[mactec54]

Hi All - A question for the electronics guys out there. Small cheap routers often connect two motors from a single driver to cut cost. I have played with this but they didn't run fast. Mid band resonance I think kicked in. So the driver becomes confused with the two motors. My question is can you run two drivers from a single BOB output? With the lifting gantry design I need more axes so this would solve part of that problem. Next time I have a test board set up I will test this but someone may know the answer already... Peter

No that is not the norm, to run 2 motors from ( 1 ) Drive, the drive would have to have the capacity and designed to do that, so you would not save much by trying this, the reliability could be the main issue

Are yes you can run 2 Drives from a single Breakout Board output, there are Breakout Boards that already have this feature.

If you use a right hand and a left hand Ballscrew, then you would not have to have any change to the wiring both Drives would receive the same signal

If both Ballscrews are the same then you have to reverse the signal to ( 1 ) of the Drives

[StrawberryBoi]

Someday I gotta learn emojis for vBulletin like Mac... (:

[StrawberryBoi]

EDIT: Removed because it was unnecessary (:

[mactec54]

Someday I gotta learn emojis for vBulletin like Mac... (:

Oh my (wedge)

You obvious have no understanding what peteeng was asking in his post. PWM has nothing to do with it,

[Zorbit]

If you use a right hand and a left hand Ballscrew, then you would not have to have any change to the wiring both Drives would receive the same signal

If both Ballscrews are the same then you have to reverse the signal to ( 1 ) of the Drives

That's new to me.

[mactec54]

That's new to me.

This is normal and how it is normally done. when you want to use ( 1 ) Breakout Board output, to run ( 2 ) motors, unless you have another way it can be done, we would love to hear, how you would do it.

[peteeng]

Thanks Mactec for clarifying that. I have been looking at BOBs and controllers with more axes. They exist but a parallel connection from the BOB seemed an easier answer. As I noted I will test next time I have a rig set up. I'm thinking about designing a 7 axis robot and that would solve some logic in getting a few motors in parallel.

Yesterday I stepped out of the shed and woke up a big brown snake sunning itself. Luckily it scurried off, must have been wired in reverse. They can be quite aggressive and nasty.. Peter

[StrawberryBoi]

Oh my (wedge)

You obvious have no understanding what peteeng was asking in his post. PWM has nothing to do with it,

Says who? Step and direction using 4 wire (rather than serial or other comms) is a PWM 50% duty and a logic binary signal. Show me one BOB that is using 4 wire step and dir that isn't using PWM.

[StrawberryBoi]

I'll just say, I'm going to avoid responding to Mac further. I feel that so long as he's never questioned or errors called out, he provides mostly helpful additions which are beneficial to the forum, but clearly is willing to sow misinformation for the sake of trolling anyone who dares to catch his mistakes or question his opinions.

[cutworkscnc]

Peteeng, iv used that board or clone/style anyways with a dual motor drive for the gantry on one of my plasma tables. I split the connection at the breakout (step,dir,com) and ran the stepper drive in parallel on the signal wires. Have had no issues. No, you dont need a left and right lead screw. That would just be silly. both of my motors run the same direction to move the gantry along the y axis with ball screws. If the motors are attached to the gantry and move it along via belt or rack and pinion, then you will need to reverse one of the motors leads to have it operate in reverse.

[peteeng]

Hi Ali - calm down, breath and move forward. I think the BOB question has been answered as best as possible. Everyone on the forum has their own views and we are lucky to be able to have that. Now Milli has slowed down. I think she has lost its rudder or steering wheel. A machine needs a purpose and Milli is purposeless at the moment. The project initially was envisioned to be a composite mill for machining composites. But the stiffness target and machine size made this difficult to realise. Plus the search for the E70 material was a good side trip. So now I have a good understanding of Steel, alumimium, EG, UHPC and how they fit with machine building. I think Milli may get reinvigorated as a Robot. I'm looking for control software for robots at the moment , that would seem to be the hurdle. So this threads output may slow down until I find the rudder again... Peter

Hi cutwork - thanks for the info. That's what I'd expect to happen. I have to set up a small router soon and will test it out then. That will sit well for the Robot as it will have two motors on 3 axes so will need lots of drivers... Peter

[peteeng]

Hi All - I've just found these on the Hiwin site. I maybe able to get rid of the saddle at last.

https://www.hiwin.tw/products/linear_guideway/ag.aspx

[mactec54]

Says who? Step and direction using 4 wire (rather than serial or other comms) is a PWM 50% duty and a logic binary signal. Show me one BOB that is using 4 wire step and dir that isn't using PWM.

