High-precision industrial spindles, such as those used in rotary stages, are crucial for applications requiring absolute precision, including semiconductor wafer processing, imaging, and inspection. Beyond the semiconductor industry, air bearing spindles are also vital in optics production, scientific research, and even automobile painting.

Air bearings, also known as fluid film bearings, utilize pressurized air to reduce friction, similar to how liquid or mechanical lubricants work. The compressed air acts as a cushion between the spindle’s rotor and stator, as well as providing stiffness, enabling highly reliable high-speed and precise movement. The complexity of predicting the performance of air bearings is rooted in nonlinear differential equations, but the benefit is seen by minimizing moving parts and wear resulting in enhance reliability. One critical design/integration aspect of air bearing spindles is the high degree of precision gained when paired with slotless motors.

Low-profile, large through hole BLDC motors are particularly suitable for spindle applications due to their large internal aperture, which accommodates optics, cabling, or prisms, while remaining compact enough for deep system integration. Another benefit of using traditional slotless or ironless stator slotless motors for air bearing spindles is architectural, due to the reduced, or in some cases, elimination of attractive forces between the rotor and stator. The lack of a stator iron enables a thinner, lighter weight, and ultimately more mass efficient spindle, saving both volume and mass.  Finally, the lack of cogging inherent in slotless motors provides a smooth rotational output and avoids even the smallest disturbance torques that can translate to the workpiece.

ThinGap’s TG Series of slotless BLDC motor kits are ideal for high-speed air bearing spindle applications due to the lack of iron in the stator, leading to zero radial and axial forces between the rotor and stator. The slotless, ironless stator delivers smooth, zero-cogging motion, making these motors perfect for spindle use. The TG Series has the added benefit of zero hysteretic and Eddy Current drag, ensuring true bidirectional repeatability in both angular and vertical movements, while also making it exceptionally efficient at high speeds. Lastly, the TG Series ironless stators boast harmonic distortion below 1%, and provide a linear current to torque output throughout the entire torque range (up to the peak torque limit) reducing servo induced disturbance and ultimately improving torque, and velocity control.

ThinGap’s TG Series of slotless motor kits stands out as an industry leader for air bearing spindle applications. With standard kits ranging from 29 to 190 mm in outer diameter and continuous torque outputs from 0.14 to 9.46 N-m, these motors are always cogless, low-profile, large through hole, and high in power density. Available in standard and modified configurations, ThinGap’s TG Series is the optimal choice for air bearing spindle motors.

ThinGap’s sister company, Sierramotion recently published an insightful article about motor constant, and has given permission to repost part of it. Many motor specifications define how a brushless DC motor will perform, but only one allows a true motor to motor comparison of torque, associated power dissipation and temperature rise. That specification is the motor constant (K_m). The units of the motor constant are Nm per square root of watts dissipated in the form of heat (these being I²*R losses, known as copper losses).

This metric is a form of efficiency, but it only considers the copper losses. In a traditional, slot wound brushless DC (BLDC) motor, there are at least two other loses, those being core losses, which include eddy current and hysteresis, and mechanical frictional losses, those being viscous friction, coulomb friction, and sometimes windage. A third form of loss that is not addressed here, is created by the pulse width modulated method of driving BLDC motors.

This is an effect that is highly dependent on the inductance and frequency of the PWM rate and could also be considered under the right conditions. An Effective Motor Constant (K_me) is introduced to include core and copper motor losses (frictional and PWM losses ignored) and offers a more meaningful comparison of motor performance at speed.

To read the rest of Sierramotion’s post, click here.

According to market research by McKinsey, the space market is estimated to more than double to $1 trillion by 2030 attributed in large part to the rapidly decreasing cost and frequency increase in launches, as well with the rising demand for high speed communications for both military and civilian needs.

The single largest driver in the rapid expansion of the space market can be attributed to the emergence of private spaceflight efforts from corporate entities known as NewSpace. With the expansion of spaceflight and the related demand for applications tied to orbiting the Earth has come a significant increase in the need for Low Earth Orbit (LEO) satellite constellations.

Satellite constellations refer to a group of networked satellites working together for a common application, such as defense or telecommunications. The ability to bring broadband connectivity to anywhere on Earth has been the mission of several internet constellations including SpaceX’s Starlink, and Airbus’s OneWeb programs.

