In recent years, five-axis machining centers, which enhance processing efficiency, are rapidly gaining popularity. The core advantage of five-axis machines lies in their ability to consolidate machining operations – even for complex parts that require multiple setups in traditional three-axis machining, they can complete multi-face machining in a single setup. This effectively reduces the number of process steps and improves accuracy. Furthermore, five-axis machining allows the cutting tool to engage the workpiece at optimal angles, which helps optimize cutting conditions, extend tool life, and improve surface finish quality. To leverage these advantages, we have specifically developed barrel cutters that enhance machining efficiency for five-axis applications and introduced a dedicated range of five-axis cutting tools.
"This article will focus on the Mirror-Finish Tapered Barrel Cutter [TPM Type] within this series."
01 What is a Barrel Cutter?
The core principle of a barrel cutter is to design an R-shaped contour (toroidal profile) for the cutting edge with a radius significantly larger than the tool radius. Compared to a ball-nose end mill of the same diameter, this design significantly reduces scallop height, thereby enabling the use of larger stepovers. Unlike a ball-nose end mill, where the entire 180° cutting edge features a large R, the effective large-R cutting range of a barrel cutter is more limited. Precisely because of this, when used in conjunction with a five-axis machining center, its flexible tool angle adjustment capability allows it to handle various complex machining scenarios effectively.
02 Mirror-Finish Tapered Barrel Cutter [TPM Type]
The [TPM Type], although a modular (indexable) cutter, achieves cutting edge precision comparable to that of solid (monobloc) tools. Its defining feature is the integration of a large-radius spiral cutting edge onto a 30° tapered cutting profile. Taking the φ16 specification as an example, it boasts a large R-value of R400. Even with this large radius, it maintains low cutting resistance. The [TPM Type] series is available as standard stock items in two specifications: φ16 (R400) and φ20 (R500). Both feature a small R2 corner radius at the tool tip. This design enables the cutter to efficiently machine large curved surfaces while also excelling in undercut cleaning within narrow areas and generating smooth contour transitions.
(Note): Custom specifications available.
Application Examples:
TPM Type Parameters:
Spindle Speed (n): 10,000 min⁻¹
Cutting Speed (Vc): 628 m/min
Feed Rate (Vf): 2,000 mm/min
Feed per Revolution (f): 0.2 mm/rev
Stepover (Pf): 1 mm, Tool Overhang 75 mm (Climb Milling)
Versus Comparison Tool Parameters:
Spindle Speed (n): 6,700 min⁻¹
Cutting Speed (Vc): 420 m/min
Feed Rate (Vf): 1,340 mm/min
Feed per Revolution (f): 0.2 mm/rev
Stepover (Pf): 1 mm, Tool Overhang 120 mm
"When using the TPM Type, tilting the spindle by 30° via the five-axis machine tool dramatically reduces the tool overhang (shown below)."
"The focus was on verifying the benefits of shorter tool overhang:"
Results show that under a 50% increase in machining efficiency, the TPM-type tool still achieves 1.4 times the service life of the reference tool. Regarding tool deflection, the reference tool exhibits significant growth with increased wear, while the TPM-type maintains stability within 5μm even after wear. Surface roughness also improved, decreasing from Ra 0.48μm for the reference tool to Ra 0.37μm.
Conclusion: In summary, while the method of tilting the spindle axis on five-axis machines to reduce overhang and boost efficiency is effective, solely relying on increasing feed rates is not optimal—this easily elevates cutting resistance and degrades surface quality. We recommend: Leveraging barrel-shaped tools to increase stepover distance, thereby achieving a substantial leap in machining efficiency while ensuring surface precision.
Practice has proven that combining barrel-shaped tools with five-axis machining technology is an effective pathway to simultaneously achieve leaps in both machining efficiency and quality. Beyond the TPM model detailed in this paper, our five-axis tool series also includes other specialized variants such as mirror-finish barrel cutters and tangential barrel cutters, all designed to deliver comprehensive solutions for complex machining scenarios.
However, the widespread adoption of barrel tools still faces technical challenges:
NC programming complexity requiring advanced CAD/CAM systems
Need for improved machining stability
Ongoing optimization of cutting force control
These areas demand collaborative efforts from industry peers to drive innovation.
Moving forward, we remain committed to:
Exploring novel machining processes
Developing next-generation tooling for greater efficiency gains
Contributing to quality enhancement and productivity growth in manufacturing.
