Rake Angle Guide for Machining

At Istar Machining, we know that getting the rake angle right can make a big difference in your machining results. This guide will help you pick the best rake angle for your job.

What is a Rake Angle?

A rake angle is the angle between the cutting tool’s face and a line straight up and down from the workpiece. Think of it like the slant on a knife. The right angle helps cut better.

When we make custom metal machining parts at Istar Machining, we always check the rake angle first!

Types of Rake Angles

There are three main types:

1. Positive Rake Angle

• Good for: Soft metals like aluminum and copper
• What it does: Cuts with less force
• When to use it: For soft, sticky materials
• Look: The tool face slants back away from the cut

2. Negative Rake Angle

• Good for: Hard metals like hardened steel and cast iron
• What it does: Makes the tool stronger
• When to use it: For tough materials and rough cuts
• Look: The tool face slants toward the cut

3. Neutral Rake Angle

• Good for: Some brittle plastics
• What it does: Balance between the other types
• When to use it: Not used much

At Istar Machining, our precision cnc machining experts know exactly which rake angle works best for each job!

Rake Angles for Different Materials

Use this table to help pick the right angle:

When doing cnc milling at Istar Machining, we use this chart to get the perfect finish every time!

How to Measure Rake Angle

You can measure rake angle with:

1. Protractors – These are simple tools that show angles
2. Special microscopes – These give very exact measurements
3. Digital tools – These can be the most exact

Picking the Right Rake Angle

To pick the best rake angle, think about:

1. How hard is your material?
   • Hard materials = lower or negative rake
   • Soft materials = higher positive rake
2. How fast are you cutting?
   • Fast cuts = might need lower rake
   • Slow cuts = can use higher rake
3. Are you using cutting fluid?
   • With fluid = can use higher rake
   • Dry cutting = might need lower rake

Our cnc turning team at Istar Machining checks all these things before starting a job!

Case Study: How Rake Angle Affects Cutting

We tested different rake angles on steel and found:

This shows that:

• 0° rake had the lowest cutting force and smoothest finish
• Negative rake had more force and faster tool wear
• The right angle depends on what’s most important for your job

Tips for Different Materials

For Steel:

• Use 8-14° rake angle
• Hard steel needs lower angles
• Use cutting fluid when possible

For Aluminum:

• Use 12-25° rake angle
• Polished tool faces help prevent sticking
• Higher rake helps with chip flow

For Titanium:

• Use 0-4° rake angle
• Negative rake can help with heat
• Slower cutting speeds work better

For Cast Iron:

• Use 3-6° rake angle
• Good for making short chips
• Helps tool last longer

At Istar Machining, we have special tips for aluminum cnc machining to get the best results!

Common Problems and Fixes

Problem: Tool breaks too fast

• Fix: Use a lower rake angle to make the tool stronger

Problem: Poor surface finish

• Fix: Try a more positive rake angle for smoother cuts

Problem: Material sticks to the tool

• Fix: Increase rake angle and use cutting fluid

Problem: Too much heat

• Fix: Use a less positive or negative rake angle

How Rake Angle Affects Your Job

Changing rake angle can:

• Make tools last 20-30% longer
• Cut with 15-25% less force
• Change cutting temperature by 10-15%
• Save 12-18% on machining costs!

Quick Guide for Picking Rake Angle

1. For soft, sticky materials (aluminum, copper):
   • Use higher positive rake angles (12-25°)
2. For hard, tough materials (hardened steel, titanium):
   • Use lower or negative rake angles (0° to -5°)
3. For shallow cuts and fine finish:
   • More positive rake works better
4. For deep cuts and roughing:
   • Less positive or negative rake is stronger

Why Rake Angle Matters at Istar Machining

At Istar Machining, we know that the right rake angle means:

• Better part quality
• Longer tool life
• Faster machining
• Lower costs

When you work with us for cnc parts machining, you get parts made with the perfect rake angle for your material and needs!

Questions People Ask About Rake Angle

Summary

The right rake angle makes a big difference in machining. Remember:

• Positive rake (12-25°) is good for soft materials
• Negative rake (-5° to 0°) is good for hard materials
• Consider material, cutting depth, and finish needs
• The right angle saves money and time

At Istar Machining, we use our rake angle know-how to make perfect parts every time! Contact us for all your precision CNC milling needs.