How to Operate a Milling Machine Safely

Machining requires saftey awareness to prevent injury.

Milling machines can be dangerous due to the speed at which they cut. If handled improperly, the material they mill can also damage your skin. Most CNC (computer numerical control) machines have built-in safety features that protect machinists from flying metal chips, but manual mills provide no such safety. You must use caution when working with either type, as freshly-cut metal is razor sharp. Small chips on the table can cut skin easily, while chips flying around during the cutting process can lodge in your eyes.

Things You'll Need

• Gloves
• Eye protection
• Chip shield

Instructions

Manual Milling Machine

1. Secure the workpiece tightly. Since you often work with sharp metal and high RPM on a manual mill, make sure the material is never loose. Use a vise, or clamp your raw material to stop it from flying off the table and causing injury.

2. Use a shield when you machine soft metals without coolant. Water-soluble oil cools the metal while it is cut. Often coolant is not used for machining metals, and the chips that come off the piece are hot enough to burn the skin. If a shield is unavailable, fabricate a makeshift version with fire-resistant material.

3. Always wear gloves when working with raw metal. When metal is cut on a milling machine, the edges are sharp and often need to be filed. Handling this sharp metal without gloves is dangerous and can cause serious injury. Eye protection is also essential to protect your vision from chips and coolant spray, as manual mills are not enclosed.

4. Keep gloves, hands or long hair away from the spinning tools. If anything catches in the spindle, serious injury may occur. Note the location of the stop button in order to cut power if something happens while you work with a manual milling machine.

CNC Milling Machine

1. Make sure all safety features of the CNC machine function. They exist to prevent damage to the machine, and to protect you against injury. Check the safety features every year to ensure nothing malfunctions. An authorized repair technician can perform this safety check.

2. Keep the milling machine doors closed when machining. Observe the process through the window of the machine. The window can absorb the impact from large chips or loose parts. Never override this feature. If the window is dirty or damaged, clean or replace it before you begin milling.

3. Tighten all tooling in their respective tool holders. Loose tools can damage the machine and injure you. When a tool breaks, stop the machine immediately to change the tool, and redo the operation. If a tool breaks and does not cut, the next tool in line may crash, causing many problems.

4. Always wear gloves when working with CNC mills. Gloves protect you when you handle the raw and recently-cut material. Safety glasses or goggles are also necessary to protect your eyesight from hot metal chips during the cutting process, and when using compressed air to clean the machining area.

References

• Canadian Centre for Occupational Health and Safety: Milling Machines
• Machine Tool Help: Machine Cutting Fluid Coolant