Dual Y motor

Dual Y motor provides a more stable bridge movements. This can be useful for bigger working area machines, reducing vibrations and increasing the precision.

3dpBurner2 A3 standard single Y motor

3dpBurner2 A3 dual Y motor

Dual Y motor

There are two ways for driving a second motor:

-The first one is as most reprap do, using a single driver and parallel connection for diving both motors. This is the most economical and could be ok for cooled electronics (more driver heat), but 3dpBurner usually don't use a fan for cooling electronics.

-The second one is the best and only adds an extra driver, using a driver for each Y motor and providing a better solution and there is no need to add any active cooling for electronics.

The second one is the goal of this page.

What extras do you need:

-1 DualYmotor 3D printed parts kit. Can be downloaded here
-1 Stepper motor.
-1 belt similar to existing Y one.
-1 GT2 20 tooth pulley
-1 Pololu based driver with heatsink.
-5 Pin jumpers (usually included on the CNC shield).
-2 623ZZ bearings.
-7 M3x20 bolts.
-3 M3x10 bolts.
-9 M3 washers.
-5 M3 nuts.
-4 M8 nuts.
-4 M8 washers.

You can see pictures for parts position reference.

Mechanical mods:

-Preasemble the second Y motor kit in similar way the first one.
-Remove the bridge and disassemble the right parts for inserting the new belt holder. Reassemble the bridge with the two holders and take it apart.
-Disassemble the existing Y tensioner and motor.
-Make the new holes according to pictures/measures and mount the two tensioners and motors.
-Reassemble the bridge to main base, add the two belts and align the two transmissions.
-Reallocate all electronics for prevent bridge movements cant touch it.

Electronics mods:

4th axis as clone of Y

-The CNC shield comes with 4 driver headers: X, Y, Z(not used) and A. "A" is a 4th axis that can be used for "cloning" any of the X, Y, Z existing ones. We need to clone the "Y" by inserting two jumpers as pictured. By this way the DIR and STEP pins on the "Y" socket will be connected in parallel with the "A" socket ones. Check this for detailed info.

-Configure micro-step jumpers in similar way than Y axis and insert the new driver.

Detailed cloning jumpers (protoneer)

    -Connect the new motor, set the current and make sure it rotates on the correct direction.

    -Reassemble the working table and enjoy!

BaseTable hole pattern with single Y motor

BaseTable hole pattern with dual Y motor

E'=(xTravel-78)/2
G'=E'

Results:

I've tested this mod on my 300x420mm (A3) working area 3dpBurner2. By engraving a picture before and after the second motor adds.
I set my acceleration at high value for producing vibration patters on engraved image.

The next pictures has been engraved at speed of 3000mm/min using an acceleration of 2000mm/min^2 instead the 1000 reccomended for this size machine. They are 35x30mm and take about 5min to engrave each.
As you can see, i take a picture of each one in macro mode for getting detailed results.

Single Y motor

Dual Y motor

On this test i can observe a little more definition and precision on the dual Y motor one, the vibration pattern (square concentric marks) has been shrunk and there is a less area affected by them.
Due to better precision the marks are less blurred and can be "more appreciated".

I think this could be a good mod for >A4 size machines. For smaller areas there is no much difference on results so is not worth it for most users.