Savvy manufacturers never stop looking for ways to reduce costs while improving throughput... While the up front price of electric power tools is undoubtedly attractive, pneumatic tools offer a lower total cost of ownership and greater productivity over the long term. In this article, we explore 5 clear cut benefits provided by the use of industrial grade pneumatic grinders.
1. No Risk of Electric Shock - Grinders of all varieties are frequently used in environments where moisture, conductive materials, and flammable liquids are present. Damaged cords and wires pose a risk to operator safety resulting from electrical shock. Furthermore, metal fabricators often rely on flammable chemicals, such as acetone, to clean and prep metals prior to welding. Pools of spilled liquids can quickly be ignited by faulty electrical cords. Vapor concentrations can be higher when working in confined spaces such as those found in the mining and tank cleaning industries. In contrast, air tools use no electricity and their rotary vane air motors generate no spark.
2. Superior Ergonomics and Power to Weight Ratio - Pneumatic grinders offer a better power to weight ratio than electric grinders. Simply put, pneumatic grinders produce more horsepower in a smaller and lighter package. Misleadingly, electric tool manufacturers often classify the power of their tools by the wattage fed into the electric motors. (incidentally, as a general rule of thumb, 750 watts equals roughly 1 horse power) What's not stated in electric tool specifications is that the power fed into the electric motor is not the same wattage that arrives to the spindle. In fact, only 50% to 60% of the rated wattage actually arrives to the abrasive mounted on the tool. Conversely, with pneumatic grinders, power in equals power out. An air tool rated for 1 horsepower will provide one horsepower of material removal power at the spindle. To further illustrate power to weight ratio, let's compare two popular 4.5" angle grinders: the Dewalt DWE402 and the Chicago Pneumatic CP3650-120AB45.
Dewalt DWE402 | Chicago Pneumatic CP3650-120AB45 |
| Weight: 6.2 Lbs. | Weight: 4.2 Lbs. |
| Watts: 1320 | Watts: 1725 |
| HP: 1.8 | HP: 2.3 |
| Power To Weight Ratio: .29 HP per Lb. |
Power To Weight Ratio: .54 HP per Lb.
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In summary, the Chicago Pneumatic Grinder offers nearly twice the horse power per pound as the Dewalt.
3. - Increased Productivity - Let's put ergonomics and ratios aside for a moment. If increasing worker output is a priority for your operation (and when isn't it?), pneumatic grinders can help you meet your goals. When working with grinders of any type, Revolutions Per Minute (RPM) play a critical role in the material removal equation. Abrasive products (grinding wheels, fiber discs, flap wheels, etc.) are engineered to perform optimally at a specific RPM. Fortunately, modern pneumatic grinders are equipped with a speed control mechanism, (also know as governor), that ensures proper RPM by regulating the air flow to the tool. As the operator places downward pressure on the abrasive, the governor "opens up", increasing air flow to the motor and ensuring the correct spindle speed.
A side note on feed force - Many operators when presented with a new tool will immediately attempt to stall it by placing large amounts of downward pressure on the abrasive. They do this in an effort to test the tools power or torque limitations. Stalling out a power tool not only places undue wear on the tool, but also poses an injury risk to the operator themselves. Furthermore, this practice actually detracts rather than contributes to material removal rates. Pneumatic grinders and abrasives perform optimally when RPM limits are respected. In a non flammable working environment, you can gauge the optimal RPM by noting when the spark stream emitted by the grinder is at its brightest.
4. - 100% Duty Cycle + High Performance in Harsh Environments - Mitch Burdick, Product Manager for Concrete Tools at Bosch Tools says "The two biggest threats affecting electric tool life are debris (dust) and heat — dropping them in water, or baking them under a hot sun doesn’t help either." By their very nature electric motors have a rated duty cycle which must be respected. Without a periodic rest, the heat generated by the motor itself will diminish performance and eventually cause premature tool failure. Furthermore, the generation of particles is inherent in any material removal process. With the open grate style motor compartments required for cooling, electric tool motors are more susceptible to the accumulation of dust and debris. In contrast, Industrial Grade Air Tools are designed specifically for use in foundries, shipyards, off-shore oil platforms, power plants, metal fabrication facilities, and petro-chemical refining plants. Air tools have a 100% duty cycle, meaning they are designed to run 24 hours a day 7 days a week (when used with a filter regulator lubricator). Air tool housings are made of aluminum or steel, not ABS plastic which makes them more resistant to the impact from repeated drops. Pneumatic grinders can even be used under water if the exhaust is vented above the surface!
5. - Ease of Servicing - An industrial grade grinder is not a disposable piece of equipment. They can be periodically rebuilt and serviced over many years. The average electric tool maintenance interval is between 60 and 120 hours afer which the tool will typically need brushes. Comparatively, a garage / maintenance grade air tool averages 200 hours between service intervals while an industrial grade air grinder can run 2000 hours between tune ups. When the time does come to service your air tools, convenient and clearly labeled kits are available that contain the most common wear parts.
Bottom Line - In conclusion, regardless if you are de-burring parts in a machine shop, preparing a surface for painting, or parting gates and risers in a foundry, everyone's goal is to get product out the door faster. With pneumatic grinders, you'll spend less time accomplishing your task and feel safer and more comfortable doing so. Additionally, with their 100% duty cycle rating and long service intervals, you'll spend more time working and less time servicing your tools. While the up front cost of a pneumatic grinder may be higher, it's the total cost of ownership that matters. Air tools are a sound investment that results in significant gains in manufacturing productivity.
