Circuitrocks Stepper Motor 18cm Lead Screw Bipolar 200 Steps/Rev 42x38mm 2.8V 1.7 A/Phase for in Home-Built 3D Printers

This linear positioning drive consists of our42×38mm NEMA17 stepper motorwith a built-in lead screw in place of the normal output shaft, which makes it easy to move an object or platform in a linear motion with the precision of a stepper motor. Motors like this are especially popular for use in home-built 3D printers (e.g. RepRap) and CNC machines. The stainless steel threaded rod extends from the face of the stepper motor, and since it is integrated into the motor itself, you do not have to deal with bulky shaft couplers or loose set screws. This stepper motor comes in three versions with different length lead screws built in:18cm,28cm, and38cm.The included copper alloytraveling nut(also known as a carriage nut) features a mounting flange with four holes threaded forM3 screws. The nut moves 8.0mm per full revolution of the lead screw, which allows for a linear resolution of 0.040mm per full step of the stepper motor. Even smaller step sizes can be achieved through microstepping, which is a feature of manybipolar stepper motor drivers. We recommend theDRV8825 stepper motor driver carrierorAMIS-30543 stepper motor driver carrierfor use with this stepper motor, which allow for a linear resolution of 1.25µm per 1/32 microstep. However, please note that the nut is not spring loaded, so changes in direction will result in loss of positioning precision due to backlash. Extratraveling nutsare also available for purchase separately.The maximum achievable linear speed depends a lot on the details of the system, including the load and motor supply voltage. Under ideal conditions (e.g. with gradual ramping up of the step rate, a high supply voltage, and no load), we were able to achieve speeds close to 30cm/s (12in/s) with the 28cm lead screw version.The stepper motor has a 1.8° step angle (200steps/revolution) and each phase draws 1.7A at 2.8V, allowing for a holding torque of 3.7kg-cm (51oz-in). The motor has four color-coded wires terminated with a JST XHP-4 connector with 0.1" spacing: black and green connect to one coil; red and blue connect to the other. It can be controlled by a pair of suitable H-bridges (one for each coil), but we recommend using abipolar stepper motor driver.OurNEMA 17 aluminum bracketoffers a variety of options for mounting this stepper motor in your project:Note:SpecificationsSize: 42.3mmsquare×38mm, not including the shaft (NEMA 17)Leadscrew:Steps per revolution: 200Linear step size: 40µm (1.6mil) per full stepCurrent rating: 1.68A per coilVoltage rating: 2.8VResistance: 1.65Ω per coilHolding torque: 3.7kg-cm (51oz-in)Inductance: 3.2mH per coilLead length: 16cm (6.5″)Output shaft supported by two ball bearingsMore specifications are available in thedatasheet(63k pdf). Note that while the datasheet is for the stepper motor with 28cm lead screw, the only difference between the three versions is the length of the lead screw.DimensionsThe following diagram shows the stepper motor, lead screw, and traveling nut dimensions in mm. The value ofLis 182mm for thestepper motor with 18cm lead screw, 282mm for thestepper motor with 28cm lead screw, and 382mm for thestepper motor with 38cm lead screw. Note that the datasheet incorrectly labels the threaded rod as “TR8×3”; it is really aleadscrew, which is the ISO designation for a trapezoidal metric thread with an 8mm nominal diameter, 8mm lead, and 2mm pitch. (Put more simply, the rod has four independent threads spaced 2mm apart, so the carriage nut advances 8mm for each full revolution of the rod.)Stepper Motor ApplicationsStepper motors are generally used in a variety of applications where precise position control is desirable and the cost or complexity of a feedback control system is unwarranted. Here are a few applications where stepper motors are often found:PrintersCNC machines3D printer/prototyping machines (e.g. RepRap)Laser cuttersPick and place machinesLinear actuatorsHard drivesNote: