Stepper motor manufacturers follow integration, miniaturization trends

Stepper motors deliver high precision and reliability, which is why they are widely used in industrial and medical equipment, office automation and military applications. There are three types - variable-reluctance (VR), permanent-magnet (PM) and hybrid motors.

Hybrid stepper motors, which combine the advantages of the first two in a best-of-both solution, are the most popular in the market as they offer "the best performance albeit at a higher cost," says Johnny Tang in Oriental Motor's Engineering Notes blog. Indeed, these outperform conventional types in terms of holding torque, speed and step resolution, the last achieved with greater precision using half-stepping and microstepping techniques.

For this reason, manufacturers in China are zeroing in on this hybrid type to expand their predominantly VR range, especially on the back of industry projections. According to Beijing-based QY Research, hybrid stepper motors will have a global market scale of $1.32 billion in 2026 from $940 million in 2019 at a CAGR of 5 percent.

Companies interviewed by Global Sources Electronic Components say two-phase hybrid stepper motors are the bestsellers at present for their high price-performance ratio. But in the coming years, R&D will move toward three- and five-phase units that are expected to replace two- and four-phase kinds that have comparatively high vibration and noise.

One of the major players in China's BLDC motor sector, Shenzhen Hamderburg has introduced five-phase hybrids with a 0.72-degree step angle and ±0.04-degree precision. These 42mm units have high speed and torque, and low vibration, noise and temperature rise.

Another trend expected to shape China's manufacturing industry for this product category is the integration of a stepper motor, an encoder and a gearbox to realize a close-loop system for better control. This technique has been used in recent years to elevate the performance of stepper motors, which have a native open-loop control, to the level of servos without the latter's high cost.

Not to miss an opportunity to expand applications, Chinese companies are continuing to develop compact stepper motors as miniaturization remains a key pursuit across categories. They are adding 25, 30, 35 and 39mm units to mainstream selections dominated by those measuring 42 and 57mm.

Assured market

The main catalysts expected to ensure growth for the stepper motor manufacturing sector in the coming years are the medical, security and automotive fields, 3D printers and 5G base stations.

Globally, the medical device market is forecast to reach $529.8 billion in 2022, according to Zhiyan Consulting. Meanwhile, Qianzhan Industry Research Institute estimates over $22 billion for 3D printers worldwide, with China accounting for more than $6.19 billion. In 2021, China's 3D printer market is expected to finish at $4.76 billion, up from $3.55 billion in 2020.

Especially for China, a major production base for this product, this means a steady rise in sales, projected to be between 7 and 13 percent from 2021 to 2022, according to Zhiyan Consulting. Banking on this upbeat outlook, most Chinese suppliers of stepper motors are planning to increase their output by 5 to 10 percent in the months ahead, anticipating growth in exports as well. Overseas-bound shipments currently represent 30 to 80 percent of volume produced.

China's manufacturing pool of domestic and foreign companies is in the hundreds. The major suppliers include Wolong, Broad Ocean and Moon on the domestic side, with the rest consisting of small and midsize enterprises offering entry-level and midrange products. The international group, with strong R&D and large-scale operations, includes Mitsubishi, Yaskawa, Panasonic, ABB, Siemens, Johnson and Delta.

The key cities hosting these companies include Shenzhen, Dongguan and Zhongshan in Guangdong, Ningbo in Zhejiang, Suzhou and Changzhou in Jiangsu, and Dalian in Liaoning.

Stepper motor types

VR stepper motors currently dominate supply in China, but PM and hybrid types are also available.

Variable-reluctance units feature a simple, low-cost structure that gives small step angles but generate heat that affects their efficiency. Although with relatively low torque, they have minimal torque drop-off at greater motor speeds, making them suitable for medium- and high-speed applications. However, their noise levels are high, so they are not recommended where this is an issue.

Permanent-magnet motors typically have large step angles but support full-, half-step and microstepping modes for greater resolution. They offer higher torque than VR kinds albeit at limited speeds, making them the motor of choice for applications requiring low to moderate torque at low to medium speeds.

Hybrid stepper motors offer dynamic performance and high torque while addressing the issues in VR and PM types. However, they have a more complex structure and therefore are not easy to manufacture and command a higher price.

Chinese manufacturers purchase rotators, stators, shafts and bearings from domestic or foreign sources, depending on buyers' preferences. Material and component costs are expected to stay stable and keep a lid on price increases throughout 2021.

Stepper motor with 90mN.m holding torque

Rated at 2.35V, 0.5A, this 42PMK22016 PM stepper motor from Guangzhou Ruibao Electrical Co. Ltd has 90mN.m holding torque, 4.7ohm±10 percent resistance, 6.8mH±20 percent inductance, 100Mohn minimum insulation resistance at 500VDC and 600VAC/sec dielectric strength at 50Hz, 1mA. The unit, with 3.6-degree±5 percent step angle and class B insulation, operates in -20 to 50 C. It meets CE and RoHS requirements.

The negotiable order quantity has a lead time of seven days.

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Stepper motor, has 20 to 1,500rpm speed

Shenzhen Shunchang Motor Co. Ltd's 16mm Stepper Motor-8304 has 3 to 12V voltage range and 20 to 1,500rpm speed. It measures 15.5x37.9mm.

The 100-set minimum order has a seven-day lead time.

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Stepper motor, has class B insulation

From Wuxi Junhong Automation Technology Co. Ltd, this MP057NA208 stepper motor has 49N.cm holding and 5.88N.cm detent torque, and 1.8-degree step angle and ±5 percent accuracy. Its phase current, resistance and inductance are 1.3A, 3.1ohm and 4.4mH. The insulation resistance is 100mohm and the dielectric strength 500VAC/sec at 2mA. The 520g unit, with class B insulation, has 80 C temperature rise. It is 51mm long.

Order quantity is negotiable. Lead time is seven days.

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4.6N.m stepper motor

ZJTEX Electric Group Co. Ltd's 86mm hybrid stepper motor, with 2.3V rated voltage and 5.5A current, has 4.6N.m holding torque and 1,400g.sqcm rotor inertia. The ZJ-86SH80-5504A's resistance is 0.42ohm and inductance 3.5mH. Weight is 2.3kg.

The 3,000-unit minimum order requirement has a lead time of seven days.

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