Safely Applying Robots to Arc Welding
How industry benefits from contributions made by the AWS D16 Committee on Robotics and Automatic Welding By DARREN PAPE, JEFF NORUK, AND VERN MANGOLD Darren Pape is chair, Jeff Noruk is second vice chair, and Vern Mangold is a member of the AWS D16 Committee on Robotics and Automatic Welding Reprinted with permission: The AWS Welding Journal To the uninitiated observer, the task of applying sophisticated servo axis robots to perform welding could appear to be quite simple and straightforward. One of the key attributes associated with robots is its ability to adapt to the environment based upon sensory input and the application of external stimuli. However, in the real world, robots do not operate entirely in a vacuum. Humans must occasionally be exposed to the operation zone and other associated hazards peripheral to the robots. Entering the robot’s operating zone can be dangerous or unsafe if not done in a controlled manner.
It is often said that a textured story such as the evolution of robot safety and arc welding should adhere to one overarching principle: Always begin at the beginning. In the beginning, it is important to agree on definitions. The definition of industrial robot popularly used in the U.S. industry for nearly 40 years can be abbreviated as follows: A robot is a mechanical manipulator or machine that has a minimum of 3 deg of mechanical freedom, computer control, some type of feedback positioning control, and the ability to operate autonomously.
The term robot is often used interchangeably in the expression robot system. Yet, the two terms are very different in their meaning and usage. This fact becomes more obvious after the most critical definition is considered at length.
The definition of safety, in the context of advanced material joining applications, describes a process or condition where human workers are protected from both known and unforeseen hazards including operation of machinery. This distinction is important because, contrary to conventional wisdom, there is no such thing as machine safety. In reality, there is only human safety. This distinction is important to understand in order to avoid a serious, lost-time injury. In addition, the robot can damage other equipment or the item being fabricated.
History Behind the AWS D16 Committee
In keeping with the long-standing tradition of the AWS, the organization issues a special call to maintain human safety. The prospects for the successful application of robotic arc welding technology became increasingly viable beginning with the 1980s as advancements in computer technology and servo feedback control introduced a new era of robotic arc welding in the United States.
In response to this burgeoning need, the AWS created a new technical committee dedicated to the advancement of robotic arc welding technology and named it D16. The D in the name signifies that the AWS considers the committee to be an industrial applications committee. The AWS Technical Activities Committee including D16 oversees the American National Standards Institute (ANSI) accredited procedures for all AWS technical standards.
For more than 30 years, the D16 Committee has been focused on the development, creation, and publication of recommended practices and standards that serve and promote the increased use of robot technology. All aspects of robot technology are addressed by the committee.
The Evolution of Robot Arc Welding Safety
To the outside observer, the current end product of the D16 Committee is a collection of documents comprising a suite of AWS standards. It would appear, without regard to the history of the industry, to be a very logical collection of documents. Although the current suite of documents could easily be considered obvious or intuitive today, in truth, the reality is different.
Prior to 1991, there were no AWS recommended practices nor standards for the use of robots performing any type of welding operation. More important than recommended practices, however, is the need for a robotic arc welding safety standard that could be developed to address unique and special circumstances associated with hazards created within a robot system to produce a welded component.
In addition, the only resources available to engineers performing their due diligence commitments were the general-purpose robot safety standard produced by the Robotic Industries Association (RIA) along with other ANSI standards, but these standards did not address specific welding safety considerations.
The only other nationally recognized robot safety standard in use within the United States during this time was a safety standard produced by Underwriters Laboratories carrying the designation of ANSI/UL 1740. The UL standard is less of an application standard and more of an electrical testing and validation standard. It can be said that the focus of UL standards is on the specific electrical aspects of robot safety. Specific programming issues and other electrical/electronic aspects of product design and testing in normal use are covered in the standard. But the UL 1740 provides no welding safety specific guidelines.
The ongoing professional disagreement within the robot industry concerns the use of safety standards that are general in nature vs. the use of standards developed with a narrow focus on the specific technology of a given robot application.
Creating AWS Standards
The D16 Committee has rededicated its efforts to producing tightly developed standards that are
focused on current robotic welding technologies. It is a long-held belief of the D16 Committee members that standards application specific in nature provide the highest degree of immediate benefit to users and stakeholders in the robotic arc welding process. General-purpose robot safety standards can be useful in understanding broad safety concepts, but the D16 Committee channels its attention to providing factual information that can be directly applied to specific robotic arc welding tasks and operations.
Standards developed and maintained by the D16 Committee today are as follows:
• D16.1M/D16.1, Specification for Robotic Arc Welding Safety
• D16.2M/D16.2, Guide for Components of Robotic and Automatic Arc Welding Installations
• D16.3M/D16.3, Risk Assessment Guide for Robotic Arc Welding
• D16.4M/D16.4, Specification for the Qualification of Robotic Arc Welding Personnel
• D16.5M/D16.5*, Training Guide for Robotic Arc Welding Personnel
• D16.6M/D16.6*, Specification for Robot Arc Welding Training and Testing Cell
* = Under development, not yet published.
Professional Robot Arc Welders: Trained to be Safe
The D16 Committee is working on the development of the D16.5 robot training standard. This training guide is unique in that it is also suitable, by deliberate design, to address the educational needs of the robotic arc welding community. It is anticipated that the D16.5 document will be published by early 2019.
Moving Ahead
In 1996, the AWS Technical Activities Committee provided a firm statement concerning the role of the D16 Committee within the AWS organization and its future activity with other AWS Technical Activities Committees.
The AWS Technical Activities Committee did not establish any type of timeline or schedule for the expansion of D16 activities, such as future additional advanced material joining processes. Since 1996, the D16 Committee has conducted numerous deliberations and discussions concerning the robot welding processes to be selected for expansion and their priority. As of date, the D16 Committee has established the following robot welding processes as candidates for future D16 expansion:
• Gas tungsten arc welding
• Resistance welding
• Laser welding
• Friction stir welding
The challenge for the D16 Committee going forward will be to attract new technical-content experts who can assist the development process for new standards. In addition, the D16 Committee will continue to nurture and support the ongoing development process. Great care must be exercised to ensure that the current Certified Robotic Arc Welding (CRAW) program thrives even with the work load imposed by the future expansion.
As previously stated in a D16 Committee update report prepared for the Technical Activities Committee last fall: The D16 Committee is currently very busy, and based upon the direction of the current committee leadership, it does not appear the D16 Committee has any intention of slowing down or avoiding any current or future obligations. 
