Good morning, everyone. My name is Antonio and I am from Spain. This is my first post and it is about a problem that I am experiencing with my recently built Killerbee. The problem I am having is that the steel plates that support the x-axis are offset from each other on the y screw. All this makes that when moving the y-axis sometimes the motors get stuck. It also happens that when homing the axes one of the plates hits the frame (the one without the limit switch). I have tried to align both sides by hand with the motors unlocked but when I move them they get out of alignment again. I leave a couple of pictures so you can see the misalignment of about 5 mm or so. Does anyone know how I can solve this problem? I think the problem has to do with the squareness of the frame, but I am new to the CNC world.
Most likely you have assembled something incorrectly, but I suggest you ask in the Facebook group in the link below. Alex. Log into Facebook | Facebook
I'll ask them. Thank you! I forgot to mention that after getting stuck and stop the steppers the machine get unlock and starts moving properly. But after homing the problem appears again. So is not like it get stuck completely. I've notice aswell that the leads screws are a little bit bowed.
Ratrig will replace bent leadscrews if needed. Have you tensioned the leadscrews? (it is possible to overdo it and that can cause the frame to distort and cause binding). Alex.
I did, but to be fair I don't know if I did properly (I think they are too loose). I gonna loose them and try again. I'll post the results later. EDIT: I measured the diagonals of my frame and their lenght are the same. So I think that the frame should be square. I'm going to double check it to be sure.
I did and is not. I tried to set it square by hand (by turning the stepper with the power off) but when it get stuck it loses the squareness again. I don't even know if this is the proper way to square the X and Y .
It is the proper way, but disconnect the steppers from the controller after turning the power off - they act as generators when turned by hand, generating back emf which can damage your stepper drivers. Alex.
I have news. I've tried lowering the maximum speed from 4000 mm/min (which is what I've seen that they usually set for others like the quenbe) to 1000 mm/min and the problem has been solved. So I have thought that my problem may be lack of lubricant in the lead screws. I changed the silicone oil for lithium grease and when I gradually returned to 4000 mm/min everything works perfectly. The x-axis stays square with the y-axis and everything runs smoothly. I don't know if the lithium grease is suitable for the lead screws but it seems to work right now. I know that at some point or another I will have more problems because as I have mentioned this is the first CNC machine I have assembled. In the meantime I want to thank you for your help which has been very helpful.
You shouldn't use silicone oil or lithium grease - the correct lubricant for leadscrews is DRY silicone or ptfe spray. Anything sticky traps dust, which is abrasive as well as potentially causing binding. Yes, I manage 4000 mm/min rapids, but the default is 2500. Alex.
I too use 2500 mm/sec for the rapids. With the heavy gantry, on the Y axis, I can stop faster without the whole machine shaking.
I'm installing a 2,2 kw chinese spindle. It weighs about 5 kg so I think I should lower the speed to a more conservative value to avoid disassembling the table in one quick movement hahaha.
