Improve 3D printer knowledge with the Simple Stepper Motor Analyzer

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Today, we’re taking a deep study into how electric stepper motors function. Stepper motors are vital to the function of any CNC production device, such as a 3d printer. Many people recognize a routine electric motor discovered in power devices, kitchen devices, and electric vehicles. Stepper motors are unique because they can likewise have continuous rotation, yet they can additionally quit at a specific placement. Today, we’re going to check out just how they function and utilize a helpful brand-new gadget to bridge the theory and method. The device we’re using today is by the designer Zappa, and it’s called the simple stepper electric motor analyzer. As you can notice, we’re on the GitHub page, and also that means that it’s an open resource, its aim is to be reduced price and also minimal, and you can not acquire it from a shop; however, if you make use of the files on GitHub, you can create your very own. I’ve never attempted to purchase a stipple electric motor analyzer in the past, but evidently, they cost a great deal of money.

Stepper Motor diagram

Simple Stepper Motor Analyzer

The touch screen can be seen before the 3D-printed case, the power port on the side, and the in-and-out stepper motor plugs under the skin. When we take it apart, we can see a 32-bit micro on a breakout board made just for it. The steppers that power the analyzer are easy to connect to a board. I used a power bank, but you could use almost anything that gives off 5 volts because the amount of current needed is very low. As soon as you turn on the power, the analyzer will turn on, and you can switch between pages by using the buttons on the touchscreen interface. You can clear the current analyses on the settings page. It’s best to do this when nothing is connected, and there’s a trash can icon on every screen that clears the information on the current screen and all others. The plan on GitHub says that all we need to do is connect the analyzer between the main board and the stepper motor.

I made a simple 4-cord loom to help me with this. It doesn’t matter what color you use. You must ensure they are the same length to keep them in the same order. Here’s how I set up my bench testing, and these few parts are pretending to be a 3D printer so I can use the analyzer. We unplug the stepper motor from the main board and plug one end of our expansion loom into it.

With a quick touch on the LCD, the stepper motor is turning as it should, and the analyzer is giving us the right numbers. In GitHub, it is said that the connection is weaker. Impedance was separated by a galvanic field. Don’t ask me to explain that, but I think it means that the analyzer’s circuitry is kept separate from the 3D printer’s. The stepper motor still works even when the analyzer is turned off.

If you can make it look like it, it might be a valuable tool in your collection or just be fun to play around with. Now we’re going to learn how stepper electric motors work, and I’m going to open up one of mine. When you turn a stepper by hand, you’ll see a notchiness that will quickly explain how it works. Let’s take apart this stepper electric motor and look at what’s inside, starting with the thing on the left, which is a complex magnet. You may remember the old horseshoe magnets, which had two different poles. Instead, let’s make a straight magnet with two bars and a handle in the middle so it can turn quickly. Every bump on this setup is a magnet; we can test this by sticking an Allen key to it. There are still posts on one ring of each of these magnets. All the attractions are set up on one call so that their north posts face out. On the other ring, it’s the other way around, with all of the south posts facing out.

When we look at this from the end, we can see that there is a line of north posts and, in between them, a line of south posts that match. On the other half of our stepper motor, there are eight different coils. You may have seen in the instructions for your first board that these eight coils are actually wired in two different groups, which we call a and b. The results of a stepper electric motor are also called a and b.

This is so that the coils in the stepper motor will match up. Every group of coils is used as an inductor to make a magnetic field. That’s a fancy way of saying they’re electromagnets. When they’re turned on, each set of coils will be half north and a half south, and if the direction of the current changes, so will their polarity. The b set of coils works the same way and can be in either of two states. Here’s another thing we can look at in the real world.

If I turn on the coils, we can see that they turn into an electromagnet and hold the Allen key until I turn off the steppers, at which point it falls. Just like our magnet was made of many small north and south posts, you can see that the inside of each coil has several points that will become either north or south electromagnets. We know that the stepper electric motor has both permanent magnets and electromagnets. How do we really make them move so that the stepper turns? We know that magnets pull in when they are turned around. If we charge up a coil, the magnet should spin to face the opposite direction. This is called a “polarity coil.”

If we then turned off the power to that coil and turned on a different one, we would expect the magnet to turn again because it would be drawn to the new coil. If we do this step again and power up another coil, we can control the permanent magnet in the middle by turning on the coils to make it turn continuously or to a set position. This is the basis of how a stepper motor works. By turning on and off electromagnets in a controlled way, we can move the permanent magnet and output shaft to the position we want. In this simple example, there are only eight possible settings, but our 3D printers have a lot more. We know that the insides of our stepper motors are pretty complex, which means that they have 200 possible positions or one degree of rotation per step. Let’s take one step at a time and look at the markings on the inside of our stepper. We can see that the analyzer is not only getting the current flowing through the a and b sets of coils but is also counting the steps as they happen. If we keep asking for one more step for long enough, we’ll eventually get to 200 and be back where we started. My computer animation skills aren’t good enough to show how a 1.8-level stepper motor works on the inside.

