1.8-Degree Hybrid Stepper Motor Accuracy
To understand the accuracy of 1.8-degree hybrid stepper motor, it's helpful to first become familiar with the key factors that define accuracy: the basic step angle and theoretical resolution, actual positioning accuracy, and the main factors that affect accuracy in real-world applications. The sections below provide a detailed explanation of each of these aspects. 
The key factors affecting the accuracy of the system are: In practical applications, the 1.8-degree hybrid stepper motor offers high accuracy potential, the overall positioning accuracy of the system is heavily dependent on various external factors: such as choosing the appropriate motor size, driver or acceleration and deceleration curve to prevent step loss, suppressing mechanical resonance, ensure the accuracy and rigidity of the transmission components (coupling/screw/gear, etc.), and use high-quality micro-stepping drives. For applications that require high absolute accuracy or strictly avoid step loss, closed-loop stepping with encoder feedback is a more reliable choice. Therefore, "1.8 degrees" figure should not be directly equated with positioning accuracy, as it only represents the basic theoretical resolution. When paired with high-performance drivers and a precision mechanical system, a high-quality motor can achieve positioning accuracy that is significantly better than 1.8 degrees.
1. Basic step angle and theoretical resolution
The term 1.8 degrees refers to the step angle of the stepper motor operating in full-step drive mode. In simple terms, this means that with each control pulse, the motor rotates exactly 1.8 degrees. As a result, it takes exactly 200 steps to complete one full revolution (360 degrees ÷ 1.8 degrees/step = 200 steps). This 1.8 degrees (or 200 steps per revolution) represents the smallest theoretical unit of angular displacement the motor can achieve in full-step mode. Theoretical resolution: From this perspective, 1.8 degrees (or 200 steps per revolution) represents the smallest angular increment a stepper motor can command to move under open-loop control. This defines its theoretical "positioning resolution". 2. Actual positioning accuracy
The actual positioning accuracy refers to the deviation between the actual position reached by the stepper motor and the command position. For example, a 1.8-degree hybrid stepper motor, the actual positioning accuracy is usually much higher than the basic step angle of 1.8 degrees. The main reasons are as follows: 1). No cumulative error (open loop): Under ideal conditions such as no step loss, constant load and absence of resonance, the stepper motor in open-loop control does not accumulate positional error. This means that if the motor is commanded to move 200 steps, it will theoretically complete one full rotation (360 degrees) with zero positional deviation. This is a distinct advantage of stepper motors in open-loop mode compared to servo systems, which typically exhibit cumulative errors when operating without feedback in open-loop position control. 2). Intrinsic accuracy (single-step error): The deviation between the actual step angle and the theoretical value (1.8 degrees) for each individual step is very small. In high-quality 1.8-degree hybrid stepper motors, step angle accuracy typically falls within ±3% -±5%. This means a single theoretical 1.8-degree step may result in an actual angular displacement between approximately 1.746 degrees and 1.854 degrees (calculated as ±3%); however, when the motor completes a full circle rotation (200 steps), the random and non-systematic nature of these individual errors causes these positive and negative deviations to partially cancel each other out. As a result, the final full circle cumulative angle error can usually be controlled within ±0.09 degrees (±5 arc minutes), with higher-precision motors achieving ±0.05 degrees (±3 arc minutes) or better. This full circle accuracy (±0.05 degrees to ±0.09 degrees) is significantly higher than its single-step theoretical step angle (1.8 degrees). 3). Microstep drive: The vast majority of modern applications use microstepping drives, which precisely control the current ratio in the two-phase windings to subdivide each full step (1.8 degrees) into smaller microsteps (such as 2, 4, 8, 16, 32, 64, 128, 256 microsteps, etc.). For example, when using 16 microstep setting, the theoretical step angle is reduced to 1.8 degrees / 16 = 0.1125 degrees, increasing the theoretical resolution to 3200 steps per revolution. Although microstepping is limited by factors such as the nonlinearity of the motor's magnetic field and the precision of the driver's current control, and therefore cannot infinitely improve absolute accuracy, it significantly improves the smoothness of the motor's motion, effectively suppresses resonance, and can achieve a positioning