Sophisticated CNC machines have revolutionised the world of manufacturing. Especially for timber producers, maintaining a variety of CNC machine tools allows them to craft higher quality, more consistent products than ever. Despite the complexity of CNC machines themselves, the tools they use are relatively simple technology. The affordability and accessibility of tools means manufacturers can take advantage of CNC machines to improve the way you do business.
Having a variety of tools on hand allows CNC machines to handle a wide range of complex tasks, improve the efficiency of production lines and reduce the need for manual labour. Changing between these tools is a simple process, but operators require specific training to ensure they get it right.
Manual CNC Tool Changes
CNC technology isn’t limited to large-scale timber manufacturing. Many smaller workshops – like furniture makers and sign makers – employ CNC routers to improve the quality and consistency of their products. By maintaining a catalogue of common CNC tools, small-scale timber manufacturers can perform a range of cutting, carving and profiling tasks without the need for expensive manual labour.
A manual tool change operation can be included in the operations of most types of 3 axis CNC machines. When the tool change occurs the machine will automatically pause and the operator will need to:
- Zero the spindle. First, the spindle is brought to its home position. This can be done manually, or some machines may handle it automatically.
- Move to the tool change position. From its zero position, the spindle can then be moved to a convenient position to change the tool. Tool change positions can be preset to avoid the need to manually operate the machine.
- Replace the tool. The tool can now be released from the spindle by loosening the chuck. Replace the tool with the next one in the operation and re-tighten the chuck before continuing.
- Zero the spindle. The spindle will need to be brought to its zero position once again to help the machine identify its location relative to the workpiece.
- Resume the program. Once the spindle is zeroed, the cutting program can be unpaused.
Using Automated CNC Tool Carousels
The entry-level CNC machines found in small-scale manufacturing rely on manual tool changes. But, commercial CNC machines found in high volume, high speed manufacturing environments need automated solutions. Automatic tool changes allow CNC machines to change tools without pausing or stopping production. This means that the CNC machine can perform complex cutting programs that call for multiple tools as part of a single operation. This type of technology is often found in large-scale manufacturing for products like moulded components, doors and window frames.
Automatic tool changes are similar to the procedure for manual tool changes. Depending on the type of CNC machine being used, the automatic tool change procedure has four key steps:
- Zeroing the spindle. The spindle is brought back to its home position relative to the cutting surface. This ensures that a new tool can be selected without damaging the component, the tool carousel or the CNC machine.
- Choosing a new tool. From its home position the spindle will move to the tool carousel, deposit the current tool in its designated spot, and pick up the next tool it needs.
- Measuring the offset. The offset of the new tool will need to be measured before operations can continue. The offset is a measurement of the length of the tool. In manual tool changes this is usually set by hand, but during automatic operations the offset of each tool is programmed into the system.
- Resume cutting. With the new tool in place the CNC machine can resume its cutting operation.
The Benefits of Changing CNC Tools
Most manufacturers carry a variety of CNC machine tools to ensure they always have the appropriate equipment on hand. Being able to change to different tooling at a moment’s notice allows you to unlock a few key benefits:
- Perform more complex processes. Different types of CNC tools have their own strengths and weaknesses. Some tools are better suited to particular types of processes, meaning the ability to switch tools allows your machine to perform multiple tasks as part of the same program. For example, changing tools could allow you to profile a shape into a workpiece and then pick up a new tool to cut out the component from the material stock.
- Manage tool condition. CNC tools all have a limited lifespan. As the tool blunts, the quality of the finished product begins to decline. High volume manufacturers can keep duplicates of important tools on hand and automatically switch to a new tool as the old one wears out.
- Switch between programs quickly. Automatic tool changes allow a CNC machine to change to new programs quickly and efficiently.
- Maximise tool uptime. Commercial CNC machines can cost millions of dollars. That means every minute of uptime counts. Automatic tool changes can occur in just a few seconds, maximising machine uptime in high demand production environments.
