In-process Cutting Tool Control

A broken tool, incorrect tool, bad edges and missing flutes, and runout problems can all be detected through the use of a laser-based tool checking system.

Laser-based systems allow for the precise setting of tool diameters and lengths as well as critical process control through confirmation of tool identification, tool form inspection, tool breakage, and cutting edge detection. This addition to the process can increase productivity, improve quality, and save costs by reducing or eliminating scrap, rework, tool failures, and even machine crashes.

Any number of tooling problems can result in bad parts. A broken or incorrect tool, a tool with bad edges, missing flutes, and total indicated runout (TIR) problems can all contribute to a nonconforming part, and possible delivery and scheduling headaches.

“I continue to see the use of this type of system increasingly in the tool and mold markets in both the Windsor and Toronto areas,” explained Blum LMT Canadian Regional Sales Manager David Tandori. “By adding a laser tool setting system to their milling machines, shops can reduce setup times, create a scenario for unmanned operation, reduce their scrap rate, and increase productivity.”

With increased competition and demand for faster delivery times, the tool and mold industry is moving aggressively toward automating the machining process to optimize machine effectiveness. This in turn can mean setting up multiple jobs utilizing rapid workholding and loading the tool magazine with a large number of cutting tools. The objective is to set up the machine to run as unattended and uninterrupted as possible. This strategy holds true for all segments of machining, including aerospace, medical, automotive, power generation, as well as general machining.

“With a laser system in place, these tools are not just measured, but also examined to make sure the proper tool is being used in the first place. This seems simple, but one small human error can lead to a potential machining problem down the road,” said Tandori.

The laser is guided by standard machine G-code macroprograms, enabled either manually or integrated directly into the CAD/CAM post, and can be called up whenever the process demands. Measurements are made while the tool is spinning at cutting speed, with the measured values automatically set in the machine tool data table. This keeps the entire procedure automated and minimizes operator interaction.

Measurement Capabilities

Laser systems are highly accurate at measuring tool length and diameter and at checking the cutting edges, form, and number of flutes to ensure that they are present and correct. In other words, the laser can verify if the tool is a three-flute, 0.5-mm flat end mill or a three-flute, 0.5-mm ball mill and stop the machine if it’s the wrong tool.

In tool and mold work, for example, the semifinishing and finishing of heat-treated tool steel can become an expensive operation if a part is scrapped or requires rework. Verifying and measuring the tool prior to cutting ensures part accuracy, allowing superior blends and surface finishes that reduce benchwork.

Additional process monitoring can include checking the tool at intervals during the machining process, again through CAD/CAM integration, for wear and even breakage. If a tool is out of condition, the machine can alert the operator or management. This can be critical if the tool cut time is long or unattended because a machine with a broken tool produces an unacceptable part and is a possible hazard.

“When working with expensive material, there must be a method to error-check before cutting due to the detrimental costs and potential errors involved,” said Tandori. “Once this type of process is implemented on a single machine, it can be easily duplicated across the entire shop. Different operators may have variations of how they pick and set a tool. With the laser system, a consistent, rapid, and repeatable method is created, removing any variance which produces inconsistencies.”

Ensuring accuracy, reducing benchwork, and eliminating rework and scrap should be the goals of any forward-thinking shop.

Production Environment

“In a high-volume production environment the concern is always cycle time,” said Tandori. “Even given the high volume of parts traveling through the system, and numerous tool changes performed, tool monitoring should not be overlooked.”

Certain tool dimensions, such as reamer flutes, runout, and forms, cannot be checked with traditional rapid broken tool detection because the defect may appear on the tool’s side and not on the tip where the check typically takes place. The problem may also be runout, which can be detected only by laser.

A defect in this tool could produce a bad part that may go undetected and enter the process stream. Even if the bad part is caught downstream, there is a threat of more bad parts entering the process flow. There are also economic costs, such as scrap, idle machine time, and, even worse, shipping a nonconforming part to a customer.

If a part’s critical features are machined first and the tool is checked immediately after, any adverse issue can trigger containment of the suspected part at that point.

“It all comes down to risk and examination of the process, the part, and systems that are in place,” said Tandori. “When in doubt, it helps to consult a process specialist.”

The Laser System

Most laser tool checking systems today are virtually maintenance-free. For example, in the Blum laser system, shutters keep out contaminants, and a positive air pressure inside the system helps it stay clean. Combining the patented Blum Laser NT technology, with a focused beam design, allows precise measurement even in a contaminated environment.

Blum laser systems are adaptable for both vertical and horizontal machining centers. Configurations include direct table mounts for vertical centers and various bracketing and retractable units for horizontal centers.

“The laser tool system helps produce accurate parts with superior surface finish quality while maximizing tool life and overall productivity,” said Tandori. “It’s an essential onboard machine process well worth the time investigating. When you evaluate the total capability of its potential, you begin to wonder how you got along without it.”

For more information, visit www.blumlmt.com.