Advanced Precision Machining

Improving Machine Shop Safety; APM Revisits Key Safety Fundamentals

[August 12, 2019] The following scene, unfortunately, plays out on the machine shop floor – an experienced employee accidentally leaves a hand tool inside a CNC milling machine. He reaches in to retrieve it and unknowingly, a co-worker proceeds to power up the machine resulting in serious bodily injury. As a result of modern safeguards, thankfully such a worst-case scenario is rare, but almost every kind of dangerous hazard can be found in a milling and machining environment. It’s a well-known fact that machine shops present many unique hazards distinct from those in other workplaces, and at Advanced Precision Machining (APM), what we more often have to remind ourselves of, and what we preach and practice, is basic machine shop safety. 

The generalized information presented in this post is by no means new, but due to the recent increased demand for high-speed milling and machining services high-speed milling and machining services, our industry is experiencing an influx of new CNC machinists. The bottom line is that even among more experienced workers at times, complacency sets in no matter what a workers skill level may be. At APM’s Colorado machine shop, we have an extensive safety and occupational health program, including some very basic operator and machine tool safety guidelines we'd like to share with readers. Running a safe facility starts and ends with the health and well-being of all employees. No matter the size of the operation, every machine shop has a variety of equipment running, each with potential hazards. From a CNC machine operator perspective, our general safety guidelines focus on:

Operator Safety

1. Eye Protection:

Milling and turning machines produce metal chips, dust, and shavings known in the industry as swarf, which can become ejected causing eye injuries. In addition, mills, lathes, and routers contain cutting tool assemblies made of hardened steel, which have the potential for breakage while rotating at very high speeds. Modern CNC machines are outfitted with guards and are fully enclosed, but unfortunately, accidents still occur as chips and other material can escape. ANSI-approved eye protection such as impact protection safety glasses or goggles with side shields should be worn at all times, including over prescription eyewear.

2. Noise Protection:

High-intensity noise is an ever-present companion on the machine shop floor, with levels sometimes reaching 100 decibels or more. A good rule of thumb is if you can't carry on a normal conversation without raising your voice, then the sound is approaching unsafe levels. Prolonged or repeated exposure can result in noise-induced permanent loss of hearing. Therefore, OSHA-approved hearing protection such as earmuffs or soft, moldable earplugs must be worn.

3. Respiratory Protection:

In addition to the unsafe and not recommended practice of processing toxic or flammable materials, a precision manufacturing facility, unfortunately, produces a number of byproducts that, when inhaled, have potential health impacts. Grinding dust, machine tool coolants, lubricants, and certain heated metals all produce fine particles, fumes, and mist. When working without proper ventilation, such as fans and ducting, or vacuum systems, or if you are unsure of a material being machined, it is advisable to always wear a respirator.

Machine Tool Safety

Because specific safety instructions vary depending on the machine, the following represents a general, partial list of the top 10 guidelines we feel are inherent to working with any CNC machine, taken from the ILO Encyclopedia of Occupational Health & Safety. For specific machine information, refer to your operating manual.

  1.   Be sure all operators are trained in all machine tool functions including the operation of emergency shut off functions
  2.   Never operate a machine without doors closed and functioning locks
  3.   Keep all electrical panels and control cabinets secured and locked to limit access and accidents
  4.   Do not attempt to modify your equipment in any way
  5.   Never enter the machine enclosure, unless for maintenance or cleaning, and then only if the machine is entirely powered off
  6.   Never operate controls with your hand on or near the tool spindle
  7.   Always remain clear of the tool changer during power up, power down and while operating
  8.   Always stop a machine before cleaning a part or taking measurements
  9.   Never lubricate a machine while it is in motion
  10.  Never remove chips, filings or shavings with a bare hand to avoid cuts

While it often seems that that machine and shop floor safety and productivity work against each other in a precision manufacturing setting, protecting workers from harm should be a number one and universal industry goal. Following these rules and guidelines can help keep a check on injuries and accidents.

Want to learn more about machine shop safety, or do you need help with an upcoming project? We're here to help and are happy to discuss your machining needs. Call us at 303.776.1910 or send us an email.

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About the Author

 Gerry Dillon is a co-founder, current owner and certified CNC machinist at Advanced Precision Machining (APM), a full-service machine shop located in Longmont, Colorado. Before making his home in the United States in 2000, Gerry was born and raised on the emerald isle of Ireland and took an interest in milling and machining from an early age, ranking #1 in the Irish National Apprenticeship Program. In 2005, he and a partner began what’s grown into a leading Colorado machine shop. Gerry brings over 30 years of machining experience to the shop floor and is certified in all aspects of geometric dimensioning and tolerancing.


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