Advantages of a Robotic PCB Assembly Process

Robotic process automation (RPA) combines AI with machine learning to produce a large volume of repetitive work with minimal human involvement. For example, you can program smart-connected machines to capture and understand data from current operations, manipulate them, generate responses, and communicate with various digital systems to increase operational accuracy and productivity. In this regard, a robotic PCB assembly also offers numerous advantages to the enterprise. It enables ODMs and OEMs to achieve better ROI while ensuring quality PCBA by CMs. Let’s examine some of the important phases of the assembly process to gain a better understanding of these advantages.

Cutting Edge Benefits of a Robotic PCB Assembly Process

Easy Traceability Through Laser Marking

A fully automated laser marking machine marks a unique serial number on each board for easy tracing. This robotic setup wins over traditional silk screen printing technology in high processing accuracy, high abrasion resistance, fast operation, and non-destructive marking. The fully automated process lowers the cost of labeling and saves time with built-in marking templates, real-time monitoring, auto barcode readability, and auto-alignment during batch labeling.

Highly Accurate Solder Pasting

Top manufacturers can even add an automatic solder paste printer for a larger stencil or PCB. This fully automatic setup collects the board from the loader, prints solder paste onto the pad at a programmable speed, and transfers them to the next process cycle without any manual intervention. Manual PCB assembly involves applying solder paste onto pins via syringe. It takes time to complete soldering components for bulk orders. Alternatively, automatic PCB assembly uses a stencil or jet printing to achieve an even application of paste that typically takes 15 to 45 seconds to complete per board.

Reduced Solder Defects

The Solder Paste Inspection (SPI) machine verifies the quality of solder placement and gives immediate printing feedback that may require fast corrective actions. Because it identifies any solder defects early, manufacturers have time to address mask alignment, impurity, bridging, or displacement issues before component placement. The solder paste printing process accounts for the majority of assembly defects. As SPI enables manufacturers to fix solder defects early in the production line, the process avoids material wastage, extra expenditure, and excessive downtime.

Improved Throughput by Pick and Place Machines

The automatic assembly process employs pick and place robots to achieve speed and consistency while keeping placement errors at bay. These robots can achieve throughputs of up to 200 products per minute. The advanced vision system can identify 100 components per second. In short, they can move products through the process much faster than manual options. With improved assembly efficiency and zero downtime on errors, manufacturers achieve increased ROI, and designers experience faster turnarounds. Pick and place machines are automatically programmed for efficiency and accuracy. Each build uses placement and component data pulled directly from the original design files. The overall process connects upstream and downstream through a single thread.

Fast and Accurate Optical Inspection

An automated PCB assembly uses Automated Optical Inspection (AOI) to identify minute board defects that are hard to notice with the naked eye. The machine utilizes photogrammetry for high-resolution, high-precision calculations of component height. Consequently, flaws like tilted components, uneven soldering, tombstones, and missing components are easily discoverable. The software converts 2D images into a 3D view and measures the IC planar graphs to detect components that are not making contact with the board. At Tempo Automation, we use the Mirtec MV-6 Omni to capture distortion-free orthographic views of components and detect board anomalies before final assembly.

Clear Visibility Through Large Components

For leadless component packages and large BGA components, manufacturers must check that the pins are inserted into layers correctly. This process requires an X-ray inspection to detect hidden assembly defects. It cannot read front-to-back orientations like AOI machines, but the translucent grayscale images of the X-ray machine can detect the following:

• Soldering defects: solder bridges, open circuits, voids, solder quality, excess solder application
• Component defects: lifted leads, component issues (faulty/missing/misaligned)
• CSP and BGA defects

The benefits of automatic premium X-ray inspection include:

• Automated component inspection
• Multiple board inspections in one go
• Quick deployment of new product lines within minutes

Tempo has integrated the Nikon XT V 160 X-ray machine into its production line assembly to achieve rapid turnarounds while still maintaining quality.

Better Approach to PCB Cleaning

Boards are prone to ionic contamination during the assembly process, which often leads to inaccuracy. They can catch ethanolamines from etching or as flux residue from the soldering process. Rosin and rosin substitute fluxes can also form ionic residue by contacting atmospheric moisture. These ionic contaminants can give rise to dendrites and electrochemical migration, leading to inaccuracy in board performance.

Manual cleaning with chemical solvents or water-based cleaners is a labor-intensive process; however, for an automated PCB assembly, several cleaning processes are available, such as ultrasonic, vapor degreaser, batch flux removal, and inline flux removal.

These processes ensure that boards are free from any moisture and ionic contaminations that fall outside the range of human detection. Thus, manufacturers save time on costly reworks and produce the best quality output for bespoke performance.

Robotic PCB assembly does come with a few shortcomings, though. It involves a high initial cost and takes time to set up. Because the components are small, expert hands are required to perform even the most minor manual jobs. Therefore, the manufacturer must operate through an agile process to identify and resolve quality issues before they happen.