1. What is Milling Plastic Feeds and Speeds Calculator?

Definition: This calculator determines the optimal spindle speed (RPM) and feed rate (IPM) for milling plastic materials.

Purpose: It helps machinists and CNC operators achieve efficient material removal while preventing tool damage or material melting.

2. How Does the Calculator Work?

The calculator uses two formulas:

Where:

• \( RPM \) — Spindle speed (revolutions per minute)
• \( SFM_{plastic} \) — Surface feet per minute for plastic
• \( D \) — Tool diameter (inches)
• \( IPM \) — Feed rate (inches per minute)
• \( IPT \) — Inches per tooth (chip load)
• \( Z \) — Number of teeth on the cutter

Explanation: The first formula calculates spindle speed based on material and tool size, while the second determines feed rate based on chip load and tool geometry.

3. Importance of Proper Feeds and Speeds

Details: Correct settings prevent tool breakage, material melting, poor surface finish, and ensure efficient material removal.

4. Using the Calculator

Tips: Enter SFM for your plastic type, tool diameter, chip load (IPT), and number of teeth. Typical SFM values range from 200-600 for plastics.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical SFM for acrylic?
A: 300-400 SFM is common for acrylic, but always check manufacturer recommendations.

Q2: How does IPT affect milling?
A: Too high IPT can cause tool breakage; too low can cause rubbing and heat buildup.

Q3: What if my plastic is melting?
A: Try increasing RPM, decreasing IPM, or using compressed air for cooling.

Q4: How do I find IPT for my tool?
A: Check tool manufacturer specs or start with 0.002-0.010 in/tooth for plastics.

Q5: Should I use coolant when milling plastic?
A: Generally no, but compressed air is recommended to clear chips and prevent heat buildup.