The selection of a solid carbide end mill begins with evaluating the machining task and tool requirements. End mills vary not only in geometry but also in application, material, number of flutes, and other characteristics. This article explores the key design features that must be considered when selecting an end mill.
Materials to be machined vary in properties - some are hard, others are ductile, and some cause abrasive wear. Creating a universal end mill that performs equally well on all materials is nearly impossible. Manufacturers offer tool series optimized for specific tasks.
For example, some 4 flute end mills are efficient for steel but unsuitable for titanium. Others, such as 3 flute or 2 flute end mills, cut aluminum well but wear quickly on harder metals. These series often differ subtly - in carbide composition, coating, tooth geometry, and more. Therefore, selecting the right series should be based on manufacturer recommendations.
Figure 1 shows two configurations of end mills. On the right: the cutting diameter (DC) equals the shank diameter (DCON) - common for sizes like 8 mm, 10 mm, 12 mm, etc. On the left: the shank is larger than the cutting diameter, typical for intermediate sizes due to manufacturing nuances.
In casual conversation, "end mill diameter" typically refers to the cutting diameter - this is a key parameter. A larger diameter increases performance by removing more material per pass and improving rigidity, reducing vibration risks at high speeds. However, size may be limited by the application - e.g., a 16 mm tool can't be used in a 12 mm groove.
Also consider:
Some of the most common fractional sizes are 1/8", 3/16", 1/4", 3/8", and 1/2 inch end mills - all popular sizes for general CNC machining tasks.
More flutes = higher productivity and feed rates. But they demand more power and torque, and chip evacuation may suffer - more flutes reduce flute space.
Figure 2 shows tools with 2 and 6 flutes.
Flute count also defines application range. End mills with four flutes or more are generally not recommended for slotting, only for side milling (exceptions exist). Catalogs often use icons for this: left for side milling, right for slotting (Figure 3).
Popular configs: 4 flutes for steel and stainless steel, 2 or 3 flutes for aluminum.
Common options include:
Within each series, standard tools have an optimal ratio of cutting diameter to overall length, cutting length, and shank. But some jobs require variations from the standard.
Figure 4: left = short cutting edge, center = standard, right = long cutting edge. Shorter lengths may be enough and reduce cost. Longer edges are needed for deep pockets or tall features - but reduce rigidity.
Shorter overhang = better rigidity. But sometimes extra reach is required due to clamping obstructions. Figure 5: standard vs extended shank.
Figure 6: reduced neck - cutting edge larger than neck diameter, allowing deeper cutting without rubbing the wall.
Choosing a solid carbide end mill isn’t just about diameter or flute count. You must consider all parameters: series, geometry, length, shank, and material. The right choice boosts tool life, productivity, and machining reliability.
If unsure, contact our specialists - they’ll help you select the right tool for the job.
