Bowden dual/quad extrusion extruder (single-nozzle single-drive) for MG995 SERVO

This remix will accept a MG995(R) Servo, This Servo is MUCH MUCH more cheaper than the ones used in original design (and have more torque also). Also I'm including changes to make a QUAD extrusion in Marlin 2.0.5.3 (tested and working !!!).

UPDATED (05/27/2020): Added a NEW idler MUCH STRONGER, this new idler uses two (2) M3 nuts for the spring screws, and one (1) nut for the bearing. This new design makes the construction more stronger to hold the screws in the idler. For the spring screw you should use a top washer and nut to tighten the screw in place.

UPDATED (05/27/2020): New body makes easy to tight the PC4-M5 fittings, MUCH STRONGER too.

Changes in MARLIN 2.0.5.3 to use 2 or 4 filaments:

In Configuration.h look for:

Uncomment the line bellow:

//#define SINGLENOZZLE

Ucomment the SWITCHING EXTRUDER line bellow and change the angles.

// A dual extruder that uses a single stepper motor
//#define SWITCHING_EXTRUDER
#if ENABLED(SWITCHING_EXTRUDER)
#define SWITCHING_EXTRUDER_SERVO_NR 0
#define SWITCHING_EXTRUDER_SERVO_ANGLES { 120, 45 } // Angles for E0, E1[, E2, E3]
#if EXTRUDERS > 3
#define SWITCHING_EXTRUDER_E23_SERVO_NR 1
#endif
#endif

Also make sure you define the SERVOS for your board:

#define NUM_SERVOS 4 // MKS Gen 1.4 supports 4 servos

Just uncomment the block above and setup the angles. You can have 4 filaments using just 2 stepper motors. Just not forget to activate your servos in the final of the configuration.h.

SLICING YOUR MODELS FOR 2/4 FILAMENTS:

Use Filament switch post-processor for Simplify 3D (3.1.1, 4.0.x) and Prusa Slic3r (1.36.2,1.37.1,1.38.6), you can download from here: https://github.com/spegelius/filaswitch

It prints perfectly, of course you need to fine tune the settings for your hardware.

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