Every industrial control manufacturer will tell you they build printed circuit boards. Fewer will walk you through the production lines that turn a bare PCB into a fanless box PC with firmware, conformal coating, and a burn-in record attached.
PCBONLINE, as an OEM industrial control manufacturing partner, provides turnkey industrial control PCBA and box-build assembly. This post shows the production of industrial control with photos, which come from the PCBA and box-build lines at PCBONLINE.
PCBONLINE covers the stages of industrial control PCB manufacturing and assembly, programming, conformal coating, functional testing, burn-in, box-build assembly, and finished-product testing.
What OEM Industrial Control Manufacturing Covers
Industrial control products include fanless box PCs, edge computers, DIN-rail controllers, HMI terminals, etc. They run for years in electrical cabinets, on production lines, and in plants.
Industrial controls usually work in environments with dust, vibration, temperature swings, and voltage noise. So the OEM industrial control manufacturing process must operate around reliability.
PCB fabrication. PCB production for multilayer, HDI, and impedance-controlled designs, with the resin system, copper weight, and surface finish selected for the cabinet environment.
Component sourcing. Passive and active component procured from factories and suppliers. They are stored at PCBONLINE's controlled warehouse for active and electromechanical parts, with full barcode traceability from receiving to placement.
SMT assembly and through-hole soldering. Automatic SMD placement, reflow soldering, selective wave or wave soldering for THT connectors and terminals.
Firmware programming. Flash loading and device-level configuration, done on the post-assembly line before the product reaches the final test.
Conformal coating, functional testing, and burn-in. The reliability steps are performed on our post-assembly lines. They ensure that the industrial control product survives for years.
Enclosure assembly and finished-product testing. The box build turns the PCB assembly into an industrial control product ready to launch to market.
When your industrial control manufacturer owns the whole chain, you get a single point of responsibility instead of coordinating different vendors. One-stop manufacturing is one of the reasons to choose PCBONLINE for industrial control manufacturing. Manufacturing quality and DFM are the other reasons.
OEM Industrial Control Manufacturing Process
Below is the industrial control manufacturing process step by step with photos from PCBONLINE.
PCBA with Heatsink and Module
After SMT and through-hole assembly, the bare PCB turns into an industrial control PCBA. Each PCBA carries a large black aluminum heatsink across the CPU area, a small system-on-module at the bottom edge, and a full set of connectors.
Why the heatsink is part of the SMT step. The PCB runs inside a sealed fanless enclosure, so there is no forced air. The thermal path goes from the processor, through thermal interface material, into the heatsink, and then into the case walls. That is why we mount the heatsink on the SMT line.
Board-Level Assembly and Record
Industrial control PCBAs sit in rows at the workstation, with their green terminal blocks and connectors already through-hole soldered. At the press, an operator seats the parts that need force.
Each label on the shelf names the folder's contents. The operator files each paper at the station as the work moves through. When a batch ships, the folder is the record of that run.
Firmware Programming and Functional Test
The next stage turns the PCBA into the customer's product. We write the firmware to the flash, then power and test the PCB against its own function list before it ever goes into a case.
We have functional tests twice: once after PCB assembly, once after we seal the unit in its chassis.
Each PCBA carries an active heatsink and fan, a green terminal block for the field wiring, and a 2.5-inch solid-state drive at the side. We power each PCBA over the harness and step through the ports, the readouts, and the power rails. The log entry for each slot follows the PCBA into the next station.
Conformal Coating
Industrial PCBAs need a protective coating against harsh environments. We automatically spray them with conformal coating and then bake it to cure.
The coating seals the traces and components against moisture, dust, and the corrosive gases that build up in electrical cabinets.
Burn-In (Aging)
After assembly, we run every finished unit through a burn-in phase inside an aging chamber. Each box PC is mounted in a rack and connected via a harness. Red status LEDs on the units show that they are powered and under load.
Burn-in catches infant mortality. Infant mortality in semiconductor components and solder joints shows up in the first tens of hours of operation. Running the system at elevated temperature and load for a set period forces the weak parts to fail at the factory.
Box-build Assembly
Final assembly brings the PCBA, heatsink, wiring harness, and I/O connectors together into the sealed unit.
At the workstation, the PCB sits inside the aluminum case. A yellow lithium coin cell sits next to the real-time clock, and the capacitor bank sits next to the power input. Cables run against the chassis walls to keep the heatsink path clear.
Why box build is a separate capability. It demands enclosure assembly, cable routing, thermal interface application, and mechanical fit checks.
Finished-Product Functional Test
Once the unit is closed, we test it again as a complete product. Our line runs dozens of finished box PCs in a row, each connected to a central test station over the same harnesses.
In the final test, the ports are exercised, the power rails are verified, and the unit is confirmed to boot and run its firmware. A full test after assembly is the difference between an OEM that delivers working products and an assembler that delivers boxes.
Learn About Industrial Control Products on Our Line
The photos on this page show two industrial control products, the fanless box PC and the 1U rack-mount computer. They are assembled and tested on the same line. Of course, they are different batches and are not assembled at the same time.
The two different industrial control products share the same board-level assembly, the same programming, the same conformal coating, the same burn-in, and the same final test.
Although their chassis differ, their PCBA and box build process and tests are the same. Our Industrial control line offers complete manufacturing capabilities and inspections/test.
