Transformerwood reuse depends on traceable identity, present condition and current design applicability. Review water exposure, protection and critical machined features to make the assembly decision on the actual stored part. [1]
Calculation basis. Project-specific values and gates in the illustrative screens below are assumptions; cited catalogue values retain their source test conditions.
Rebuild the available history before deciding which checks can resolve its condition. Identify the stock batch, grade, layup, drawing revision and prior processing. Record packaging failures, liquid contact, temperature exposure and handling damage where known.
A condition-based review
| Finding | Evidence to obtain | Decision consequence |
|---|---|---|
| Identity and revision intact | Match part and material records to the current assembly | Continue condition checks for that specific use |
| Changed critical dimension | Same-state measurement and directional moisture evidence | Distinguish reversible state change from damage or an unsuitable fit |
| Edge swelling or distorted profile | Location map and comparison with original dimensions | Examine affected holes, contacts and layer boundaries |
| Crack, separation or tool-contact damage | Extent and relationship to the loaded/electrical region | Require a qualified disposition rather than routine release |
| Unknown liquid or environmental exposure | Material-specific investigation and relevant witnesses | Limit reuse until the missing state evidence is resolved |
Röchling’s handling note for L X-2-E3-HQ distinguishes large-stock thickness tolerance from edge moisture change [2]. It covers a different construction from the named L I/2 data sheet. Obtain the actual supplied grade’s handling basis and compare finished holes and mating surfaces against their released part requirements.
Recheck the features that govern reuse
Measure contact dimensions, hole locations, threaded regions and notches from the original functional datums. Include support state for flexible or bowed parts. A changed measurement procedure can create an apparent storage change.
Examine exposed edges and accessible bond lines for damage, staining, residue or separation. Surface condition does not establish internal moisture. Where the thick region or exposure history makes it necessary, use representative moisture or section evidence rather than relying on one surface indication.
Do not assume a later drying operation restores all properties. It may change dimensions without removing contamination, closing a crack or recreating the original bond condition. Any proposed conditioning or rework needs a material-specific qualified route and subsequent checks.
Confirm the intended load and electrical environment have not changed. A support that was qualified for one winding arrangement or contact footprint may no longer be represented by that evidence after a design revision, even if storage caused no visible deterioration.
Keep disposition specific to the part. If a critical bore has moved, assess that fit; if layer damage enters a washer seat, assess that contact. A generic shelf-life extension cannot answer either question.
Reuse becomes supportable when identity, current design applicability and relevant condition are established together. Where those checks leave a damaged or unexamined critical region, remove the part from routine assembly until the qualified material and design review resolves it.
Use storage change to define the requalification gap
Match the material identity and relevant test direction before comparing densified-wood evidence [3].
Assume a 100 mm directional dimension was recorded at 100.00 mm before storage and 100.35 mm afterward, both measured at an assumed 20 °C under the stated conditioning and support arrangement. Change is 0.35%. An assumed assembly tolerance of ±0.20 mm would be exceeded by 0.15 mm. Reconcile moisture, irreversible change and datum repeatability before reusing the stored transformerwood part.
References
- Röchling Industrial, Lignostone L I/2-E3-HQ (P2R), Technical Data Sheet, version 2.0, released 20 September 2023.
- Röchling Industrial, Product Handling Information Sheet, Lignostone L X-2-E3-HQ, version 4.0, released 30 June 2025, section 5.
- IEC, IEC 61061-2:1992, Specification for non-impregnated, densified laminated wood for electrical purposes — Part 2: Methods of test.