Multi-axial gimbals, like those used in Coarse and Fine Pointing Assembly systems can leverage the benefits of high performance cogless Ring Motors. These motors are used to directly drive movement and maintain position to enable high bandwidth communication to wirelessly network these satellites. Frameless motor kits offer the ability to integrate the actuation function as part of optimized systems, offering Size, Weight, and Power (SWaP) savings, which are highly desirable in spacecraft applications.

ThinGap’s LS Series of slotless motor kits is an industry leader for gimbal applications requiring high performance and efficiency, decisive move-and-hold positioning, and smooth motion for long-range target lock. LS motors have been widely used in OCT systems and even NASA’s PACE Mission’s optical scanner payload.

Using its proprietary design, thin wire-wrapped stators, and optimized permanent-magnet rotors, ThinGap provides motors with specifications that can match the torque output of slotted motors while avoiding the cogging that plagues them. ThinGap’s LS line of slotless motor kits range in size from 25 to 267 mm diameter and torque from 0.1 to 12 N-m continuous. With standard and modified configurations, the product line will cover voltages from 24-400 volts and current from 1 to 100 amps.

The increased frequency of massive wildfires, capable of inflicting billions of dollars in damages annually, demands enhanced technology to combat the threat. The innovators at Xiomas Technologies, headquartered in Ann Arbor, Michigan, strive to empower humanity in the battle against these catastrophic forces with cutting-edge systems and advanced imaging technology.

Xiomas is developing advanced high-resolution imaging instruments that will help map wildfires in greater detail to aid firefighters with coordination and safety when battling these large fires. Current wildfire imaging technology captures fire data in infrared wavelengths to map the ground temperatures and cut through the smoke, and typically operate at altitudes around 10,000 feet, which only gives a 6 mile wide field of view for each pass, which represents a limiting factor.

Xiomas’s Thermal Mapping and Measurement Sensor (TMMS) is the latest evolution of their high altitude fire mapping sensor. Designed to operate at around 40,000 feet, the Xiomas sensor captures a 16 mile wide path, resulting in triple the ground coverage in a single pass and without compromising critical resolution and data collection.

Despite operating at much higher altitudes than contemporary infrared sensors, TMMS can create an image with the same ground resolution as current technology by creating a mosaic of many smaller images and patching them together in software to create a much larger image. Xiomas’ goal is to create a more efficient airborne sensor to reduce operation costs, decrease flight time, and increase coverage to better help firefighters on the ground.

Xiomas’ technology has attracted the attention of NASA, who have funded the development and testing of a few generations of thermal mapping instruments, the WAI (Wide Area Imager), TMAS (Thermal Mapping Airborne Simulator), TBIRD (Three Band IR Detector), and now the TMMS sensors. Set to begin testing by NASA in Fall 2024 aboard their ER-2 High-Altitude Airborne Science Aircraft derived from the famous U-2 spy plane, Xiomas is hoping to expand the TMMS sensor to be integrated into satellites in the next few years.

The ThinGap-designed turnkey assembly integrates one of its slotless motor with an optical encoder and bearing set into a precision aluminum housing.

At the heart of the Xiomas’s TMMS is the Across-Track Scanner, which is built around a custom motor assembly and ThinGap’s OTS LSI 75-12 Brushless DC motor. The ThinGap engineered assembly is based on a cog-free, low profile “slotless” motor integrated into a precision-machined aluminum housing, with a high resolution optical encoder, pre-loaded bearing set, and paired with a high-PWM, low-inductance controller, all of which drives a lightweight scan mirror.

The TMMS sensor has a 110 degree field of view, enabled by each 5.85 degree movement of the scan mirror, which triggers the camera to take an image. The ability to deliver a framed assembly (link to modified/custom page) based off an off-the-shelf motor kit with is another example of ThinGap’s ability to deliver an optimized, yet cost and budget effective turnkey motor assembly for rapid customer integration.

Many members of ThinGap’s team have been directly affected by the wind-driven brushfires that Southern California is famous for, so the ability to directly contribute to community safety is a matter of pride.

To learn more about Xiomas Technologies, please visit their website.

ThinGap stands atop a proud 25-year history supporting customers in aerospace and other precision industries. The ability to serve such a diverse customer base is due to ThinGap’s heritage and unique capabilities as an organization. In May of 2022, it became part of the greater Allient organization (formerly named Allied Motion).

