Discover Your Advantage! Technical Brochure Everything You for Engineers Need to Know About Stepper Motors Outstanding reliability: The stepper motor’s real advantage! The reliability of stepper motors is sometimes Discover underestimated, and most people are surprised to learn that they are in fact just as reliable as the facts servomotors. This brochure introduces the true strengths and advantages of stepper motors. CONTENTS A motor with real benefits Discover Your Advantage! Everything you need to know about stepper motors What is a stepper motor? Five-minute guide to the basics of stepper motors Addressing the cost problem A case in point Is there a way to reduce costs? Discover Your Ask the expert Advantage Which offer better stopping accuracy: stepper motors or servomotors? Pinpoint Stepper Motors Pulse signals are precisely synchronized, and position and speed positioning controlled accurately just by sending pulse signals from controller to driver. Our stepper motors’ low-speed yet high-torque, low- vibration operation makes them ideal for applications that require short-distance, short-time interval positioning. Free brochure: Please take one Discover Your Advantage Everything You Need to Know About Stepper Motors There are a lot of people who think servomotors outperform stepper motors – but nothing could be further from the truth. In fact, stepper motors are used in a wide range of devices, from cutting-edge equipment to everyday automatic machinery. So, why should people choose stepper motors? Instead of using technical data, we’ll explain using the perspective of actual users. Illustrated by Yoriyuki Suzuki New 5-phase stepper motor and Tell us why you chose a stepper motor: driver package Ease of use 34% A user survey highlighted “ease of use,” RK Series Low cost 17% “simple” structure and system configuration Our newest model combines a high-efficiency Simple 16% and “low cost” as key reasons for choosing a 5-phase stepper motor with a digitally No adjustments needed 12% stepper motor. controlled compact driver. It also has the Other 21% appealing price of 377 Euro, including cables. Based on answers from 258 respondents in a company survey (more than one answer was permitted) Some readers may have never even seen a stepper be the motor of choice for so many applications and torque and various other characteristics that a motor motor, but they are in fact used in a wide-range of fields? Let’s find out the surprisingly little known needs to perform? Without actually using a stepper applications and fields as the drive force for systems answer to this question. motor, it’s very difficult to grasp the differences that require precise control. These range from compared to servomotors and other control motors. factory automation applications to semiconductors Ease of use, simple and low cost What’s more, some people may be worried that and flat-panel displays. They are also used in solar there simply isn’t enough information out there to panel manufacturing devices, medical equipment, Actual users will be quick to mention the ease of make an informed decision, and more often than analysis equipment, precision stages, devices used use, simplicity and low cost of stepper motors. This not, when it comes to control motors, “servomotor” in the financial industry, packaging and other food is no surprise considering their simple structure automatically comes to mind – especially for young processing machinery and camera diaphragm and system configuration. However, despite these engineers. adjusters. So, why do stepper motors continue to advantages, do they really possess the precision, If that’s the case for you, we want you to stop and 2 POINT Outstanding stopping POINT Ideal for mid- and 1 accuracy 2 low-speed operation Stepper motor stopping accuracy is the equivalent of ±0.05° Stepper motors have especially high torque at when measured in the same units as a ball screw mechanism mid- and low-speeds, as the representative Usage requirements characteristic graph (below left) makes clear. For example, a product with 85 mm attachment RK Series stepper motor dimensions running at 1000 r/min has rated torque 10 mm ball screw lead equivalent to a 400 W servomotor. At low speeds it can generate up to more than 5 times the torque. Stopping accuracy ±1.4 μm Generating high torque at mid- and low-speed is Typical ground ball screw accuracy is ±10 μm. crucial to short distance positioning. While it is What’s more, since roller ball screw accuracy drops to only a rough guide, a simple conversion of stepper ±20 μm, it’s easy to see that stepper motor stopping accuracy motor torque output looks something like the chart is superior to ball screw mechanisms. on the right below. How much power does a stepper motor generate equivalent ±0.05° to servomotor watts? Motor output Frame Model Price RK Series/85 mm and 400 W and size (estimate) ± 1. 