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What is a soldering robot? What are the benefits and future challenges of automation?

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June 26, 2023
Soldering Robot Automation

What is a soldering robot? The benefits and future challenges of automation.

Table of Contents

Soldering Robot for Automated Soldering Work

A soldering robot is a type of industrial robot that performs soldering work. It belongs to the category of automatic assembly machines and performs soldering work automatically, replacing humans.

The first appearance of soldering robots can be traced back to the 1970s when industrial robots such as those used in automobile assembly, welding, and painting were introduced, establishing the category of industrial robots. Initially, these robots had a soldering iron attached to the end of their arm, but their precision was not sufficient at that time. Even after the introduction of soldering robots, soldering remained primarily a skilled craftsmanship performed by experienced workers.

However, with technological advancements, the precision of soldering robots has improved. In addition, the transition to lead-free soldering since the 2000s has increased the difficulty of soldering. Furthermore, factors such as the increasing complexity of circuit board designs, labor shortages, and the challenge of knowledge transfer have contributed to the widespread adoption of soldering robots.

The significant difference between humans and robots lies in the time required to master the skills. Skilled human soldering operators can make fine adjustments based on their senses, making them suitable for soldering delicate components. However, achieving that level of skill requires a considerable amount of training over a certain period of time.

Modern robots, on the other hand, can start operating immediately after initial setup and are capable of soldering at a higher speed than humans from the day of their introduction.

Differences between Automated Soldering Equipment and Soldering Robots

There are two main methods for automating soldering: “automated soldering equipment,” which efficiently performs soldering in batches, and “soldering robots,” which perform precise and detailed soldering. Each has its strengths and weaknesses, so they are used selectively in production lines according to specific requirements.

Automated Soldering Equipment

Automated soldering equipment is a suitable method for mass-producing the same item efficiently. There are two methods: the “flow method,” which involves applying pre-melted solder to the soldering area for joining, and the “reflow method,” which involves applying solder paste to the soldering area, placing the components, and then melting the solder through heat for joining.

Both methods are used when efficient soldering of electronic components onto a circuit board in bulk is desired. However, the flow method is not suitable for fine soldering in densely packed areas, while the reflow method cannot be used for soldering heat-sensitive components.

Soldering Robots

Soldering robots are not as efficient as automated soldering equipment, but they are suitable for the production of various product varieties. They excel at selective soldering, soldering of heat-sensitive components, and precise and detailed soldering. Their strength lies in the ability to perform these tasks accurately and repeatedly.

Advantages of Soldering Robots

Soldering robots have three main advantages: “reproducibility of repetitive soldering operations,” “stabilization (quantification) of quality,” and “visualization of data.”

For example, in the case of Japan Unix’s soldering robots, the soldering position is adjusted with a correction accuracy of ±0.05mm using a soldering iron tip position correction mechanism, ensuring high reproducibility. Furthermore, by setting optimal conditions for up to 255 items, such as solder feed rate, speed, and approach for raising and lowering, they achieve stability in soldering quality.

Additionally, various log data can be stored, ensuring traceability of the production process. It is possible to monitor soldering temperatures, set counters, save and view error histories, and manage QR codes.

By introducing

soldering robots, soldering can be performed with high speed and accuracy compared to when the same task is carried out by humans, which is the advantage of using soldering robots.

Challenges for Soldering Robots

Soldering robots struggle with tasks such as “soldering in extremely narrow areas,” products like harnesses where “fixing with jigs is difficult,” soldering “components with varying shapes and sizes,” and “soldering for high-mix, low-volume products” that require frequent fixture changes and cannot have a standardized soldering iron tip.

For these types of soldering tasks, skilled human operators are more suitable, and currently, not all soldering work can be replaced by robots. While there have been significant advancements in technology, it still takes time to fully replicate the skills of skilled human workers.

History of Soldering Robots

Soldering, being a skill that requires hand dexterity, visual judgment, sense of smell, sound differentiation, and comprehensive mental judgment, took some time for its automation compared to the emergence of general industrial robots.

Japan Unix, in collaboration with an automatic machine manufacturer, developed the first soldering robot that aimed to replicate “human hand movements” in the early 1980s. By 1983, they began supplying full-fledged soldering robots.

In 1985, the vertical multiple-joint 5-axis soldering robot “UNIX-511” was completed. Since then, research and development have been ongoing to improve performance, including repeatability, operation speed, and external input/output capabilities, leading to the present day.

Previously, soldering robots were considered as a “replacement for simple tasks performed by humans,” but with a decline in skilled soldering workers, the user needs have shifted to “using robots to handle tasks that are difficult for humans.”

Types of Soldering Robots Based on Structure

“Vertical multi-joint type (5-axis, 6-axis)”
A versatile type capable of handling three-dimensional work

“Cylindrical coordinate type (scalar multi-type)”
High-speed with good planar accuracy

“Orthogonal desktop type (4-axis)”
No need for line configuration, easy to introduce

“Orthogonal type (4-axis in-line type)”
Good planar accuracy, ideal for flat boards

Demands for Future Soldering Robots

Currently, the manufacturing industry faces various challenges such as labor shortages, skill transfer, delayed IT utilization, and the transition to forms aligned with carbon neutrality and SDGs. Soldering robots are expected to address these challenges. When considering future soldering robots, the following four perspectives are particularly important:

Addressing Labor Shortages

The introduction of soldering robots helps alleviate labor shortages, but it also introduces the need for robot maintenance. Currently, tasks such as cleaning and replacement due to dirt from flux (soldering flux) or wear and tear caused by production require human intervention. In the future, there will be a demand for reproducible functions and methods to automate maintenance.

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Further Visualization of Soldering Processes

To optimize and improve production efficiency and enable manufacturing with fewer workers, it is essential to collect various data and “visualize” the manufacturing floor through digital transformation (DX). When considering DX, soldering robots require the ability to break down soldering processes, which skilled workers perform, into reproducible and quantifiable functions. In the future, there will be a demand for functions that enable anyone to improve quality, production speed, and prevent/troubleshoot issues that were previously supported by skilled production managers and maintenance personnel.

Adapting to High-Mix Low-Volume and Variable Production

In the future, products in various industries are expected to be individually optimized according to customer needs, leading to further high-mix, low-volume production lines. Therefore, soldering robots also need to be more flexible in terms of line configuration. There will be a need for multi-variety support, simplified switching, and automation.

Approaching CO2 Reduction Goals

Consideration for the environment and SDGs has become common sense throughout the manufacturing industry. Governments and major manufacturers in various countries have begun setting CO2 reduction goals and taking actions at the factory level to achieve these goals. In this context, there will be increasing demand for soldering robots that utilize the required selective heat capacity, thereby avoiding unnecessary power consumption.

The Evolution of Soldering Robots Will Continue

Soldering robots, which were born in the late 20th century, have undergone remarkable evolution through continuous development and improvement. However, they are still unable to replace human workers in performing all soldering tasks because they lack the sensory abilities (vision, smell, hearing, touch) and cognitive capabilities of humans. While sensing capabilities have significantly improved, there is still a long way to go to reach the level of skilled workers. It is anticipated that there will be further advancements in the basic improvement of robot hardware, soldering functions, and software in the future.