These heatingcooling cycles remove the original tempering of the steel Collets

These heatingcooling cycles remove the original

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These heating/cooling cycles remove the original tempering of the steel. Collets are made from spring steel allowing them to have a certain amount of elasticity to grip the tool. As the heat cycle is repeated this elasticity diminishes. Over time, a collet requires increased tightening to maintain the tool in proper position. As over tightening increases, the collet is distorted, creating eccentricities in the tool holder. Therefore, instead of over tightening older collets and creating a number of other problems, the collet should be replaced. Often the cost of a new collet can be offset by the cost of needlessly broken tools in one shift alone. Proper positioning of the tool in the collet is critical. The tool should only be gripped on the shank portion of the tool. At no time should any portion of the flute fade out be inside the collet. Proper Collet Use & Maintenance Many users select tools without regard to the importance of adequately holding them in the collet. Think of the spindle/collet system as a chain and just like a chain is only as strong as its weakest link, so too is the collets relation to the tool. A high performance tool can only perform if the collet is properly maintained each and every time the tool is changed. FULL GRIP COLLETS Full Grip Collets are identified by their slits that run from both ends, almost cutting the collet in pieces. This type of collet tends to have more flexibility and often comes in what is termed as ''Range Collets'' , which allow gripping in a range of shank sizes. This full grip type allows gripping over the entire length of the collet and to be properly used, the collet should be 75-80% full. The most important portion of the collet is the mouth, which is at the bottom. This area is important because all the lateral pressure taken by the tool must be evenly distributed on all ears of the collet for it to cut true or concentric. It is very critical that the 80% rule be followed when using a full grip collet due to the ability of the collet to flare at the back if not full. The collet can actually allow tool movement in even minute amounts often times resulting in tool breakage. There are times that the 80% rule is not possible due to the shank length available, so it is necessary to fill this void in the back of the collet with a life plug that is of the same size as the shank, thus to avoid the collapsing problem. Equally as important as filling the collet properly, it should also be understood that it is possible to over-collet as well. This is when the ''Flute fadeout' portion of the tool is allowed to extend up inside the collet. This does not allow a firm equal grip by all ears of the collet at the mouth. This allows the tool to have uneven support at the most critical area often times with solid carbide, or high speed steel tools, the tool material is hard enough to actually scar the inside of the collet, causing permanent damage to the collet.
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  • Fall '19
  • Tools
  • Milling cutter, High speed steel, Cutting, Collet, Downcut Spiral

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