This article has been replaced. Click here to read our new safety guide. 

Introduction

When using SmartBench, you need to be sure to keep safety in mind at all times. If you are using SmartBench in the correct way, you significantly minimise the risk of any incidents that may arise. Before using SmartBench, we strongly recommend you read the following information.

Machine attendance

Never leave machines unattended. We understand that a CNC machine is automated, reducing the need for human intervention. However, if something were to go wrong, you are expected to be able to react to the situation in a timely manner.

Risk of fire

When using any CNC router, It’s always best to minimize the risk of fire in the first place. You can never eliminate it, but you can reduce practices that outright encourage it.

There are a number of factors which can cause this:

Processing flammable materials

Materials can vary in flammability. This is certainly increased when processing woods with resins (Pine and birch plywood) which can act as an accelerant. The humidity can also cause woods to become more dry, meaning heat build up can happen faster.

Improper feeds and speeds

Use the proper feeds and speeds. Improper feeds and speeds can lead to rubbing, which generates excess heat, which can lead to fires. Please see our published feeds and speeds article here

If you’re in doubt about a new job, run it for a minute or two, stop the spindle, and check the cutter temperature. If it’s too hot to touch, you should try to fix it with better feeds and speeds or a new cutter.

Dull or blunt cutters

Use sharp cutters. Cutters can dull rapidly, especially when you’re cutting materials like plywood or MDF that can often contain grit. Use carbide for these materials and make sure you’re replacing the cutter often enough. A dull cutter can cut the material, but rub at the same time and build up heat quickly.

Variation in extraction

Clear the Chips! Speaking of chip clearing and ramping, any time the cutter is re-cutting the same chips the potential exists to create more friction and more heat and there’s more material right next to the source of the heat to catch fire.

Incorrect toolpath

Ramp into your cuts–don’t plunge. Ramping in a straight line or helixing down in a circle is a much gentler entry to a cut than plunging the cutter down like a drill. It makes it easier to clear the chips from the cut out of the way.

Incorrect cutter type

Use the right cutter if you are plunging. In particular, never plunge a down cut or compression bit. They force the chips down into a hole where they have no place to go. This can create heat and provide fuel that very quickly leads to a fire.

Fire Safety

After initially reducing the risk of a fire, you also need to think about what to do should the above preventative measures not work.

It’s often hard to see a fire as it may be just a little smouldering ember of your spoil-board, buried under your workpiece. 

1.  Never leave the machine unattended unless you’ve invested in purpose-built CNC Router fire sensing and suppression equipment for Lights Out operation.  It’s so tempting to walk away from a CNC Machine to do something else, and you can do that to an extent with a router, but stay close enough to spot the signs of fire if they are there. Never leave one running alone in a room by itself.

2.  At the first sign of smoke or the “red cherry” that often signifies a fire is underway, you need to check whether there is a fire. You need to have worked out your procedures for what to do when checking.

If you are running a vacuum pump, remember that it is feeding the fire oxygen, but turning it off may make the fire flare up and engulf the spindle of your machine. You’ll want to get that spindle up and away from the scene of the potential fire first and quickly. Then shut down the vacuum pumps and take a careful look at what’s going on.

Blow or brush the chips out of the area so you can see better. Take care not to shift the work if you plan to go back to it when you turn the vacuum table back on.

3.  The smoke smell may be at the exhaust of your vacuum or dust collecting system. Are you in a position to notice that?

4.  What are the chances the fire could be sucked into a vacuum or dust collection system where there is potentially a lot more fuel handy? Are you set up to spot that problem quickly before the fire gets serious?

5.  If a cutter breaks, conditions may have been optimal for a fire.  Pay particular attention to the possibility each time a cutter breaks.

6.  You can’t rely solely on normal fire detection sensors. Smoke alarms and the like will typically require the fire to get much further out of hand than you’d like before they’re triggered. They’re not a substitute for properly monitoring the machine while it works.

7. Have a suitable fire extinguisher nearby in case a fire does break out. For electrical item you will need a either a dry powder or CO2 extinguisher.

You can find more information on CNC router safety here.