Melt pressure observer for electric injection molding machine

Electric injection molding machines and systems are disclosed in which a melt pressure value is provided without pressure sensing through solving one or more state equations using measured motor performance parameters such as position or velocity, and torque or current. The pressure value may be used to control melt pressure during an injection step, or may be used for monitoring. Methods and computer-readable media are also disclosed for providing or estimating melt pressure in an injection molding machine without a melt pressure sensor.