4 μm RKS543 From 377 Euro 750 W servomotors 50–100 W 42 mm RKS544 From 377 Euro 8 equivalent RKS596AC- RKS545 From 383 Euro RKS599AC- - RKS564 From 415 Euro 6 RKS5913AC 100–200 W 400 W servomotor (rated torque) m] 750 W servomotor (rated torque) RKS566 From 420 Euro equivalent N- 60 mm e[ 4 200–400 W u RKS569 From 424 Euro rq equivalent To 2 RKS596 From 465 Euro 400–750 W 85 mm RKS599 From 498 Euro 0 equivalent 0 200400 600 8001000 R KS 5913 From 533 Euro RPM[r/min] *Calculated for the RK Series 42 mm frame sizes generate output equivalent to a 50–100 W servomotor, while 85 mm frame sizes generate 400–700 Rotary table positioning Ball screw positioning W. While this will vary depending on series and model number, this is a handy benchmark when choosing a stepper motor. When it comes to short-stroke applications, Excellent stopping accuracy, even stepper motors cannot be beat! with open-loop control. And they come at a very affordable price. think for a moment – because if you understand the Advantages of stepper motors: (without load), and since measurement errors do advantages of using a stepper motor and apply them stopping accuracy, mid- and low- not accumulate between steps, a stepper motor sets to the operating requirements, equipment costs speed operation and adaptability positions with a high degree of accuracy. Moreover, can be significantly reduced. Let’s take a look at an the motor structure does not need an encoder, which easy-to-understand explanation of the surprisingly Coming to the conclusion that stepper motors do not makes stepper motors’ drive system simpler than other motors and helps keep its cost low. little-known advantages and technical information ensure very precise stopping accuracy is something The fact that stepper motors produce high-torque at of stepper motors. We want to completely dispel that may come to cost you. A stepper motor, in fact, mid- and low-speeds is another advantage that must any vague doubts or misconceptions you may have has outstanding stopping accuracy. This advantage is not be overlooked. Servomotors generate flat torque about stepper motors, such as whether you can thanks to an open-loop that enables precise control. from the mid- to high-speed ranges – a feature For example, the RK Series determines rotary really put them to use and how they differ from aimed at multi-rotation tables and other long-stroke servomotors. table position with stopping accuracy within ±0.05º (high-RPM) machines. Stepper motor torque, on 3 Great for these uses, too! POINT Excellent 3 adaptability! The synchronized operation of multiple motors is easy to set up Low-rigidity mechanisms Substrate conveyor Frequent starts and stops Stepper motor AC servomotor RPM RPM Time Setting time Time Variable loads Positioning time Positioning time (Open-loop control) (Closed-loop control) Runs in sync with operation Lags behind operation commands commands the other hand, is not flat. The mid- and low-speed Excellent adaptability and positioning in vibration-sensitive image inspection torque curve is relatively high, while torque drops at outstanding synchronization processors, cam drives and other mechanical devices higher speeds. Besides providing stable rotation at that servomotors have difficulty controlling, and the very low speeds that servomotors have trouble The third noteworthy feature of stepper motors is mechanisms with changing loads and low rigidity such handling, stepper motors generate high-torque at the none other than its adaptability. The open-loop as belt drives. Of course, stepper motors also make it high-speeds necessary for short-stroke (low-RPM) control transmission of commands to the motor possible to greatly reduce costs by switching from a operation – ideal for angle indexing, inching and unilaterally means that commands have excellent ball screw drive to a belt drive. Most of all, since they other rotary motor tasks. followability. Since a servomotor relies on encoder don’t need to be adjusted when load, inertia or rigidity Given these features, it is interesting to consider feedback, there is a command-response lag. In change, stepper motors are great for anyone busy just where today’s servomotors stand in regard to contrast, stepper motors’ commands are synchronized trying to keep up with the day’s work. delivering high performance at the very highest to a pulse to give them excellent adaptability speeds. Since the actual positioning time for short- with almost no lag at all. For this reason, stepper Use stepper motors to their stroke operation is short, when a servomotor motors are extremely well-suited for uses such as advantages and reduce costs reaches top speed, it soon decelerates and stops. the synchronized operation of multiple motors – for example, attaching motors to two conveyors In other words, these motors don’t actually need Stepper motors have all kinds of advantages, not sandwiching a substrate and producing conveyance.