ENStarting point
A design that supports recycling combines access to components, identifiable materials, feasible separations and an application for recovered fractions. Testing should follow the product through to output quality, without confusing theoretically recyclable composition with actual recovery.
Start with an existing pathway
Before modifying a housing, describe how the product reaches the end of use: business returns, servicing, dispersed collection or a reverse logistics programme. Identify who receives it, what equipment they use and which materials they sell. A design that is easy to dismantle on a workbench may remain unviable if the actual flow does not include that operation or the part never reaches the appropriate operator.
RecyClass provides specific guidelines for plastic components in the automotive and electrical and electronic equipment sectors. Its stream-based approach reinforces the need to assess design within a defined recycling system. These references help formulate technical questions; they do not in themselves prove a product's recyclability in the Brazilian chain. [1] Record the chosen pathway, its limitations and the assessment date so the conclusion can be updated.
Turn the bill of materials into a separation map
A bill of materials needs to say more than “plastic” and “metal”. For each relevant component, connect polymer family, mass, pigmentation, fillers, coatings, adhesives and function. Separate confirmed information from assumptions. Where formulation is confidential, agree on a technical declaration mechanism that allows compatibility and restrictions to be assessed without unnecessarily disclosing the supplier's recipe.
Map what will be separated before and after shredding. A small part may remain attached to another and change the batch composition. A metal insert may require removal or subsequent separation. The map aims to reveal interfaces that generate mixing, cost and material loss. The analysis of plastics characterisation helps when origin information is insufficient for a decision.
Assess access, joints and product safety
Compare fastening alternatives across all functions: assembly, strength in use, repair, dismantling and separation. An accessible screw may facilitate a specific removal but add metal, assembly time and failure points. A snap-fit may simplify assembly and hinder access if it breaks unpredictably. The decision requires product testing and assessment of application requirements.
In dismantling tests, record sequence, tools, time, recovered mass and damage to parts considered for reuse. Access to components requiring specific treatment should be assessed by qualified professionals. Never eliminate a protective function to improve a recyclability indicator. For electrical housings, changes in material, thickness or joints may require renewed functional and safety verification before any production release.
Verify identification and separation using actual material
Markings help communicate the polymer family of a whole part, but do not guarantee identification after grinding. Industrial sorting may rely on physical properties or sensors. The study by Wu and colleagues assessed the identification of plastics from household appliances and electronics using near-infrared spectroscopy; the existence of this method does not imply uniform performance for every colour, surface or formulation. [2]
Make the comparison using representative samples, including ageing, dirt and product variants. Record correct separations, losses and contamination of the selected fraction. For each design change, ask which stage actually improves and which new difficulty appears. Reducing material diversity represents progress only when it preserves the required performance and improves the pathway's result, without shifting a problem to washing, extrusion or application.
Calculate successive losses without adding percentages
A hypothetical example: a housing contains 1.00 kg of polymer considered for recovery. In a test, 95% of that mass reaches separation; the next stage retains 90% of what it receives; and 92% of the resulting fraction meets the output specification. The result is 1.00 × 0.95 × 0.90 × 0.92 = 0.7866 kg, or 78.66% of the initial mass considered.
This calculation tracks only the defined polymer and does not automatically measure the recyclability of the complete equipment. It also excludes the collection rate. If the analysis begins before receipt, that stage and its database must be included. Do not add percentage losses: each has a different denominator. Also document whether the rejected mass has another recovery, treatment or disposal pathway.
Visual explanation · hypothetical example
Each stage starts with what remains
Polymer mass remaining from a 1 kg input. Each stage's rates are applied successively.
- Defined input
- 1.0000 kg
- After the first stage
- 0.9500 kg
- After separation
- 0.8550 kg
- Conforming material
- 0.7866 kg
Common scale: 0 to 1 kg.
95% × 90% × 92% = 78.66% of the input. Adding loss percentages would produce a different result.
View the example's data and calculations
| Stage | Remaining mass | Rate basis |
|---|---|---|
| Defined input | 1.0000 kg | Housing polymer |
| After the first stage | 0.9500 kg | 95% of input |
| After separation | 0.8550 kg | 90% of the previous stage |
| Conforming material | 0.7866 kg | 92% of the previous stage |
Test variants using criteria defined before results
Build a comparative protocol using the current version and one or two alternatives. Use equivalent receiving, preparation and processing conditions. Define in advance what will be measured: time per unit, purity, yield, resource consumption and output properties. Keep results by variant; mixing variants before measurement removes the ability to identify which modification worked.
Consider the effect of scale. Ten parts carefully dismantled by a specialist may not represent thousands of heterogeneous units. A second round should test the intended routine, including setup time, changeovers and operational limitations. Where the test does not reproduce an industrial stage, identify that gap in the report. The test should support a decision to proceed, correct the design or retain the existing configuration.
Document the gain and the trade-off accepted
Engineering approval should link the drawing, bill of materials, evidence and destination application. If more material per unit is needed to achieve the required strength, that effect must appear in the analysis. Increased recovery can coexist with higher raw material consumption. The environmental balance requires an assessment compatible with the product's function, not merely an output percentage.
In communication, prefer a bounded claim: which component was assessed, through which pathway and under which conditions. Extending the conclusion to other models, countries or partners requires new evidence. Also organise change management: replacing a pigment, adhesive or supplier may alter separation behaviour even without changing the commercial appearance. The history helps identify when the assessment needs to be repeated.
Feed recycling lessons back into design
Establish periodic feedback between development, servicing, procurement and recyclers. Photos of problematic joints, samples of contaminated fractions and recorded times are often more useful than generic assessments of “easy recycling”. Turn findings into verifiable requirements for the next revision, with owners and testing deadlines.
Integration with an industrial closed-loop programme can bring design and application closer together, provided quality and return are demonstrated. The expected deliverable is a set of supported decisions: what was changed, what gain appeared, which functions were preserved and under what conditions the pathway works. Design then moves from environmental intent to guiding concrete product and supply chain choices.
Sources and references
References accessed on 5 October 2026. The numbering in the text indicates the concepts supported by each source.
- RecyClass. Design for Recycling Guidelines — Automotive & Electrical and Electronic Equipment. Sector guidelines and stream-specific limits.
- Wu, X.; Li, J.; Yao, L.; Xu, Z. Auto-sorting commonly recovered plastics from waste household appliances and electronics using near-infrared spectroscopy. Journal of Cleaner Production, 246, 118732, 2020.
Circuvia corporate content to support project discussions. Methods, acceptance criteria and applicable requirements are defined within the scope of each operation.
