Grinding machines get upgraded

Rollomatic's GrindSmart 660XW is a 6-axis tool and peel grinding machine that performs blank preparation for common-shank rotary cutting tools, neck grinding for long-reach mold and die end mills, and plunge grinding operations in addition to grinding the cutting geometry. Rollomatic

Over the past few years many machine shops have been suffering from labour shortages. Some argue that young people are not choosing manufacturing jobs because they are unaware of what the career path offers. Others say that processes like grinding seem like black magic and complicated, while some believe it's because manufacturing is considered a dirty job.

It's true that many young people don't know about the many rewarding careers available in the manufacturing industry. But the other assumptions are nothing but a bad rap. Many of today's shops are extremely clean with the latest equipment that shortens the learning curve and makes operations smooth and efficient. Grinding technology has recently undergone significant upgrades and advancements to increase flexibility, productivity, and ease of use.

Here are five ways in which grinding machines are improving.

Shop floor space can be at a premium. The latest grinding machines take this into account with smaller footprints.

"More and more customers are asking for a smaller footprint machine because real estate is very valuable," said Simon Manns, vice-president, tool division, United Grinding North America, Miamisburg, Ohio. "The more machines they can get on the floor up and running, the more spindles are turning, and the more money they make."

One way this is done is through a vertical configuration, meaning the platform footprint can be much more compact than older models.

"With the platform designed vertically, the robot system and machine grinding area are located on one side, and then the wheel changer on the other side," said Eric Schwarzenbach, president, Rollomatic Inc., Mundelein, Ill. "Stacking features and components in a vertical arrangement saves space. This is great for small shops that don't have capital to invest in expanding infrastructure, or even larger companies that want to add several machines into the space without having to rebuild or extend the building."

Some grinding machine models can be both scalable and modular. Shops that are looking for flexibility can buy a basic machine and pick and choose the options that are available.

"The benefit of this is that an existing machine can be retrofitted on the shop floor at a later date of choice," said Schwarzenbach. "For small shops, they can start with a basic system that is hand-loaded. The shop can make money and then invest that money in additional features like a robot to allow for unattended operations, upgrade the wheel changer from four to eight or 12 stations, or put in a cassette changer. A scalable machine can allow shops to grow the equipment with the needs of the company."

Other major machine enhancements include changes to the motor system. Many of today's grinding machines have switched over to linear motors instead of drivetrain. This new advancement allows for better surface finishing, extended longevity of the slide system, better acceleration and deceleration, and faster speeds.

United Grinding's flexLoad is a fully enclosed and integrated part-loading system for many OD and ID grinding machines. United Grinding

Grinding machines are expanding to incorporate additional operations. Some of the latest models combine several grinding functions, while others incorporate secondary operations like milling, as well as ancillary processes. Any of those configurations can help increase flexibility and reduce cycle time.

"One of the latest hybrid models combines peel and tool grinding," said Schwarzenbach. "If you have an end mill with a neck, a long-reach end mill, or mold end mill with the same long neck, you can produce that from solid rod in one setup on one machine. This is definitely something new we are seeing in the industry."

A system like this requires a steady rest to support the tool during grinding and allow three operations to be performed in one chucking. The first operation plunges the end mill diameter. In the second operation, geometry grinding or tool grinding produces the flutes, and the third operation grinds the neck. A hybrid machine with different grinding operations allows shops to perform back tapering of the drill, flute grinding, and point grinding all in one chucking.

"We’re seeing a move in profile grinding that leads us towards what milling machines have been delivering for years," said Larry Marchand, vice-president, profile division, United Grinding North America. "The more value-added operations you can complete in a single trip inside the machine, the better. The addition of secondary operations (like mill, drill, deburr, and polish) is something we are seeing more and more. On one of our newer models we can complete a variety of non-grinding operations that were not feasible before automatic tool changing was adapted to profile grinders."

A hybrid system like this is beneficial for customers that are working on parts that require mostly grinding but may have one or two features, like a couple of holes, slots, or grooves, that they can now mill directly on the grinding machine. This eliminates the need to take the part to a new machine for secondary operations. In a lot of ways, it's a very complementary technology.

"If you have a part and it takes four operations, that's four machines or four setups, four times the operator has to load and unload the part and put it in the next machine," said Manns. "The ability to combine operations is probably No. 1 for productivity. The next wave we are seeing will also combine grinding with auxiliary operations. A grinding machine can include something like a cleaning station that cleans the tool after grinding, or even a coat tray that the tool can go into, where a robot can then take it out and move it somewhere for coating."

With newer models, shops are also getting the latest controls. With the advent of 3D software, which requires a lot of powerful rendering, machines with basic controls were unable to keep up with the latest technology.

"The new controls allow shops to use the latest 3D software," said Manns. "Also, with an older control, there were many cables and wires to deal with. New controls—while more powerful—are simpler in the way they are connected, but you are getting a lot more capability and better connectivity to networks."

