Manual repositioning of the workpiece lowers the achiev able accuracy Pros Cons

Manual repositioning of the workpiece lowers the

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- Manual repositioning of the workpiece lowers the achiev- able accuracy. Pros Cons 3-axis CNC milling Workpiece Tool Spindle
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9 > The workpiece is held on the spindle while rotating at high speed. > A cutting tool or center drill traces the outer or inner perimeter of the part, forming the geometry. > The tool does not rotate and moves along polar directions (radially and lengthwise). 3-axis CNC turning (lathes) CNC lathes are extensively used, because they can produce parts at a much higher rate and at a lower cost per unit than CNC mills. This is especially relevant for larger volumes. The main design restriction of CNC lathes is that they can only produce parts with a cylindrical profile (think screws or washers). To overcome this limitation, features of the part are often CNC milled in a separate machining step. Alternatively, 5-axis mill-turning CNC centers can be used to produce the same geometry in one step. Learn more about CNC turning + Lowest cost per part than all other CNC machining operations. + Very high production capabilities. - Can only produce parts with rotational symmetry & simple geometries. Pros Cons Workpiece Tool Spindle
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10 > The cutting tool can move along three linear and two rotational axes relative to the workpiece. > All five axes can move at the same during all machining operations. Continuous 5-axis CNC milling Continuous 5-axis CNC milling systems have a similar machine archi- tecture to indexed 5-axis CNC milling machines. They allow, however, for the movement of all five axes at the same time during all machining operations. This way, it is possible to produce parts with complex, ‘organic’ geom- etries that cannot be manufactured at the achieved level of accuracy with any other technology. These advanced capabilities come of course at a high cost, as both expensive machinery and highly-trained machin- ists are needed. Pros + Manufactures complex parts at an accuracy that is not possible with any other process. + Produces very smooth “organic” surfaces with minimal machining marks. - Highest cost per part of all CNC machining. - Tool access restrictions still apply. Cons
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11 > During machining the cutting tool can only move along three linear axis. > Between operations the bed and the toolhead can rotate, giving ac- cess to the workpiece from a different angle. Indexed 5-axis CNC milling Indexed 5-axis CNC milling systems are also known as 3+2 CNC milling machines, since they are using the two additional degrees of freedom only between machining operations to rotate the workpiece. The key benefit of these systems is that they eliminate the need of manually repositioning the workpiece. This way parts with more complex geometries can be manufactured faster and at higher accuracy than in a 3-axis CNC mill. They lack though the true freeform capabilities of continuous 5-axis CNC machines.
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