MEGA Drilling Harrow Tool for High Hardness and High Precision Hole Machining

1. Development purpose
For high-precision hole machining of hardened materials (HRC50~62), rough machining is usually performed by electric spark or high hardness carbide drill; then semi-finishing is performed with end mill and boring tool to correct the bending of the hole and Aperture size; then coordinate grinding and finishing, followed by heat treatment; finally finishing with high hardness carbide reamer. This processing method is complicated in process, low in processing efficiency, and takes a lot of time. In addition, when machining high-hardness and high-precision holes, the number of tools used in each process is large due to the short tool life of the drill and the reamer, and the tool is greatly increased. cost. In order to efficiently process high-hardness and high-precision holes, Miller GmbH of Germany developed the MEGA drill-hinge HARD tool. The optimal matching design of the three elements of the tool base material, coating and cutting edge shape effectively solves the problem of high-hardness and high-precision hole machining, making it an epoch-making cutting tool.

2. Matrix material
MEGA drilling hinge HARD tool uses high-quality cemented carbide with high strength and hardness balance, high reliability in damage resistance and wear resistance, and is suitable for high hardness material processing. The material characteristics are: type: ultrafine grain Cemented carbide; particle size: 0.8 mm; WC content: 89.7 wt%; Co content: 10 wt%; TiC+TaNbC content: 0.3 wt%; flexural strength: 4.2 Gpa; hardness: HRA 92.0; density: 14.5 g/ Cm2.

3. Coating material
The MEGA drill-hinge HARD tool uses a MxF coating (TiAlN series) with both uniformity of construction and high bonding strength. The surface hardness of the coating is extremely high, and it has excellent surface lubrication performance while improving heat resistance and wear resistance, and can greatly reduce the friction coefficient, and is exhibited in the processing of 3 times diameter deep hole. Excellent suppression of sticking knife performance and smooth chip removal.

4. Cutting edge shape
The MEGA drill-hinge HARD tool has a unique cutting edge shape and consists of eight cutting edges. The drill has two cutting edges, the reamer has two coarse cutting edges, two semi-finished cutting edges and two fine cutting edges. While the drill bit is being drilled, the cutting edges of the reamer are finely hinged while being chipped, and the high-precision hole can be processed at one time.

5. Tool features
MFGA Drilling Harrow Tool is a kind of high precision, high rigidity machine tool and tool system. It adopts wet cutting method, can achieve high hardness (HRC50～62), high precision (aperture size, straightness, hole spacing, 3S). Surface roughness, etc.) Hole-finished tool. However, if there is a problem with the rigidity and precision of the machine tool, or if the hole pitch accuracy is strict, and it is found that the tool tip is worn out, it is recommended to punch the center hole of 135?~140? before processing. MEGA drill hinge HARD tools can be used as separate drilling or reaming tools in addition to drilling and reaming.

The MEGA drill-hinge HARD tool can reduce the processing steps of high-hardness and high-precision holes, shorten the machining time, eliminate the need for tool change, reduce the number of tools, and greatly reduce the processing cost.

6. Machining performance
Use the MEGA drill-hinge HARD tool to machine 20mm deep blind holes on SKD11 (HRC60) material. When machining, use high-precision vertical machining center and high-precision, high-rigidity BT40 tool system, with AA-grade precision collet chuck Holding the tool, the aperture accuracy can be controlled within 0.01mm. Externally cooled with a water-soluble cutting fluid (10 times diluted) with a tool diameter of 8.0 mm and 50 holes (90 seconds per hole). Processing precautions: 1 When the primary processing aperture size is too small, if the roundness and cylindricity are unqualified, do not remove the workpiece, and repeat the reaming 2-3 times under the same conditions. At this time, step feed is recommended; When the hole is drilled, the tip of the drill reamer is prone to chipping, and a jig should be used to prevent the formation of the drill through hole.

7. Tool usage precautions
The selection criteria of the tool diameter are: machine tool: high precision vertical machining center with good spindle rigidity; tool system: high rigidity and high precision tool holder, AA grade spring chuck; cutting fluid: water-soluble cutting fluid (emulsion), external cooling Workpiece material: SKD11 (HRC60); center hole: use drill tip angle 140? MEGA carbide drill bit; hole accuracy: precision when machining f10.0H7 (0-0.018); finishing with M2273-10.00 tool: Select f10.001 ~ f10.01; use M2273-10.01 tool finishing: select f10.011 ~ f10.02; according to the above results, use the M2273-10.0 or M2273-10.01 tool for the one-hole hole processing after the center hole; or After punching the center hole, the bottom hole was machined with the M2273-10.0 tool, and then the M2273-10.01 tool was used for the precision hinge processing.

The precautions for using the tool are as follows: 1 High-rigidity, high-precision machine tools must be used; 2 High-precision, high-clamping tool systems and AA-class precision collet chucks must be used; 3. When the surface of the workpiece is uneven, it should be pre-punched. The center hole of 135?~140?; 4 must be cut according to the cutting conditions provided by the product sample. Among them, items 1 and 2 are important items that determine the processing accuracy, and must be given sufficient attention during the preparation stage.