Maintenance & Reliability · SOP

Scale Calibration For Glue Mixing

Ensure accurate weight measurement for glue formulation, maintaining product consistency and reducing waste. This procedure applies to all digital bench scales used in glue mixing operations.

Estimated Time

30 min

Difficulty

Intermediate

Regulation

NIST Handbook 44

Version

1.0

Free download — no sign‑up, no email.Take this SOP to your shop floor and make it yours.

↓ PDF (print‑ready) ↓ Word (editable)

Purpose

This standard operating procedure establishes a consistent method for calibrating digital bench scales used in glue mixing. Accurate weight measurement is critical for batch-to-batch consistency, bonding strength, and material cost control. Regular calibration prevents off-spec product, reduces scrap, and complies with quality management system requirements.

Scope

This procedure applies to all digital bench scales with a capacity of 150 kg or less that are used for measuring glue components (resin, hardener, filler) in the mixing department. Calibration must be performed monthly, after any scale impact or relocation, or whenever readings deviate from expected values. This SOP does not cover platform scales over 150 kg or laboratory balances used for quality testing.

Safety Precautions

LOTODisconnect the scale from power before cleaning or adjusting internal components. If scale is hardwired, follow facility lockout/tagout procedure LOTO-001.
PPEWear safety glasses and nitrile gloves when handling calibration weights and cleaning solvents. Use back-support belt when lifting weights over 25 kg.
LIFTTwo-person lift required for calibration weights exceeding 50 kg. Ensure weights are stored on a low shelf to prevent dropping.

Required Tools & Materials

NIST-traceable stainless steel calibration weight set (includes 25 kg, 50 kg, 75 kg, 100 kg, 150 kg)
Lint-free cotton cloth (microfiber preferred)
Anti-static electronic wipes (isopropyl alcohol 70% based)
Calibration log sheet (Form CL-001) and pen
Scale operation manual (for specific calibration mode entry)
Torque wrench (if scale has adjustable feet for leveling)

Stop Chasing Maintenance Blindly

Track every calibration, pressure drop reading, and machine performance trend in one place. ServiceGrid logs your tasks automatically and alerts you before failure.

Try ServiceGrid →

Procedure: Step-by-Step

1 Clean the scale platform thoroughly using a lint-free cloth and anti-static wipe. Remove any dried glue residue, dust, or debris from the platform and surrounding area.

2 Power on the scale and allow it to warm up for at least 30 seconds. Press the ZERO/TARE button to ensure the display reads 0.0 ± 0.1 kg. If the scale does not zero, check for platform binding or load cell obstruction.

3 Place the first calibration weight (e.g., 50 kg) in the center of the platform. Allow the reading to stabilize (typically 3–5 seconds). Record the displayed value on the calibration log sheet.

4 Compare the displayed reading to the known weight. If deviation exceeds ±0.1% of full scale (e.g., ±0.15 kg for a 150 kg scale), enter calibration mode per the scale manual. Adjust the span setting until the display matches the known weight.

5 Remove the weight and repeat steps 2–4 at 50% and 100% of the scale’s rated capacity (e.g., 75 kg and 150 kg). Record all readings. If adjustments were needed, perform a verification run with a weight midway between the adjusted points.

6 Lock the calibration settings (if applicable) and exit calibration mode. Perform a final verification using a known intermediate weight (e.g., 25 kg). The reading must be within ±0.1 kg of expected value.

7 Sign and date the calibration log sheet. Attach a calibration sticker to the scale showing the due date (next month). Return calibration weights to their storage case. Notify the mixing team lead that the scale is ready for use.

8 If any step fails or the scale cannot be calibrated to within tolerance, tag the scale as "OUT OF SERVICE" and initiate a repair request per facility PM procedure PM-003. Do not use the scale for production until repaired and recalibrated.

Scale Calibration For Glue Mixing

Stop Chasing Maintenance Blindly

Software that works like your best tools.