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Better Tool Library - Feeds & Speeds calculator

The built-in Feeds & Speeds Calculator may be one of the most powerful on the market. It isn't just a "naive, basic, calculator", but rather an optimizing calculator that "renders and simulates" your tool.

It can also visualize the result.

Credits: The algorithm is based on the work done by Bryan Turner. Check out his work!

Features

It takes into account a dozen of factors:

Factor
Tool shape
Tool elasticity
Tool inertia
Tool endpoint deflection
Tool angular deflection
Tool min and max chipload
Tool bend limit
Tool shear strength
Tool shank vs flute strength
Material/Tool-specific power factor
Material/Tool-specific chipload table
Material/Tool-specific min/max speeds
Spindle power
Spindle torque (naive torque curve)
Spindle min/max RPM
Machine feed limit

Known Limitations

  • Only the following types of tools are supported:

    • Square endmills
    • Torus (=rounded corners)
    • Ballend
    • Chamfer
    • V-Bit

  • Tools that are wider than they are long (stickout) are not supported.

  • The calculator outputs SI units (metric) only. All input fields support entering any supported unit and the calculation should succeed, but the calculator output is displayed in SI units only. If you want support for imperial outputs, please submit a pull request.

Supported units

  • International (SI): nm, um, mm, cm, dm, m, km, Nm, W, kW
  • Imperial: in, ft, yd, mi, lbs-in, HP

Screenshots

Feeds & Speeds

Instructions

One time set-up: Creating a machine

Before using the Feeds & Speeds calculator, you have to let BTL know your machine parameters. This is done as follows:

  • Open BTL by clicking the icon in the task bar:

Toolbar

  • If not done already, create a library (File -> Create Library) and your tool bit first (File -> Create Tool)
  • Once the tool is created, open the tool editor by double-clicking on the tool in the BTL main window.
  • Switch to the "Feeds & Speeds" tab.
  • At the top, press "+" to create your machine.

Note about machine parameters: The torque is important and has a big impact on the calculator. If in doubt, aim low. For reference, my 2.2 kW China spindle provides realistic results at around 4 Nm max torque.

Running the calculator

  • First, make sure your tool is all set up and all parameters are correct. The tool material is especially important (HSS, Carbide).

  • If your tool does NOT have a chipload defined (i.e. chipload = 0), then the calculator will estimate an ideal chipload for you, based on the material of the tool, and the material you are milling.

  • Then, switch to the Feeds / Speeds tab. For the initial setup, you will have to define a machine by pressing the "+" button. This is a one-time activity, BTL will remember your machine. See the instructions in the previous chapter of this document.

  • The stickout is also very, very important. By default, BTL estimates the stickout to be the Flute Length + 3mm. Try to minimize stickout for a better result.

  • If you want to contribute more materials, check out the required parameters here.