Electronic Lead Screw on an Bernardo Profi 700 Pro

[Poppey]

I did som math and found out on my lathe the following:
My lead screw has a pitch of 3mm that would be something like 8.5 TPI while the feed screw run at a ratio of 1:1 with feed lever in C

With lead screw at its lowest longitudinal feed in position C the spindel running at 75 rpm, the servo will run at some 26 rpm with the 5:1 gear box. This is om my lathe a little less than a feed of 0.003" per rev. What is your step or micro step setting? May be increase the micro step setting can help.

As the servo you are using is a hybrid stepper, you may be able to change the micro step setting to X16 or X32.

I’m not an expert and don’t know if it this will solve the problem.

 

[Poppey]

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[Poppey]

I decided to go for the ELS from electronicleadscrew.eu and it was nearly plug and play. Very easy to set up and it is working perfectly. I have a Nema 23 stepper motor with a 5:1 gearbox mounted direct to the lead screw gear box shaft as I have shown earlier. The spindel shaft gear that is 40 teeth is perfectly 5 mm som I have a 5 mm timing belt with a 44 teeth timing belt pully on the encoder. To support the encoder I put a ball bearing and a 6 mm shaft on the bracket, oposite side of the encoder. I use 6400 steps per rev on the stepper motor drive. I have mounted the ELS controller beside the DRO that I find very convinient. I´m 3D printing a small cover to put over the cables entering the ELS controller box.

 

[Poppey]

As you mentioned, Todd, there are quite a bit og drag in the gearbox and the lead screw. I tested it and found out that the brake away torque is 9.3 kg/cm and after the the brake away it was the half.

 

[Poppey]

I had some missing steps or the stepper motor stalled and realized that I needed to increase the stepper motor size. I cold have got the largest Nema 23 or a Nemo 24 but I decided to go for a Nema 34. I made an adapted plate and a stub shaft to fit the Nema 34 motor to the :1 worm gear box. This worked very well.


As I now have a more powerful motor I think a 1:1 gear ratio would be better so I tried to find an 1:1 90 degree gear that would fit under the cover, without success. In lack of a new project I decided to see if I cold make one my self. I did not find bevel gears on the marked that would fit but Modul 1 36 teeth seems to work. I had a bronze bar and Modul 1 gear cutting set so it should not be a problem to make the my self. I also had a aluminium block to make the housing out of.


After som Fusion360 design trial I found the perfect fit. And it works perfectly and is running very smoothly.

 

[Poppey]

Here are a cut through of the model. The gears and the stub shaft have a bit narrow 5 mm key way. I cut the keyway on the stubshaft sleeve and treaded M15x1 5 mm deep, the same on the stub shaft and silver soldering them together before machining the shaft end.

 

[Poppey]

I´m very happy with the ELS from electronicleadscrew.eu. The tread features where it stops at a pre-set value is fantastic, especially when making small internal treads. Just vind out the cross slide, hit the return button and the apron moves out and returns in 5 mm to take up any backlash. Than set the compond and cross slide, hit the in button and off it goes.

 

[tweinke]

Glad you got it working well! the gearbox looks awesome.

 

[Poppey]

Thank you, Todd

 

[RaisedByWolves]

I´m very happy with the ELS from electronicleadscrew.eu. The tread features where it stops at a pre-set value is fantastic, especially when making small internal treads. Just vind out the cross slide, hit the return button and the apron moves out and returns in 5 mm to take up any backlash. Than set the compond and cross slide, hit the in button and off it goes.

This is good to hear as Ive been eyeing this very one for a while now but there are not many reviews for it.

To me it looks more user friendly that the one clough42 uses.

Can you describe the feature and setup of the automatic threading stop?