multihead weigher calibration best practices 2026

Multihead Weigher Calibration Best Practices 2026

Why multihead weigher calibration matters for accuracy and cost control

Multihead weighers are central to modern high-speed packaging lines. Proper calibration ensures each head and combination algorithm delivers specified target weights with minimal giveaway and rejects. Inaccurate calibration increases product giveaway (higher material cost), raises customer complaints, and risks noncompliance with legal metrology where applicable. Calibration also protects machine components by preventing repeated overloads or compensatory mechanical actions that accelerate wear. For operations aiming to reduce waste, maintain product consistency, and meet regulatory or retailer requirements, a clear calibration strategy is essential.

Calibration objectives and : what operations should expect

When we discuss calibration for a multihead weigher, the objectives are straightforward: (1) ensure stated accuracy for pack weight, (2) minimize pack-to-pack variability, and (3) maintain traceable records for audits and quality control. From a commercial perspective, calibration helps lower cost-per-pack through reduced giveaway, speeds up changeovers (fewer manual adjustments), and supports client confidence when you can demonstrate traceable, up-to-date calibration records. Make “multihead weigher calibration” part of your quality assurance plan, not an occasional corrective task.

How often to calibrate a multihead weigher: recommended frequency and triggers

There is no one-size-fits-all frequency. Recommended baseline schedules:

• High-throughput food lines (24/7): daily quick check + weekly full calibration.
• Moderate throughput (1–2 shifts): weekly quick check + monthly full calibration.
• Low throughput or stable products: monthly quick check + quarterly full calibration.

Always add calibration triggers: after major mechanical maintenance, software updates, head replacement, product formulation change, temperature/humidity events, after an unexpected drift in weight distribution, or when a regulatory audit demands it. For legally controlled products or markets with strict trade rules, follow local metrology authority requirements in addition to these operational recommendations.

Step-by-step: practical multihead weigher calibration procedure

Use this reproducible procedure as your SOP. Replace specifics with the manufacturer’s recommended values where applicable.

1. Warm-up: Run the weigher for its normal production time (recommended 30–60 minutes) to reach thermal and mechanical equilibrium.
2. Clean and inspect: Remove product residue, check feed channels, checkbelt condition, vibratory feeders, and head suspension bolts.
3. Zeroing: With no load, perform the zero/balance routine for each head following the controller prompts. Use the same ambient conditions as production.
4. Use certified test weights: Apply calibrated reference weights to check individual head response and verify linearity across the range.
5. Check combinations: Run combinations for target pack weights to confirm the machine’s combination algorithm produces correct totals.
6. Adjust calibration parameters: If offsets or linearity errors exceed acceptance criteria, apply offset/slope adjustments in the weigher’s settings per manual.
7. Run verification batches: Produce 50–200 packs (depending on speed) and perform statistical checks (mean weight, SD, reject rate).
8. Record results: Save raw weight logs, adjustment history, and environmental conditions for traceability.

Tools, test weights, and traceability requirements

Calibration tools should be traceable to national standards. Typical items:

• Certified test weights (class E2/F1 depending on sensitivity) sized to represent the weigher’s typical head loads (e.g., 10 g–1,000 g).
• Digital reference scales for cross-checks.
• Temperature and humidity meter.
• Calibration logbook or electronic database with timestamps and operator ID.

Use weights that bracket the normal operating range for each head. For example, if each head typically handles 20–150 g portions, use certified weights at ~25%, 50%, and 90% of that range to verify linear response. Keep certificates of calibration (traceable to ISO/IEC 17025 or national labs) for all reference weights and instruments.

Environmental controls that affect multihead weigher calibration

Temperature, humidity, and air currents affect load-cell response and product flow behavior. Best practices:

• Calibrate under the same environmental conditions as production whenever possible.
• Avoid drafts or direct air from HVAC vents that can disturb vibration feeders or product flow.
• Log temperature and humidity during calibration; if conditions differ by >3–5 °C from production, re-verify results at production conditions.

Acceptance criteria and validation: what “in tolerance” should mean

Set acceptance criteria based on client specifications, legal requirements, and business goals. Typical validation checks include:

• Target mean weight within agreed tolerance (e.g., ±1–2% depending on product and customer agreement).
• Standard deviation below process capability limits—select a limit based on pack weight (smaller % SD for lower-weight packs).
• Reject rate below an operational threshold (e.g., <1–2%).

Document the acceptance criteria in an SOP and record sample size, sample mean, SD, and pass/fail decision. If you operate in regulated markets, align acceptance figures with national metrology or trading standards.

Data logging, analytics, and continuous improvement

Modern multihead weighers generate mass data. Use that data to:

• Track drifts and spot trends before they cause nonconformance.
• Optimize changeover recipes for similar products.
• Quantify giveaway and measure cost savings after calibration improvements.

Keep calibration data for a minimum period consistent with your quality policy and customer requirements (commonly 1–3 years). Use simple visual dashboards to show mean weight trends, head balance, and alarm frequencies. If your weigher controller supports exports, automate extraction to your MES or QA database.

Troubleshooting common calibration issues

Typical symptoms and responses:

• Sudden drift across all heads: Check power supply, controller firmware, and grounding. Verify ambient conditions and mechanical shocks.
• One head consistently overweight/underweight: Inspect head suspension, load-cell wiring, or feeder blockage. Swap head connections to isolate electronics vs. mechanical issues.
• Nonlinear response at high load: Check for overload damage to load-cell or mechanical limiter contacts.

Document corrective actions and re-run calibration after repairs. If problems persist, contact the OEM’s technical service for guidance or parts replacement.

