My Cheapo Chineese 3020t mini CNC Build (more like improvements) leanring all the way

[ravihotwok]

Did a bit more on the machine this weekend, my new 600w spindle and pwr supply arrived as well


I have allso installed the limit switches, 2 on each x and y axis and one on the z axis

[ravihotwok]

A common problem with this model of cnc machine is excess play on the z axis, this is caused by a small gap from the top of the screw and the bearing just where it meets the motor. It is only about 1.5mm but is enough to worry you. Using a 3d printed washer I have solved this problem and now there is zero play in the z axis, got the idea from a funny chap off youtube.

Here is the excess play before
https://www.youtube.com/watch?v=r9aK...ature=youtu.be

Here is how I solved it:
I started with printing some washers
8mm id 11mm od 2mm thickness


Now to remove the motor, and then the 2 retaining screws on top of the bearing


Now slide the printed washer onto the screw


Now install the bearing again, you must make sure that the bearing is flush with the top of the housing it is seated in, I had to sand about half a mm off to achieve this, once happy tighten the 2 retaining screws and then install the motor.

Here is the result
https://www.youtube.com/watch?v=YBEN...ature=youtu.be

No play at all and the axis still moves nice and freely. An easy fix to what really should of been sorted at factory.

Hope this helps someone in the future :-)

[ravihotwok]

Been very busy with work so been restricted when I can play with the machine, I have been plodding along in the back ground though. I have no fully re wired the stepper motors to the controller, I have binned the cheap 5 core unscreened power cables for a thicker screened 5 core cable and freshly soldered them to the plugs. These were a complete nightmare to try and fish through the cable track but I got there in the end. Once wired up the motors were making a high pitch noise, also when trying to jog any of the axis they just seemed to move back and fourth which is a tell tale sign of the wrong core pairs being wired up. For anyone interested, my motors are 4 cable motors, which means it has 2 coils with 1 pair of cables per coil. I used the multimetre to find when 2 of the cables were connected a circuit was made, that way I could establish which cables were paired together. The I wired one pair to pins 1 and 2, and the other to 4 and 5 of the 5 pin plug and hey presto it worked well. I have made the length of the cables just shy of 3m for now as im making a full enclosure so thought it is much easier to cut the cables back than to add in AND RE-FISH THROUGH THE CABLE TRACK LOL

Anyway here is a few pics, limit switches are to be done tonight then I can start setting the controller up through the software which I really have no idea how to do but got plenty of literature from Planet CNC to guide me, would like to mention they have been very supportive throughout this build even though I have been bombarding them with daft question constantly.

[Clive S]

I have no fully re wired the stepper motors to the controller, I have binned the cheap 5 core unscreened power cables for a thicker screened 5 core cable and freshly soldered them to the plugs.

Did you ground the screens at one end?

[ravihotwok]

Nope, Planet said there was no need to?

[Clive S]

Nope, Planet said there was no need to?

That must be ok then The vast majority on here would disagree I think.

[Gary]

Screened cable without the screen being grounded is acting like un screened cable. so ground the screen at one end. It may not make a differnce, but if you have screened cable, it makes sence to use it how it is intended to be used.

[ravihotwok]

Thanks Gary, can you advise on how the best way to earth it please? can I earth it to the machine? or to the control box? Any examples?

Cheers

[ravihotwok]

Thanks Gary, can you advise on how the best way to earth it please? can I earth it to the machine? or to the control box? Any examples?

Cheers

[Gary]

in the control cabinet and to a star point.

and make sure the cabinet is also grounded.