Method of mixing and extruding viscous materials and gearbox for dispensing the same

1. A method of mixing and dispensing viscous materials, comprising the steps of:

a) Inserting a cartridge containing one or more viscous materials in a chamber;

b) Activating a first motor to move a plunger via an output drive shaft from a first position to a second position within the cartridge;

c) Activating a second motor to move the plunger via said output drive shaft from the second position further within the cartridge to dispense the material,

wherein the speed of said output drive shaft is (i) the sum or (ii) the difference of the driving speed of the first motor and the second motor.

2. Method according to claim 1 , wherein the second motor is activated before or when the plunger reaches the second position.

3. Method according to claim 1 , wherein both motors are working at the same time.

4. Method according to claim 1 , wherein the first motor is deactivated before or when the plunger reaches the second position.

5. Method according to claim 1 , wherein the first position is a position in which the cartridge can be inserted in and/or removed from the chamber, and the second position is a position in which the plunger contacts the material.

6. Method according to claim 1 , wherein the second position is a position in which the plunger contacts the material.

7. Method according to claim 1 , further comprising providing a sensor to monitor the load of the first motor to detect whether the plunger has reached the second position.

8. Method according to claim 1 , comprising the step of deactivating the second motor after materials has been dispensed.

9. Method according to claim 1 , comprising the step of deactivating the second motor to stop the dispensing.

10. Method according to claim 1 , comprising the step activating the first motor and/or second motor in opposite directions when the dispensing is completed.

11. Method according to claim 1 , wherein the second motor is used for mixing the material.

12. Method according to claim 1 , comprising the steps of:

a1) driving one of the first motor or the second motor; and

b1) activating the other one of the first motor or second motor to accelerate the drive shaft to a higher speed;

and/or:

a2) driving the first motor and the second motor at the same time; and

b2) deactivating one of the first motor or second motor to decelerate the drive shaft to a lower speed.