The high hardness and high strength of the workpiece are the main reasons for the cutting edge and short life of tungsten carbide drilling reamer blade. It is mainly reflected in the following aspects:

(1) the main deflection Angle of the reamer cutting cone is small, the cutting width is large, and the radial cutting force is large when cutting, so it is very easy to cause the blade of the reamer blade.

(2) in the process of quenching steel, the front Angle of the reamer should be negative, which will increase the strength of the blade and reduce the collapse.

(3) replace the material of cemented carbide blade, preferably select ultra-fine grain carbide blade to ensure high hardness and good strength.

(4) strict control of hinged margin. Because the ream allowance is too big, will increase each blade cutting load, destroyed the stability of the process of ream, and increased the cutting heat, make the diameter of the reamer swell, aperture has been expanding, the surface roughness of the processing quality is poor.

Major changes are made in the following aspects:

(1) adjust the size of the reamer properly. When using tungsten carbide drilling reamer machining hardened steel hinge holes have a certain amount of shrinkage, depending on the size of the hole, shrinkage rate is generally 0.005 ~ 0.02 mm, so the reamer tolerance zone up appropriately, and keep the correction part of the front end with 6 mm long cylindrical blade, the backend to make 0.01 mm inverted cone, in order to reduce friction on the surface of the blade and is ream, try to avoid surface damage.

(2) shorten the length of the reamer to improve the overall rigidity of the reamer. In the case of ensuring the depth of the reaming, shorten the length of the reamer properly, and keep the distance between 15 ~ 20mm from the end surface of the spindle.

(3) appropriately increase the diameter of the blade section to improve the rigidity of the reamer, while at the same time, in the external grinding process, the knife will be rounded to the outside, ensuring the coaxial degree of the blade and Morse taper shank.

(4) increasing the reamer cutting cones Angle, increased from the original 15 ° to 30 °, and radial cutting force to reduce the cutting width.

(5) the reamer Angle from 3 ° to 10 ° before (in front of the blade offset 1 mm), can protect the blade reamer blade does not crack.

(6) after reamer cylindrical blade Angle from 15 ° to 8 °, and retain cylindrical blade with 0.1 ~ 0.15 mm.

(7) in cutting cone grinding reamer law Angle, back from the original tool grinding process to shovel grinding process, namely blade back to curve, can increase the strength of the reamer cutting cones, reduce the reamer blade cutter tooth crack. Reamer cutting Angle of cone method backward shoulds not be too much at the same time, choose to 7 ° when machining hardened steel, shovel mill when actual value is 1.1 K.

( change the carbide welding blade model from E518 to E315, and increase the blade thickness from 1.5mm to 2mm to improve the blade strength.

(9) carbide blade material is changed from YG8 to YS8 or YT726 suitable for processing quenching steel. That is, the blade hardness is increased from 89HRC to 92.5hrc, which greatly extends the life of reamer.

(10) properly reduce the hinged margin and reduce the cutting load. Increase the original value of 11.7mm hinged bottom hole to the value of 11.8mm, that is, the hinged margin will be reduced from 0.3mm to 0.2mm, so as to improve the quality of reaming holes.

By users to use the improved reamer, after more than 20 sets of mold in continuous processing, remove the blade reamer observation, no collapse edge, only slight traces of wear, still can continue to use, reamer life was improved.

For the improvement of carbide taper shank machine reamer, the following requirements should be paid attention to in the process of quenching steel: it is an important condition for cutting and quenching steel. It is necessary to have reasonable geometrical parameters of the tool to effectively perform the cutting performance of the tool material. According to the physical and mechanical properties of tool material and workpiece material, the workpiece shape, the rigidity of the process system and the machining allowance are used to select the reasonable cutting amount.

Posted by: hannahgwendolyn at 09:39 AM | No Comments | Add Comment
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