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ESD trolley maintenance protects two different functions: safe material handling and the electrostatic-control role declared for the cart. Wheels, brakes, shelves, frames, fasteners, stops and handles must remain mechanically sound, while conductive or static-dissipative paths must be verified using the site-approved method. Dirt, oil, loose hardware, unauthorized paint, replacement casters and improvised repairs can alter both functions. A cart that still rolls is not necessarily fit for sensitive assemblies, and a resistance reading cannot prove that the loaded cart is mechanically safe. This checklist helps electronics factories establish daily inspections, planned cleaning, periodic verification, repair controls and retirement criteria for ESD trolleys.
Start from the approved trolley configuration
Keep a controlled record of model, asset number, drawing or supplier configuration, shelf count, caster type, brakes, grounding features, load rating and intended route. Photographs can help identify unauthorized changes, but they do not replace the approved technical record.
Define whether the trolley carries exposed assemblies, closed protective packaging, tools or general materials. This determines the required packaging boundary and verification. Do not assume the cart itself provides shielding or corrects uncontrolled packaging.
Perform a short inspection before every shift
Walk around the unloaded trolley. Look for bent frames, cracked welds, loose bolts, sharp edges, damaged shelves, missing stops, unstable handles, contaminated surfaces and illegible labels. Roll it slowly and listen for binding, flat spots, excessive noise or caster wobble. Apply each brake and confirm it holds on the approved test surface.
Remove a trolley from service if it tips, tracks unpredictably, has a failed brake, exposes a sharp edge or cannot retain the expected load. Use a visible quarantine method so another operator does not return it to the line before repair and release.
Clean without changing the electrical or mechanical system
Use only an approved cleaner and controlled wiping method. Residue-forming products can coat shelves or wheels, while aggressive chemicals can attack polymers, coatings, labels and adhesives. Prevent liquid from entering bearings or electrical monitoring hardware where fitted.
Clean wheels and caster pivots because fibers, tape and debris can impair steering and braking. Do not scrape surfaces with tools that expose metal, damage coatings or create loose particles. Record unusual contamination because repeated oil or solder-paste exposure may indicate a process problem.
Verify declared ESD paths with a documented method
The ESD coordinator should identify what is measured: shelf surface, point-to-point path, frame, wheel-to-floor path or another declared feature. Use calibrated equipment, defined electrode placement, environmental conditions and acceptance limits from the site program or product specification.
Do not infer whole-cart behavior from one convenient spot. Replacement casters, shelf liners, coatings, fasteners and dirt can interrupt an intended path. When a cart is used with containers or racks, verify relevant interfaces in the actual loaded configuration if the control plan requires it.
Control repairs, parts and return to service
Require approved replacement casters, brakes, shelves, fasteners and grounding components. A wheel that matches diameter may still differ in load, tread, bearing, braking and electrical behavior. Record the old and new part, reason for change, repair date and responsible person.
After repair, repeat the relevant mechanical and ESD checks before release. Review caster alignment, fastener torque where specified, brake operation, stability, route clearance, labels and measurement results. Retire the cart when structural damage, recurring instability or unavailable controlled parts make reliable restoration impractical.
Practical control table
| Frequency | Inspection item | Action on failure |
|---|---|---|
| Each use | Visible damage, cleanliness and labels | Quarantine if function is uncertain |
| Each shift | Wheels, tracking, brakes and shelf security | Remove from service for safety failure |
| Planned cleaning | Shelves, frame, wheels and handles | Use approved cleaner only |
| Periodic | Declared electrical path and records | Verify with approved method |
| After repair | Changed parts and affected functions | Retest before release |
| Annual review | Route, load, configuration and procedure | Update plan when use has changed |
Build a controlled procedure and approval sample
Convert the supplier instructions and this planning framework into a short site procedure with an owner, approved materials, sequence, pass criteria, stop conditions and records. Use an identified approval sample or photograph set so operators know the expected configuration. Train with the real route and equipment, then observe several normal cycles. The procedure should state what an operator may correct immediately and what requires quarantine and review.
