3D printer is an amazing tool with a vast variety of applications in a number of areas including but not limited to concept modeling, tooling, injection molding, casting, etc. It is loved equally by the professionals as well as people looking to have some creative fun. Without the stepper motors—a very essential part of the 3D printers, for the most part, they neither would have been as common as they are today nor it would have been possible to appreciate them the way they are appreciated today.
What is a Stepper Motor?
To begin with, a stepper motor is a brushless electric motor that distributes the full rotation into numerous steps of equal sizes. It is a variant of DC motor and due to its motion being divided into steps, it is called stepper motor (and is also referred to as stepping motor or simply stepper). The rotor in the stepping motor is a rotating shaft while the stator is electromagnets. The stepping motion is achieved by converting the digital pulses from sequentially switched DC power supply into the rotation of its mechanical shaft which comprises equal angular movements. It is a digital input-output device that works best where the digital pulses instead of analog voltages are used as control signals. One digital pulse results in one precise angular movement while continuing pulses result in complete rotations. With stepping being controlled by computer, quite a precise positioning can be achieved which makes stepping motors an excellent choice for devices employing precision motion control such as a 3D printer.
Stepper Motor and 3D Printer
3D printers make extensive use of stepper motors. They are used in various ways based on the type of printer. A typical motion control system of a 3D printer for the movements along the different axis requires rather a precise positioning as well as the movement of the drive systems. Stepper motors, therefore, are excellent and a cost-effective option to achieve this goal. Furthermore, the extrusion mechanism of the 3D printer also usually employs a geared stepping motor for forcing the desired amount of filament into the extruder and subsequently out to the hot end.
Types of Stepper Motors Used in 3D Printer
There is a huge variety of stepper motors based on a number of different specifications. However, the National Electrical Manufacturers Association (NEMA) standard has made the distinction rather easier. Based on the size of the faceplates of the stepping motors, the common sizes are NEMA 14, NEAM 17, NEMA 23, and NEMA 24. NEMA 17 is the standard stepping motor which is widely used in many 3D printers. Furthermore, each motor of one NEMA class would feature the same mounting hole beside the same size of the frame which makes it possible to replace the motor in the 3D printer.
The NEMA standard deals with the size but does not specify the length or the depth of the stepping motor. Hence, a stepping motor with a larger faceplate does not mean more torque too. Usually, the longer stepper motors offer more torque. Therefore, another useful distinction is the torque rating of the stepping motor which is measured in Newton-centimeter (N-cm). Thus, different NEMA categories would come with different torque ratings. Depending on the torque rating the stepper motors that are used in 3D printers can be classified into the following three categories.
- Low Torque Motors
These motors are informally referred to as pancake motors as well. Their torque rating varies from 20 N-cm to 25 N-cm. they are used in relatively smaller printers or the portable ones in which larger motors will not fit properly. Further, these low torque stepper motors are also used in direct drive extruder as well.
- Standard Torque Motors
These are the most commonly used stepper motors in 3D printers given their standard size and sufficient amount of torque. The torque rating of the standard motors ranges from 40 N-cm to 45 N-cm. They offer adequate torque as well as sufficient speed which make them standard for a great number of applications.
- High Torque Motors
The torque rating of this class of stepping motors may vary from 50 N-cm to 56-Ncm. These stepper motors are quite rare when it comes to their usage in the 3D printers as they are quite large and heavier which makes moving them difficult and unfeasible for 3D printers. However, there are a few applications as well; for instance, in order to move large and heavy print beds, these motors work the best.
Installation of Stepper Motors in 3D Printers
Many 3D printers make use of standardized connectors which makes the installation of the stepping motors quite easy and convenient. All it takes is to plug the stepper into the correct slot in the control board. Nonetheless, there are a few things that should be taken into consideration while installing a stepper motor in a 3D printer.
First, it is very important to make sure that the printer is not plugged in while changing the motor. A minor mistake may make one shock oneself and it may result in damaging the printer or starting a fire as well. Therefore, installing the motor, or uninstalling it for that matter, while the printer is plugged in is not a good idea at all.
Second, it is also crucial to check that the supply of current to the motor, once it has been installed, is in the right amount. The necessary adjustments can be made using the potentiometer on the Stepper Motor Driver board as well as through the printer’s software if this option is available. Insufficient level of current would result in a lack of adequate amount of torque while too much current than is necessary would result in overheating the motor and subsequently the printer.
Finally, if there seems to be something not right about the operation of the motor once it has been installed, stop using the printer and unplug it. Inspect cautiously the circuitry of the driver and the wiring to see if there is anything obviously wrong with it. If nothing seems wrong to make sure that the motor, driver and software are compatible with each other before continuing the use of a 3D printer.
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All in all, use of stepping motors in 3D printers has been a great innovation. There are a number of types of these motors and are available to meet the needs of many different 3D printers made for different uses. If one is into the world of 3D printers it is good to know about the stepping motors to employ them properly.