Tapping creates internal threads in previously drilled or punched holes, allowing threaded fasteners to be used in the finished assembly. WSi supports both standard tapping and sheet tapping (thread-forming in thin sheet metal without a pre-drilled hole).

When to use this process

Use Tapping when:

• The design requires threaded holes for assembly or attachment
• You need to specify thread size, pitch, and depth for CNC tapping operations
• Thin-sheet applications use sheet tapping (thread-forming) rather than cutting threads

Tapping is supported on Sheet cutting, Sheet bending, and Tube cutting workstep types. In WSi v3 and above (or with the experimental tapping feature enabled), the full tapping workflow is available.

Step-by-step

1. Select the Sheet Cutting node or Die Bending node in the Tree View or Graph View.
2. Right-click the node and choose Append node(s) (or Prepend node(s)) from the context menu.
3. In the process selector dialog, choose Tapping. WSi shows proposed thread positions from the hole geometry. Review thread size and pitch.
4. Adjust any parameters as needed.
5. Click OK. A Transform node (Tapping) appears in the Graph View.

Result

After running Tapping:

• A Transform node (Tapping) appears in the Graph View
• The Tree View shows thread positions, sizes, and any warnings
• Export data includes thread specifications for CNC machining equipment

Editing thread parameters

To change thread parameters after the Tapping node is created, right-click the Tapping node in the Graph View and select Edit num. threads to adjust how many threaded holes are produced, or Edit Tapping Parameters to change the thread size, pitch, or depth for individual holes.

For sheet-level tapping overrides, right-click and select Edit Sheet Tapping Parameters to configure thread parameters at the sheet level rather than per-hole.

WARNING

Tapping is available in WSi v3 and above, or when the experimental tapping feature is enabled in your licence. If the feature is not available, contact your sales representative at WSoptics.

Parameters

The parameters for this process are configured in the database — see the Tapping page.

Technical Background

Tapping cuts or forms an internal thread in a pre-drilled (or self-drilled) hole so that a threaded fastener can be inserted and secured. There are two main approaches: thread cutting and thread forming.

Thread cutting uses a tap — a hardened tool with thread-shaped flutes — that is rotated into the hole. The flutes evacuate the chips (swarf) as the threads are cut. This requires a pre-drilled hole slightly smaller than the thread's outer diameter. Hand tapping turns the tap by hand using a T-handle and is used for maintenance, low volume work, or hard-to-reach holes. Machine tapping uses a CNC machine or tap unit that rotates the tap at controlled RPM and feed rate, which is the method of choice for production work.

Thread forming (also called sheet tapping) uses a forming tap with no flutes that is pressed into the hole, displacing the material to create threads. No chips are produced, which is cleaner and faster. This method only works in ductile materials such as aluminium and soft steel, and is most effective in thin sheet.

Hole diameter is critical: too small and the tap will break; too large and the resulting thread will be shallow and weak. Tapping is typically the last operation before assembly, and threads must accept the specified fastener without going too deep or bottoming out.