The fourth Industrial Revolution (IR 4.0) rides on the saddle bag of Printed Circuit Boards (PCB). Whether its electric vehicles (EVs), automation or drones, PCBs are important components enclosed within them.
When PCBs functioning have been amplified to such unprecedented levels, following standards in both designing and manufacturing them cannot be ignored. By now, we have understood the importance of standards and IPC, and the PCB Standards for medical and military.
In this article we will be discussing PCB standards in automotive and aerospace, both the fields which have evolved over time owing to advancement in the electronic world.
PCB Standards for Automotive
While an automotive in the 20th century hardly consisted of any electronic parts, today an automotive consists of more than 200 electronics parts at dynamical system, body and chassis.
These electronic parts range from sensors to automation, from entertainment devices to safety. The importance of PCBs in automotive today can be understood from the worldwide shortage of microchips due to pandemic leading to crippled manufacturing of automotive and their availability in the market.
Purpose of Electronic Systems in Automotive
Application of electronic systems aims to increase auto performance, covering mainly four aspects:
- Optimisation of Cost: This includes fuel saving, non-wear and tear of parts, high efficiency and mileage.
- Environment Consideration: Reduction of fuel consumption, tail gas emission, fuel transformation from gasoline, natural gas, bio-fuel to hybrid power and pure power to reduce air pollution and prevention of exhaustion of natural resources. Electric vehicles, thus, have become a strategic direction for the automotive industry.
- Security Enhancement: Approximately 1.3 million people die globally due to road traffic crashes. Therefore security enhancement of automotive is of utmost importance. This includes traffic accident reduction, air bag, radar monitoring, stereo camera, infrared monitoring and automatic avoidance to autonomous driving.
- Convenience and Comfort: It is generally rooted in audio, video display, air-conditioner, computer, mobile communication, internet, navigation and electronic toll collection for considerations of convenience and humanization.
Electronic systems become efficient when the PCBs within them are efficient. To fulfil the above mentioned purposes, the PCBs fitted in the electronic system must meet the fundamental requirements as listed:
- Quality Assurance: To make the automotive usable for the long term, quality assurance is needed. This is achieved by following a sound quality management system, that is, ISO9001 from an international perspective.
Further in 1994, a quality management system unique for the automotive industry, QS9000 was established.
At the beginning of the 21st century, ISO/TS16949, a new quality administration system was published by world automotive manufacturers based on regulations of ISO9001.
It integrates special requirements for the automotive industry and focuses on defects prevention, quality fluctuation and waste reduction in the supply chain of automotive components.
- High Reliability: Automotive reliability is tested on two fronts, first on service life of the electronic system and second on the functioning of electronic systems in extreme environments. Thus, a reliable electronic system enhances both the performance and the life of the automotive.
- Thermal Resistance: An automotive has to withstand harsh conditions of weather such as rain, snow, humidity and scorching sun. In such conditions the vulnerability of PCBs increases which might alter their efficiency.
A reliable PCB model will not only endure these extremes but remain undeterred in its functioning and resist thermal shocks.
- Light Weight and Miniaturization: On an average an ordinary car is approx. 6 feet wide and 15 feet long, it might sound like a lot but considering the driver and passenger comfort it’s really not much. Such compact dimensions restrict the space available to put in everything that makes an automotive what it is. Therefore, the PCBs put in them need to be miniaturized as was in medical devices.
Further, to take the most advantage of aerodynamics, automotive needs to be as light as possible. The fact that PCBs go into more than 200 parts of an automotive, from speedometer to navigation devices, air conditioning and control system, PCBs have potential to add bulk of weight. Therefore, lightweight PCBs are a necessity.
This is an oil circuit control system PCB:
Simple PCB inside a CAR
Some Widely Accepted PCB Standards for Automotive
- Automotive Electronics Council (AEC) – In the 1990s this council was set up by JEDEC to build separate quality adherence standards for automotive. Some of them are:
- AEC-Q100: Failure testing qualifications for integrated circuits (IC).
