PCB Assembly Robot Cells: Solder Iron to ABB SCARA

Almost every electronic product starts as a bare circuit board, and the PCB assembly robot is now the main way components get onto it. Placing tiny resistors and chips has been automated for decades. The steps around it, such as fitting connectors, pressing boards into housings, soldering odd parts and driving screws, often still need people. This post follows the job from hand soldering and the first printed circuits, through wave soldering and surface mount pick-and-place machines, to final assembly cells built with ABB robots such as the IRB 910SC and IRB 930 SCARA arms and the YuMi cobot.

A through-hole circuit board from a Revox B215 cassette deck, with capacitors and chips soldered in place. Photo: Retired electrician / Wikimedia Commons (CC0)

From hand-wired radios to the pick-and-place machine

Early radios and instruments were wired by hand. Workers mounted parts on a metal chassis and ran wires point to point between them, soldering every joint with an iron. It was slow, and each set depended on the skill of the person at the bench. The Austrian engineer Paul Eisler, working in London, built a radio on a printed circuit around 1936, with copper tracks etched onto a board in place of loose wires. Printed circuits went into mass production during the Second World War, in proximity fuzes for anti-aircraft shells, where they had to survive being fired from a gun.

Soldering electrical wiring by hand at Douglas Aircraft, Long Beach, California, October 1942. Photo: Alfred T. Palmer / Library of Congress via Wikimedia Commons (public domain)

The first big automation step came from the US Army Signal Corps. In 1949 Moe Abramson and Stanislaus Danko developed a process called Auto-Sembly, in which component leads were pushed through holes in a copper foil pattern and the whole board was dipped in molten solder at once. Wave soldering machines, which run boards over a standing wave of solder, refined the idea in the following decades, and insertion machines learned to push through-hole parts into boards. Hand soldering moved to repairs and the parts that machines could not handle.

A Seho wave soldering machine, which runs boards over a wave of molten solder. Photo: Pedro ximenez / Wikimedia Commons (CC BY-SA 2.0 DE)

Surface mount technology changed the job again from the 1980s. Components shrank and were soldered onto pads on the surface instead of through holes, which made them too small for fingers. Pick-and-place machines, in effect specialised gantry robots, took over. They pull parts from reels of tape on feeders, check them with cameras and place them with vacuum nozzles at rates of thousands per hour, before the board goes through a reflow oven. On a modern SMT line very few components are placed by hand, but the line ends where the boards leave the oven.

Inside a Juki pick-and-place machine: the placement head moves over rows of tape feeders. Photo: Peripitus / Wikimedia Commons (CC BY-SA 3.0)

Final assembly cells with SCARA and YuMi

Robot numbers keep climbing. On 24 September 2026 the International Federation of Robotics reported that 5 million industrial robots are now working in factories worldwide, after more than 600,000 were installed in 2025. In India, where electronics output is expanding, the Hindustan Times ran a piece in September on building a home-grown robotic soldering system, and Pune-based SlightGen Solutions makes one for through-hole PCB soldering. It is aimed at small manufacturers who find imported machines from Japan, China and Korea too expensive, since through-hole parts still need soldering after the SMT line.

A NeoDen SMT pick-and-place machine on a production line stand at Electronica India in Bangalore, September 2025. Photo: Gpkp / Wikimedia Commons (CC BY-SA 4.0)

After the SMT line, boards need connectors and cables plugged in, shields fitted, screws driven, and the finished unit tested and packed. The parts change with every product and are often handled by people at benches. ABB built YuMi for this kind of work. The dual arm IRB 14000 was launched in 2015 for small parts assembly in electronics and can work beside people without a fence, for example holding a housing in one hand while the other clips in a board. The single arm YuMi IRB 14050 fits tighter stations, and ABB's PickMaster vision software helps robots find parts that arrive loose.

ABB YuMi assembling small parts beside a lab worker. Photo: ABB

ABB's first SCARA robot, the IRB 910SC, came out in 2016 with a payload of up to 6 kg and reaches of 450, 550 and 650 mm, for small parts assembly, component placement and tray kitting. In late 2023 ABB added the IRB 930, aimed at consumer electronics, automotive electronics, EV battery cells and solar panels. It handles 12 or 22 kg and can press down with up to 250 N, enough for press fits and screwdriving, with a cycle time of 0.38 seconds on ABB's OmniCore controller. Cells like these are usually laid out and checked first in RobotStudio.

An engineer with an ABB IRB 930 SCARA robot, launched in 2023 for electronics and battery assembly. Photo: ABB

Where electronics assembly robots go next

The hardest remaining work is anything soft or flexible: ribbon cables, wire harnesses, flexible circuits and connectors that have to be felt clicking into place. Force sensing and AI vision are making progress here, but each product still needs careful engineering, as we saw in our post on wire harness assembly. Larger plants are already automating whole lines. ABB uses robots on its own production, for example the switchgear assembly line that JOT Automation built for ABB Smart Power in Vaasa, Finland, which builds its next generation of switching products.

Close-up of an ABB robot picking parts in a switchgear assembly cell. Photo: ABB

Cost is the other limit. Electronics models change every year or two, so a cell has to be retaught quickly, and many plants that assemble small batches cannot justify a robot for each step. Shorter teaching time, through tools such as ABB's Wizard easy programming for YuMi and GoFa, is one way to close that gap. Skills are a third problem. Someone on site has to understand vision calibration, force limits and the quirks of a connector that sometimes jams, and that know-how takes time to build on every new line.

A Juki KE-2080L surface mount placement machine with component reels at Megger's plant in Dover, 2008. Photo: Megger Ltd. / Wikimedia Commons (CC BY 3.0)

Over the next few years the likely pattern is more reshoring and more mixed lines, where the SMT line runs unattended and SCARA and cobot stations handle final assembly, test and packing. For people at home, the effect shows up in the products. Boards assembled and tested by robots are more consistent, and the same cells could also handle disassembly and repair if products are designed for it. For engineers and students, final assembly is a good place to start, because it combines vision, force control and fast motion in one small cell.

A worker at an electronics assembly line. Photo: Bananovaya / Wikimedia Commons (CC BY-SA 4.0)

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