Sustainability Checklist

This checklist is prepared to ensure long-term operability, serviceability, energy efficiency, and environmental durability of the product after production. The goal is to both extend product life and facilitate maintenance, spare parts supply, and safe use processes.

Assembly, Access and Ease of Maintenance​

1. Is the system designed for easy assembly?​

Assembly time and error rate are directly related to product design ergonomics.

Good design accelerates not only production but also maintenance and disassembly operations.

• Modules should be placed in logical order (e.g., power module → control board → sensor board).
• All screw holes, cable directions, and connector placements should be arranged for easy accessibility.
• Number of screws should be minimized, preferably using single screw type.
• Each assembly step should be visually supported in production and maintenance documents.
• If necessary, "Tool-less" (tool-free) assembly solutions should be evaluated.

This approach complies with Design for Assembly (DFA) and Design for Maintenance (DFMnt) principles.

2. Are labeling and identifications specified in appropriate places?​

Clear labeling of each connection point, signal line, or function significantly reduces error rates in both production and field maintenance.

• Definitions such as "PWR", "UART", "BATT", "FUSE", "TP1" should be readable on PCB.
• Font, print thickness, and contrast value should be selected not to erase during production process.
• Labels on mechanical surfaces should be UV and solvent resistant (UL 969 compliant).
• Labels can be used not only for information but also for access guidance (e.g., "Lift Here", "Replace Fuse").

3. Is access to battery, fuse, or serviceable components easy?​

During service, user or technician should be able to safely access consumable components (fuse, battery, filter, fan) without cutting power. Batteries and fuses should be positioned not requiring complete device disassembly.

Locations of these components should be clearly marked on product or visually indicated in manual. Access covers should be designed tool-free (e.g., latch, clip).

Insulation should be provided during access to components near high voltage lines. Recycling warning (♻️) should be present for battery replacement.

Hard-to-access service components extend field maintenance time and increase total cost of ownership (TCO).

4. Is availability and sustainability of spare parts verified?​

Product service life is directly related to component availability. Therefore, long supply life and alternative manufacturer planning should be done for critical parts. "Active", "NRND", "EOL" status should be checked in manufacturer documents.

Long-life components (≥10 years production support) should be preferred. At least two different approved sources (dual sourcing) should exist in supply chain. Drop-in replacement alternatives should be predetermined for EOL components.

Storage, packaging, and labeling processes of spare parts should be integrated into ERP system.

5. Are status indication LEDs placed in system (or optionally disabled)?​

Status LEDs are the fastest information source during both production tests and field diagnostics. However, unnecessary LED use can increase energy consumption; therefore, right balance should be established.

Basic indicators:

• Power (green): System is energized
• Fault (red): Failure or error state
• Status (blue or yellow): Normal operation or communication indicator

LED brightness should be limited suitable for both indoor and outdoor use (e.g., 5–10 mA). LED descriptions should be indicated with symbol or label on PCB or panel.

Optional LED disable option (jumper or firmware configuration) can be offered in field applications.

Automatic Diagnostics and Event Logs​

6. Can system self-test (Self-Test Mode)?​

In advanced systems, automatic self-diagnostic (Power-On Self-Test) mechanism should work during device startup. This function checks basic functionality of hardware and software components when product is powered up.

Scope:

• Power lines (voltage and current sensors)
• Memory (RAM/EEPROM integrity check)
• Communication interfaces (UART, I²C, SPI, CAN, Ethernet)
• Sensors and peripherals
• Watchdog timer activation

Purpose: To detect possible production errors, loose connections, or component failures before system starts operating.

Implementation: "OK / FAIL" notification can be made via LED or display based on test result, Errors should be written to system log and sent as warning to user if necessary, System should remain in "safe mode" in critical errors.

7. Are abnormal situations written to Event Log?​

Most effective way to measure product's field durability is traceability of past events. Event logging system creates critical data source for both service engineers and user support.

Recommended situations to log:

• Over-temperature / low temperature warnings
• Low voltage or high current protection activation
• Communication errors (timeout, CRC error, bus-off)
• Watchdog reset or software restarts
• Firmware updates or user setting changes.

Technical recommendations: Log data should be kept in circular buffer structure, Each event should be stored with RTC time-stamp, In memory-constrained systems, summary data (hash-based entry) can be used, Log files should be downloadable via serial port, USB, or BLE during service.

This system is fundamental tool for both reliability engineering and sustainable service infrastructure.

Mechanical Durability and Environmental Conditions​

8. Do system and modules have vibration tolerance?​

Vibration is one of most destructive external effects for electronic systems especially in mobile platforms (automotive, aerospace, industrial machinery). Mounting elements and heavy components should not loosen or break under vibration.