I’d recommend this video on how to mechatronics because it shows exactly how the magnets’ pulses interact with the bumps on the coils. On paper, 200 steps per turn seem like a lot, but it’s not even close to being accurate enough to control any kind of CNC device. Against this. When we get the coils going again, we can do some smart things. Previously. In our simplified example, we looked at how applying full current to a single coil turned the magnet in that direction. When we apply full current to the next coil, the magnet turns to face the direction of the current.

This is what we call a complete action, and in this representation, we have a resolution with eight positions, so how about that? Instead, after giving the first coil a fresh start. Then, we send 50 amps to this coil and the next one. So the magnet is pulled toward both and ends up in the middle. By using this strategy, we have actually increased our resolution all the way around.

These are called “half steps,” and in this diagram, we now have 16 possible positions, so we can use this strategy better. We’ll start by energizing the first coil to 100, and then randomly divide the current between the second and third coils by 75/25. This should put the magnet in the middle, but a little closer to the higher current. Next, we’ll adjust to 50-50, and then to 75-25. This pattern has doubled our resolution again. These are called “quarter actions” because we have split our full entry into four parts. In this representation, the resolution is now 32, which is a huge improvement over the resolution of “full actions.” This can go on with eight steps or with the much more common third-person view.

Micro-stepping for printers 1 through 16 Even though my example is way too simple, the idea is still the same. We don’t have to turn on and off the present all at once to take full steps. Instead, we can turn it on and off in small steps to be more accurate. Can we use this analyzer to figure out how to do this? This set-up for the testing bench has a specific goal. All of the stepper motor drivers are the same, but I’ve set up the jumpers below so that each one has a different number of mini.

Stepping is now done in the firmware of tmc stepper motor drivers, but for a long time, this had to be done by hand from left to right. There are clear steps. Half of the steps, a quarter of the actions, eight actions, and sixteen micro steps. I have set up the firmware for this board so that each axis has the same manual, feed rate, acceleration max feed rate, and number of steps per millimeter. This way, they all turn at the same speed, even though they have different stepping settings. As expected, the current pattern for complete tipping is a square wave with sharp sides.

Even the phase pattern shows this. When we switch to half steps, we see that our square wave is getting rougher and more rounded. When we step, the shape gets even smoother, and by the time we reach it, it’s starting to look like a sine wave, and the stage pattern is a circle. As we expected, we begin to see a process with a smooth sine wave and round face pattern when we take the eighth step. 1/16 micro tipping gives us a soft sine wave and a pretty circle, which proves the concept. So, let’s keep using this analyzer to help with challenging tasks and setting the brief for a stepper electric motor driver’s current. Assessing the current for some stepper motor drivers required analyzing a vref formula and then measuring this v-ref with a multimeter.

This is hard to do on a bench, but it’s even harder on a printer that’s already set up. The other problem is that we set the v-ref, but we don’t know for sure that our present is the way we want it to be. Our analyzer gives us a real-time display of the current going through the coils whenever they are energized. This means that we can make real-time changes to the stepper motor driver and be sure that they are working as planned. Depending on how we have things set up, the other graphs will confirm the current that we’re running with tall heights or much shorter tops. The analyzer works just as well for tmc vehicle drivers as it does for g-code drivers, which is what we use now.

After making the change, we manually turn on the coils and can see that the 900 milliamps we set to match the edge of the phase pattern. Let’s make an additional charge. Turning the current up to 300 milliamps, which you can see is confirmed by the analyzer. As you’re about to see, the more current that goes through a stepper motor driver, the hotter it gets. The driver in the middle doesn’t have a heat sink, but if we turn up the current on the driver with a heat sink, it won’t get as hot. It’s still possible to get it really, really hot, but only to the point where it gets too hot and turns on and off by itself, with the stepper motor’s output pulsing in an uncontrolled way. Let’s use the analyzer to look at another real-world problem.

Can we tell when access is likely to skip steps and cause a layer shift at the same time? The GitHub site does a great job of explaining what each screen is and what kind of information you’re looking for. The page we’re going to use here is the “current by speed” page. We want the current to be the same no matter how fast we’re going, but if the current starts to drop off at broadband, we know we’re losing torque and may skip steps to try to fix this. I checked with two printers, starting with my core XY socket sk go. I raised my speed and feed rate limits for each axis and then printed single-sided dice at a reasonable feed rate. The graph below shows the number of spy actions per second.

