.mrr-calc-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #ffffff;
padding: 20px;
border: 1px solid #e0e0e0;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.mrr-calc-header {
text-align: center;
margin-bottom: 25px;
padding-bottom: 15px;
border-bottom: 2px solid #0056b3;
}
.mrr-calc-header h2 {
margin: 0;
color: #333;
font-size: 24px;
}
.mrr-input-group {
margin-bottom: 20px;
}
.mrr-input-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 15px;
}
.mrr-col {
flex: 1;
min-width: 200px;
}
.mrr-label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #444;
}
.mrr-input, .mrr-select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.mrr-input:focus, .mrr-select:focus {
border-color: #0056b3;
outline: none;
}
.mrr-btn {
background-color: #0056b3;
color: white;
border: none;
padding: 12px 24px;
font-size: 16px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background 0.3s;
}
.mrr-btn:hover {
background-color: #004494;
}
.mrr-result-box {
margin-top: 25px;
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 6px;
padding: 20px;
display: none;
}
.mrr-result-item {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #ddd;
}
.mrr-result-item:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.mrr-result-label {
font-weight: 600;
color: #555;
}
.mrr-result-value {
font-weight: bold;
font-size: 18px;
color: #0056b3;
}
.mrr-article {
margin-top: 40px;
line-height: 1.6;
color: #333;
}
.mrr-article h3 {
color: #0056b3;
margin-top: 25px;
}
.mrr-article h4 {
color: #444;
margin-top: 20px;
}
.mrr-article ul {
padding-left: 20px;
}
.mrr-article li {
margin-bottom: 8px;
}
function updateLabels() {
var system = document.getElementById("unitSystem").value;
var diameterLabel = document.getElementById("diameterLabel");
var feedLabel = document.getElementById("feedLabel");
var penetrationLabel = document.getElementById("penetrationLabel");
var diameterInput = document.getElementById("drillDiameter");
var feedInput = document.getElementById("feedPerRev");
if (system === "metric") {
diameterLabel.innerText = "Drill Diameter (mm)";
feedLabel.innerText = "Feed per Revolution (mm/rev)";
penetrationLabel.innerText = "Penetration Rate (Calculated mm/min)";
diameterInput.placeholder = "e.g. 12";
feedInput.placeholder = "e.g. 0.2";
} else {
diameterLabel.innerText = "Drill Diameter (inch)";
feedLabel.innerText = "Feed per Revolution (in/rev)";
penetrationLabel.innerText = "Penetration Rate (Calculated in/min)";
diameterInput.placeholder = "e.g. 0.5";
feedInput.placeholder = "e.g. 0.008";
}
// Clear results when switching systems to avoid confusion
document.getElementById("resultBox").style.display = "none";
}
function calculateMRR() {
// Get Input Values
var system = document.getElementById("unitSystem").value;
var diameter = parseFloat(document.getElementById("drillDiameter").value);
var rpm = parseFloat(document.getElementById("spindleSpeed").value);
var feedPerRev = parseFloat(document.getElementById("feedPerRev").value);
// Validation
if (isNaN(diameter) || isNaN(rpm) || isNaN(feedPerRev)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (diameter <= 0 || rpm <= 0 || feedPerRev <= 0) {
alert("Values must be greater than zero.");
return;
}
var area = 0;
var penetrationRate = 0;
var mrr = 0;
var areaUnit = "";
var rateUnit = "";
var mrrUnit = "";
// Math Logic
// Area = pi * r^2 = pi * (d/2)^2
// Penetration Rate (Vf) = RPM * FeedPerRev
// MRR = Area * Vf
penetrationRate = rpm * feedPerRev;
area = Math.PI * Math.pow((diameter / 2), 2);
// Initial MRR calculation (base units: mm^3/min or in^3/min)
var rawMRR = area * penetrationRate;
if (system === "metric") {
// Inputs: mm, mm/rev.
// Area: mm^2
// Penetration: mm/min
// Raw MRR: mm^3/min
// Standard display for Metric MRR is cm^3/min
mrr = rawMRR / 1000;
areaUnit = "mm²";
rateUnit = "mm/min";
mrrUnit = "cm³/min";
} else {
// Inputs: inch, in/rev
// Area: in^2
// Penetration: in/min
// Raw MRR: in^3/min
// Standard display for Imperial is in^3/min
mrr = rawMRR;
areaUnit = "in²";
rateUnit = "in/min";
mrrUnit = "in³/min";
}
// Display Results
document.getElementById("calcPenetration").value = penetrationRate.toFixed(2);
document.getElementById("resPenetration").innerText = penetrationRate.toFixed(2) + " " + rateUnit;
document.getElementById("resArea").innerText = area.toFixed(2) + " " + areaUnit;
document.getElementById("resMRR").innerText = mrr.toFixed(2) + " " + mrrUnit;
document.getElementById("resultBox").style.display = "block";
}
Drilling Material Removal Rate Calculator
Metric (mm, m/min)
Imperial (inch, ft/min)
Penetration Rate ($V_f$):
0
Hole Cross-Sectional Area:
0
Material Removal Rate (Q):
0
Understanding Material Removal Rate (MRR) in Drilling
The Material Removal Rate (MRR), often denoted as Q, is a critical machining metric that represents the volume of material removed from a workpiece per unit of time. In drilling operations, calculating the MRR allows machinists and engineers to estimate productivity, calculate power requirements, and optimize cycle times.
The MRR Formula for Drilling
Drilling is essentially a process of removing a cylinder of material. The rate at which this cylinder is formed depends on the cross-sectional area of the drill and the speed at which it penetrates the material.
The standard formula used in this calculator is:
Q = (π × D² / 4) × f_n × N
Where:
- Q = Material Removal Rate (cm³/min or in³/min)
- D = Drill Diameter
- f_n = Feed per Revolution (how deep the drill goes in one turn)
- N = Spindle Speed (RPM)
Why is MRR Important?
- Efficiency Analysis: Higher MRR means faster production, but it must be balanced against tool life.
- Power Consumption: The power required by the machine spindle is directly proportional to the MRR. Knowing the MRR helps prevent stalling the machine.
- Chip Evacuation: A high MRR generates a large volume of chips. If the drill flutes cannot evacuate these chips fast enough, the tool may break.
Example Calculation
Let's assume you are drilling a hole using a 12 mm diameter drill bit. The spindle speed is set to 1,500 RPM, and the feed rate is 0.2 mm per revolution.
- Calculate Penetration Rate: 1500 RPM × 0.2 mm/rev = 300 mm/min.
- Calculate Area: Area = π × (12/2)² ≈ 113.1 mm².
- Calculate MRR: 113.1 mm² × 300 mm/min = 33,930 mm³/min.
- Convert to cm³: 33,930 / 1000 = 33.93 cm³/min.
Metric vs. Imperial Units
This calculator switches between Metric and Imperial systems. In the Metric system, MRR is typically expressed in cubic centimeters per minute (cm³/min). In the Imperial system, it is expressed in cubic inches per minute (in³/min).