Possible causes of chipping and crumbling i Excessive feed per tooth ii Poor

Possible causes of chipping and crumbling i excessive

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Possible causes of chipping and crumbling: i. Excessive feed per tooth ii. Poor cutter design iii. Running cutter backwards iv. Chatter due to a non-rigid condition v. Inefficient chip washout vi. Built-edge break away Built-up edge occurs when particles of the material being cold-weld or otherwise adhere to the faces of teeth adjacent to the cutting edges. When this occurs the tool can no longer cut cleanly. Two other factors to be taken into consideration are rigidity of the table and if coolant will be use. When machining aluminum, coolant should always be applied, if you are to have any success. When it comes to rigidity, if your machine is loose, you will not be able to machine at fast feed rates. Router Table Rigidity Basically any vibration in the Router tables arm will be transmitted to the tip of the end mill. The faster you go the greater this vibration is amplified and the more likely that you will break the bit because of it. As a general rule the heavier the gantry the better. As you increase cutting speed the gantry at some point will begin to vibrate. At this point you are running too fast for the design of the Router table. Slow down. In larger tables, this vibration should only become a factor in larger diameter bits, i.e. greater than 1 /4 inch. With smaller bits the speed limitation imposed by other variables will prevent you from reaching the point where it will vibrate. In smaller tables with lighter gantries this vibration will be a limiting factor. Misting When cutting metals, a mister is of critical importance. Without it the end mill and/or the chips heat up to the point that the bit will break or the material chips will melt. If you are doing a lot of metal cutting, dual misters are required. There are two types of misters, positive feed and non-positive feed. The positive feed type actually pumps a measured amount of misting fluid out of the nozzle. Feed and Speed Calculations Parameter Formulas Cutting speed, (srm) SFM = .262 x x RPM Revolutions per minute (rpm) RPM = 3.82 x SFM/0 Freed rate, in/min Fr = Cpi x N x RPM Feed per tooth, in CPI Fr/N x RPM Cutting time, min t L / Fr Rate of metal removal, cu in/min mrr=Wx0xFr Symbol Definitions Diameter of milling cutter, inches Revolutions per minute of cutter Cutting speed, feet per minute Feed rate, inches per minute Feed, inches per tooth number of teeth in a cutter Rate of metal removed, cubic inches per minute Cutting time, minutes Length of cut, inches Depth of cut, inches Width of cut, inches
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Solid Carbide Double Edge Upcut Spiral Application: Designed for perfect balance and ultra smooth finish over a wide speed range. CED CEL SHK DIA OAL 1/4 3/8 1/4 2 1/2 1/4 3/4 1/4 2 1/2 3/8 1 3/8 3 1/2 1 1/8 1/2 3 1/2 Solid Carbide Three Edge Finisher Slow Helix Application: Designed for perfect balance and ultra smooth finish over a wide speed range.
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  • Fall '19
  • Tools
  • Milling cutter, High speed steel, Cutting, Collet, Downcut Spiral

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