The latest generation of CNC machine tools feature higher spindle speeds and feed rates, but cutting faster creates more heat at the tool tip and accelerates tool wear. Plus, customers for precision machined components don’t just want the job done faster, they want less downtime, higher accuracy and smoother finishes.

Addressing these expectations and challenges is driving innovation in tooling for precision machining. If you’re looking for a precision machine shop capable of high quality work, ask if they’re taking advantage of the new and emerging technologies discussed here.

Faster, and With More Precision

Minimizing the cost of CNC machining demands high material removal rates and extended cutting tool life. To reduce floor-to-floor times, modern spindles turn faster and machine feed rates are higher. Plus, modern machines are engineered with stiffer structures to handle the increased loads.

In parallel, product design teams want tighter fits and reduced part-to-part variation, which results in better and more consistent operation. They also want parts made from harder and tougher materials, which last longer but can be challenging to machine. As a result, tolerances on many metal components are getting tighter and more attention is being paid to surface finish.

Challenges at the Tool Tip

Cutting faster generates more heat. There’s more friction across the cutting tool surface, tool chips and erosion are more likely and wear rates are higher. The rate of chip production is higher too, making chipbreaking and chip management a bigger challenge.

Other problems are that thermal expansion, plus the deflection caused by increased cutting forces, tend to reduce accuracy and worsen surface finish.

Trends and Innovations

The tooling companies that supply precision machine shops have stepped up to meet these evolving needs. The biggest trends and innovations are:

• Materials and coatings: Carbide inserts have been the norm for decades, often with friction and wear-reducing coatings. Today new grades of carbide provide higher strength and toughness, modified geometries improve chip evacuation, and innovative coatings like titanium-aluminum-nitride (TiAlN) and titanium-carbon-nitride (TiCN), perform at higher temperatures and last longer.

In addition, diamond-like coatings (DLCs) are becoming more widely available, and new grades of cubic boron nitride (CBN) and polycrystalline diamond (PCD) are extending their reach into ferrous and nonferrous machining.

• Coolant delivery: To lower temperatures at the cutting interface, toolholders and cutting tools are available with coolant channels. These direct the fluid to where it has the greatest impact, reducing insert erosion and extending life.
• Sensors: Toolposts and even toolholders themselves can now be instrumented with sensors for temperature, vibration and cutting forces. This data lets cutting tool engineers optimize speeds and feeds, and potentially, in an Industry 4.0 scenario, will let CNC machine controllers adjust cutting conditions dynamically, on-the-fly.
• Presetting: Historically, tool offsets were entered into the CNC controller either by making measurements with a height gauge or micrometer and noting down the values, or directly at the machine. Today, to increase accuracy and reduce machine downtime, optical tool presetters use calibrated cameras to produce higher resolution measurements. In addition, this data can be transferred to the controller either with barcodes/QR codes on the toolholder or by RFID chip.
• 3D Printing: Increased cutting forces demand that greater attention be paid to workholding. 3D printing is useful for creating custom clamps and supports that absorb loads better than is possible with off-the-shelf devices.
• Heat-shrink collets: Used for holding cutting tools, continued refinement is increasing concentricity, enabling higher precision machining and improved finishes.

Higher Performance From New Technology

In industries from aerospace and automotive to medical devices and hydraulics, the components used in sophisticated products are becoming ever more complex. Tolerances are getting tighter and expectations for surface finish are rising, but at the same time, cost pressures are unrelenting.

Meeting these challenges means partnering with a CNC machining business that uses the latest metal cutting technology. This blog has covered the main advances enabling higher cutting speeds and improved precision. If you have a need for precision machining, please contact us for a discussion.