Since 1999, ThinGap has developed hundreds of motor designs, and shipped thousands of motors to customers ranging from NASA to Fortune 500 companies, and even top Formula 1 teams. One of the key enabling factors is the close integration of production, engineering, and operations within a single location.

ThinGap’s ability to rapidly react to customer needs is reflected in sample quantity products often shipping within a week or less, with a ramp to production volumes in 3-4 months. Additionally, preliminary custom electro-magnetic designs and space-claim CAD models are available in 48 hours, with first deliveries often happening in 9-12 months from project kickoff. Because of ThinGap’s advanced analytical modelling, final designs are promised to be within 95% of predicted performance. Well defined production processes, 3D-printed tooling, refined modeling, and analytical tools all contribute to the ability to quickly support customers in a fast paced marketplace.

ThinGap has the capability to take any off-the-shelf motor kit and modify it to the customer’s exact requirements for both its LS and TG Series, such as winding changes, or environmental conditions like space-rating or submergible applications. Modified and custom motor designs address the need for very specific performance specifications, operational requirements, cost optimized solutions, and unique form factors that may be required for a given project.

Additionally, ThinGap has the in-house capability to design and manufacture framed or housed motor assemblies as a pre-integrated solution. Housed and framed assemblies enable more cost-effective, turnkey solutions desired by programs with tight schedules which need to be able to rapidly integrate a motor into a system.

To learn more about ThinGap’s capabilities, please reach out for further information.

With an outer diameter of 105 mm, and a 21 mm axial height, the LSI 105-21 provides 1.2 N-m of continuous torque output, yet only weighs 414 grams

The latest LS Series motor set uses a fiber-wound technique to bolster magnet retention of the rotor assembly 

Camarillo, CA (May 31, 2024) – ThinGap continues to build out its LS Series of slotless motor kits with the latest release, the LSI 105-21. The new part has an outer diameter (OD) of 105 mm, and an axial height of 21 mm. With a maximum operating speed of 3,000 RPM, the LSI 105-21 has a 1-second peak torque output of 13.5 N-m, and a continuous one of 1.2 N-m.

Designed from the ground up, the LSI 105-21 was developed for use in space-based gimbals, such as Coarse Pointing Assemblies (CPAs) that perform critical laser-based satellite communications. All types of multi-axial gimbal systems can leverage the benefits of high-performance cogless motors, such as ThinGap’s LS Series, to directly drive movement and maintain position, while offering a large aperture and significant Size, Weight, and Power (SWaP) savings.

The LSI 105-21 marks the first time that an LS Series motor kit comes standard with a fiber-wound rotor. For high-speed and fail-safe applications, ThinGap deploys a thin, but strong filament of epoxy-coated fiberglass over the magnets in building the rotor assembly. This enhanced rotor provides an additional safety margin called out by some customers.

ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm diameter, and torque from 0.1 to 12 N-m continuous and voltages from 24-400 volts. Most LS motors are available with an optional space-rating that includes the use of low outgassing materials, leaded-circuit boards and a Materials and Processes (M&P) list that conforms to NASA’s standards.

While the majority of ThinGap’s motors are bound for space or airborne gimbal applications, we have been proud to support Motocrane with their new advanced cinema gimbal system, Titan. Motocrane has integrated ThinGap’s LS Series of zero-cogging slotless motor kits into Titan, enabling smooth, high precision motion with even the heaviest camera systems. To learn more about Titan, see Motocrane’s video below.

While a majority of ThinGap’s motor kits are destined for airborne or spaceborne applications, the same attributes that help serve aerospace customers also are desirable for many medical applications. Smooth, zero-cogging, high precision motor kits, such as ThinGap’s are ideal for not only surgical robotics, but diagnostic and imaging equipment as well.

Modern surgical robotics systems require precise, exacting movement with no chance for mechanical disturbances to ensure the highest level of patient care. Zero-cogging motor kits are the ideal solution for true and accurate operator haptic feedback, as well as precision actuation. ThinGap’s TG Series motor kits have been used for haptic feedback for a surgical robotic system, due to the lack of both hysteretic drag afforded by the ironless motor architecture, enabling true force feedback without any disruptions.