Separate safety, cleanliness, mechanical function and ESD verification. A single visual check cannot cover every risk, and one electrical reading cannot prove cleanliness or mechanical integrity. When a measurement is required, identify the instrument, method, locations, environment and acceptance limits. Keep equipment calibration and personnel training current under the facility system.
Incoming inspection and change control
At receipt, match the item, quantity, revision, supplier lot and packaging label to the purchase order. Inspect for damage, contamination, missing identification and unexpected differences in color, texture, geometry, odor, hardware or packaging. Sample dimensions and functional attributes according to the agreed plan. Quarantine unexplained changes rather than allowing production pressure to turn an exception into an undocumented approval.
Require notification before changes to material source, additive, adhesive, tooling, dimensions, cleaner, construction or critical hardware. Requalification should focus on the functions affected by the change but should still check interactions. A stronger adhesive may affect removal; a new caster may affect tracking and electrical paths; a new cleaner may affect labels and surface behavior.
Qualification trial and records
Run the trial under representative environmental and operating conditions. Record date, location, operators, samples, lot numbers, equipment, cleaning preparation, route, observations and deviations. Include a current approved item as a baseline where possible. Do not hide a hard failure inside an average score. Safety, product protection, contamination, usability, documentation and ESD requirements need their own pass decisions.
Review results after enough cycles to expose normal variation. A single successful demonstration can miss operator differences, traffic peaks, wear, loading and cleaning effects. The report should state limits: what was not tested, which claims remain supplier declarations and which conclusions apply only to the tested configuration. Retain evidence with the item or process record so future teams can understand the approval basis.
Audit the process after release
Observe the process during normal work after release, not only during a planned demonstration. Confirm that users follow the approved sequence, materials remain available, labels are readable and stop conditions are understood. Sample records for missing results, repeated failures and unexplained substitutions. Ask operators where the procedure is difficult, because workarounds often reveal a fit, access, traffic or training problem before it becomes a product defect.
Trend failures by item, location, shift and supplier lot where the available records support that analysis. Repeated issues should trigger a cause review, not simply more frequent replacement. Update the procedure when the product, floor, equipment, cleaner, traffic route, packaging or control plan changes. Keep the revision date visible and withdraw obsolete copies so the approved method remains unambiguous.
RFQ checklist for buyers
State application, environment, dimensions, interfaces, construction, required function, test method, acceptance criteria, cleanliness, packaging, labeling, traceability, sample quantity, documentation and change notification. Review the SWESD ESD trolley product and the SWESD product center as starting points; final approval must match the supplied item and the buyer’s own control program.
- Describe the real use route and protected product.
- Identify hard pass criteria and acceptable evidence.
- Request drawings, materials and traceable test results where relevant.
- Define sample and first-article quantities before production.
- List approved cleaning, inspection and replacement assumptions.
- Require written disclosure of exceptions and changes.
Related SWESD resources
- defining ESD transport cart load requirements
- reviewing the role of an ESD trolley
- planning trolley, box and rack combinations
Educational video: Fundamentals of Electrostatic Discharge
This neutral educational video from Maxim Integrated provides background for the controlled process. The written guide remains complete without it.
Frequently asked questions
How often should an ESD trolley be tested?
Set the interval from the facility control plan, risk, use, environment, repair history and verification results rather than a universal calendar.
Can ordinary replacement casters be used?
Only when the replacement meets the approved mechanical and electrical requirements and the affected functions are retested.
Is a resistance test enough to release a trolley?
No. Mechanical safety, load retention, brakes, wheels, cleanliness and configuration also need acceptance.
When should a trolley be quarantined?
Quarantine it after a safety failure, unexplained change, damage, contamination, failed verification or unauthorized repair.
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