Drill Calucation
Autor: Taruvamba Kennedy • October 30, 2016 • Coursework • 3,313 Words (14 Pages) • 673 Views
4 Calculation of cutting conditions for drilling
Task. For given conditions of processing holes calculate optimum cutting conditions for drilling
Table 4.1-Initial data for calculating the cutting
The dimensions of the hole, precision cutting, setting and roughness length drilling | Material blanks | Description of the hole | |||
∅D, mm | Ra, m | lmm | |||
9H12 | 5.0 | 4 | Steel 40x | Deaf |
4.1 Determination of the cutting optimization criterion for drilling
Treatment mounting holes with precision size IT12 traditionally carried out drilling. With increased requirements for precision processing of drilling holes in solid material or reaming holes are pre-treated rough stage (the first technology transfer) processing of internal surfaces final treatment precision IT7-IT10 and roughness parameters Ra = (10 ... 1.25).
For optimization criterion rough stage machining cutting performance taking conventional process, which is given by:
P = 1 / It → max | (4.1) |
The maximum value of the performance achieved provided
Then→ min | (4.2) |
The main drilling given by:
[pic 2] | (4.3) |
lhi - stroke length of the tool; n-frequency spindle, rev / min; So- traverse mm / rev, and the number of working-moves (drilling, reaming). In turn, the spindle speed is given by n = 1000V / (π D), and the number of job moves by the formula; i = zomax / h. With this in mind we obtain the formula:
[pic 3] | (4.4) |
where [pic 4] |
Obtain such final dependence for determining optimization:
It → min | (4.5) |
h → max; S → max; V → max
Accordingly, it is necessary to determine the maximum value of elements of cutting mode for drilling in accordance with the conditions specified processing
4.2 Formation and initial data analysis
4.2.1 Analysis of the quality characteristics of the hole that must be processed
In accordance with the objectives necessary to consistently handle a through hole ∅9Н12; surface finish roughness parameters Ra5,0; drilling length l = 4mm in the workpiece, which is made of ductile steel 40Х.
...