Indonesia’s metrology law makes unverified scales illegal, and cement packers are pairing daily-to-annual calibrations with 100% inline check‑weighing to cut variability, curb giveaway, and boost throughput.
Run a cement bagging line in Indonesia without verified scales and regulators can shut it down. Under Metrology Law No. 2/1981 and Permendag 67/2018, any scale used in trade must carry a valid verification (“tera”) stamp and be re-verified (“tera ulang”) on schedule—authorities have seized unverified weighbridges and warned that “an unverified scale will definitely harm consumers because there is no accuracy without a valid tera stamp” (kemendag.go.id) (kemendag.go.id).
The business case is equally stark. Tightening filling controls has cut off‑spec cement bags by 39% in one study, adding an estimated $249,000 in annual sales value (researchgate.net). Add an inline check‑weigher and one U.S. cement terminal improved bagging speed by about 50%—cycle time dropped from 12–15 seconds to 8–9 seconds per bag—and reduced staffing to one operator (packagingdigest.com).
Here’s how cement producers are building a calibration and verification program that satisfies the “tera” law and keeps giveaway in check—then enforcing it with automated rejection on the line.
Legal metrology verification in Indonesia
Commercial weighing devices must be officially verified before use and periodically re‑verified. Indonesian Metrology Law No. 2/1981 and Permendag 67/2018 forbid using any scale in trade without a valid verification stamp (kemendag.go.id) (kemendag.go.id).
In practice, cement packers schedule annual legal verification by a certified metrology lab (commonly overseen by the local trade/metrology office) and retag scales before verification expiry (kemendag.go.id) (bmtdigital.co.id). Equipment that fails verification must be repaired or replaced. Violations can bring legal penalties—up to 1 year’s imprisonment or fines under 1 million IDR (kemendag.go.id)—and risk consumer complaints or product recalls.
Daily and shift accuracy checks (zero, repeatability)
Before each shift, operators run a static zero (scale reads zero with no load) and a dynamic zero on the running conveyor (tdipacksys.com). Then they verify with known test weights or sample filled bags—e.g., a standard 50 kg cement bag—checking that readout stays within tolerance, such as ±0.5 kg. To assess repeatability, TDI Packsys advises running multiple test cycles (≥6 runs) (tdipacksys.com). Any drift or inconsistent reading triggers adjustment.
Full calibration with traceable weights (ISO/IEC 17025:2017)
At least weekly—or after maintenance—a full calibration uses certified reference weights traceable to national standards (bmtdigital.co.id) (baopackmachinery.com). Following ISO/IEC 17025:2017 (a competence standard for testing and calibration), technicians check zero, adjust sensitivity (gain), and confirm linearity across the range (baopackmachinery.com). Example: if a 10 kg certified weight reads 10.05 kg, the 0.5% error is removed via gain correction. Every step is documented—date, reference weights, measured vs. true values, and any correction factor—and, as Baopack notes, records prove compliance and traceability (baopackmachinery.com).
Bagging machine fill‑head calibration and recipes
For volumetric or multi‑head feeders, each spout/bin is calibrated. Plants batch‑fill sets of empty bags per fill head and weigh them on a calibrated bench scale or test rig (researchgate.net) (packagingdigest.com). They tune vibrators and cutoff timing until the average bag weight from each spout matches the target (often 50 kg) within spec. Rinker Materials replaced analog scale beams (±1 lb accuracy) with electronic load‑cell controls targeting ±0.5 lb (packagingdigest.com). Iterative sampling—fill 5–10 bags, weigh, adjust, repeat—becomes standard at startup and after equipment changes, and modern systems store “recipes” to autoset offsets for each product.
Calibration intervals and labeling (SNI ISO/IEC 17025:2017)
Beyond daily checks, plants set formal intervals for in‑house calibration—monthly or quarterly is common—and Indonesia’s SNI ISO/IEC 17025:2017 mandates annual calibration of all testing and weighing equipment (bmtdigital.co.id). Every event goes on a schedule; calibration labels show the date and next due date. One cement producer said that after upgrading “the calibration is simpler…we can do it ourselves,” though critical scales still need accredited lab verification annually under metrology rules (packagingdigest.com).
Inline check‑weighers and automated rejection
A check‑weigher (an inline unit using a fast load cell, controller/software, and a rejecter) weighs every bag on the conveyor and ejects out‑of‑spec product in real time. Some systems use dual air‑jet nozzles to eject underweight bags to one side and overweight to another (packagingdigest.com).
With tolerance windows pre‑set—e.g., –500 g to +500 g for a 50 kg bag—the controller kicks any out‑of‑range bag before palletizing. This replaces manual sampling (for instance, pulling a bag every 30 minutes) and eliminates human error (packagingdigest.com). At Rinker, the unit “pushes off‑spec bags off the conveyor without someone having to handle the bag,” improving safety and throughput (packagingdigest.com).
Data capture and process control
Rockwell Automation reports that check‑weighers capture every underfill/overfill event and generate metrics—rejects, total weight, throughput—supporting continuous tuning and compliance with net‑weight laws (rockwellautomation.com). Eliminating overweight bags cuts material waste; catching underweight prevents fines and returns (rockwellautomation.com) (baopackmachinery.com).
In practice, firms report major efficiency gains: Rinker’s bagging speed improved by ~50% (cycle time down from 12–15 seconds to 8–9 seconds per bag), the line now runs with one operator instead of two, and weight is monitored continuously “without having to stop the operation” (packagingdigest.com).
Heavy‑duty equipment and adoption trends
Ruggedized check‑weighers exist for harsh, dusty cement environments. Thompson Scale’s Model 4693 handles 1–500 lb (≈0.5–227 kg) at more than 50 bags per minute and features a weight base residing below the conveyor (packagingdigest.com).
Adoption is climbing globally. Depending on market scope, analysts value the check‑weigher market at roughly $0.7–3.5 billion, with mid‑single to high‑single digit CAGR (globalgrowthinsights.com) (dataintelo.com). One analysis estimates roughly 50% of manufacturers use check‑weight systems, with adoption in food/pharma up about 40% in recent years (globalgrowthinsights.com).
Outcomes and market context
A calibrated system pays off. Engineers report that better filling control cut off‑spec bags by 39%, translating to ≈$249,000 more in annual sales value (researchgate.net). Check‑weighers have raised bagging rates by ~60% at a cement terminal while providing full data on weight variation (packagingdigest.com).
Against Indonesia’s strict metrology backdrop and a growing cement packaging market—the 15–30 kg segment was ≈ US$1.4 billion in 2024, with a stated CAGR from 2025 to 2030 (grandviewresearch.com)—a robust calibration/verification program plus 100% check‑weighing helps deliver fewer off‑spec shipments, lower waste, higher throughput, and compliance.
Sources: industry case studies and packaging analyses (packagingdigest.com) (packagingdigest.com) (researchgate.net) (rockwellautomation.com); regulatory and standards documents (Indonesian Metrology Law 2/1981, Permendag 67/2018) (kemendag.go.id) (kemendag.go.id); calibration standards (SNI ISO/IEC 17025:2017) (bmtdigital.co.id); engineering blogs and reports (tdipacksys.com) (baopackmachinery.com); market research (grandviewresearch.com) (globalgrowthinsights.com) (dataintelo.com).
