DDB V2.2 Dual Gear Extruder

Compatibility:

• Bowden extruder machines
• Fits NEMA 17 size stepper motors

Please note: We notice a recent extruder stepper motor update on Creality machines. Before ordering this kit, please check your extruder stepper motor. If your extruder motor gear is pressed in, you will need to purchase a new stepper motor to be able to complete the installation. [Purchase new 40-42 stepper motor: Purchase Link]

Please get these tools ready:

• M1.5- Hex Wrench 
• M2.0- Hex Wrench 
• M2.5- Hex Wrench 
• Hobby knife with sharp tip or similar.

This guide shows the installation on an Creality Ender 3 Pro printer. Start by unloading any material from your printer. Please remember to heat up the hotend when unloading materials (We recommended using marlin built in unloading function via screen). If it via hand, please ensure extrude some filament before retracting and removing the filament. 

1. Rotate the printer so you can access the back side.
2. Disconnect the Bowden tube from the extruder by removing blue clip, pressing the top collar down and pulling the tube out at the same time  
3. Discount Motor Wire
4. Loosen and remove the M3 screws that holds the extruder and motor attached to the bracket and just leaving blank mount.
5. Remove the existing drive gear using 1.5mm hex key.
6. use the new brass(golden) gear included in the set and place it onto the motor shaft. (Ensure the set screw is aligned with flat plane of the motor shaft and note the orientation shown in below photo).
7. Leave around 1.5mm clearance between the gear and motor and tighten the grub screw.
8. Place the motor back onto the bottom bracket and the extruder ontop of the bracket. (Careful and guide the motor gear into the extruder so it has correct proistionson the black gear. Using the provided 3 long bolt screw extruder to the motor.
9. Now you can connect back the motor cable, do note you may need to reverse the direct as this extruder is gearing in opposite direction, please refer to next section of guide. (If you using printed bracket you don't have to change direction of the stepper driver, you can just flip the extruder around as there should not be any interface, this part may require printing the bracket beforehand)
10. After you have setup the direct correctly, you can reinstall the bowden tube.

You have two options: You can recompile your firmware and flip direction of motor or re crimp your existing motor cable. 

Why? Since the DDB Extruder uses a gearing the rotation direction of the motor may need to be revered.

Guide: To re crimp motor wire.

1. To change the rotation direction of  the motor one of the two coils needs  to be reversed polarity. 
2. Use a Hobby knife and gently lift the small plastic tab and pull out the cable from the connector from position 1 as in the photo. 

1. Repeat this for the cable in  position 4 (position 2 is empty) so  both cables is loose. Now place the cable that was in position 1 to position 4 and the cable that was in position 4 to position 1. 
2. This is how the cables is connected once they are moved, compare to the photo in the top. 

Electrical configuration 

As the new extruder uses a gear reduction the possible force it an feed the filament with will be very high when using the stepper motor that came with the printer, in order to reduce the risk of pushing the Bowden tube out of the connector if there is a blockage in the hotend it is strongly recommended to lower the current for the motor so it will skip steps instead of pushing the tube out of the pushfit connector. 

Identify the stepperdriver for the extruder and use a multimeter set to DC voltage, put the negative sensor probe on the negative terminal and the positive sensor probe to the small screw on the potentiometer, read the value and then turn the potentiometer until the value is reduced with about 50-60% of the original value.  

(Note: If you have TMC drivers you can reduce the current to around 650 ma, this should be ok for stock extruder but if you notice skipped step increased current)

GCode to Adjust Direction

The negative value will switch the direction of the motor via gcode, either have this in your slicer or use M500 to save onto EPROM or sdcard.

M92 E-145

(Do Note: this is setting is saved onto sdcard for most printer unless you board have on board EPROM. So if you removed your sd card this setting won't be remembered)

Slicer / Marlin Changes

You will need to change extruder e steps to 145 initially, and perform calibration of e-step to find tune the extruder. https://teachingtechyt.github.io/calibration.html#esteps

Depending on your stepper driver, the current can be reduce if you notice extruder heating up during printing. If you need some advise, contact us and provide us with your printer/board information.