The Complete Guide to CNC Mill Feeds and Speeds
WRITTEN BY BOB WARFIELD
Getting the best possible results from your CNC machine requires a solid grounding in Feeds and Speeds as well as many related tips and techniques. This Guide will walk you through the details. You can either treat it as a course, or use search and this table of contents page to zero in on specific topics. There is a lot here in terms of tips and techniques that go beyond straight up feeds and speeds too!
To begin with, there are several different goals we might be trying to optimize for:
- Best Material Removal Rates
- Maximizing Tool Life
- Good surface finish
You'll need to decide what your priorities are among these three, as different techniques emphasize each goal and you can't necessarily get great surface finish, maximum material removal rates, and the best tool life all at once.
In this series of articles, we'll go through some CNC Cookbook recipes that help you achieve your goals, whatever they may be. You'll learn a many ways to become a Better CNC'er through improved Feeds and Speeds as well as other techniques. This is the one-stop in-depth place where we talk in great detail about cutting-related issues of all kinds. Each article is a short bite-sized nugget of CNC Knowledge, so it's easy to get through it all a little at a time, or to jump ahead directly to a topic you need to focus on fast.
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To help you absorb, master, and put into effect all of this, we recommend you get a free 30 day trial copy of our G-Wizard Feeds and Speeds Calculator. It will let you work along with the many examples in this Guide, and by being able to experiment with the numbers and ask your own "What-If" questions, it'll make you much more familiar with the concepts. Playing with the different scenarios will help you to improve your intuition and gut feel about all sorts of cutting situations. The trial is plenty long enough for you to get through this course completely free.
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Table of Contents
Section 1: Basics Every Machinist Should Know
Basic Concepts for Beginners: You gotta start somewhere!
More visually oriented? Try a Quick Video Course in Feeds and Speeds.
Chiploads, Surface Speed, and Other Concepts: Key concepts and terminology.
Calculating Feeds and Speeds: How do you calculate your feeds and speeds? (Hint: Use a state of the art Speeds and Feeds Calculator)
Calculating Feeds and Speeds with G-Wizard: See some quick videos and a tutorial on how it works.
Toolroom vs Manufacturing Feeds and Speeds: Do you know the difference between toolroom and manufacturing feeds and speeds?
INFOGRAPHIC: Why you need a Feeds and Speeds Calculator
Coolant and Chip Clearing: Best practices for coolant and chip clearing on the mill.
What Now: My CNC Won't Go Slow Enough or Fast Enough? CNC Router and DIY users especially, check this one out. These are workarounds for cases when you can't get to the right feeds and speeds because your machine can't feed fast enough or turn the spindle slow enough. It's a blog post, not part of the tutorial, but it can really help.
Is Carbide Always Faster? If your machine's spindle won't go as fast as carbide can in softer materials, maybe HSS is the answer. Let's put together what we've learned so far and explore it further.
Section 2: Up Your CNC Game
Tips for Getting the Best CNC Milling and Turning Surface Finish: And the truth about mirror finishes.
Turning Down the Heat in a Cut: Reducing heat prolongs tool life.
Dry Machining: Yes, you can machine without flood coolant. Often, it's even better.
Tool Deflection Control: Critical to Your Success: Are you in control of tool deflection, or is it something that just happens?
Cut Depth and Cut Width for Pocketing: How to choose these to maximize tool life and MRR's.
Climb Milling vs Conventional Milling: There are times when Conventional is better!
Toolpath Considerations: How is your CAM program treating your tooling?
What Now, My CNC Won't Go Fast Enough or Slow Enough? Sometimes the recommended Feeds and Speeds are not something your machine can even do. This blog post is designed to help you around those problems.
INFOGRAPHIC: 4 Ways Geometry Affects Your Machining and What to Do About It
How to Choose Stepover for 3D Contouring: Choose the best stepover for speed and surface finish.
Guides for Specific Cutter Types
Our Guides for Specific Cutter types includes articles that have tips, techniques, and feeds and speeds information for specific cutter types including twist drills, CNC Router cutters, face mills, engraving tools, broaching, and many more.
Material Specific Guides
Our Guides for Specific Materials includes articles that have tips, techniques, and feeds and speeds information for specific materials including Aluminum, Stainless Steel, Composites, Wood, Plastics, and many more.
Section 3: Making You the Expert!
High Speed Machining: Tool Engagement Angle, Trochoidal Milling, Peeling, and all that Jazz.
Plunge Roughing: Try this special technique when rigidity or machine performance are making things difficult.
Dealing With Chatter When Milling: Fixing Chatter via Rigidity or Tuning Speeds and Feeds.
Carbide vs HSS and Chatter for Small Mills
Micro-Machining: How to avoid breaking those tiny little cutters.
Premium Coolant Options for CNC: Programmable Coolant Nozzles, Through Spindle Coolant, High PressureCoolant, and more.
What is Cryogenic Machining? Learn the advantages of using Liquid Nitrogen as a coolant.
Long Reach Tools, Thin Walls, and Other Rigidity Challenges
Milling Tough Materials
Using a Cutting Knowledge Base to Beat Manufacturer's Recommended Feeds and Speeds
More Feeds and Speeds Resources
CNCCookbook Blog Posts Relating to Feeds and Speeds: Lots more in-depth information in bite-sized posts.
10 Tips for CNC Router Aluminum Cutting Success: Take these shortcuts and skip a lot of pain.
7 Software Excuses for Bad Surface Finishes: It isn't just about Feeds and Speeds.
Thinning and Other Ways to Speed Your Cuts: Learn about cases where
you should be upping your speeds and feeds and how to exploit them.
CNC vs Manual Cutting Speeds: Why is CNC so much harder to figure out?
Tips for Improving Surface Finish on Mills
Maximizing Material Removal Rates
Tips for Longer Tool Life
Recipes for Increasing Workholding Rigidity
Recipes for Toolholders and Tooling
A Quick Video Course in Feeds and Speeds