Closely following the assembly instructions and using the default Device settings are a good starting point for FarmBots to achieve reliable movements on all three axes. However, this might not work immediately for every installation, especially non-standard or home-built installations. If you are experiencing unreliable movements, try out these troubleshooting steps:
Did a recent change occur?
The first thing to think about is if a recent change to your Device settings or hardware is causing the issue. For example if you adjusted a belt’s tension, you might have over-tightened the belt, which is causing a motor to stall. If you increased your bot’s max speed, then it might be trying to accelerate or deccelerate too quickly, causing missed steps. If you recently made a change and then began experiencing issues, consider reverting the change.
Also consider changes that may have occurred that you did not make. For example a child or animal might have stepped on the tracks and caused them to become unaligned. If you share your FarmBot with other people, someone else might have changed the device settings. Before diving in any deeper, inspect both your hardware and software settings to ensure nothing changed without you knowing it.
Is this happening consistently?
Next, see if the failed movements are happening consistently or not. Some questions you want to ask yourself are:
- Are the failed movements always happening on a specific axis? For example, it always fails when moving the z-axis up.
- Are the failed movements happening in a specific place? For example: it always fails when the gantry is about 2/3 the way down the tracks.
- Are the failed movements always happening at a specific step in a sequence?
Answering the questions above will help you focus in on the issue and save you troubleshooting time. Once you’ve identified if the issue is happening consistently or not, investigate the following possibilities.
V-wheels are too tight
If the v-wheels are spaced too closely together then you will introduce significant resistance into your FarmBot which can cause the motors to miss steps and stall. Ensure that you can move your FarmBot freely (and wobble free) along each axis by hand. If you feel a lot of resistance, adjust the eccentric spacers according to the documentation.
Belts are too tight
Over tensioning the belts can apply large forces to the pulleys and motors which can cause them to have trouble rotating. Make sure your belts are not too tight.
Tracks are misaligned
If you are having issues along the x-axis, most likely your tracks are misaligned. Either they are not parallel (diverging/converging) which is causing the gantry to bind more and more as it moves down the tracks. Make sure that your tracks are a consistent distance from each other throughout their entire length.
The tracks might also be skewed or twisted, which will also cause the gantry to bind in certain areas. Ensure your tracks are straight and level to each other.
The track extrusions may not be joined seamlessly, causing the gantry to stall at the joint. Ensure the faces of the extrusions are aligned when you tighten them to the track joining plate, and that there is no gap between the extrusion ends.
Also see the general track maintenance guide.
Gantry is not equalized
The gantry must be perpendicular to the tracks in order to move smoothly. Make sure you have equalized your gantry.
Pulleys or other components are rubbing/catching
The pulleys might be installed on the motors such that they are rubbing against the metal plates that the motors are mounted to. This will introduce friction that can cause failed movements. Other components such as screw heads or cable carriers could be rubbing or catching as well. As your FarmBot moves, closely watch and listen to see if anything is rubbing or catching.
The leadscrew may need to be lubricated so that it more easily moves through the leadscrew block.
If you have gone through these troubleshooting suggestions and are still experiencing problems, consider finding help here in the forum. Please keep in mind though that it is very difficult for anyone to help troubleshoot your FarmBot remotely, as there are an infinite number of ways for the hardware installation or software settings to be incorrect or suboptimal, but only a few ways for it to work well. Let the forum know what you have tried already (for example: everything suggested in this post) and if you have any other insights. Screenshots, photos, and videos can help.