Vibration test should be performed according to IEC 60068-2-6 (Sinusoidal Vibration) or MIL-STD-810H Method 514.8 standard.

Test range: 5 Hz–500 Hz, 3 axes, 30 minutes/axis. Mounting screws, heavy components (transformer, heat sink, relay), and cable bundles should be observed for mechanical durability during test. Strain relief and cable clamps are mandatory on cable connections.

In automotive class applications, module vibration tolerance should be verified at least 10 g RMS level according to ISO 16750-3.

9. Are surge currents on all semiconductors within manufacturer limits?​

Surge current pulses are main causes of early aging and thermal fatigue in power electronics. Manufacturer datasheet limits should not be exceeded especially for MOSFET, IGBT, diode, and rectifier elements.

Parameter check:

• MOSFET ID(pulse) – Pulsed Drain Current
• Diode IFSM – Non-Repetitive Surge Current
• Regulator ISurge – Start-up Inrush Current

Test scenario: Current measurement during power on/off cycles and load changes. Soft-start circuit or NTC current limiter should be used in critical components. Otherwise, components may fail early due to micro cracks or semiconductor degradation.

10. Is system resistant to thermal cycling?​

Temperature changes create stress in solder joints and PCB laminate structure, leading to microscopic cracks over time. Therefore, thermal cycling tests are one of fundamental parts of long-life validation.

Typical test profile: -40 °C → +85 °C range with 15-minute cycles, Minimum 200 cycles (industrial) or 500 cycles (automotive).

Monitoring points: PCB solder points, connector pins, under BGA and QFN connections. X-ray or thermal profile analyses should be performed to detect solder cracks. This test is basis of thermomechanical reliability (Thermal Fatigue Reliability) validation.

11. Are capacitors positioned away from heat-emitting elements?​

Heat significantly shortens lifetime especially of electrolytic capacitors. Every 10 °C temperature increase approximately halves capacitor life (Arrhenius rule). Electrolytic and polymer capacitors should be placed away from heat sources such as regulator, MOSFET, transformer, power resistor.

If necessary, they should be separated from cooler area with thermal barrier or air channel. Temperature gradients on PCB should be analyzed with thermal camera.

Capacitor life estimation should be verified with manufacturer life-time calculator data.

12. Is resistance to ESD (electrostatic discharge) provided throughout product?​

ESD (Electrostatic Discharge) is one of most frequent but least noticed stress types that shortens hardware life. ESD paths should be safely defined on both electronic circuit and mechanical body.

Test standard: IEC 61000-4-2 – ESD Immunity Test. Level 4 test: ±8 kV air discharge, ±6 kV direct contact. Protection methods: TVS diodes or transient suppressors, Input filters (RC, ferrite bead), Spring contacts or carbon coating for metal body grounding. ESD current should be directed to chassis GND through shortest path.

13. Is resistance path against ESD verified throughout product?​

Adding protection elements alone is not sufficient; these elements must be correctly connected to ESD discharge path. Each module should be able to safely discharge static loads to ground line (PE or Chassis GND).

ESD paths on PCB should be routed with low-impedance traces going directly to ground. Spring finger or conductive gasket should be used to provide contact between body and PCB. Total resistance path throughout product should be measured to be ≤ 1 Ω.

Thermal and Electrical Sustainability​

14. Are thermal limit values (ΔT) measured and verified for all components?​

Each electronic component has temperature limit determined by manufacturer. Exceeding these limits can result in performance degradation, early aging, or permanent failures. Temperature rise (ΔT) during operation should be measured for all critical components (MOSFET, regulator, CPU, power resistors, coils, converters).

General target according to manufacturer limit: ΔT below 40 °C, maximum surface temperature Tcase below 105 °C. Measurement should be performed using thermal camera, thermocouple, or PCB embedded sensors (NTC).

Measurements should be performed separately at full load, half load, and standby states. For overheating components, solutions such as heatsink, thermal pad, or copper area expansion should be applied.

15. Are power components (MOSFET, LDO, regulator) positioned not to thermally affect each other?​

Close positioning of components in power electronics circuits increases heat accumulation and thermal interaction risk. This situation leads to thermal "hot spot" formation especially in high-current circuits.

Power components (e.g., MOSFET, LDO, DC/DC, transformer) should be placed at least 15–20 mm apart. Thermal distribution analysis should be performed during placement; heat density should be equalized.

If necessary, copper heat dissipation areas (thermal plane) should be created in PCB bottom layers. In thermal tests, if high-temperature operating elements are close together, heat transfer (coupling effect) should be examined. Thermal camera or simulation tools (e.g., Ansys Icepak, Altium PDN Analyzer) can be used for analyses.

