The technical requirements of milling machine processing steps and right angle grooves are dimensional accuracy, parallelism, perpendicularity, symmetry and inclination.
1.Steps milling method
The steps are usually machined on a horizontal milling machine with a three-edge cutter or a face milling cutter or an end mill on a metal vertical milling machine.
(1) With three blade cutter milling steps
Three-sided cutter has two kinds of straight teeth and wrong teeth. Large diameter teeth of the three teeth cutter, mostly for the tooth-type structure, when a knife after the damage, the replacement of a knife can be. Three sides of the cutter diameter and knife size are relatively large, the strength of the teeth on the large, chip removal, cooling better, higher production efficiency. Therefore, three sides milling cutters are generally used for milling steps. When milling, the three-edge milling cutter cylindrical cutting edge mainly from the cutting effect, the two side cutting edge from the role of light.
1) With a three-sided milling cutter milling steps
①Milling cutter selection. The width should be greater than the step width, that is, L> B, diameter should be calculated according to D> d +2t. Where D is the diameter of the three-edge cutter; d is the outer diameter of the milling rod washer; t is the step depth. In order to meet the requirements of the use of the premise should be used in smaller diameter three blade cutter.
②Workpiece clamping and correction. General workpiece can be used flat clamp clamp, larger size of the workpiece can be used pressure plate clamping, complex shape of the workpiece or mass production can be used special fixture clamping.
③Milling method. After the workpiece is clamped, cut the paper. When the step depth is deep, multiple milling is used. The last time the feed, the bottom of the steps and the side of the same time fine grinding to the technical requirements.
④With a three-blade cutter milling double-sided stage. as the picture shows. The first step, the milling side of the steps to the size requirements, and then exit the workpiece, the milling machine table horizontal feed a distance A, tighten the horizontal feed mechanism after the rough, fine milling the other side; or side of the rough. After milling, loosen the flattened pliers, turn the workpiece 180°and then re-clamp, fine milling the other side of the steps, and then turn 180°fine milling the other side of the steps. This method of milling can achieve a higher degree of symmetry.
2) Combination of three blade milling cutter milling steps for mass production. This method not only can improve the production efficiency, but also simple operation, and can guarantee the quality of the workpiece. But the diameter of the two three-edge cutter should be the same, with a cutter rod washer to adjust the two cutting edge of the cutter blade between the cutting edge of the distance between the two milling cutter should be staggered half a tooth to reduce the milling vibration.
(2) Face milling cutter milling steps
Wide width and shallow depth of the steps, often use the face milling cutter in the vertical milling machine processing. Face milling cutter knife strength, milling, chip thickness changes in small, smooth cutting, processing surface quality, high productivity. Face cutter diameter generally take (1.4 ~ 1.6) B.
(3) With an end mill milling steps
Deep step or multi-step steps can be machined with an end mill on a vertical mill machine.
2. Step measurement
Generally measured with a vernier caliper, depth vernier caliper. When the dimensional accuracy is high, it is measured with an outer diameter micrometer or a depth micrometer. Large volume can be used when the limit gauge detection.