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CNC Guide

A guide to using the Shopbot CNC machine in MAKE ll at Library 21c

Adding Your Own Bits

If you brought your own tools to use with the CNC, you will need to manually add them to the Tool Database in VCarve. To add new tools, open VCarve and either start a new file or open an existing one. Then, in the Toolpaths menu, select Tool Database. In the lower left corner below the list of tools is the menu for managing tools.

From left to right:

  1. Add a new tool (first click on a group name if you want it to automatically be added to a group).
  2. Add a new group (click on a group name to create a subgroup).
  3. Copy the selected group or tool.
  4. Import a tool database, which can either replace the existing database or be merged into it.
  5. Export the selected tool or group that can be imported later on. Selecting a group will include all tools and subgroups so to export the entire database, choose the top most group name.
  6. Remove the selected tool or group. Deleting a group deletes all tools in that group.

Additionally, tools and groups can be reordered or moved to other groups by dragging and dropping the names on the tool list.

Adding Tools

Caution! VCarve does not know what is in the spindle, only what the settings tell it. Incorrect information can result in damage to the tool and the material.

When you first click the button to add a new tool, it will prompt you for the type of tool, diameter, and number of flutes. You can also add notes / a description, set what units to use, and rename the tool. Click "Create Settings" and it will display the rest of the form with the fields automatically propagated with default values. Chance any values you need and then click "Apply" to finish adding it to the database.

Things you will need to know before adding a tool:

  1. Geometry - The diameter of the tool. This refers to the cutting part, not the diameter of the shaft that goes into the spindle.
  2. Pass Depth - How far the tool will plunge into the material on a single pass. Do not exceed the tool diameter, but most of the time it should be half the diameter.
  3. Stepover - How far forward the tool will move after finishing a line during clearance cutting. Normal is between 10-49%, with 50% being equal to the diameter of the tool. Higher number can result in faster cuts but run a higher risk of damaging the tool.
  4. Spindle Speed - How fast the spindle moves in rpm. Higher speeds can clear more material but may risk damaging the tool or material. Ideal spindle speed is specific to the material - see the "Calculating Chiploads, Feed Rates, and SPindle Speeds" section for more information.
  5. Feed Rate - How fast the tool will move along the XY axis while cutting. This is also related to chip load and ideal rates depend on the material. Most of the time the feed rate should be around 1 in/sec for woods.
  6. Plunge Rate - How fast the tool will move along Z axis.1/4 - 1/2 in/sec is ideal for most tools.
  7. Tool Number - An index number for the entry. To prevent warnings and false error messages, use a unique number for each tool.

Some types of tools have different information requirements. Most of the time this information can be found on the manufacturer of the tool's website.

Copying Tools & Groups

When you copy a tool, a second entry is automatically added under it (if you copied a group, the group and entries are all added). However, the new entries are not yet in a state that can be used. In order to make the tool usable, you will need to finalize it by confirming what tool you are copying over and then clicking Copy. Change any information if necessary, and then click Apply to make it fully usable.

Important Note

The library PCs that have VCarve installed are all in a frozen state so any information on them will be lost when the computer is rebooted, including changes to the tool database. Therefore, if you want to preserve your changes, you must export the tool database and store it off of the computer (such as on a flash drive or in cloud storage).