Exploring Industrial PCB Boards and Their Applications

PCBs constitute the foundation of electronics, providing the mechanical structure and electrical connections upon which components assemble into functional circuits and systems. While commercial information technology and consumer gadgets capture much attention, equally vital yet less conspicuous PCBs empower critical industrial automation, energy infrastructure, transportation, aerospace, defense, instrumentation and other integral systems.

Ruggedness, extended temperature tolerance, interference immunity, specialized form-factors, environmental sealing, and reliability quantifiably exceeding typical commercial specifications make these boards suitable for deployment into demanding embedded settings rife with vibrations, contaminants, moisture, and electrical noise disturbances. This paper explores common industrial PCB applications, capabilities required to engineer boards surviving years of uninterrupted 24/7 operation across adverse conditions, and component selection criteria guiding designers. Insight into this significant domain within electronics aids selecting optimal partners for manufacturing customized boards meeting application lifecycle milestones.

Defining Industrial PCBs

Industrial printed circuit boards generally possess some combination of the following differentiating attributes making commercial grade boards ill-suited for embedded deployment:

Environmental Hardening: Protection against moisture, gaseous or airborne chemicals/particulates, thermal swings, and mechanical shock/vibration through conformal coatings, potting compounds, sealing, and reinforcement.

Extended Temperature Range: Functionality persisting between -40°C to +85°C or beyond instead of 0-70°C commercial range allows installing boards into unconditioned spaces seeing weather shifts and internal heat buildup. Widened scope accommodates military/aerospace de-ratings.

Interference Hardening: Shielding, ground planes, filter integration and careful layout techniques improve noise immunity and emission containment for electronics operating amidst substantial interference from motors, ignitions, contactors, pumps, and other industrial machinery in close proximity. Susceptibility hardening assists signal integrity.

Safety Certifications: Certification per IEC 62368 ensures operational integrity and hazard avoidance for electronics deployed into hazardous industrial environments and explosives atmospheres. Specialized testing validates construction techniques.

Reliable Lifespans: Component selection, de-rating, cycle testing, burn-in screening and assembly workmanship aim for 25-30 year lifecycles exceeding commercial expectations.

While superficially resembling everyday consumer PCBs on inspection, engineering and validating rugged boards meeting these stringent survival criteria requires specialized design experience and manufacturing expertise eventually determining whether systems thrive or prematurely fail in the field.

Common Applications of Industrial PCBs

The necessity for electronics tailor-made to withstand hostile ambient operating conditions comes from applications like:

Industrial Automation: PLCs, sensors, motor drives, HMIs, I/O modules and communications infrastructure get mounted directly into heavy machinery on factory floors with debris, vibration, moisture and narrow temperature margins prone to fluctuating.

Smart Grid Infrastructure: Grid-tied solar inverters, battery energy storage systems, EV charging stations and electrical distribution equipment endure years of unsupervised outdoor deployment at the network edge across diverse uncertain ambient circumstances.

Transportation: Railway signals, on-vehicle controls, mission-critical avionics subsystems and engine management electronics experience prolonged exposure to electrical noise interference, moisture and vibration.

Energy Infrastructure: Well logging tools for oil/gas drilling send sensor telemetry from depths exceeding 5 kilometers in 150°C+ environments. Power generation equipment withstands extremes. Mining electronics see corrosives.

Defense Systems: Missile guidance, ordnance fusing electronics, vehicle controls and communication systems impose stringent environmentals beyond commercial grade securing supply independence.

Test & Measurement Equipment: Spectrum analyzers, multimeters, oscilloscopes and scientific instrumentation experience human handling along with electrical and mechanical stresses during transportation/operation.

The necessity for hardening electronics against actual deployment environments routinely encountered “outside the lab” escalates for industries where continuity proves paramount over convenience or cost savings. We next explore common methods improving PCB ruggedness.

Design Techniques Improving Industrial PCB Robustness

 While suggestions focus on design-for-environment practices assuming well-controlled assembly and quality processes, collaboration between OEM designers and chosen manufacturing partners early during development further ensures achieving field reliability goals through DFX conformity.

Thermal Design Verification

Confirming adequate ventilation paths and heat dissipation ability prevents components exceeding maximum junction temperatures causing immediate or accumulated deterioration. Beyond electrical deratings, thermal simulation, prototyping and testing establishes viability by measuring temperature rises under load to avoid undetected failure modes escaping design reviews.

Conformal Protective Coatings

Spray coatings like acrylics or silicones get selectively applied onto assembled boards covering sensitive traces and components without impeding ventilation or connector interfaces. By preventing atmospheric gasses/moisture from reaching susceptible regions while absorbing mechanical/electrical stresses, coatings furnishing 30-50 micron insulation layers improve contamination resistance and immunity greatly. Periodic inspection ensures coating continuity.

Vibration Isolation Mounts

Shock-absorbing rubber, elastomer or spring standoffs securing the PCB to chassis structures absorb kinetic energy induced by equipment vibrations or environmental excitation protecting solder joints and pathways from cumulative fatigue related failures and intermittent contacts.

Potting Compounds

Encapsulation into solid protective media like epoxy, silicone or polyurethanes guards entire board assemblies when ventilation proves unessential. By eliminating atmosphere contact and weighs securing components, potting furnishes the ultimate securing against contaminant ingression and rapid pressurization even enabling underwater deployments. Tradeoffs involve servicing difficulty should rework become necessary.

Conformal Shielding

Selective application of conductive metallic layers onto critical surface mount components provides EM isolation preventing stray interference pickup. Grounding continuity must take precedence with shielding to avoid antenna effects. Techniques range from clip-on cages to selective conductive dispensing over ICs.

Rugged Connectors

Waterproof, dust-proof, immunized and physically reinforced connectors sustain continual mating endurance without deterioration. Redundant pins, protective shrouds, backshells, EMI grounding and cable clamps prevent moisture and dynamic stress related intermittent contacts.

Component Level Hardening

Modules packing complex integrated circuits like microcontrollers, FPGAs, DC/DC converters or interface bridges incorporate internal strengthening against ionizing radiation, magnetics, electrostatic discharge and electrical noise penetration creating robust building blocks for external ambient threats.

The necessity for and extent of hardening measures depends strongly on intended deployment environments and anticipated lifecycles. Overengineering risks unnecessary costs while underengineering jeopardizes premature field failures. DFX collaboration with experienced industrial manufacturing partners steers the prudent middle course.

Reliable Component Selection Criteria

Component choices profoundly impact resultant system lifespans, tolerances and maintenance needs given the open-air operating conditions frequently encountered. Common selection practices embrace:

Manufacturer Qualification

When producing printed circuit boards for mission-critical industrial applications, vendor selection is paramount. Preference should be given to manufacturers with a proven track record of delivering high-reliability solutions over many years. Field-proven vendors demonstrate strong supply chain continuity and control necessary to minimize risks.

Rigorous sampling and qualification programs ensure all materials meet specifications to prevent counterfeiting or quality gaps. Extensive reliability testing validates designs will withstand demanding operating environments. For the most robust systems underpinning vital infrastructure, only proven industrial PCB vendors with a commitment to quality above all others should be considered.

Worst-Case Ratings

MIL-spec screening for early failures coupled with derated voltage, thermal and duty cycle guard bands improves survival probabilities where parameters fluctuate during struggle operating conditions.

Endurance Testing

Highly accelerated lifetime testing (HALT) exposes component samples to extreme temperature, vibration, voltage and humidity conditions pinpointing strength margins far exceeding data sheet listings and revealing susceptibilities prior to wide deployment.

FMECA

Maintainability predictions via failure modes, effects and criticality analysis on schematics highlight vulnerable spots guiding redundancy and monitoring provisions when proactive replacements make sense over reactive failures.

While costlier and lead time intensive, these practices reward manufacturers and OEMs deploying electronics into unpredictable environments with radically improved field reliability essential where services proves prohibitively expensive. Staunch verification overtakes trust for industrial-grade expectations.

conclusion

In contrast to consumer electronics prioritizing low-cost and convenience over longevity, industrial PCBs mandate rigorous design and manufacturing processes to satisfy exacting reliability requirements. This ensures mission-critical systems remain fully functional regardless of unpredictable field conditions. Building long-term relationships between manufacturers and customers also cultivates invaluable domain expertise over time.

Rather than seeking transient profits, focusing on design for environment, modularity, and prolonged service life yields most efficient fulfillment of purpose. Authentic reliability results from durable construction able to outlast unpredictable operational realities. Industrial PCB vendors providing tailored solutions demonstrate invaluable commitment to excellence at scale. This exploration aims to illuminate best practices for engineered electronics indispensable to infrastructure that must perform without interruption.