Things happen pretty often, as you can see. This device has never had any layer shifts or bad moves, and with these results, I wouldn’t expect it to. Next, I made the test harder at the end of step 5 by giving it a really fast feed rate and a high speed for these y-axis moves. I also decreased the amount of current in the y-axis. Under these conditions, we were able to start some habits that could become troublesome as our speeds go up.

We can see that our stepper current is going down, so it wouldn’t be strange if we started to miss steps and have layer shifts. This is a useful tool for lowering the stepper motor driver current to keep things running well while still knowing where the safe limit is. Let’s use it now to accomplish some simple goals: 3d. Printing. I started with a normal print and a 3D bench, and it was interesting to look at the different graphs here as the first layer went down slowly.

We can see the back-and-forth movements that are needed to make the solid infill. This is followed by a much less usual part where we’re pulling the edge of the hull at the start of the print. By looking at how things are now, we can see that most of our emotions don’t change very quickly. I can also tell that my stepper electric motors are working the way they should. When the print is done, we can see that the pie chart’s distribution has changed, and it will change at an even faster rate before the next print. We can erase the saved information.

Next, I tried a speed test item made by my calibration website for the cheapest section. The speed was very slow, and it looked like things were moving slowly at the beginning and end. This is shown in the patterns we see today, where some wavelengths are very short to show fast motions, and others are very long to show slow motions. The edges of the story in the steps chart are also rounded, which shows that the rate of action will change gradually as the print goes on. As the speed goes up, we can see that the data for the second part of the print are different.

We can see that the edges of the actions graph are sharper when the acceleration is higher, and they get even sharper as the print goes on and the acceleration values get more hostile. When we look at our speeds for the test print, we can see that we did a lot of medium-speed work and then a lot of really fast work when the printer picked up speed. So far, we have been watching the x-axis, but down below, we can see that the analyzer is connected to the extruder stepper and that the line is going up. That’s when we’re squeezing out filament as usual, but then we get the dips down, which show where we’re pulling back. There is also a specific retraction graph for this, which shows the whole sequence of retraction in a very clear way. So, let’s look at another case, which is trying to figure out why a stepper motor isn’t working well.

From the idea, we know that we’re looking for a clean sine wave in the way our stepper motors work and in the face pattern. I did have one stepper that didn’t want to play nice, and no matter what stepping mode I used, it gave me a very spiky graph that looked like a circle. The shape of the stage was also not a circle but a ruby. The GitHub readme says that this can be a sign of a stepper that isn’t working well because it has low current or bad inductance. This is a great example of how a device like this can help you find problems that would be nearly impossible to find otherwise.

If you disagree or agree with this, please let me know in the comments section below. Remember that the GitHub page has everything you need to build your own if you want to. I liked making this video because it gave me a chance to learn more about how stepper motors work. So I hope you did the same by having fun. I’m really glad that programmers like zapper are willing to put in the time and effort to make great tools and are also kind enough to make them open source.

Thank you very much for watching, and thanks a lot to Zapata. Until next time, happy 3d publishing g’day! Again, it’s Michael! If you like the video, click “Like.” If you want to see more videos like this in the future, click “Subscribe” and make sure you click the bell to get all notifications. Visit my Patreon page if you really want to support the network and see exclusive content by becoming a patron. See you next time. On top of a 3D-printed case, there is a power port on the side and stepper motor connections for in and out under the skin. When we take it apart, we can see a 32-bit micro placed on a custom breakout board to control the connections for the steppers. Getting power to the analyzer is very easy.

Before you remove or put in any stepper motor connections, you must first go to the steppers and turn them off. If you like how it looks, it could be a useful tool for you to have in your collection, or it could just be a fun project for you to try. Right now, we’re going to learn how stepper motors work, and I’m going to open one of mine. Up so you don’t have to, since disassembly is usually not recommended. When you turn a stepper by hand, you’ll notice a notchiness that will quickly explain. Let’s take apart this stepper motor and look at its important parts, starting with the item on the left, which is a clever magnet. If we do this again and again to another coil, we can control the permanent magnet in the facility by turning on the coils to make them turn continuously or to a certain position. This is also how stepper motors work. Let’s keep going with this analyzer to help with difficult tasks like setting the vref for the stepper electric motor driver current. Setting the current for some stepper motor drivers required figuring out a vref formula and then using a multimeter to measure the v-ref.

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