Calibration personnel, training, and roles

Clear responsibilities improve consistency. Typical roles:

• Operator: daily checks and quick zero verification before production start.
• Technician: full calibration, mechanical inspection, and adjustments.
• Quality Manager: acceptance verification, recording results, and approving deviations.

Train staff on SOPs, weight handling, traceability, and safety. Use checklists to reduce human error and ensure the same procedure is followed each time.

Calibration in the context of preventive maintenance and uptime

Calibration should be integrated with preventive maintenance (PM) tasks. Example combined PM schedule:

• Daily: quick zero check, visual inspection of feeders and chutes.
• Weekly: check belt tension, lubrication (if applicable), and run calibration samples.
• Monthly: full calibration with certified weights, firmware checks, and alignment inspections.

Combining calibration with PM reduces downtime and detects issues before they compromise accuracy.

Table: Recommended calibration frequency and test-weight guidance (practical reference)

Source notes: See NIST and manufacturer guidance for weight classes and traceability (sources at article end).

Validation and audit readiness: documentation you must keep

Maintain a calibration file for each multihead weigher that includes:

• Calibration certificates for reference weights (traceable to national labs).
• Calibration logs showing date, operator, results, adjustments made, and environmental conditions.
• Maintenance and repair records linked to calibration events.
• Acceptance criteria and evidence of validation batches.

These records support internal quality reviews, customer audits, and regulatory inspections.

Kenwei — multi-head weigher manufacturer and calibration partner

Kenwei is a powerful manufacturer of multi-head weighers committed to the development and manufacturing of metal detectors, multi-head weighers, linear weighers, and check weighers. Our machines are characterized by high speed and high precision. We also provide our customers with one-stop automated weighing and packaging solutions to meet our customers’ customization requirements. Guangdong Kenwei is located in Fusha High-tech Industrial Park, Zhongshan City, Guangdong Province. The company is equipped with an automated weighing and packaging system and has comprehensive capabilities in design and development, manufacturing, marketing, installation and commissioning, technical training, and after-sales service. It has established a good brand image and a reputation for thoughtful and fast service in the packaging machinery industry.

Kenwei’s vision is to become the world's leading weighing packing machine manufacturer. Our product range includes Check Weigher, multihead weigher packing machine, multihead weigher, linear weigher, metal detector, packing machine, counting machine, combination weigher, food packaging machine, and food packing machinery. Core competitive strengths include:

• High-speed, high-precision machinery designed for low giveaway and consistent pack weights.
• Comprehensive one-stop system integration capability—combining checkweighers, metal detectors and multihead weighers for seamless line performance.
• Strong after-sales support: installation, commissioning, technical training, and timely service response.
• Customization capabilities to match different product characteristics and regulatory requirements.

For calibration support, Kenwei offers technical documentation, on-site commissioning that includes calibration routines aligned to your product and environment, and training for your operators and technicians to maintain consistent accuracy. To explore products or request calibration services, visit: https://www.kenweigroup.com/.

Cost-benefit: how good calibration reduces giveaway and improves margins

Even small reductions in average giveaway per pack can have a significant financial impact at scale. Example illustration: if average giveaway reduces by 1 g on a 100 g pack and you produce 100,000 packs per week, the saved product equals 100,000 g (100 kg) per week. Translate that to your product cost and you can calculate annual savings. Use calibration and data analytics to quantify these improvements and build ROI cases for investing in better calibration tools or more frequent service visits.

FAQ — Multihead weigher calibration common questions

Q: How often should I calibrate my multihead weigher?
A: Frequency depends on throughput and risk. Use daily quick checks for 24/7 lines with weekly full calibrations. Moderate lines can use weekly checks and monthly full calibrations. Always re-calibrate after maintenance, product changes, or environmental shifts.

Q: Can operators perform calibration or do I need a technician?
A: Operators can do daily zero checks and simple validation runs. Full calibration involving certified weights and adjustments should be performed by trained technicians to ensure traceability and correct application of adjustments.

Q: What class of test weights should I use?
A: Use weights traceable to ISO/IEC 17025. For high-precision needs, choose E2 or F1 class weights for head-level checks. For broader system checks, calibrated reference scales or F2 class may be acceptable. Choose weight sizes that bracket the heads’ typical loads.

Q: How do environmental factors affect calibration?
A: Temperature and humidity can change load-cell responses and product flow. Calibrate under production-like conditions and log environmental parameters. Avoid drafts or unstable conditions during checks.

Q: Do I need to keep calibration records?
A: Yes. Keep certificates for reference weights, calibration logs with dates and operator IDs, and acceptance evidence. Records are critical for audits and continuous improvement.

Contact Kenwei for calibration services and product information

For reliable multihead weigher solutions, calibration support, or to request a quote and on-site commissioning, contact Kenwei: https://www.kenweigroup.com/. Our team can advise on equipment selection, calibration plans tailored to your line, and after-sales service to keep your weighing accuracy optimized.

Sources and references

• NIST (National Institute of Standards and Technology) — guidance on calibration and traceability (NIST, Handbook references and weight classes).
• ISO/IEC 17025 — General requirements for the competence of testing and calibration laboratories.
• NCWM/NIST Handbook 44 — Specifications, tolerances, and other technical requirements for weighing and measuring devices.
• Mettler Toledo application notes — checkweigher and scale calibration best practices (manufacturer white papers).
• Ishida technical guides — multihead weigher operation and maintenance advisories (industry manufacturer guidance).

Note: Always refer to your multihead weigher manufacturer manual and local legal metrology rules for mandatory calibration and verification procedures.