16. Are cooling and airflow paths considered in mechanical design?​

Product's thermal performance is determined more by mechanical airflow management design than efficiency of electronic components. Device's internal structure should be optimized by determining air inlet–outlet paths. Fan or vent placement should be designed considering hot air rises principle (chimney effect).

Fans should be positioned close to cold air inlet line, not hot spot. Airflow direction should be planned according to sequence of heat-emitting components on PCB. Cable, connector, or wall effects causing unnecessary air resistance should be reduced. Fan speed control should be done with PWM, ensuring energy efficiency.

Long-Term Service and Reliability​

17. Are error prevention strategies determined for product to protect itself throughout its life?​

Long-term reliability is ensured not only by component quality but also by automatic error prevention mechanisms. Hardware and software should work together to develop product's self-protection capability.

Automatic error management strategies:

• Watchdog reset: System restarting itself against software lockups
• Redundant sensor: Backup sensor use for critical measurements (e.g., temperature, pressure)
• Fallback mode: Device continuing to operate in safe state when error detected
• Brown-out reset: Preventing software corruption in low voltage situations.

Error prevention strategies should be consistent with FMEA (Failure Mode and Effects Analysis) outputs.

18. Can firmware updates be supported throughout product life?​

One of fundamental conditions of hardware sustainability is that software support be compatible with its lifetime. Security patches, bug fixes, or new features should be provided via remote or local firmware update while product is in field.

FOTA (Firmware-Over-the-Air) or update support via USB/Serial service port should be available. Update system should be signed and encrypted (digital signature + hash verification).

Update history (revision log) should be stored in product memory. Update policy should be maintained for minimum 5–10 years after production.

19. Is service documentation (assembly manual, maintenance instructions, test report) prepared?​

Product cannot be considered sustainable without service manuals. Service documentation should cover all maintenance, repair, and test steps of product.

• Assembly manual: Disassembly–assembly sequences, screw torque values, cable directions
• Maintenance instructions: Cleaning, calibration, part replacement intervals
• Test report format: Measurement points, reference values, and acceptance criteria.

Documents should be accessible via PDF + web portal. Service documentation should be stored in revision-controlled system (Git/PLM).

20. Is post-production spare parts plan (Spare Parts Policy) defined for product?​

Sustainability is not limited to production process; spare parts availability should be planned even while product is working in field. Minimum stock level should be determined for critical components (e.g., "Min Qty: 100 pcs").

Alternative suppliers and manufacturer codes should be added to AML/AVL system. EOL (End of Life) or NRND (Not Recommended for New Design) statuses should be tracked. Part tracking module should be active via ERP for service and supply teams.

21. Are energy consumption targets (idle / active) defined?​

Energy efficiency is main indicator of environmental sustainability and low operating costs.

• Standby (idle) mode: Power consumption should be targeted below 1 W.
• Active (nominal) operation: Power efficiency should be higher than 85% (e.g., AC/DC power supply).

Power measurements should be performed according to IEC 62301 (Standby Power Measurement) standard. Sleep modes, duty-cycle optimization, and dynamic power management (DPM) should be applied if necessary.

22. Are modular repair and Right-to-Repair requirements evaluated?​

Modern sustainability concept makes repairability a design criterion. Each module of product should be independently removable and replaceable. Modules should be separated according to power, sensor, communication, or control layers.

Disassembly operation should be possible without requiring special equipment. Connections should be socketed or header-based (instead of soldered fixing). Module code (part ID) and service directive should be available for parts.

23. Is recyclable material ratio of product calculated?​

Sustainable production requires planning material recycling ratio at design stage. Recyclable ratio should be specified for each component such as plastic, metal, cardboard, glass.

Target: ≥ 70% of total mass consisting of recyclable material. Material selection should comply with ISO 14021 – Environmental Labels and Declarations standard.

PCB and plastic parts should be RoHS compliant (lead-free, halogen-free). Recycling symbols and material codes should be present on product packaging.

24. Are packaging and logistics processes compliant with environmental management standards (ISO 14001)?​

Packaging is invisible but critical link of sustainable product chain. Transportation and storage processes should also be integrated into environmental management system. Packaging materials should be recyclable (cardboard, EPE, PE). Printing inks should be selected from environmentally friendly types containing no heavy metals.

Logistics companies should be selected from ISO 14001 certified suppliers. Pallet and carton sizes should be optimized to increase transportation efficiency. Packaging and transportation processes should be included in carbon footprint (CO₂e) calculation.