Piezoelectric Cavity Pressure Sensor Setup in Micro Injection Moulding
Direct piezoelectric cavity pressure sensing in micro injection moulding requires sub-micron bore tolerances, rigid preloading, and active thermal drift compensation.
Force Transmission Loss
Meaning
In hydraulic and electromechanical moulding machines, the reduction between applied clamp or injection force and the actual load felt inside the tool cavity identifies mechanical efficiency. Mechanical resistance within hydraulic cylinders and friction along guide pins create measurable energy losses during mold closure. During the injection stroke, force transmission loss occurs as hydraulic piston pressure passes through melt channels, nozzle tips, and runner gates.
Melted polymer drag against cold cavity steel reduces effective packing pressure in distant product sections.
Friction Mechanism
Mechanical components lose energy to sliding friction during machine movement. Platen bearings moving along tie bars encounter surface friction that absorbs a portion of the clamp tonnage. High force transmission loss at the machine platen reduces actual clamping force applied to the mold parting line.
Insufficient parting line compression permits tool flashing when injection pressure peaks.
Viscous Dissipation
Polymer melt flowing through narrow runners experiences pressure drops caused by shear resistance. High viscosity resins require higher energy input to fill distant corners of thin-walled parts. Viscous dissipation generates localized frictional heating while diminishing the pressure wave transferred from the injection screw tip.
Cavity Gradient
Uneven force distribution across mold cavities alters part density and dimensions. High force transmission loss increases volumetric shrinkage in tail-end cavity regions.