is it possible to replace a stepper moter with a dc moter you found in a cheap toy car

Gearing it down it should be able to do to job as moving the z gantry or bed doesn't usually require fast and precise movements

Z is the axis that requires the most accurate movements

Otherwise your z0 is to low or to high and that is the end of that print or even the hotend.

And no.

All 3d printer firmwares are step and direction engines. You would need to provide a step and direction interface to the DC motor, with sufficient electronics that 1 step moves the motor a set repeatable small distance.

Edited 1 time(s). Last edit at 04/25/2025 12:31AM by Dust.

... or you attach an encoder to the axis or dc motor shaft and use a STEP/DIR-Servo-driver ... but it's much pricier, than steppers ...

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No I don't think it need to be precises in that it needs to move 0.5 millimeter up or down my reasoning is that traditional corexy the bed only goes down excluding homing etc. which should be resolved by placing end switches on the nozzle

Edited 1 time(s). Last edit at 04/26/2025 10:15AM by Vorroriw.

adding endswitches will tell the printer where it is. The dc moter moving down at a constant speed using gears to ratio it down to average speeds using the speed we SHOULD be able to predict what position it is

no i dont think thats needed if the moter moves at a constant speed Distance = Speed*Time

Edited 1 time(s). Last edit at 04/26/2025 10:23AM by Vorroriw.

To have constant speed A closed loop system it required(PWM)

All 3d printer firmwares are step and direction engines. You would need to provide a step and direction interface to the DC motor, with sufficient electronics that 1 step moves the motor a set repeatable small distance.


yes but that is possible to mimic a step by pulsing the power to to moter and

sorry i was doing this on a whim just done some research (AI) can using the distance = speed * time
Yes, you can use the basic physics equation distance = speed * time to estimate the distance traveled by a DC motor, but with some crucial caveats and limitations.
How to apply it:
Measure or estimate the motor's speed: This is where it gets tricky. Without feedback, the speed will not be perfectly constant. You can estimate the speed based on the applied voltage and the motor's speed constant, but it won't be highly accurate.
Measure the duration of movement: Use a timer to record how long the motor runs at that estimated speed.
Calculate the distance: Multiply the estimated speed by the measured time.
Caveats and limitations:
Inaccurate Speed Estimation: Without an encoder or some form of feedback, you're making an estimation of the motor's speed. The actual speed can vary significantly due to factors like load changes, variations in the power supply, motor heating, and mechanical imperfections. This will directly impact the distance calculation.
Open-Loop Control: You're running in "open-loop" mode where the motor's actual speed doesn't affect the control signal. This makes the system less robust against disturbances.
Limited Accuracy for Positioning: This approach is generally suitable for basic estimation but not for precise position control. You'll accumulate errors over time, especially if the motor speed isn't consistent.
Overshoot and Undershoot: When starting and stopping, the motor might have some inertia causing it to rotate slightly further than intended (overshoot) or not reach the desired distance (undershoot), affecting the calculation.
Not Suitable for Slow Speeds: At very low speeds, DC motors can have inconsistent motion, making this calculation unreliable.
Alternative techniques for more accuracy:
Encoder Feedback: Using an encoder with a DC motor is the most accurate way to measure distance. You can count the encoder pulses to calculate rotations, which can then be converted to distance if you know the motor's geometry (e.g., if it's connected to a wheel or leadscrew).
Sensorless Control: Some sensorless techniques (e.g., back-EMF sensing) can improve speed estimation and provide some degree of closed-loop control, but they're still not as accurate as using an encoder.
Conclusion:
The distance = speed * time equation can provide a rough estimate of distance traveled by a DC motor without an encoder. However, for applications requiring accuracy, it's strongly recommended to use an encoder or other feedback mechanism.