Drilling Time Calculation for Steel Plate

Calculating the drilling time is a fundamental aspect of machining and manufacturing processes. This problem requires us to determine the time taken to drill a hole in a steel plate given specific parameters like plate thickness, feed rate, and spindle speed.

Key Parameters for Drilling Time

Let's list the given parameters for this drilling operation:

• Hole Diameter (D): \(\text{25 mm}\) (Note: The diameter is provided but is typically not directly used in the basic drilling time formula unless considering factors like approach/overrun or tool geometry, which are not mentioned here.)
• Plate Thickness (or depth of hole, L): \(\text{30 mm}\)
• Feed rate (f): \(\text{1 mm/rev}\)
• Drill Spindle Speed (N): \(\text{60 rpm}\)

Drilling Time Formula

The standard formula to calculate the drilling time (\(T\)) is given by the total length of the hole to be drilled divided by the product of the feed rate and the spindle speed.

The formula is:

$$T = \frac{L}{f \times N}$$

Where:

• \(T\) = Drilling time (in minutes or seconds, depending on units of N)
• \(L\) = Length or depth of the hole (in mm)
• \(f\) = Feed rate (in mm/rev)
• \(N\) = Spindle Speed (in revolutions per minute, rpm)

Step-by-Step Calculation of Drilling Time

Now, let's substitute the given values into the drilling time formula:

1. Substitute the values:

   \(T = \frac{30 \text{ mm}}{1 \text{ mm/rev} \times 60 \text{ rev/min}}\)

2. Perform the multiplication in the denominator:

   \(T = \frac{30 \text{ mm}}{60 \text{ mm/min}}\)

3. Calculate the time in minutes:

   \(T = 0.5 \text{ min}\)

4. Convert time from minutes to seconds:

   Since the question asks for the time in seconds, we convert 0.5 minutes to seconds. We know that 1 minute = 60 seconds.

   \(T_{\text{seconds}} = 0.5 \text{ min} \times 60 \text{ seconds/min}\)

   \(T_{\text{seconds}} = 30 \text{ seconds}\)

Summary of Drilling Parameters and Result

Therefore, the time taken to drill the hole is 30 seconds.