Product-contact parts
Inspect hoppers, trays, chutes, seals, gates and fasteners for build-up, damage, looseness or surfaces that can retain product. Record which parts are product-specific and which can be shared between recipes.
Direct answer
A multihead weigher maintenance plan should protect weighing accuracy, product flow, hygiene, access and reliable line recovery.
The plan should define routine inspection, cleaning boundaries, calibration or verification checks, feeder and hopper condition, electrical and pneumatic inspection where applicable, critical spare parts, fault evidence and safe isolation. Maintenance frequency and replacement intervals must come from the approved machine documentation, duty and site conditions rather than a generic calendar.
Weighing and feeding components
Check feeder operation, free movement, zero stability and any condition that can introduce vibration, contact or mechanical restraint. A weight symptom may originate in the product path rather than the load cell itself.
Controls and fault history
Retain recipes, settings, alarms, stops and corrective actions. A reliable fault history helps distinguish a recurring component problem from product variation, refill behaviour or a downstream-line delay.
Maintenance evidence
Use condition and production evidence rather than replacing parts by guesswork.
| Observed symptom | Evidence to collect | Maintenance boundary |
|---|---|---|
| Weight variation | Zero checks, calibration/verification results, feeder settings, product distribution, hopper movement and ordered pack weights | Confirm product and setup causes before condemning a weighing component |
| Reduced output | Product-level history, waiting time, feeder cycle, discharge delays, packer-ready state and short stops | Identify whether the weigher, feed system or downstream machine is limiting the line |
| Product sticking or retention | Product condition, contact surface, build-up location, temperature, coating and cleaning result | Review product-contact design and cleaning method before increasing vibration indiscriminately |
| Intermittent hopper fault | Head number, repeat frequency, drive command, obstruction, wiring/connector condition and restart behaviour | Follow the approved diagnostic procedure and competent electrical/mechanical assessment |
| Unexpected product damage | Feed setting, drop points, collisions, chute path, timing and before/after product samples | Check the complete product path, not only the weigh hopper |
| Seal-zone contamination | Discharge timing, product scatter, chute alignment, pouch or bag opening and packer state | Review the weigher-to-packer interface and fault recovery sequence |
Spare-parts planning
Hold parts according to production risk, lead time and the installed configuration.
A useful spares list identifies the exact machine, head count, hopper arrangement, drive system, controller version and optional equipment. It should separate routine wear items, critical production items and low-probability major assemblies. Do not order by a generic machine description when the installed configuration can be identified from serial and drawing information.
Production-critical items
Identify parts whose failure would stop the line and which cannot be substituted safely. The list may include configuration-specific drives, sensors, connectors or control components, but the exact item numbers must come from the approved parts documentation.
Product-contact and change parts
Record hoppers, trays, chutes, gates and seals by machine and product route. Consider whether a second clean set would reduce changeover time, subject to hygiene, storage and inspection requirements.
Consumables and service tools
Confirm approved cleaning materials, lubricants where applicable, fasteners, seals and diagnostic tools. Using an unsuitable chemical, lubricant or replacement part can introduce product-contact or reliability problems.
Records and escalation
Keep the machine identifier, parts list, drawings, software/recipe backup, service history and supplier contact route together. Define which tasks are operator checks, planned maintenance or specialist service work.
Maintenance questions
Questions to answer before the maintenance plan is approved.
How often should a multihead weigher be maintained?
There is no responsible universal interval. The approved machine manual, duty, operating hours, product, cleaning method, environment and fault history determine the schedule. Daily operator checks and planned technical work should be separated so that responsibilities are clear.
Can an operator calibrate a multihead weigher?
Only procedures authorised for the installed machine and the operator's competence should be used. Routine verification, calibration and repair are different activities. The site should define which checks operators perform and when a technician or metrology specialist is required.
Which spare parts should be held on site?
Prioritise parts by production consequence, expected wear, supplier lead time and the exact installed configuration. Use the machine serial, drawings and approved parts list. A generic stock list can be expensive while still missing the component that stops production.
Does weight variation always mean a load-cell fault?
No. Product distribution, contact between a hopper and surrounding structure, build-up, unstable refill, feeder settings, vibration and check method can all create weight variation. Collect ordered results and inspect the product path before replacing a weighing component.
What safety boundary applies before maintenance?
Maintenance must be planned and completed by competent people using the site's isolation and risk-control procedures. HSE guidance states that plant should be made safe, power isolated and stored energy controlled before maintenance. See HSE maintenance guidance.
What information helps Lancing support a fault?
Send the machine identity, product, target weight, current recipe, affected head or stage, alarm text, ordered results, photographs or video, what changed before the fault and what has already been checked. Do not send passwords or bypass safety controls.
Support evidence
Send the machine identity, fault history and operating conditions.
Lancing can use clearer evidence to identify the appropriate technical next step and parts information.
Discuss maintenance and sparesRelated guidance