Spark Out Time for Horizontal and Vertical Spindle Surface Grinder given Machining Time Calculator

Spark Out Time Formula:

\[ t_s = t_m - \left( \frac{d_{cut}}{2 \times f \times n_r} \right) \]

Machining Time (t_m):

sec

Depth of Cut (d_cut):

Feed Rate (f):

m/rev

Frequency of Strokes (n_r):

Tolerance:

Spark Out Time (t_s):

1. What is Spark Out Time in Surface Grinding?

Definition: Spark out time is the additional time required for the grinding wheel to pass over the workpiece without further depth of cut adjustment, ensuring complete material removal and surface finish.

Purpose: It helps achieve the desired surface finish and dimensional accuracy in horizontal and vertical spindle surface grinding operations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ t_s = t_m - \left( \frac{d_{cut}}{2 \times f \times n_r} \right) \]

Where:

\( t_s \) — Spark out time (seconds)
\( t_m \) — Machining time (seconds)
\( d_{cut} \) — Depth of cut (meters)
\( f \) — Feed rate (meters/revolution)
\( n_r \) — Frequency of reciprocating strokes (Hz)

Explanation: The formula calculates the additional time needed after the main cutting operation to achieve proper surface finish.

3. Importance of Spark Out Time Calculation

Details: Proper spark out time ensures:

Accurate dimensional tolerances
Improved surface finish
Reduced grinding burns
Consistent part quality

4. Using the Calculator

Tips:

Enter machining time in seconds
Depth of cut in meters (typically small values like 0.0005-0.005 m)
Feed rate in meters/revolution
Frequency of strokes in Hz
Tolerance percentage (default ±5%)

5. Frequently Asked Questions (FAQ)

Q1: Why is spark out time important in surface grinding?
A: It allows the wheel to remove remaining material and achieve the desired surface finish without changing the depth of cut.

Q2: What's a typical spark out time range?
A: Typically 5-30% of total machining time, depending on material and finish requirements.

Q3: When would I increase spark out time?
A: For finer surface finishes, harder materials, or when tighter tolerances are required.

Q4: How does feed rate affect spark out time?
A: Higher feed rates generally require longer spark out times to achieve the same surface finish.

Q5: What does the tolerance percentage mean?
A: It shows the acceptable range (±%) around the calculated spark out time based on process variations.