Flint on steel coupled with some easily-combustible kindling makes for a cozy fire. That combination is just one of the tricks up a scout’s sleeve for survival. However, that same formula can spell trouble when milling woods, plywood, or even plastics. Fast-moving metal tools cutting against combustible materials can result in a not-so-cozy fire on a workpiece, in piles of cuttings and shavings, or in a dust collector.
CNC fires are not only costly, but they are also dangerous and potentially deadly. To mitigate the potential risks associated with machining combustible materials, here are four tips to help you prevent machining fires.
Know Combustible Materials
For a fire to start, there needs to be a spark and an oxygen source. For it to catch, it needs fuel. In the context of CNC machining, that fuel is a combustible or flammable material. Wood, plywood, and paper materials are common sources of fuel. Plastics are also excellent fuel sources – after all, they are made of petroleum. However, as outlined by OSHA, dust is also a common source of combustible fuel, including metal dust. With this in mind, it’s wise to adhere to fire prevention procedures no matter what material is being machined.
Check Feeds and Speeds
Maintaining proper feeds and speeds is important for addressing all sorts of machining concerns, from poor surface finishes to improper tool wear. So, it should be no surprise that using proper feeds and speeds is beneficial for fire prevention as well. Incorrect feeds and speeds can increase friction, which in turn generates heat. With materials like wood, it’s also essential to adjust the cutting depth so you’re not cutting into the spillboard to prevent heat buildup.
A spinning tool sitting and dwelling can generate a great deal of heat in a short amount of time. That heat buildup can quickly reach the point of combustion and spark a fire. In addition to potentially burning a workpiece, that hot spot can easily ignite chips or dust. Smoldering dust and chips can carry flames into collections systems, causing a fire to spread.
Have a Fire Safety Plan
Any shop’s safety plan should include fire response procedures. Fire extinguishers should be readily available, in an accessible location, and in proper working condition. Some operations, especially those handling a large number of flammables or generating a significant amount of dust, should consider a fire suppression system, facility alarms, automated emergency call systems, and evacuation procedures. Even for small or single-person facilities, a fire response plan is critical.
The good news is, machining combustible and flammable materials can be safe and easy as long as the risks are mitigated with proper precautions.