ThinGap’s LS Series has seen integration in high-precision robotics due to the motor architecture’s extremely smooth, highly precise motion. Additionally, low profile motion solutions with a large internal aperture are desired for the ability to route optics or cabling through the center as part of deep system integration.

ThinGap’s motor kits have near zero Eddy-current, low or zero hysteretic drag, and a harmonic distortion of less than 1%, so torque output is directly proportional to current throughout the operating range, as well as providing smooth, zero-cogging motion. Additionally, ThinGap has maintained a long-standing relationship with a leading surgical robotics manufacturer supplying motors, and regularly works with other medical industry OEMs to produce tailor-made solutions that meet regulatory approval.

In recognition of Earth Day, ThinGap is excited to share NASA’s public release of data from the recent PACE Mission.

Image Credit: NASA

Launched in February, PACE is a mission to study the Earth’s oceans and atmosphere, and marks the first time ThinGap motors have received NASA flight certification. ThinGap supplied its LS Series motors that drive the satellite’s main instrument, the Ocean Color Instrument (OCI).

Read the full blog here

As a recent example of its custom motor capabilities, ThinGap recently shipped an assembly in support of a defense project that utilizes structural carbon fiber composite components to increase performance. While the company is no stranger to working with composites, with many current off-the-shelf products utilizing them, this project marks the first time these components have been sourced from a commercial vendor.

What is commonly referred to as “carbon fiber” in reality Carbon Fiber Reinforced Polymer (CFRP), a composite material typically composed of an epoxy-impregnated sheet of woven carbon-filament cloth that is layered, formed into a mold, and then cured in a kiln under vacuum conditions. The components made of the material that results from this process are extremely lightweight, and incredibly stiff with an excellent strength-to-weight ratio.

The individual fibers in modern carbon fiber are mostly composed of petroleum byproducts, with the development of pure, crystalline carbon fibers being how the material matured and was later industrialized. First synthesized throughout the late 19^th and early 20^th centuries, including by Thomas Edison for use as light filaments, these early attempts were unsuccessful as they were of low purity. It wasn’t until the early 1960s when Japanese and American chemists were able to produce fibers of the appropriate purity to be used as reinforcement in composites.

After substantial investment by the Royal Aircraft Establishment, a part of the British Ministry of Defense, the first industrially-produced carbon composite components came with the integration of a carbon composite compressor fan assembly in the Rolls-Royce Conway and RB-211 jet engines in the late 1960s. Through the 1970s, the material further matured with improvements in the quality of the filaments and adhesives, and by the early 1980s motorsports became another testbed for carbon composite materials.

The Rolls Royce Conway jet engine was designed for the Vickers VC-10 Airliner

Introduced for the 1981 Formula 1 championship, the McLaren MP4/1 was an early racing car with a fully carbon composite chassis. Similar to the high-performance nature of aerospace, motorsports benefitted from composites by enabling weight reduction without sacrificing strength and rigidity, ensuring McLaren a competitive edge, and before long carbon composites were prevalent in all forms of racing.

By the 1990s, production of even larger carbon composite pieces became possible, helping to reduce weight in the new Boeing airliner, the 777. The 777 was critical in introducing large composite pieces to aerospace, with the plane being 9% carbon composites by weight, being used in the rear fuselage, engine cowlings, control surfaces, and floor beams. In addition to saving weight, these new composite components were corrosion and fatigue resistant, which helped save on maintenance over the old industry-standard aluminum.

In 2007, Boeing introduced the revolutionary 787 Dreamliner which saw a massive increase the use of composites, now up to 50% by weight. Due to Boeing’s ability to produce large carbon composite pieces, the fuselage of the 787 is composed of three large single-laid sections that are then mated during assembly. Additionally, the wings of the 787 are primarily composed of carbon composites, with the materials ductility lending to the plane’s iconic wing flex.

With these desirable characteristics in mind, it was only a matter of time before an application came up that required carbon composites. To minimize unit weight and maximize rotor inertia in the new TGD 129-114 generator unit, ThinGap’s new assembly uses carbon composite for both the inner and outer sleeves that retrain the rotor’s magnets and are joined together by a purposely designed metallic top cap with fan blades that forces airflow across the stator. To learn more about ThinGap’s custom and modified capabilities, click here.