A robot end effector for dispensing an extrudable substance, the robot end effector comprising: a chassis; a mixer mount, extending from the chassis and configured to rotatably receive a static mixer that comprises a mixer inlet and a mixer outlet, which is in fluidic communication with the mixer inlet; cartridge bays, extending from the chassis, wherein: each one of the cartridge bays is shaped to receive a corresponding one of two-part cartridges; each one of the two-part cartridges comprises a cartridge outlet; and fluidic communication between the cartridge outlet of a selected one of the two-part cartridges and the mixer inlet is established when the cartridge bays are moved to a predetermined position with respect to the chassis, linearly along a first axis and linearly along a second axis, which is transverse to the first axis; a drive mechanism, attached to the chassis and selectively operable to rotate the static mixer relative to the cartridge bays when the static mixer is received by the mixer mount; a dispensing valve, attached to the chassis and comprising a valve inlet and a valve outlet, wherein: the valve outlet is in selective fluidic communication with the valve inlet; and the valve inlet is in fluidic communication with the mixer outlet when the static mixer is received by the mixer mount; and a head assembly, comprising pairs of fittings, and wherein each of the pairs of fittings is configured to selectively supply compressed air from a pressure source to contents of a corresponding one of the two-part cartridges when the two-part cartridges are received by the cartridge bays and the cartridge bays are translated along the first axis and along the second axis relative to the chassis so that the cartridge outlet of the corresponding one of the two-part cartridges is in fluidic communication with the mixer inlet. a chassis; a mixer mount, extending from the chassis and configured to rotatably receive a static mixer that comprises a mixer inlet and a mixer outlet, which is in fluidic communication with the mixer inlet; cartridge bays, extending from the chassis, wherein: each one of the cartridge bays is shaped to receive a corresponding one of two-part cartridges; each one of the two-part cartridges comprises a cartridge outlet; and fluidic communication between the cartridge outlet of a selected one of the two-part cartridges and the mixer inlet is established when the cartridge bays are moved to a predetermined position with respect to the chassis, linearly along a first axis and linearly along a second axis, which is transverse to the first axis; each one of the cartridge bays is shaped to receive a corresponding one of two-part cartridges; each one of the two-part cartridges comprises a cartridge outlet; and fluidic communication between the cartridge outlet of a selected one of the two-part cartridges and the mixer inlet is established when the cartridge bays are moved to a predetermined position with respect to the chassis, linearly along a first axis and linearly along a second axis, which is transverse to the first axis; a drive mechanism, attached to the chassis and selectively operable to rotate the static mixer relative to the cartridge bays when the static mixer is received by the mixer mount; a dispensing valve, attached to the chassis and comprising a valve inlet and a valve outlet, wherein: the valve outlet is in selective fluidic communication with the valve inlet; and the valve inlet is in fluidic communication with the mixer outlet when the static mixer is received by the mixer mount; and the valve outlet is in selective fluidic communication with the valve inlet; and the valve inlet is in fluidic communication with the mixer outlet when the static mixer is received by the mixer mount; and a head assembly, comprising pairs of fittings, and wherein each of the pairs of fittings is configured to selectively supply compressed air from a pressure source to contents of a corresponding one of the two-part cartridges when the two-part cartridges are received by the cartridge bays and the cartridge bays are translated along the first axis and along the second axis relative to the chassis so that the cartridge outlet of the corresponding one of the two-part cartridges is in fluidic communication with the mixer inlet.