Rice. 3. A one-piece, cup-fed, quick-change tool stored in the left cabinet controls equipment orientation and separation (ensures proper equipment alignment and positioning). The right cabinet holds various anvils and shuttles.
Ron Boggs, sales and service manager for Haeger North America, continues to receive similar calls from manufacturers during the recovery from the 2021 pandemic.
“They kept telling us, ‘Hey, we’re missing fasteners,’” Boggs said. “It turns out that this was due to a staffing issue.” When factories hired new employees, they often put inexperienced, unskilled people in front of machines to insert equipment. Sometimes they miss the clasps, sometimes they put in the wrong clasps. The client returns and finalizes the settings.
At a high level, hardware insertion appears to be a mature application of robotics. Eventually, a plant could have full punching and forming automation, including turrets, part removal, and maybe even robotic bending. All of these technologies then serve a large part of the manual installation sector. With all this in mind, why not put a robot in front of a machine to install equipment?
Over the past 20 years, Boggs has worked with many factories using robotic insertion equipment. More recently, he and his team, including Haeger Chief Engineer Sander van de Bor, have been working to make it easier to integrate cobots with the insertion process (see Figure 1).
However, both Boggs and VanderBose emphasize that focusing solely on robotics can sometimes overlook the larger problem of inserting hardware. Reliable, automated and flexible installation operations require many building blocks, including process consistency and flexibility.
The old man died horribly. Many people apply this adage to mechanical punch presses, but it also applies to presses with manual feed equipment, mainly because of its simplicity. The operator positions fasteners and parts on the bottom support before manually inserting them into the press. He pressed the pedal. The piercer descends, contacts the workpiece and creates pressure to insert the equipment. It’s pretty simple – until something goes wrong, of course.
“If the operator is not paying attention, the tool will fall and touch the workpiece without actually applying pressure,” said van de Bor. Why, what exactly? “The old equipment didn’t have feedback by mistake and the operator didn’t really know about it.” The operator could not keep his foot on the pedals during the entire cycle, which, in turn, could lead to the operation of the safety system of the press. “The top tool has six volts, the bottom tool is grounded, and the press must sense conductivity before it can build pressure.”
Older insert presses also lack the so-called “tonnage window”, which is the range of pressures within which the equipment can be correctly inserted. Modern presses may feel that this pressure is too low or too high. Because older presses don’t have a tonnage window, Boggs explained, operators sometimes adjust the pressure by adjusting a valve to fix the problem. “Some tune too high and some tune too low,” Boggs said. “Manual adjustment opens up a lot of versatility. If it’s too low, you’ve installed the hardware incorrectly.” “Excessive pressure can actually deform the part or the fastener itself.”
“Older machines also didn’t have meters,” adds van de Boer, “which could cause operators to lose fasteners.”
Inserting hardware manually may seem easy, but the process is hard to fix. To make matters worse, hardware operations often occur later in the value chain, after the gap has been filled and formed. Equipment problems can wreak havoc on powder coating and assembly, often because a conscientious and diligent operator makes small mistakes that turn into headaches.
Figure 1. The cobot shows the part by inserting the equipment into the press, which has four bowls and four independent shuttles that feed the equipment into the press. Image: Hagrid
Over the years, hardware insertion technology has solved these headaches by identifying and eliminating these sources of variability. Equipment installers shouldn’t be the source of so many problems just because they lose a bit of focus at the end of their shift.
The first step in automating fitting installation, bowl feeding (see fig. 2), eliminates the most tedious part of the process: manually grabbing and placing fittings on the workpiece. In a traditional top feed configuration, a cup feed press sends the fasteners down to a shuttle that feeds the hardware to the top tool. The operator places the workpiece on the lower tool (anvil) and presses the pedal. The punch is lowered using vacuum pressure to lift the hardware out of the shuttle, bringing the hardware close to the workpiece. The press applies pressure and the cycle is completed.
It seems simple, but if you dig deeper, you can find some subtle complexities. First, equipment must be fed into the workspace in a controlled manner. This is where the bootstrap tool comes into play. The tool consists of two components. One dedicated to positioning ensures that the equipment coming out of the bowl is positioned correctly. The other ensures proper segmentation, alignment and placement of equipment. From there, the equipment travels through a pipe to a shuttle that feeds the equipment to the top tool.
Here’s the complication: Autofeed tools—orientation and division tools, and shuttles—need to be replaced and maintained in working order every time the equipment is changed. Different forms of hardware affect how it supplies power to the work area, so hardware-specific tools are just a reality and cannot be designed out of the equation.
Since the operator in front of the cup press no longer spends time picking up (possibly lowering) and setting up the equipment, the time between inserts is drastically reduced. But with all these hardware-specific tools, the feed bowl also adds conversion capabilities. Tools for self-tightening nuts 832 are not suitable for nuts 632.
To replace the old two-piece bowl feeder, the operator must ensure that the orientation tool is properly aligned with the split tool. “They also had to check bowl vibration, air timing and hose placement,” Boggs said. “They have to check the shuttle and vacuum alignment. In short, the operator has to check a lot of alignments to make sure the tool works as it should.”
Sheet metal operators often have unique equipment requirements that may be due to access issues (inserting equipment into tight spaces), unusual equipment, or both. This type of installation uses a specially designed one piece tool. Based on this, says Boggs, an all-in-one tool for a standard cup press was eventually developed. The tool contains orientation and selection elements (see Fig. 3).
