Inserts
Deep Hole Drill Insert Geometry Design
Deep Hole Drill Insert Geometry Design
When machinists set up a drill for deep CNC holemaking, they must ensure the tool has the correct depth and diameter.deep hole drill insert geometry design This is important because a deep hole drill needs to be able to cut through a thicker piece of workpiece material than a conventional spade or indexable insert (IC) drill.
In addition, deep hole drills s must have a geometry design that can handle interruptions, cross-holes, fly cutting and entering in and exiting angled surfaces like castings.deep hole drill insert geometry design This is why a high-quality deep hole drill requires a robust and durable drill body, holder and inserts.
Drill body manufacturers are incorporating technology into their designs that allows for a more accurate tool that is better able to maintain its proper depth and diameter throughout its life. This includes using computer controlled systems that monitor the axial position of the drill to ensure the axis is straight during machining. These new drills are also being designed with a more stable tip shape, which helps improve the holder’s ability to hold and guide an insert through the hole.
The helix angle of a deep hole drill insert is another critical factor that helps to ensure the correct hole size is created. This is because helix angles help to transfer chips from the cutting zone to the flutes, which in turn facilitates proper coolant evacuation and prevents recutting of the chip.
A helix angle of 12deg - 22deg is recommended for materials such as cast iron, brass and hardened steels that are short chipping, which means that the drill can cut more efficiently while still transferring the chips effectively to the cooling system. For abrasive or long chipping materials like titanium and high strength steels, a higher helix is required, which helps to break up the larger chips and allow them to flow more easily out of the hole.
An optimized drill insert can also significantly improve the tool’s performance by reducing its wear rate. This is achieved by utilizing a unique design that features kidney-shaped coolant flow holes running the length of the tip, as well as a nose grind contour known as N4 that minimizes the impact of the cutting edge on the workpiece surface. This enables the drill to achieve up to a 30 percent increase in tool life when compared to standard commercial gundrills.
Allied’s DeepTri-Drill line of indexable insert drills is one example of a high-performance deep hole drill that utilizes this advanced geometry to maximize efficiency and durability. The drills are also paired with a range of support tools to further optimize holemaking performance, including Guide Bushings that provide stability over extended lengths and prevent tool deflection; High-Pressure Coolant Systems that deliver coolant at elevated pressure directly to the cutting edge to reduce overheating; and Filtration Systems to prevent clogging and damage to the tool and the workpiece. These tools, when used with a cautious approach, modern thinking, offline presetting and attention to coolant and chips, unlock the potential of these new replaceable-tip drills in demanding applications.
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