| 摘要 |
<p>A broaching tool (10) has a plurality of cutting teeth (22) for broaching a small, deep hole with high precision and surface finish. Three to eight teeth (22) are engaged in the hole for cutting at any one time. For broaching sticky metals such as stainless steel, each cutting tooth (22) has a face angle, backoff angle and rise which are sufficiently large to prevent thermal hardening of the hole surface. A ring (22c) is provided between the front face and land (22a, 22b) of each cutting tooth (22), and has a width selected to prevent formation of axial and ring-shaped tool traces. V-shaped notches (30) having a large radial angle and a small backoff angle are formed in the land (22b) of each cutting tooth (22) to break chips and prevent clogging. The tool (10) further includes a rear pilot (24) having a plurality of smoothing teeth (26) with a diameter larger than the finished diameter of the hole. A set of rough and fine broaching tools can be provided, with the fine tool being processed to convert it to a rough tool when it is worn beyond tolerance. A lubricant/coolant including molybdenum disulfide powder dispersed in a liquid suspension is coated on the tool (10) during broaching.</p> |
