What Is an HSS End Mill?
An HSS end mill is a tool used primarily for machining square metal or non-metal objects. Unlike a twist drill, which creates a circular hole, an end mill rotates and moves straight to enlarge a hole horizontally. End mills are made of two primary materials: HSS (high-speed steel) and cemented carbide. HSS end mills are common, while cemented carbide ones are better suited for cutting harder materials.
Uses of HSS End Mills
HSS end mills are employed as machining tools in milling machines. They are used for a variety of operations, including machining flat and side surfaces, grooves and pockets, chamfering, and mortising. This versatility enables them to be used in tasks like cutting out molds, forming gear keyways, and more. Given the wide range of tool types, each with unique features, it’s crucial to choose the most appropriate tool based on the specific machining requirements, such as the surface shape, depth, and dimensional accuracy.
Principle of HSS End Mills
HSS end mills comprise three main elements:
- Bottom Cutting Edge: The square end with a flat bottom is ideal for machining horizontal and side surfaces. The ball end, with a rounded bottom, suits curved surface machining. The radius end, an intermediate type, is best for R-machining and corner wall parts.
- Peripheral Flute: The ordinary blade is widely used, and suitable for a broad range of applications from roughing to finishing. The rafting blade, with a wavy shape, improves chip evacuation and reduces cutting resistance, making it ideal for roughing but less suitable for finishing. The tapered blade, with a tapered outer edge, is used for molding relief and inlays.
- Shank: Straight shanks are common, while long shanks are suitable for deep drilling. Long-neck shanks, with a partial neck, are useful for deep grooving, and tapered-neck shanks, with a tapered neck, are ideal for deep grooving near sloped walls.