Why Does Bag Weight Drift? 5 Signals of Multihead Weigher Drift and the 5-Step Calibration

Why Does Bag Weight Drift? 5 Signals of Multihead Weigher Drift and the 5-Step Calibration

A 0.1g drift is tons of silent loss a year — master initialization and calibration to stay on spec

VFFS Machine Series  — for operators, QC and floor supervisors

Cover: QC weighing a pouch — scale accuracy decides net weight

The multihead combination weigher is the scale of the VFFS heart — whether it weighs right decides net-weight compliance and whether every bag gives away product. Yet many floors just nudge amplitude when weight drifts, never doing proper initialization and calibration. This article gives you 5 drift signals and a 5-step calibration. Follow it and accuracy gets back on spec.

01 Why Bag Weight Drifts: Four Sources

•  Sensor drift: weighing hoppers lose their zero over long use — the most common, check it first;

•  Vibration disturbance: main/linear vibrator parameters were changed, feed is uneven and combination accuracy drops;

•  Material change: a new batch with different density or particle size makes old parameters obsolete;

•  Environment: floor vibration, air fluctuation, EMI — sensor readings become unstable.

✔ Iron rule: run 【Initialize】 every morning — auto-clear hoppers and zero sensors. It is a must-do written in the scale manual.

Fig. 1: Hopper status colour quick reference — read the scale at a glance (from the scale operation flow)

02 Five Drift Signals: Read the Hopper Colours

Every hopper on the touchscreen shows a colour state — the first alarm of accuracy problems:

•  Orange U (overweight): the hopper is over limit and skipped — frequent U means unstable feeding;

•  Light-blue L (low): hopper empty and waiting — vibrator feed parameters or supply lag;

•  Red E (comm error): weighing data interrupted — power-cycle first, then check wiring;

•  Black D (disabled): a bad hopper bypassed — the more D, the worse the combination, repair soon;

•  Mean weight on screen drifting from target: no alarm needed — the most direct drift signal.

⚠ When orange and black dominate, the scale is working on one leg — every bag it makes risks overweight or giveaway.

03 Calibration in 5 Steps: From Initialization to Production

For inaccurate weighing or a new machine, follow the scale's calibration flow (calibration password 222222):

•  Step 1 Initialize: 【Initialize】on the main screen — auto-clear hoppers, zero sensors;

•  Step 2 Zero: clear hoppers, touch 【Zero】 on the empty hopper;

•  Step 3 Full-scale: place a standard weight (≤2kg) at the hopper centre, touch 【Full-scale】 — the value must match the weight;

•  Step 4 Sample test: enter 【Manual test】, check main/linear vibrators and hopper doors, sample error ≤0.1g passes;

•  Step 5 Resume: touch 【Run】, fine-tune amplitude as needed, turn on AFC auto-tracking.

Fig. 2: Calibration in 5 steps — accuracy back (from the scale operation flow)

04 Daily Anti-Drift: Grow Accuracy into Habits

•  Every morning: 【Initialize】 to clear and zero, then scan the hopper colours;

•  Material/product change: enter 【Parameter setting】(password 111111), fill product name, target weight, tolerance, speed, then 【Download parameters】;

•  Formula backup: parameters export to a USB drive — formulas survive staff changes and machine changes;

•  Shutdown care: short stops use 【Clean】 to open all hoppers; end of shift use 【Empty】; lubricate hopper shafts weekly, clean cabinet dust every 2 months.

Table 1. Common scale faults and quick fixes (from the scale operation flow)

Final Thoughts

Weight drift is not magic — it is a skipped process. One initialization a day, one status scan a week, calibrate on every changeover, release only when sample error ≤0.1g. Four habits hold the spec, and every bag ships honest.

Reply with the keyword “weigher” to get the Combination Scale Operation & Calibration Quick Card (printable). Stuck on calibration? Photograph the screen parameters and send them — the source factory will check item by item.

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