The electrification and automation of manufacturing have realized tremendous benefits in efficiency and productivity. Where humans once engaged in labor-intensive manual tasks, cyber-physical systems such as robots now ply their craft. These systems still need to coexist harmoniously with humans who occupy other tasks in the manufacturing space, such as the maintenance of automated equipment. Therefore, discussions regarding machine safety go together with discussions of machine availability and productivity.

Risk Factors

There are two major sources of injury risk when working with industrial machinery and control systems: electrocution and thermal injuries. These may be due to contact with energized control panels and crushing trauma from contact with the equipment’s automated mechanical systems.

One of the key concerns in working with control panels is incidents of arc flash. When enough electrical energy exists in the system and there is low enough impedance between the circuit and ground it allows the energy to discharge over the open air (like lightning). This can occur through the simple act of opening the enclosure door if the system is not sufficiently de-energized. With arc flash, air temperatures rise instantly to over 30,000°F resulting in first, second and third degree burns to exposed tissue. Additionally, the arc flash is often accompanied by an arc blast which results in a pressure wave containing molten metal and shrapnel projected away from the panel. In 2017 alone, OSHA documented 26 incidents of electric arc injuries with one fatality. The slow-motion gif in Figure 1 illustrates the danger to personnel from arc flash.

Arc flash accident

With the increasing use of robots, Automated Guided Vehicles (AGVs) and other automated mechanical systems in factories, a significant risk of physical trauma exists if thorough safety procedures are not observed. From 2015-2017, OSHA documented eight incidents of robot-specific injuries with three fatalities. One of the better-documented cases was the fatal accident involving 20-year old Regina Elsea at Korean automobile parts manufacturer Ajin USA’s plant in Cusseta, AL (full story). Ms. Elsea moved inside the machine guarding to troubleshoot a fault on a robot and was crushed when the robot restarted abruptly. This resulted in her tragic death and a $2.5M fine issued by OSHA against Ajin for safety violations.

In dealing with potential injuries from control panels and automated machinery, there are documented methods for protecting worker safety. This is contingent on personnel following these procedures. Most of industrial accidents are attributed to some form of human error, often from poor training or prioritizing productivity over personal safety.

Mitigating Risk

The simplest way to reduce the number of safety incidents is to reduce the number of people who physically interact with equipment or work in active production areas. For the sake of this discussion, we will focus on reducing the risk involved in servicing equipment.

With industrial machinery, there is various service personnel responsible for making sure the equipment runs to specification. Sound lockout/tag out procedures will always need to be followed to allow electrical and mechanical personnel to safely work on equipment, but significant risk can be eliminated by moving programmers and engineers responsible for maintaining the intelligent portion of machine controls safely away from the equipment. This is particularly true with 3rd party service personnel who may not be as well trained on plant safety procedures as internal personnel.

This can be achieved using devices that create connectivity into machine networks and industrial Ethernet, in its many flavors, has become the primary network used for machine control. This opens the possibility of using 802.11 wireless technology to create a physical separation of personnel from equipment.

Wireless Connectivity

There are various devices to connect machines to plant-level wireless LANs, but often time the simplest solution is to create the wireless network on the machine itself. Think of it as a Machine Area Network. The device on the machine would act as a wireless “lite” access point and allow access to programming interfaces within proximity. Personnel is mobile enough to stay clear of electromechanical components while still maintaining an eyes-on-machine approach to see how software changes affect performance.

Additionally, one can take the approach of removing programmers from the plant floor completely forcing software changes to be made remotely to protect their personal safety. The key to achieving this is getting machine-level networks connected to internet-connected networks that allow programmers to access the devices on the machine from various locations.

With remote connectivity, creating secure connections to machinery is the key consideration as open networks can allow bad actors to create unsafe machine conditions. VPNs can be employed to provide secure connections for internal personnel, but this becomes challenging when 3rd party contractors are needed to support equipment. Using remote access appliances that employ high levels of encryption, device and user authentication provide the right combination of security and availability for service personnel.

Whether local or remote, networked machinery makes it easier to service effectively and maintain worker safety. Learn more about the products that can help you maintain your safety: