Meaning
Mass measurement devices determine the exact weight of solid polymer granules and liquid additives delivered into a processing hopper over specified time intervals. Incorporating a gravimetric balance into an injection moulding or extrusion line isolates feed rates from bulk density variations in the raw material. Precision strain gauges continuously track weight loss in the supply hopper to regulate screw dosing speed.
This apparatus sets the physical boundary between volumetric dosing approximations and precise mass control in continuous compounding.
Feed Control
Mechanical vibrations from surrounding presses disrupt load cell readings when damping mounts degrade. Operating a gravimetric balance under uncompensated plant floor motion causes artificial weight fluctuations that trigger false screw speed adjustments. Enclosing the scale assembly and applying digital filtering algorithms stabilizes the control loop.
Proper calibration against certified test masses maintains accuracy across low masterbatch feed rates.
Dosing Offset
Inconsistent virgin pellet geometry alters material flow dynamics through the feed gate. A gravimetric balance corrects for bulk density shifts caused by irregular regrind flakes or varying pellet sizes. Uncorrected volumetric feeding produces color variations across consecutive production shifts.
Cost Shift
Overdosing expensive color concentrates and flame retardants inflates part unit costs without providing structural benefits. Precise mass metering keeps additive ratios at the minimum specification threshold required for UV resistance or flammability compliance. Scrap rates fall when consistent material composition eliminates molding defects like splay and flash.