resolution far higher than 1.8 degrees. In microstepping mode, the actual positioning accuracy (mainly referring to repeated positioning accuracy) of a high-quality system can usually reach several arcminutes, such as ±0.05 degrees (about ±3 arc minutes) to ±0.02 degrees (about ±1.2 arc minutes) or higher. Therefore, the basic step angle of 1.8 degrees represents the theoretical minimum step size of the motor in full-step mode (i.e. the starting point of theoretical resolution), rather than the actual positioning accuracy that the motor can achieve. The actual accuracy mainly depends by the motor's manufacturing quality (such as magnetic circuit symmetry, tooth groove processing accuracy, etc.) and the performance of the driver (especially micro-step accuracy and current control).3. Main factors affecting the accuracy of practical applications
1). Step loss: Step loss is one of the primary factors affecting the accuracy of stepper motors under open-loop control. It occurs when the load torque exceeds the motor's available output torque at a given speed (torque deficiency), or when acceleration/deceleration settings are too large. In such cases, the motor may fail to complete the commanded number of steps—resulting in fewer actual steps than instructed. Once step loss occurs, it introduces cumulative positional error. 2). Resonance: Stepper motors can experience mechanical resonance within certain speed ranges, resulting in increased vibration and noise, and even cause loss of steps. This can significantly degrade both positioning accuracy and motion smoothness. Resonance can be effectively mitigated by using microstepping drives or by optimizing the mechanical system—for example, through the use of dampers or added damping mechanisms. 3). Mechanical system error: Even if the motor itself is very accurate, the overall precision of the actuator is still constrained by the mechanical transmission components (such as couplings, screws, guides, gear boxes), backlash (lost travel), elastic deformation and thermal deformation. These are often the main bottlenecks of system accuracy. 4). Driver and control signal: Driver performance (especially micro-step current control accuracy), input pulse signal quality (frequency stability, rising/falling edge steepness) and power supply voltage stability will directly affect the final positioning accuracy. 5). Load inertia matching: If the load inertia is disproportionately high relative to the motor's rotor inertia, the motor's dynamic response will degrade, increasing the likelihood of step loss during acceleration and deceleration phases. 6). Temperature: Motor heating can lead to changes in coil resistance, performance drift in permanent magnets, and thermal expansion of mechanical components—all of which may theoretically introduce minor errors. However, in most practical applications, such temperature drift is typically negligible.Therefore, the brief conclusion is as follows:
1. Basic step angle 1.8 degrees: It means that in full-step drive mode, the motor theoretically rotates 1.8 degrees (200 steps per revolution) for each pulse it receives. This is the starting point of its theoretical resolution. 2. Actual positioning accuracy: Under open-loop control and without step loss, the single-step accuracy is about ±3% - ±5%, that is, the actual deviation of the theoretical 1.8-degree step angle is about ±0.054 to ±0.09 degrees. However, full-revolution positioning accuracy is generally much better due to the partial cancellation of random, non-systematic errors. High-quality motors can reach ±0.05 degrees (±3 arc minutes) or even better. After adopting micro-step drive, both theoretical resolution and the actual achievable repeatability can be much better than 1.8 degrees, and can even reach angular grading (arcminute) or sub-angular grading (for example, ±0.02 degrees).The key factors affecting the accuracy of the system are: In practical applications, the 1.8-degree hybrid stepper motor offers high accuracy potential, the overall positioning accuracy of the system is heavily dependent on various external factors: such as choosing the appropriate motor size, driver or acceleration and deceleration curve to prevent step loss, suppressing mechanical resonance, ensure the accuracy and rigidity of the transmission components (coupling/screw/gear, etc.), and use high-quality micro-stepping drives. For applications that require high absolute accuracy or strictly avoid step loss, closed-loop stepping with encoder feedback is a more reliable choice. Therefore, "1.8 degrees" figure should not be directly equated with positioning accuracy, as it only represents the basic theoretical resolution. When paired with high-performance drivers and a precision mechanical system, a high-quality motor can achieve positioning accuracy that is significantly better than 1.8 degrees.