In order to avoid the loss of more experienced operators due to retirement, the processing shop is turning to more modern automated surface grinders

Machining workshops that smooth metal or alloy surfaces to remove material or obtain precise thicknesses now have "infinite possibilities" that can improve their accuracy, production speed and control through more advanced automation devices.​​​

Today's rotary surface grinders provide sophisticated sensors and control devices that can reliably achieve tighter dimensional tolerances, flatness, parallelism, and surface finish in a shorter time. This equipment can be used to grind flat metals, alloys and ceramics to precise dimensions before polishing.

The operator's control of the process is unparalleled by the new automatic grinding machine. The user can input specific requirements, such as: spindle 712 RPM, table 22 RPM, downward feed rate is 0.003 inches per minute, with a certain dwell period. Essentially, the machine can be programmed to meet almost any requirement.

Compared with traditional grinding equipment that requires experienced machinists to be familiar with the nuances of each machine, these automated equipment consistently produces higher quality parts in a shorter period of time. Therefore, more and more machining workshops are installing new grinders that can be operated by inexperienced personnel while still achieving the desired results.

In mechanical workshops that use metals and alloys, specifications usually specify factors such as thickness, parallelism, and surface conditions. Grinding is also often used to remove a large amount of material to bring the sheet or sheet to precise dimensions.

For this reason, the machining workshop mainly uses a surface grinder with a reciprocating worktable and a horizontal spindle to rotate the grinding wheel, but the process is very slow.

"Reciprocating bench grinders have high accuracy, but the material removal speed is slow and requires multiple passes," said Erik Lawson, an engineering manager at DCM Tech, a designer and manufacturer of industrial rotary surface grinders.

Older rotary surface grinders are another option, but problems can arise in the hands of inexperienced operators. Due to limited control over spindle speed and manual control, older equipment requires complex operators who can perform complex calculations. Considerable expertise and experience are required, which can be a challenge as skilled operators retire.

In modern vertical spindle and turntable surface grinders, the worktable rotates and the workpiece is firmly fixed under the vertical spindle. Grinding is not carried out through the periphery of the grinding wheel, but through the entire diameter of the abrasive surface, which is conducive to grinding performance and consistency.

"With a rotary table surface grinder, the entire part passes through the grinding wheel, which is more effective than a reciprocating bench grinder that may have a wider workpiece than the grinding wheel," Lawson said.

Today, surface grinders are designed with more advanced sensors and control devices that can automatically maintain very tight tolerances and remove materials to within one-thousandth of an inch of the final thickness. Digital technology allows the use of an easy-to-use touch screen control interface. When combined with automation, surface grinder operators no longer need to be well-trained personnel.

For example, DCM Tech's IG 280 SD and other rotating devices are equipped with a 24-inch variable-speed table and a 20HP variable-speed grinding spindle motor. Almost anyone can successfully operate the device. One of the innovative examples available in this model involves the automation of the initial contact between the grinding wheel and the part, which usually must be carefully handled by the operator. With this updated option, advanced sensor technology can detect vibration, not only can automatically fine-tune the pressure of the spindle motor, but also automatically fine-tune the speed at which the wheel moves down onto the part. When the machine senses that the grinding wheel touches the part, it will automatically start the grinding cycle.

"Automatic part detection eliminates the need for operators to perform the time-consuming and error-prone'manual trigger'. They will manually feed the [grind] machine until it just touches the surface of the part, then exit and restart it," Say Lawson.

In terms of production efficiency, advanced rotary surface grinders are also much faster than reciprocating grinders, because these devices can get closer to the precise dimensions required before any finishing steps. This ability can reduce or even eliminate some grinding and polishing steps.

Using a traditional surface grinder, if a standard thickness blank needs to be ground, the operator will stop the required removal and leave an unpolished surface. It is usually necessary to use another machine to remove the remaining material, but this will take too much time and labor.

"Rotating surface grinders can usually complete the work of a reciprocating grinder in a short time. For the manufacture of cemented carbide blocks, an original equipment manufacturer recorded that the cycle time was shortened by 14 after replacing the reciprocating grinder with a DCM rotary surface grinder. Times the record," Lawson said.

The process also consistently achieves high throughput and eliminates variability, allowing the machine shop to mass produce high-quality final parts. In addition, programmable human machine interface (HMI) controls allow the operator to enter almost any requirement into the touch screen. This function enhances the flexibility of workshop processing, so any grinding factor can be easily adjusted to prevent the problem from recurring.

For conventional processes, the use of various grinding "recipes" with specific part parameter sets can further speed up production, improve quality, and facilitate rapid conversion. "Different grinding recipes can be set for different customers, material types and even part numbers, so there is no need to enter complex programming or data at the beginning of each job. New recipes can be created for job changes, such as different surface treatments or number of parts, "Lawson explained.

If the workpiece deviates a bit during the first pass, the grinder can also be programmed to take corrective actions in subsequent passes. There is no need to pick up the workpiece and measure after each movement like the old machine.

According to Lawson, the automation provided by advanced rotary grinders allows operators to set up the machine and then handle other tasks. The machine does not need continuous monitoring because it has built-in load monitoring. "Load monitoring allows users to set limits so that the machine does not overburden the parts being ground or overload the spindle. If something unusual happens, it can continue without interruption or shutdown," Lawson said . He added that the automation device also helps to create a safer and cleaner workshop environment because the grinding is done under a closed shield that contains debris and prevents it from entering the work area.

As the tolerances of metal and alloy grinding become stricter and production requirements are getting higher and higher, even if experienced operators retire, machining workshops using advanced automated rotary surface grinders will surpass competitors. "Using an automatic rotating surface grinder, you can train a mechanic to operate the equipment proficiently at lunch time on the first day. It only takes a few hours of training instead of decades of experience like the old machine," Lawson concluded. He added that a fully automated system is now being developed that will use robots to load, set up and run parts without requiring an operator to be nearby.

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