On the technological innovation of adjustable cutt

2022-07-19
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In the mid-1980s, the indexable structure has been applied to various turning tools, boring and milling tools and special tools. The annual cost of cutting in the world exceeds 250billion US dollars, of which the cost of cutting tools accounts for 2% ~ 3%

at present, the challenge in the field of tool technology is the process performance of tools. From the improvement of the cutting function of a single cutting area in the past (such as cutting efficiency, precision, tool life, etc.) to the improvement of the efficiency of the entire automatic production process, last year included the improvement of tool identification technology, monitoring technology and management technology

the author believes that this is firstly reflected in the further dynamic optimization research on the static reasonable geometric parameters of the non adjustable tool, and the qualitative and quantitative analysis according to the basic laws of the cutting process, so that on the basis of improving the adjustable performance of the tool structure, the flexible adjustment of the similar reasonable geometric parameters and the timely replacement and transposition of the blade can be realized, so as to improve the processing performance and operating performance of the tool. Cutting theoretical knowledge and practical cutting technology is actually a revolutionary evolution of cutting tool cutting - forming ability, structure and operation, and needs a comprehensive and practical description, which is conducive to the profit creation of cutting technology. 1.1 practical cutting model and adjustment performance

practical cutting model is an abstract model for the continuation and change of the cutting part of the adjustable tool in the machining system. It is an image transformed from the tool adjustable structure system, and mainly reflects the adjustable performance and mutual relationship of the smallest unit constituting the functional system of the tool cutting part [2]. The efficiency and level of practical cutting model application are determined by the deep understanding and innovative ability of machining system and various cutting technologies. Figure 1 shows the simplified cutting model. Figure 1 Schematic diagram of simplified cutting model figure 1 shows that the cutting part (or blade) is assembled in the groove above the center line of the cutter head with a certain clamping state or preload, and can rotate back and forth with the cutter head around its center point o. The m-xyz coordinate system coincides with the corresponding main section reference system of the non adjustable tool in the initial state that the bottom surface of the tool groove is parallel to the base plane through the selected points m, X-axis parallel groove depth, Y-axis parallel groove length and z-axis parallel groove height on the cutting edge

therefore, at the limit positions of X, y and Z axes (one is the initial stay state and the other is the limit stay state), the cutting part is in a static and stable state and can normally participate in the cutting process, just like simplifying the cutting model. The difference is that, in order to facilitate the regrinding and adjust the initial function of the main deviation, the cutting part (blade) properly extends out of the joint surface of the tool table, forms a variable cross-section combination with the tool heat, and cooperates with the composite upward pressure adjustable mechanism to realize the continuous regrinding and parameter performance adjustment, mainly in the following aspects:

(1) the x-axis and y-axis can be adjusted by adjusting the blade prestress or its clamping state, That is to say, it extends along the depth and length of the cutter groove to achieve the purpose of continuous regrinding in the new limit state

(2) the cutting part can make a limited round-trip around the cutting speed through the plane rotary pair inside the cutter groove, and achieve the purpose of randomly adjusting the main deflection angle at the new limit position

(3) regrinding cannot be continued and is directly transposed. Pay attention to adjusting the positioning and clamping mechanism

(4) the x-axis is parallel to the base surface of the cutting part, so the cutter head (together with the cutting part) is rotated together, that is, the center of the cutter bar is rotated back and forth in a limited way, and the front and back angles of the cutting edge are adjusted at the new limit positions of X, y and Z. When the cutting force is overloaded, the cutter head rotates in reverse (counterclockwise) to another limit position to protect the cutting edge

(5) the peripheral curve of the lower bottom of the cutter head is an equal strength curve or logarithmic helix, which is mainly to reduce the geometric constraints in the cutting process after grinding and adjusting the geometric parameters

(6) the cutting part (blade) is located above the center line of the main section of the cutter head, mainly to greatly adjust the rake angle

practice has proved that the accuracy and reliability of the metal separator depend on the stability of the frequency of the electromagnetic transmitter. It is clear that as long as the initial angle and adjustment range of the front angle RO, back angle do and the main deflection angle NR are properly selected, the non regrinding or appropriate regrinding of the rear tool surface can not only improve and expand the processing performance and benefits of the tool, Moreover, it can also reduce the types of indexable cutters and the varieties of blades that are different due to the difference of the main deflection angle NR and the normal back angle an. Therefore, it also provides a broad prospect for the development and application of adjustable tools. 1.2 regrinding rule

the regrinding rule represented by the practical cutting model is consistent with the innovation of research and maintenance regrinding technology at home and abroad, and is consistent with the objective requirements of maintaining tool regrinding

(1) regrinding generally refers to the grinding along the flank and the trimming of the edge shape parameters. This is the only means for the integral and welded tools to improve the processing performance and prolong the service life, but it reflects the objective law of certain continuous cutting performance under the condition that the front corner and chip breaking groove parameters have little change after the reasonable geometric parameters are polished and trimmed. The adjustable tool is grinded along the flank, the grinding area is small, the grinding process is optimized, and it is easy to meet the requirements of quality and quantity

(2) regrinding also refers to the necessary and appropriate regrinding of the blade shape parameters and the polishing edge and secondary edge. The blade shape parameters are relatively small, so it is convenient and flexible to change an appropriate amount of grinding into similar geometric parameters, but it is necessary to have a systematic understanding of various process performance of the tool and a high cutting process and strain capacity

(3) the performance of the adjustable tool in adjusting the rake angle and the main deflection angle makes the regrinding law fully developed and applied, and provides a technical guarantee for simplifying the blade shape parameters of the indexable blade. It can not only improve the processing performance and benefit of the cutting tool, but also reduce the types of indexable cutting tools and the varieties of blades that are different due to the difference of the main deviation surface and the normal back angle. At the same time, it also provides a prospect for the development and application of adjustable cutting tools. 1.3 innovation and operation requirements of chip breaking groove Technology

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