“It’s designed for quick changeovers,” says van de Boer. “All control parameters, including air and vibration, time and everything else, are controlled by the computer, so the operator does not need to make any switching or adjustments.”
With the help of dowels, everything stays in one line (see fig. 4). “The operator doesn’t have to worry about alignment when converting. It always levels out because everything locks into place,” Boggs said. “Tools are just screwed on.”
When an operator places a sheet on a hardware press, they line up the holes with an anvil designed to work with fasteners of a certain diameter. The fact that new diameters require new anvil tools has led to some difficult mass production over the years.
Imagine a factory with the latest cutting and bending technology, fast automatic tool change, small batches or even complete production. The part then goes into a hardware insert, and if the part requires a different kind of hardware, the operator moves on to mass production. For example, they can insert a batch of 50 pieces, change the anvils, and then insert the new hardware into the correct holes.
A hardware press with a turret changes the scene. Operators can now insert one type of equipment, rotate the turret, and open a color-coded container to accommodate another type of equipment, all in one setup (see Figure 5).
“Depending on the number of parts you have, you’re less likely to miss a hardware connection,” van de Bor said. “You do the whole section in one pass so you don’t miss a step at the end.”
The combination of cup feed and turret on an insert press can make kit handling a reality in the hardware department. In a typical installation, the manufacturer ensures that the bowl supply is exclusive to normal large equipment, and then places less frequently used equipment in color-coded containers near the work area. When operators pick up a part that requires multiple hardware, they start plugging it in by listening to the machine’s beep (indicating it’s time for new hardware), rotating the anvil turntable, viewing a 3D image of the part on the controller, and then inserting the next hardware part.
Imagine a scenario where an operator inserts one piece of equipment one by one, using auto feed and turning the anvil turntable as needed. It then stops after the top tool grabs the self-feeding fastener from the shuttle and drops onto the workpiece on the anvil. The controller will warn the operator that fasteners are the wrong length.
As Boggs explains, “In set-up mode, the press slowly lowers the slider and records its position. So when it is running at full speed and the fixture touches the tool, the system ensures that the length of the fixture matches the specified [[Tolerance] Measurements out of range, too long, or too short, will cause fastener length error This is due to fastener detection (no vacuum in the top tool, usually caused by hardware feed errors) and tonnage window monitoring and maintenance (instead of the operator manually adjusting a valve) creates a proven reliable automation system.
“Hardware presses with self-diagnosis can be a huge advantage for robotic modules,” said Boggs. “In an automated setup, the robot moves the paper to the right position and sends a signal to the press, essentially saying, ‘I’m in the right position, go ahead and start the press.’
The hardware press keeps the anvil pins (installed in holes in the sheet metal workpiece) clean. The vacuum in the upper punch is normal, which means there are fasteners. Knowing about all this, the press sent a signal to the bot.
As Boggs says, “The press machine basically looks at everything and says to the robot, ‘OK, I’m fine.’ It starts the stamping cycle, checking for the presence of fasteners and their correct length. If the cycle is complete, make sure the pressure used to insert the hardware is correct, then send a signal to the robot that the press cycle is complete. The robot receives this and knows everything is clean and can move the workpiece to the next hole. ”
All of these machine checks, originally intended for manual operators, effectively provide a good basis for further automation. Boggs and van de Boor describe further improvements such as certain designs that help prevent sheets from sticking to the anvil. “Sometimes fasteners stick after a stamping cycle,” Boggs said. “It’s an inherent problem when you’re compressing material. When it gets stuck in the bottom tool, the operator can usually turn the work piece a little to get it out.”
Figure 4. Shuttle bolt with dowel pin. Once set up, the shuttle feeds the equipment to the top tool, which uses vacuum pressure so that the equipment can be secured and transported to the workpiece. The anvil (bottom left) is located on one of the four turrets.
Unfortunately, robots do not have the skills of a human operator. “So now there are press designs that help remove workpieces, help push fasteners out of the tool, so there is no sticking after the press cycle.”
Some machines have different throat depths to help the robot maneuver the workpiece in and out of the work area. Presses can also include supports that help robots (and manual operators, for that matter) securely position their jobs.
Ultimately, reliability is key. Robots and cobots can be part of the answer, making them easier to integrate. “In the field of collaborative robots, vendors have made great strides in making it as easy as possible to integrate them with machines,” Boggs said, “and press manufacturers have done a lot of development work to ensure that the right communication protocol is in place.”
But stamping techniques and workshop techniques, including workpiece support, clear (and documented) work instructions, and proper training also play a role. Boggs added that he still receives calls about missing fasteners and other problems in the hardware department, many of which work with reliable but very old machines.
These machines may be reliable, but the installation of the equipment is not for the unskilled and unprofessional. Recall the machine that found the wrong length. This simple check prevents a small error from turning into a big problem.
Figure 5. This hardware press has a turntable with stop and four stations. The system also has a special anvil tool that helps the operator to reach hard-to-reach places. Here the fittings are inserted just below the back flange.
Tim Heston, Senior Editor of The FABRICATOR, has been in the metal fabrication industry since 1998, starting his career with the American Welding Society’s Welding Magazine. Since then, it has covered all metal fabrication processes from stamping, bending and cutting to grinding and polishing. He joined The FABRICATOR in October 2007.
FABRICATOR is North America’s leading steel fabrication and forming magazine. The magazine publishes news, technical articles and success stories that enable manufacturers to do their job more efficiently. FABRICATOR has been in the industry since 1970.
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