The only PWM on these boards is for spindle speed control, which is PWM to analog 0-10v, all axes outputs are step/dir outputs, peteeng posted the Breakout Board which is the most common type used.

[mactec54]

Hi All - I've just found these on the Hiwin site. I maybe able to get rid of the saddle at last.

https://www.hiwin.tw/products/linear_guideway/ag.aspx

The Price may change your mind

There is a way you could use less motors and drives, using belts like this.

[peteeng]

Hi Mactec - I look at that and see complexity and hassle. I'd just go more motors... Belts have to be tight and aligning all those pulleys is still a challenge. Price of bearings maybe high but if its a better technical solution it maybe worth the $$$.. Peter

[Zorbit]

This is normal and how it is normally done. when you want to use ( 1 ) Breakout Board output, to run ( 2 ) motors, unless you have another way it can be done, we would love to hear, how you would do it.

I think you are confused, see Cutworkscnc post;

" No, you dont need a left and right lead screw. That would just be silly. both of my motors run the same direction to move the gantry along the y axis with ball screws. If the motors are attached to the gantry and move it along via belt or rack and pinion, then you will need to reverse one of the motors leads to have it operate in reverse."

[mactec54]

I think you are confused, see Cutworkscnc post;

" No, you dont need a left and right lead screw. That would just be silly. both of my motors run the same direction to move the gantry along the y axis with ball screws. If the motors are attached to the gantry and move it along via belt or rack and pinion, then you will need to reverse one of the motors leads to have it operate in reverse."

Correct that was a mistake on my part with the left and right hand screw for normal use, I did not pick it up, but should of been referring to a helical rack and not a Ballscrew, the Racks have to be left and right hand

[badhabit]

Hi All - I've just found these on the Hiwin site. I maybe able to get rid of the saddle at last.

https://www.hiwin.tw/products/linear_guideway/ag.aspx

...interesting!

[badhabit]

About the previous epoxy discussion, would I fill it with steel powder or pure epoxy, when it comes to gluing plates to concrete/granite?

There is products for this, i'm using https://www.diamant-polymer.de/en/products/dwh/ for this...

[mactec54]

I think you are confused, see Cutworkscnc post;

" No, you dont need a left and right lead screw. That would just be silly. both of my motors run the same direction to move the gantry along the y axis with ball screws. If the motors are attached to the gantry and move it along via belt or rack and pinion, then you will need to reverse one of the motors leads to have it operate in reverse."

I should of explained it better a Left and Right hand Ballscrew is need when using ( 1 ) motor, 2 Ballscrews, here is an engineering post on this subject so nothing silly about it at all, Helical racks also have to have left and right hand which a lot of builder's are now using

Depending on the drive arrangement this could still be done with ( 2 ) right hand Ballscrews with ( 1 ) motor being used like you are saying but with any gearing being used ( 1 ) Ballscrew would be reversed so then would need a Right and Left hand Ballscrew

Why in the world would anyone need a ball screw with a left-handed thread? Why not simply reverse the program and drive the device in the opposite direction? Unfortunately, this may not always be the best solution. Several industrial applications require a left-handed ball screw to help resolve high-precision programming requirements and reduce the number of needed expensive components.


For example, a system designed with two ball screws; one right-handed and the other left-handed, with each unit positioned on either side of one drive motor moving in opposite directions. This configuration is less expensive and much more practical because only one motor is required and there is no need to synchronize two separate right-handed ball screw systems driven with two servo or stepper motors.