GWizard: The Ultimate CNC Feeds & Speeds Calculator

Mastering Feeds & Speeds with GWizard — A Beginner’s Guide

Purpose: Learn how to use GWizard to calculate feeds, speeds, and cutting parameters for CNC milling and turning.
Audience: Beginners with basic CNC knowledge who want practical, step-by-step instructions.
Outcome: Be able to produce safe, efficient cutting parameters and understand the trade-offs between speed, tool life, and surface finish.

GWizard is a feeds & speeds calculator tailored for CNC machining that helps choose spindle speed (RPM), feed rate, chip load, and cutting depth based on tool, material, and machine constraints.
It reduces trial-and-error, helps prevent tool breakage, and can extend tool life by optimizing parameters.

Set machine limits
- Enter your machine’s maximum RPM, maximum feed rate, and maximum horsepower/torque.
Select material
- Choose the workpiece material (e.g., 6061 aluminum, mild steel, stainless) so the software can apply appropriate cutting data.
Pick the tool
- Enter or choose tool diameter, number of flutes, coating, and material (carbide/HSS).
Define operation
- Select milling vs turning, and the operation type (slotting, side milling, drilling, etc.). Specify axial and radial depths of cut.
Generate parameters
- Let GWizard compute RPM, feed rate, chip load per tooth, and estimated horsepower. Review recommended adjustments for tool life vs productivity.
Simulate and adjust
- Use conservative starting values if unsure. Increase speeds gradually while monitoring tool wear, chatter, and part finish.
Document and save
- Save setups for recurring jobs and note any shop-specific tweaks (coolant use, tooling brands).

Chip load (IPT/MMT): The thickness of material removed per tooth—primary determinant of tool life.
Surface speed (SFM/M/min): Material-dependent suggested cutting speed; higher speeds increase productivity but can shorten tool life.
Axial vs radial depth of cut: Axial is lengthwise engagement; radial is side engagement. Radial engagement has a larger effect on cutting forces.
Material removal rate (MRR): Volume removed per minute; balances productivity with power and tool limits.

Start conservative: Use lower RPM/feed than the maximum recommendation for your first run.
Watch for chatter: Reduce radial engagement or speed if you hear vibration.
Use proper coolant: Especially for ferrous materials to manage heat and chip evacuation.
Keep a log: Track what worked for each tool/material combination to build a shop database.
Use chip thinning adjustments when machining with small stepovers or high helix angles.

Using too high a feed for a small-diameter tool.
Ignoring machine power limits—overloading causes poor finish and tool failure.
Neglecting tool runout and spindle condition—these dramatically affect recommended chip loads.