Question

Can a 3D printer use a NEMA 17 stepper motor? How much is a 3D printer? What is the normal number of pulses in the stepper motor of a 3D printer?

Answer 1

Can a 3D printer use a NEMA 17 stepper motor? 

Nema 17 stepper motor 2A bipolar 1.8 degrees 

How much is a 3D printer? 

What is the normal number of pulses in the stepper motor of a 3D printer?

Can a 3D printer use a NEMA 17 stepper motor?

Overcoming stepper motor design challenges in 3D printers.

3D printing is a fast-growing market with huge growth potential.

3D printers create complex three-dimensional objects by continuously depositing materials directly from computer-aided design models. 

The agriculture, healthcare, automotive, locomotive and aviation industries were the first adopters of 3D printing design prototyping and production.

With the widespread adoption of these industries, there is a growing demand for small, accurate, energy-efficient, and silent 3D printers.

All 3D printers produce high-quality prints using multiple stepper motors that move the printer base along the X-Y-Z axis, or select colors as well as features such as an extruder. Using a high-performance stepper motor driver can help printer motors move quietly, precisely, and efficiently. In this article, I'll explore how to find the right stepper motor driver to build a 3D printer from scratch or upgrade an existing one.

3D printer stepper driver system-level requirements and performance metrics

Most 3D printers use NEMA's 17-size stepper motors with torque ratings between 0.3 N-m and 0.5 N-m.

The stepper motor moves in discontinuous strides during its rotation, and the step length is defined by the step angle. It has two current windings, each of which can be controlled by an H-bridge.

As shown in Figure 1, a stepper motor driver applies a current waveform close to one sine wave (blue) to one coil and a cosine wave (red) current waveform to another coil. One (90 degree) quadrant of the current waveform corresponds to a stepper motor rotation by one step angle – 1.8 degrees for most hybrid stepper motors in use today.

How much is a 3D printer?

3D printers are generally $200.00 - $900.00, depending on the selection plan.

Answer 2

What are the main system-level requirements for stepper drivers in 3D printers? 

The main system-level requirements for stepper drivers used in 3D printers.

H-bridge supply voltage

The offline AC power supply is converted by an AC-DC converter to a low-voltage DC supply to operate the H-bridge of the stepper driver. The most common DC supply voltage in use today is 12 V or 24 V. For the same output power, the average current is halved when operating at 24 V compared to 12 V.

Some manufacturers are designing their 3D printers to operate at higher nominal supply voltages, such as 36 V or 48 V. Higher supply voltages and lower average currents reduce transmission losses and cable weight. Higher voltages also result in higher high-speed usable torque, resulting in faster print speeds.

A nominal supply of 36 V means that the stepper driver should be able to withstand at least 45 V, assuming a maximum tolerance of 25% for the supply rails.

 For a nominal 24 V supply, a stepper driver with an absolute maximum voltage rating of 30 V is sufficient.

The difference between the rated voltage shown in the stepper motor datasheet and the supply voltage of the stepper motor driver can be confusing. What you must remember is that the rated voltage of a motor is only the product of its rated current and the resistance of the windings. 

The supply voltage of the stepper driver can be safely higher than the rated voltage of the motor.

Step driver current rating

Most 3D printers use NEMA's 17-size stepper motors with torque ratings between 0.3 N-m and 0.5 N-m. Depending on the application, stepper motors can be rated from a few hundred milliamps to 2 A or, in rare cases, even higher. Stepper motors used for printer bed X-Y-Z movement or extruder movement have a higher current rating than stepper motors for color selection.

Answer 3

Channel-to-channel current matching of stepper motor drivers affects overall position accuracy.

One coil current is a pure sine wave and the other coil current is a pure cosine wave will ensure that the output current is constant and the increment angle is the same for each microstep.

Any mismatch with the ideal value will result in uneven angular position increments and lead to uneven output torque, incorrect position, and increased motor vibration.

The choice of driver attenuation mode also plays an important role in determining system accuracy.

Any ripple in the current waveform deviates from the desired shape, manifesting as vibration and poor accuracy. Whenever possible, stepper motors should be operated in slow attenuation mode rather than fast or mixed attenuation to reduce ripple.

However, current waveforms that only have slow attenuation are distorted at high speeds due to back EMF. Therefore, a slow decay mode that can accommodate high speeds is the best way to improve accuracy. The smooth operation of the stepper motor should result in the monotonic position accuracy plot shown in Figure 3a, rather than the abrupt change in step angle shown in Figure 3b.