oyostepper

Is pancake stepper motor possible for an extruder?

 

Q1:What"s the smallest motor possible for an extruder?

Looking at the E3D titan, some people are claiming 18Ncm nema 17 motors, which weigh around 140g. Would this provide enough push on a 1.75mm filament? I"m dubious that this will do it, but my only experience is with my direct drive extruder, running a pretty beefy 59ncm motor. I"m pretty sure this is too much, but I"ve not had any problems so far apart from the weight.

 

Anyone had any experience with running these small pancake stepper motors on an E3D titan?

A1:1. The steps/mm in the formula takes account of the gearing and the hobbed insert diameter. So don"t multiply the motor torque by the gearing ratio, just multiply it by the steps/mm.

2. I am not saying that you can"t extrude with less torque than my rule suggests, but in my experience you need that amount for reliable extrusion in a range of situations and with as range of filaments. My rule also allows about 25% margin, because you want a little spare torque and you don"t want to run the motor at full current. You can increase temperature to allow extrusion with lower torque, but that generally increases stringing when printing PLA.

Some examples:

Direct drive extruder with 100 microsteps/mm @ x16 microstepping and 60Ncm motor: 100/16 * 60 = 375. Below 500 so marginal.

Ormerod extruder with 420 steps/mm @ x16 microstepping and 22Ncm motor: 420/16 * 20 = 525. Above 500 so OK.

 

Q2:dc42 - Interesting rule of thumb. If I apply that to my Wade extruder 747 steps/mm 9:47

required motor torque = 500 /(747/16) = 10.7Ncm

which could be easily be handled with a NEMA 14 or NEMA 17 pancake ~120-140gr

So if for nothing else than to reduce overshoot, I should be replacing my 40Ncm 285gr NEMA 17 on my existing Wade with a NEMA 17 pancake.

It"s not a common problem for a wade extruder gear to wear out or break. So the Wade could be put on a diet. Gears also printed in nylon. Lower ratio. Lower gear module. (I print functional servo gears down to 0.5 module).

Seems like the advantage of the Titan is that it is small, light weight, and off the shelf....but where"s the fun in that? I think we"re all getting lazy and drinking the Cool-Aid. I"ve got this 3d Printer thingy sitting in the corner of my basement...

Has anybody seen a pancake stepper motors, 3d printed gear, direct drive/non-bowden extruder for a core XY like a d-Bot?

 

What"s the smallest motor possible for an extruder?

How To Choose A CNC Stepper Motor With Useful Standard

Which Has Higher Stopping Accuracy - Stepper Motor or Servo Motor?

Customer Inquiry: Looking for a motor with good stopping accuracy. How much of a difference is there between stepper motors and servo motors?

Assumption: The AC servo motor NX Series (compared to integrated servo motor) is equipped with a 20-bit encoder, thus it should have a fine resolution and good stopping accuracy.

First, it is necessary to clarify the difference between resolution and stopping accuracy: Resolution is the number of steps per revolution and it is also called a step angle for stepper motors. It is needed when considering how precise the required positioning needs to be. Stopping accuracy is the difference between the actual stop position and theoretical stop position.

Does this mean that the AC servo motor equipped with a high accuracy encoder has better stopping accuracy than stepper motors?

Not quite. In the past there was no issue with the concept of "stopping accuracy of servo motors is equal to encoder resolution within ±1 pulse." However, recent servo motors are equipped with the encoder of 20 bits (1,048,576 steps) which has a very fine resolution. Because of this, errors due to the encoder installation accuracy have a huge effect on stopping accuracy. There- fore, the concept of stopping accuracy has started to change slightly.

According to the comparison charts, stopping accuracy between stepper motors and AC servo motors is almost the same (±0.02°~ 0.03°). Performance of stopping accuracy is the same between the two. Furthermore, accuracy depends on the mechanical precision of the motor for stepper motors, thus if stop position can be done per 7.2°, positioning is done by the same small teeth on the rotor at all times, according to the motor structure. This makes it possible to further improve stopping accuracy.

However, stepping motors may generate displacement angle depending on the load torque value. Also, depending on the mechanism condition, AC servo motors may have wider hunting width as a response to gain adjustments. For these reasons, some caution is required.

Newly Released 0.72° Stepper Motor and Driver Package RK II Series: Compared with the conventional RK Series, the new RK II Series not only achieves lower power consumption and extends functions by implementing the high efficiency motor, but also reduces the size of the driver.