板材送进夹钳装置设计(工作原理+任务书+说明书+CAD图纸+英文参考文献) 第3页
Angular tool
Designation
Back rake 0°
Side rake 0°
End relief 5 °
Side relief 5 °
End cutting edge 52°
Side cutting edge 3°
Nose radius 0.88mm
Nose radius Cutting Back rake angle
Side rake angle
Figure 3-2 Assembled tool geometry
Figure 3-3 Photograph of the cutting insert fixed on the tool holder
Figure 3-4 coolant stream direction.
3.3 Cutting Conditions
Based on I803685 [46] five cutting speeds were used throughout the testing as listed on Table 3-6. Cutting speeds corresponding to 410 m/min for the coated carbide tools and180 m/min for the uncoated carbide tools were approximately the upper limit of the application range. Since any further increment resulted in very short cutting tool life or premature tool damage soon after the test was started.
The turning experiments were carried out under dry and wet cutting conditions at different cutting speeds, while fixing both feed rate at 0.14 mm/rev and depth of cut at(1mm). Five cutting speeds were selected for the three types of cutting inserts, as listed in Table3-6.
3.4 Experimental Procedure of Tool Life Testing
A Clausing 1300 lathe with maximum 7.5HP was used f alloy steel SAE4140H work piece, and the turning process was carried out in the way or the turning of the Hot rolled previously described. A Tachometer was used to measure the rotational speed before each single cut occurred on the work piece in order to ensure that the cutting was performed at the exact speed.
An optical microscope was used to measure the flank wear of the cutting inserts. The experiment was terminated if either of the two following conditions occurred
1- The maximum flank wear 0.7 mm and/or;
2- The average flank wear 0.6 mm.
Preliminary experiments were carried out in order to determine the wear limit. It was found that the cutting inserts were worn out regularly on the flank side. Therfore, VB,nax =0.7 mm, is chosen to be the wear limit for the tool life. The flank wear was observed and measured at various cutting intervals throughout the experiments. Figure (3-5) shows flank wear as a function of cutting time for the cemented carbide (KC313) under dry and wet conditions, and includes only three cutting speeds for clarity.
Figure 3-6 presents the flank wear as a function of cutting time for sandwich coated inserts ( KC732) under dry and wet conditions. Figure 3-7 shows the flank wear as a function of cutting time for TiALN coated cutting inserts (KC5010). Previous figures included three cutting speeds. Clarity of cutting speed curves are presented at the attached appendix for both conditions of machining. The aforementioned figures, present the effect of coolant emulsion in extending the tool life for the KC313, and KC732 cutting inserts; especially after 3 minutes for KC313, and after 7 minutes for KC732 of cutting. However, the usage of coolant emulsion on KC5010 showed negative influence.
Figure 3-5, and Figure 3-6 show that at any set of turning conditions, the flank wear increased at a higher rate at dry cutting during the gradual wear stage. Figure 3-7 shows that at any set of turning conditions, the flmk wear increased at a higher rate at wet cutting during the gradual wear stage. The explanation of this material behavior will be covered in detail though-out chapter 5 (wear
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