.mrc-calculator-container {
max-width: 600px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 25px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.mrc-header {
text-align: center;
margin-bottom: 25px;
border-bottom: 2px solid #0056b3;
padding-bottom: 15px;
}
.mrc-header h2 {
margin: 0;
color: #333;
font-size: 24px;
}
.mrc-input-group {
margin-bottom: 20px;
}
.mrc-label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #444;
}
.mrc-input {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s;
}
.mrc-input:focus {
border-color: #0056b3;
outline: none;
}
.mrc-help-text {
font-size: 12px;
color: #666;
margin-top: 5px;
}
.mrc-btn {
display: block;
width: 100%;
background-color: #0056b3;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
}
.mrc-btn:hover {
background-color: #004494;
}
.mrc-result-box {
margin-top: 25px;
padding: 20px;
background-color: #e8f4ff;
border: 1px solid #b6dfff;
border-radius: 6px;
text-align: center;
display: none;
}
.mrc-result-label {
font-size: 14px;
color: #555;
text-transform: uppercase;
letter-spacing: 1px;
margin-bottom: 10px;
}
.mrc-result-value {
font-size: 32px;
font-weight: 800;
color: #0056b3;
}
.mrc-article {
max-width: 800px;
margin: 40px auto;
font-family: inherit;
line-height: 1.6;
color: #333;
}
.mrc-article h2 {
color: #0056b3;
border-bottom: 1px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.mrc-article ul {
background: #f5f5f5;
padding: 20px 40px;
border-radius: 6px;
}
.mrc-article code {
background: #eee;
padding: 2px 5px;
border-radius: 3px;
font-family: monospace;
}
@media (max-width: 480px) {
.mrc-calculator-container {
padding: 15px;
}
.mrc-result-value {
font-size: 26px;
}
}
function calculateMetricFeedRate() {
// Get input values using var
var rpm = document.getElementById('spindleSpeed').value;
var flutes = document.getElementById('numFlutes').value;
var chipLoad = document.getElementById('chipLoad').value;
var resultBox = document.getElementById('mrcResult');
var output = document.getElementById('feedRateOutput');
// Parse values to floats
var n = parseFloat(rpm);
var z = parseFloat(flutes);
var fz = parseFloat(chipLoad);
// Validation
if (isNaN(n) || isNaN(z) || isNaN(fz)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (n <= 0 || z <= 0 || fz <= 0) {
alert("All values must be greater than zero.");
return;
}
// Calculation: Feed Rate (mm/min) = RPM * Flutes * Chip Load
var feedRate = n * z * fz;
// Display result
output.innerHTML = feedRate.toFixed(2) + " mm/min";
resultBox.style.display = "block";
}
Understanding Milling Feed Rates in Metric Units
In CNC machining and manual milling operations, the Feed Rate is one of the most critical parameters for ensuring tool life, surface finish quality, and machining efficiency. Unlike the imperial system which uses Inches Per Minute (IPM), the metric system measures feed rate in Millimeters Per Minute (mm/min).
This calculator helps machinists, programmers, and engineers quickly determine the correct table feed based on the spindle speed, the number of flutes on the cutter, and the desired chip load.
The Metric Feed Rate Formula
The standard formula for calculating feed rate ($v_f$) in metric units is:
vf = n × z × fz
- vf (Feed Rate): The speed at which the cutter engages the workpiece, measured in mm/min.
- n (RPM): Spindle speed in Rotations Per Minute.
- z (Teeth): The number of cutting edges (flutes) on the tool.
- fz (Chip Load): The thickness of material removed by each tooth, measured in mm/tooth.
How to Use This Calculator
To get an accurate result, you need data often found in your tooling catalog or based on material recommendations:
- Spindle Speed: Enter your current RPM. If you only have Surface Speed (m/min), calculate RPM first using:
RPM = (Vc × 1000) / (π × Diameter).
- Number of Flutes: Enter the number of teeth on your end mill or face mill. Common values are 2, 3, 4, or more for high-efficiency cutters.
- Chip Load (Feed per Tooth): Enter the manufacturer's recommended chip load in millimeters. For example, a standard carbide end mill in aluminum might take 0.05 mm to 0.15 mm per tooth depending on diameter.
Why is Chip Load Important?
Chip load ($f_z$) is arguably the most vital variable. If the chip load is too low, the tool will rub against the material rather than cut, generating excess heat and dulling the edge (work hardening). If the chip load is too high, the tool may deflect or break due to excessive cutting forces.
Example Calculation
Let's say you are milling steel with the following parameters:
- Spindle Speed: 2500 RPM
- Tool: 4-Flute Carbide End Mill
- Recommended Chip Load: 0.04 mm/tooth
Using the calculator:
Feed Rate = 2500 × 4 × 0.04 = 400 mm/min
You would program your CNC machine with a feed of F400.
Optimization Tips
Always adjust your calculated feed rate based on the setup rigidity, tool overhang, and depth of cut. If you are taking a full-width slotting cut, you generally reduce the chip load. For light peripheral finishing passes (radial chip thinning), you may need to increase the feed rate significantly to maintain the proper chip thickness.