It goes without saying: Finding skilled machine operators isn’t getting any easier. Neither is manufacturing overall. Shops of all sizes and specialties face shorter lead times, tighter tolerances, tougher materials and increasing competition from low-labor-cost countries. The solution to some of these challenges is automation, followed by an ongoing need to improve efficiency through the adoption of new technologies.
Stamping Productivity had a recent opportunity to speak with Benjamin Richards, a design engineer at Greenerd Press & Machine Co., Nashua, N.H., a manufacturer of hydraulic press solutions for nearly 100 years. Richards is part of the team responsible for designing, programming, testing and servicing hydraulic press systems and works closely with customers on automation design and implementation. Here’s what he had to say.
Stamping Productivity: When should a company consider automation and, going further, lights-out manufacturing?
Benjamin Richards: Stamping companies and other manufacturers should consider lights-out manufacturing when they are having difficulty finding skilled labor or when a particular operation or process is unsafe for an operator to perform. Lights-out manufacturing also serves to reduce process cycle time and product waste, greatly increasing system output.
However, while automation is suitable for many industries, some applications just don’t fit well into a full lights-out system and may require some level of operator interaction, either with tool changeover or product manipulation. It’s for this reason that Greenerd works closely with our customers to analyze their processes and develop methods of incorporating aspects of lights-out manufacturing into our equipment.
For example, we designed a series of forming presses that use a shuttle table to transport finished parts out of the press area. Once free of the press, robots can take the parts and automatically load them into an oven for curing.
StP: What kinds of parts and quantities are best for automation?
Richards: The applications are basically limitless. Heavy, awkward or bulky parts that may be unsafe for an operator to handle alone can instead be manipulated with robots. Electronics and other fragile components that are easily damaged may also benefit from automated manufacturing techniques. And lights-out manufacturing can be beneficial for large parts and high quantities of items. Parts that require multiple orientation changes are a great application because it’s typically easier to achieve higher throughput than with a human operator.
In one recent case, Greenerd developed a system that required a vision sensor to determine the orientation of parts placed at a pre-determined drop location. The system takes an image of the part stack and processes it in the press PLC. A robot automatically positions its end-of-arm tooling (EOAT) in the right orientation to securely pick up the part. The same sensor then confirms that the part is properly nested in the tooling before proceeding, after which a robot passes it over an ultrasonic sensor to measure the part thickness and check for double-stacked parts.
StP: What kinds of tooling and material handling do you typically recommend?
Richards: Tooling and material handling equipment selections are often dictated by the parts they must handle. For instance, vacuum grippers may work well for large, flat parts but can struggle to manipulate complicated geometries or porous materials. Grippers are an option when the parts being handled are not at risk of damage from the actuator’s high gripping forces. Either way, special features can be designed into the tooling to ensure proper journaling and nesting of parts. Doing so can help to keep parts secure while robots and other equipment maneuver about the system.
StP: How is remote monitoring and control achieved?
Richards: Remote monitoring can be achieved through a managed ethernet switch and the machine’s PLC, with industrial equipment placed on a machine-specific network separate from the rest of the business. This allows maintenance personnel to collect data without risking the security of the business network. Similarly, manufacturers can use Supervisory Control and Data Acquisition (SCADA) systems to monitor and analyze industrial equipment. These systems can look at trends in the data, and if at any point the data is outside a particular threshold, signal the operators that maintenance might be needed.
It’s also possible to analyze historical data to identify operating trends and overall productivity. Greenerd has worked with customers that have these systems, and we have used them to troubleshoot our equipment remotely. In one such instance, we received a call from a customer stating that their press had started producing an increased number of rejected parts. They showed us the trend data they collected, pointing exactly to when and how the equipment began behaving differently.
This capability allowed us to quickly narrow down the problem and identify exactly which valves on the machine needed replacement. Greenerd takes pride in providing these types of post-installation services, which are especially important in a lights-out or highly automated manufacturing environment.
StP: Do you have any recommendations for quick-change technology?
Richards: Several technologies are available to reduce changeover times. For robots, EOAT quick-change mechanisms can be installed on both the robot arm and the EOAT, which allow the robot to swap tools automatically. These devices can often secure air and electrical connections, requiring no outside operator assistance. Greenerd works with customers to analyze their processes and identify ways to reduce tooling changeover times.
One design used quick-change technology to quickly swap the EOAT on a robot in a production cell. The tooling was placed on a die cart by the operator and slid into the system where the robot could reach it. Once ready, the robot went over to the cart and swapped tooling, automatically making the needed electrical and pneumatic connections without any additional operator interaction.
StP: How is product quality ensured in a lights-out environment?
Richards: Both contact and non-contact/visual measurement devices can help to ensure product quality in these applications. Contact methods can include cylinders or digital sensors that touch off on part faces to record their measurements while laser sensors and camera systems are two examples of non-contact measurement devices. Contact methods are good choices where physical contact with the probe will not alter the objects being measured or where the lighting in the work environment is poor.
If parts are small or fragile, then vision systems can be used to avoid damage. Vision systems are also useful when it is necessary to inspect the color or pattern of a part. Data collected by these systems can be stored in the machine’s PLC, which can help troubleshoot exactly when and where a system error may have occurred if there is an increase in the number of rejected parts.
One Greenerd project uses a camera system to monitor the temperature of a part in a mold. Once the camera determines that the part has reached the desired temperature, the press automatically opens, allowing the part to be removed and prepped for the next operation. The insertion of a bearing into a housing is another example of an application that can be monitored in a lights-out system. A linear transducer can be used to record the distance of the bearing while monitoring pressure until a set value has been reached, confirming proper tonnage for the operation.
StP: Do you have any additional customer success stories?
Richards: Greenerd has worked with many customers to incorporate robots into their press systems when it became necessary to run a complex operation with a limited number of operators. One such example used multiple robots and a 7-axis gantry to transfer parts down a press line to various stations that performed different operations on the parts. This automation cell enabled the customer to produce the same output level with 75 percent less labor.
Greenerd has also had success incorporating conveyors and shuttle systems into our presses, even going so far as to design our own conveyor systems, ensuring accurate positioning and alignment of parts for a punching application. Here, sensors and transducers monitor the press status and movement of the parts. This monitoring enables the machine to stay in operation longer, increasing the output of the system and improving customer productivity.
StP: Are there any other important points you’d like to mention?
Richards: A variety of applications and products that can benefit from a lights-out manufacturing method exist, each one unique in some way. Because of this, Greenerd takes a very customer-centered approach, working with our customers to tailor our abilities to their specific applications and needs. Having conversations about their process and learning how it works allows us to make the proper design choices that will lead to a successful project.
What is right for one customer may not be the right solution for another with a similar product; it’s all about finding the right balance for that particular customer. As markets have grown and the push for lights-out manufacturing grows stronger, customers come to us with more and more requests for automation systems to incorporate into hydraulic press designs. As a Fanuc Tier 1 authorized integrator, we can develop material handling methods for our designs and provide our customers with full turnkey systems, ensuring successful completion of their projects.