The Fanless Industrial Box PC
The rear I/O of the finished box PC carries multiple RJ45 Ethernet ports, blue USB 3.0 ports, VGA, HDMI, and audio jacks. A D-sub connector covers legacy field wiring. The large circular industrial connector carries high-reliability cable connections.
The port mix. Serial and Ethernet connect the PLCs and field devices. The USB ports serve configuration. VGA and HDMI drive a local HMI. The rugged multi-pin connector carries the main cable run into the cabinet.
The enclosure. A one-piece aluminum extrusion forms the housing. The fins and the case walls are a single continuous profile, with no bolt-on parts.
Fanless cooling. A fanless design removes the most common failure point in industrial electronics, the fan. No moving parts means no bearing wear, no dust intake, and no filter to replace.
The case is the heatsink. The whole case becomes the heatsink in this build. The CPU temperature drops through the enclosure surface and the thermal interface inside. The heatsink sits directly against the PCB and the case, and the finished unit has to stay flat and evenly torqued through assembly.
The 1U Rack-Mount Industrial Computer
The 1U rack-mount industrial computers sit stacked on pink ESD foam along the conveyor.
The front panel. A seven-segment display and a row of green terminal blocks sit on the front panel. The terminal blocks take the field wiring.
The 1U form factor. The 1U height lets the unit mount in a standard 19-inch rack.
Why the Line Choice Determines Your Field Failure Rate
Specs describe a product's behavior, and the production line determines whether the behavior holds up for years.
When you choose an industrial control manufacturer, the questions worth asking are not about the processor or the number of ports. They are about the process.
Does the manufacturer test at board level, or only on the finished unit? Board-level testing catches faults while rework is still cheap. Final-only testing hides them inside the box.
Does it run conformal coating and bake? A coating line with a controlled cure profile is reliable. An industrial PCBA without a conformal coating may not be that durable in its long service life.
Does it run a burn-in phase, and does it give you the record? A burn-in record is evidence. A burn-in promise is marketing.
Does it own the assembly, or does it outsource the box build? Every handoff between vendors is a place where feedback gets lost, and the paper trail thins out.
Does the firm run programming, or do you have to send a programming step to a third party? A line that programs, tests, and ages the same product has a shorter feedback loop than one that hands the firmware off to a separate shop.
The answers determine your industrial control products' field failure rate. A one-stop plant keeps the PCB build and the box-PC assembly on one process record, while a separate vendor leaves the PCBA history out of the box-PC record.
Whichever way you go, ask for the process record. A manufacturer with aging test, conformal coating process, and functional test capabilities can provide the record files.
Industrial Control Manufacturing at PCBONLINE
PCBONLINE provides industrial PCB manufacturing, PCB assembly, conformal coating, IC programming, aging testing, functional tests, and box-build assembly under one roof.
Where is our industrial control manufacturing? We operate PCB bases in Jiangsu and Jiangxi and a one-stop assembly factory in Shenzhen. Our Shenzhen turnkey PCBA factory runs four automatic SMT lines with post-placement and post-reflow 3D AOI, X-ray inspection, and a temperature- and humidity-controlled component warehouse with full barcode traceability.
Our services for industrial control projects. We offer free DFM, firmware programming, conformal coating, functional testing, burn-in, and box build. Engineering support runs through both prototype and volume production.
Quality system. We perform assembly and finished-product inspection to IPC-A-610 Class 3, and our factory holds ISO 9001, IATF 16949, RoHS, REACH, and UL certifications.
If you are taking a fanless box PC, edge computer, or controller all the way to a shipped product, PCBONLINE will be a reliable industrial control manufacturer for you. Send your Gerber and BOM to info@pcbonline.com, and we will come back with a quote, a lead time, and engineering feedback from a line that builds industrial products every day.
Below are a few industrial control PCBA and box-build projects we've made.
Automotive navigation module – 6-layer HDI PCBA with FPGA assembly, automotive-grade testing, and box-build integration.
AI camera device – Compact AI-powered camera with behavior recognition, achieving >95% accuracy and integrated into a robust enclosure.
EV charging station controller – From PCB fabrication to enclosure assembly and final product testing, delivered with industrial-grade quality.
Waterproof IoT devices – Using IPX8-rated enclosures and potting encapsulation to protect PCBAs for outdoor and smart city applications.
FAQs about Industrial Control
Q: What is an OEM industrial control manufacturer?An OEM industrial control manufacturer builds industrial control products from PCB fabrication through final product, including board assembly, firmware programming, conformal coating, functional testing, burn-in, and box build, often under the customer's brand.
Q: Why is burn-in important for industrial control products?Burn-in runs finished units under load at elevated temperature to force early component and solder joint failures to happen at the factory. That catches infant mortality that would otherwise show up during the first months on a customer's production line.
Q: What is conformal coating and why does an industrial PCB need it?Conformal coating is a protective layer sprayed over a PCB and baked to cure. It seals traces and components against moisture, dust, and corrosive gases in electrical cabinets, which is a common cause of field failure in industrial equipment.
Q: What is box build and why is it separate from PCB assembly?Box build is final assembly, where the PCB, heatsink, wiring harness, and I/O connectors go into the enclosure. It requires mechanical fit, cable routing, and thermal interface work that a PCB-only manufacturer does not do.
Q: Why test at board level and again after assembly?Board-level testing catches faults while they are still easy and cheap to rework. Final testing confirms the assembled product works as the customer will use it, including ports, power rails, and firmware boot.
PCB assembly at PCBONLINE.pdf
