A useful structural-insulation specification connects material construction, directions and test states to the part’s duty. Define those relationships so purchasing receives evidence that engineering can use. [1]
Calculation basis. Project-specific values and gates in the illustrative screens below are assumptions; cited catalogue values retain their source test conditions.
The requirements below form a working framework for a pressboard, transformerwood or glass-reinforced structural part. Complete the numeric values and methods from the qualified design; do not fill them with unrelated catalogue averages.
Material requirement entries
- Identity and construction. State the selected material designation, reinforcement or veneer arrangement, bonding system and applicable controlled revision. Record the manufacturer’s identification without inventing an equivalence to another supplier’s grade.
- Directional convention. Define part axes and their relation to MD/CD, grain, reinforcement and the layer-plane normal as applicable. Attach the required cutting or layup orientation to the drawing.
- Conditioning states. Name the states used for supply measurements, property tests and final part acceptance. Specify the qualified oil, moisture and temperature conditions where they affect interpretation.
- Mechanical evidence. Identify compression, bearing, flexure, shear, thread or time-dependent duties separately. Require the matching specimen direction, contact geometry and test method for each reported result.
- Electrical and thermal evidence. Preserve dielectric test direction, waveform, electrode path and reporting units. Define required thermal-property directions and the relevant state rather than requesting one generic temperature rating.
- Finished-part characteristics. List critical dimensions, surfaces, holes, interfaces and damage categories. State the measurement supports and datums where a flexible or state-dependent geometry needs them.
- Batch evidence. Link delivered stock and parts to the specified material batch and processing records. Distinguish actual batch test results from a general product datasheet or statement of conformity.
- Changes and substitutions. Identify which construction, source, layup, bonding, processing and machining changes require review of the affected property or part qualification.
Make the evidence hierarchy usable
A manufacturer technical sheet may provide average guideline values with explicit qualifications. Keep its footnotes and test directions with the data. It does not establish the lower-bound strength or finished-part performance of a delivered batch.
A statement of conformity confirms a defined assertion; a test report contains measured evidence under stated conditions. Specify which is needed for each requirement. Require deviations to be identified against the actual drawing or material entry, rather than hidden behind a general “equivalent” statement.
Sampling should follow the criticality and variability of the duty. The approved plan should explain how batch material evidence connects to the representative machined parts and their critical regions.
For a new supplier, review the designation and construction first, then compare matching test directions and states. If the supplier offers a different laminate, assess that substitution through the affected load, oil, thermal and electrical duties before using its certificate.
The finished specification should let purchasing identify a missing result and let engineering identify its consequence. An absent directional compression test is a different gap from an unverified surface condition or an obsolete layup revision; keep those requirements distinct so they can be resolved.
Select evidence by load direction and conditioned state
Match the material identity and relevant test direction before comparing densified-wood evidence [2].
Assume a structural support requires three independent directions of compression evidence, two dielectric directions and one conditioned bond assessment: six distinct entries. Assume the supplier provides both in-plane compression results and both dielectric directions but lacks through-thickness compression and the conditioned bond result. Four of six entries gives 66.7% completeness, yet the two missing functions remain unqualified. An assumed 100 MPa in-plane value cannot replace a missing through-thickness result. Close the actual directional gaps before approving the material designation.
References
- Röchling Industrial, Lignostone L I/2-E3-HQ (P2R), Technical Data Sheet, version 2.0, released 20 September 2023.
- IEC, IEC 61061-2:1992, Specification for non-impregnated, densified laminated wood for electrical purposes — Part 2: Methods of test.