller compensation). Although it is more difficult to fully compensate for the second peak due to the combined effects of more factors (compared with the first peak), NSK can now present the machining industry with a solution to this problem.

Using real digital-twin simulation and friction analysis, NSK has developed a new ball screw with an optimised internal design. Key to this outcome was the company’s understanding of the underlying mechanism of friction fluctuations in ball screws.

Among its many features, the new ball screw stabilises drive torque and reduces friction fluctuations when reversing its direction of motion, thereby improving motion accuracy and reducing quadrant glitch motion errors. The result is a near elimination of the second peak. Indeed, up to 20% less friction fluctuations also contributes to reducing the height of the first peak.

Through a combination of NSK's new ball screw and software servo controller compensation, machine tool manufacturers can assure their customers of significant improvements in machined surface quality. Furthermore, the enhanced surface quality eliminates or reduces the need for any previously required burnishing or polishing processes, reducing lead times, while lower drive torque contributes to energy savings. All of these benefits provide machine tool builders with the opportunity to pitch unique selling points to potential customers.

PR Ref. L062022-N | 1/3

1/3

 To maximise convenience for machine tool manufacturers, the mountings of NSK ball screws with quadrant glitch control are fully interchangeable with those of conventional products, allowing adoption without costly equipment changes. The ball screw will be available in shaft diameters from 25 to 63mm, with leads from 5 to 30mm. Preload types will include: offset preload (Z preload), double nut preload (D preload) and spring-type double nut preload (J preload).

1) Motion error during circular interpolation machining (with servo controller compensation)

2) Enlarged view of machined surface (simulated image)

www.NSK.com

 This article also featured in the December/Jan issue below