- AEC-Q101: Failure testing qualifications for discrete semiconductors.
- AEC-Q104: Failure testing for multi-chip modules.
- AEC-Q200: Failure testing for passive components.
- International Automotive Task Force (IATF) – It is an ad hoc group of automotive manufacturers active worldwide and publishes standards. IATF 16949 defines guidelines and requirements for automotive industry quality management systems (QMS).
- IPC: Association Connecting Electronics Industries – IPC has been discussed previously in length//hyperlink. Various IPC for automotive are:
- IPC-6011: It defines generic performance specifications for PCBs.
- IPC-6012DA: It defines tolerances and test procedures for rigid PCBs used in automotive systems.
- IPC-6013DA: It defines performance specifications for flex and rigid-flex PCBs.
- Society of Automotive Engineers (SAE) – SAE is an international association of over 1,28,000 engineers. One of their widely accepted standards is SAE J3016_201401 that defines classes for automated driving systems.
Automotive and electronics are blended together to make the perfect match for us. It not only enhances performance, comfort, convenience but also provides viable options to look beyond fossil fuels.
PCB Standards for Aerospace
As globalization increased so did the use of aviation and aerospace. Further, the 21st century can be pinpointed as the century of shooting satellites into space. Another term that entered our parlance only a few years back is ‘drones’.
All the above mentioned applications require some high end electronic system based on PCBs.
Aerospace comes within IPC-A-610E Class 3, which refers to high-performance electronic devices with guaranteed continuous operation uninterrupted, even in the most difficult and critical operating conditions.
The PCBs in avionics and aerospace must conform to following conditions:
- Withstand severe environment conditions.
- Withstands high pressure above the atmosphere and zero gravity beyond the atmosphere.
- High tolerance for heat and quick heat dissipation.
- Endure vibration of considerable intensity and absorb shocks.
- High frequency application and equipped with radio communication.
To achieve above mentioned conditions, PCB design and manufacturing requirements are:
- Usage of High Quality Material: To ensure reliability and durability, material used should be of high quality. Life span of aerospace electronics is more than 15 years and they need continuous functioning without interruption. Apart from longevity, material should possess necessary chemical and physical properties.
Anodized aluminium is preferred over FR4 because of its higher thermal conductivity and minimization of heat induced oxidation.
- Heavy Copper Technology: Copper thicknesses ranging between 2 to 6 oz/ft2 (or more), allows heat dissipation in a natural way. Thus, eliminates the requirement of additional cooling systems even in the presence of high intensity currents.
- Conformal Coating: Application of conformal coating shields the PCB against humidity, heat, water and vibration. The common conformal coating techniques include electrolytic nickel gold, ENIG (Electroless Nickel with Immersion Gold Coating), chemical silver, HASL (Hot Air Solder Levelling) and lead-free HASL.
Some Widely Accepted PCB Standards For Aerospace
- AS 9100 – For quality management system.
- AMS2750E – Covers pyrometric requirements for devices such as thermal sensors, instruments, thermal processing equipment. Further, it also provides standards for assessment, testing and surveying to ensure adherence to heat treatment specifications.
- AS478N – Specifies the type of markings and where they should be located for aerospace components.
- AS5553A – For the aerospace based supply chain standards that procure or integrate components.
- AS9006A – Specifies requirements for software and software support components.
- AS9100D – Sets the QMS requirements for suppliers to the aerospace industry. Covers in-house and outsourced manufacturing processes, management responsibilities and emphasizes customer satisfaction.
- AS9101E – Specifies guidelines for the auditing and reporting of the QMS.
- AS9102B – Lists baseline first article inspection (FAI) requirements.
Today aerospace advancement has made possible GPS systems, remote sensing, satellite communication and looking beyond our galaxy. Non-adherence to PCB standards may result in mishaps which will be difficult to contain and may overhaul our everyday life. On the other hand a standard complied PCB will make life simpler. Just as a rising tide lifts all boats, a rising PCB lifts all that carries it, be it drones or satellites or airbus, the sky surely isn’t the limit then.