Many of the latest control panels are designed with ease of use in mind. Younger generations are used to working on smartphones with touchscreens, and panels with similar features are more accessible for a new generation of workers.

"Built into our panel is a camera so we can do videoconferencing with the operator on the machine for troubleshooting," said Manns. "It's all about support and being able to access the machine remotely and get the customer back up and running if there is a problem. With the latest software and new panel, shops can expect more functionality, but also it makes the learning curve less challenging as you can get new operators up to speed running the machine more quickly."

Rollomatic's 6-axis tool grinder includes shank guidance and steady rest. Rollomatic

The user interface allows for a better, easier way to train operators, because many shops don't have expert grinding engineers, or the grinding knowledge is no longer available. The user interface, control software, and grinding software work together as a teaching tool.

One of the driving forces behind the need for automation is not just the lack of operators, but also that current operators don't want to constantly stand in front of a machine to perform periodic checks anymore.

"Whether it's a small job shop or a large production company, many shops are looking to invest in lights-out or various unattended operations," said Schwarzenbach. "Grinding machines need to be able to be autonomous, and that includes adding robots, but also measuring inside that machine to allow for automatic adjustments. This is very important for any shop to run lights-out."

Automation today can range from small collaborative robot systems used for loading/unloading to robotic cells that tend machines. With grinding machines, there are a few areas where automation makes sense. Shops can look to automate around the cutting tools, but also automatically load the machine.

"Automation could be in the form of transfer stations, conveyors, or systems to automate the upstream and downstream processes," said Simon Bramhall, general manager, engineering and project management, United Grinding North America. "We have focused on two standard loaders, the latest of which has really been designed to help shops that are having difficulty finding operators to tend the machine. It's going to sit in front of many of our models and will almost duplicate what a human will do—opening the door on the machines, putting the part in, and creating the cycle start function. It's a very versatile unit with very quick changeover."

Robots can be applied to various aspects of the grinding process. Robots on wheels can move to the grinding machine to change tool cassettes and move the processed parts to another machine, cleaning stations, laser marking, or tubing station where the parts are then put into tubes.

"Robots that can load cassettes just make sense," said Schwarzenbach. "The robot is able to take the blank out of the box, look at each end, and identify the one with the chamfer. This is important because with this information, the robot can then put the correct end into the cassette."

Grinding machine manufacturers today are developing various automation and robotic systems specifically designed to handle grinding applications.

"When we were designing our system, we really wanted to make sure it was the right robot for the right project," said Bramhall. "The robot could be used to go inside a grinding machine, which could have coolant dripping or have oil or emulsion come in contact with it. We are aware of all the challenges and considerations of having a robot go inside a grinding machine, so we always make sure it has that durability."

Grinding is still seen by many as an art. It's not something that can be fully understood by simply reading a book or watching a YouTube video—it takes practice.

The Studer LaserControl enables contact-free laser measurement of small to large workpiece diameters, as well as interrupted diameters such as shafts with splines or grooves, cutting edges of tools, tool flutes, and the external diameters of gears. United Grinding

"It's equally important that grinding machine operators learn to measure the cutting tools and understand cutting tool parameters," said Schwarzenbach. "And to translate that into a fully fledged measuring system inside the machines. Currently, we can gather four to five different parameters. The existing parameters checked are ones that are most affected by wheel wear during unattended production. That's really a challenge with unattended production—the wheel wears, moving the geometry slowly out of tolerance. Right now, we are still looking for ways to measure the more complex features being produced on the machine."

Some grinding machines’ measuring systems use a laser or camera to scan a tool inside the machine and measure it accurately. From there, the measuring system can accurately produce intelligent commands to adjust the machine automatically.

"Laser measuring technology addresses the need for flexibility, quick changeovers, and reduced setup time," said Hans Ueltschi, vice-president, cylindrical division, United Grinding North America. "If you have a non-contact device, there isn't an issue with wear on the gauge. Wear on the gauge theoretically deteriorates the accuracy of it. When processing very hard materials, like carbide or polycrystalline diamond (PCD), the gauge can wear, as it's made of material that is softer than that being worked with. But with a laser system you still get the accuracy that is typically seen with contact gauges."

Another advantage of a laser system is that it offers a huge range of diameters. Typically, contact gauges can only be used for one particular diameter size. For shops producing cutting tools with multiple diameter ranges, laser is a great option.

"With a laser, you can measure features or the whole part before it comes out of the machine. If you have to regrind some aspects, that can be done without removing the part and putting it back in, which can be extremely helpful when it comes to accuracy," said Ueltschi. "This allows shops to monitor the process, the machine status, and components and use the data that's generated by the device and machine to improve the process, reduce downtime, and prevent non-scheduled downtime."

Associate Editor Lindsay Luminoso can be reached at [email protected].

Rollomatic, www.rollomatic.ch

United Grinding North America, www.grinding.com