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moldmakingtechnology.com through a step, uneven entry or exit, drilling on a point, or even drilling through a welded seam. Chip formation is always a critical aspect of a machining operation. The goal is to achieve a consistent chip shape and size, easing chip evacuation. Since complex chipbreaking topographies can be pressed into an insert, it is relatively easy to get a good drill to form a consistent chip when running with the proper insert grade, geometry, coating, speed and feed. Using the tool in a plunging operation adds an interruption to the cut, which aids in chipbreaking, but it also requires an insert edge that can handle the added shock. It is typically advisable to use an insert topography with a large land width and hone for a strong edge, and a suitably strong substrate grade that will not fracture under impact with the material. Chip evacuation is the final key characteristic of a solid drill that can be used for plunging. Most drills have a flute configuration that is sufficient for solid- diameter drilling, with material completely around the circumference of the tool. However, when plunge milling, the drill will commonly no longer be fully engaged based on diameter, and there will be an open area along the circum- ference of the tool into which chips will fall instead of falling axially along the drill flutes. Damage will result if the chips that fall through the open area get caught between the tool body and the workpiece. Special care should be taken to ensure the chips are being evacuated cleanly when using a new plunging drill in a difficult application for the first time. Indexable milling tools can also be used in plunge roughing operations, but they have a more limited stepover equal to their insert land width. This is the length of insert edge that can be used for cutting in that orientation without damage or wear to the second side of the insert that could be used if indexed. If the stepover of the tool is greater than the insert land width, it is possible that the steel body of the tool will also contact the material, causing tool failure and part damage. In turn, the amount of material that can be removed per stroke with indexable milling tools is limited compared to drills of a similar size. However, there are benefits to using an indexable mill in plunge roughing. For example, it often has a stronger body than a drill, since these tools are much shorter and typically have very small flutes, so radial forces are not as much of When plunge roughing a chamber or cavity, it is always best practice to drill the solid diameter holes first at a much faster feed rate, then drill the rest of the material between those first holes. • Compact w/ Multiple Mounting Options • Greater Max Pressures & Stroke Range • Quality Control: Better Steel, Extra Seals, & 100% Pre-Tested • The Only Small Block Cylinders with Integrated Switches We Only Make MOld Cylinders injection Molding is in Our dna For Sales and Support in North America contact: Call: 909.941.0600 www.albaent.com Design custom cylinders and download 2D & 3D files, catalogs & tech manuals. Register Now at: VegaCylinder.com Configure Your CYlinders