Revamped Line of Chicago Pneumatic Impact Wrenches Offers Tools for Every Application, Fills Gap in The Market

Revamped Line of Chicago Pneumatic Impact Wrenches Offers Tools for Every Application, Fills Gap in The Market

How To Maximize Air Tool Performance Part #1 | Pressure and Flow

San Diego, CA - April 21st, 2013

 

Throughout the course of our daily operations, we often receive calls from customers asking which is the best "brand" of air tool. This is almost always a loaded question and rather than engage them in the Ford versus Chevy debate, a little further questioning usually reveals dissatisfaction with the performance of one of their tools. While in almost all cases an industrial production grade air tool is going to provide better performance than an automotive / maintenance style tool, there are some sure fire ways to ensure optimal performance regardless of the quality of the tool selected. In this article we will focus on the two most important factors in air tool performance, these being pressure and flow.

 

Proper Air Pressure (PSI) - The vast majority of air tools on the market are designed to run on 90 pounds per square inch of pressure, commonly known as PSI. The misconception is that a 2-1/2" drive impact wrench requires more air pressure than a small right angle die grinder. The reality is that both of these tools are designed to run optimally on the industry standard 90 PSI. Exceeding the manufacturers recommended air pressure can actually damage components, shortening tool life and creating a potentially dangerous situation by compromising the burr, wheel, or other accessory in use. Furthermore, you want to be sure that you are getting 90 PSI of pressure when the air tool (or tools if working with multiple stations) is running. Use an air regulator to gauge the pressure while the tool is wide open. If the needle reads 90 PSI when the throttle of the tool is closed but dips below that when the tool is engaged you need more pressure. Again, most air tools are designed to run at 90 PSI and will underperform if under pressurized.

 

Air Flow (CFM) - What varies widely from tool to tool is the required air flow rate which is measured in cubic feet per minute (CFM). Before selecting an air tool for any application be sure that your air compressor can generate the necessary CFM. As a very generalized rule of thumb you can conclude that for every one horse power that your compressor puts out, you will receive 3 to 4 CFM. To put it in perspective a small right angle die grinder uses about 25 CFM while a 1" impact wrench requires 60 CFM. In addition to verifying that your compressor has the guts to power the tool on hand, make sure you aren't starving the tool by restricting air flow through the use of a small diameter air hose. Never use reducers to adapt a 3/8" NPT or 1/2" NPT to a 1/4" air line. In fact, if you can avoid it try not using 1/4" air lines at all. Free unrestricted air flow is paramount to maximizing air tool performance and it's better to error on the side of too large a hose rather than choke the tool. Nothing will sabotage your project faster than an underpowered tool and lack of flow is definitely a deal breaker.

 

In the next installment of this five part series we will look at why every air tool deserves to be paired with a good filter, regulator, lubricator.

 

Thanks for reading...

 

Mark Schieber

 

About the author:

 

Mark Schieber is an air tool entrepreneur, international business fanatic, internet marketer, and avid surfer. He is the owner of International Air Tool & Industrial Supply Company and is passionate about helping his customers maximize productivity related to air tools and their applications. For questions about this topic or anything else air tool related that might be on your mind email info@intlairtool.com

Fein Power Tools Affirms International Air Tool & Industrial Supply Co. as Authorized Distributor | PRLog

Fein Power Tools Affirms International Air Tool & Industrial Supply Co. as Authorized Distributor | PRLog

Pneumatic Assembly Tool Ergonomics - Preventing Torque Reaction

Pneumatic Assembly Tools -  When is it Appropriate to Use Clutch Tools, Pulse Tools, and Torque Arms when Attempting to Reduce Torque Reaction?

By Mark Schieber, MBA - Director of Sales at International Air Tool


When working with assembly customers in the field I frequently receive questions about torque reaction and more specifically, at what level of torque should some type of reaction limiting device be implemented.... In order to properly answer this question, let's first define the vocabulary that will be used in the discussion:

Clutch Tools - (aka Torque Controlled Screwdrivers featuring an Adjustable Precision Shut Off Clutch)

Clutch tools are pneumatic screwdrivers (either inline or pistol grip) that utilize a mechanical spring, ball, and cam type clutch (see picture below) to limit the amount of torque delivered to a fastener. Rather than have the screwdriver bit connect directly to the pneumatic screwdrivers motor via the spindle, an adjustable clutch is installed between the bit and the motor to regulate the amount of torque delivered to the fastener. Different screwdriver models offer clutches with different torque ranges (typically measured in inch lbs.) from which to choose. This torque range is adjusted by changing the clutch adjustment settings by either loosening or tightening the tension placed on the clutch spring. During a run down, when the force applied to the fastener overcomes the driving force of the tool (controlled by the clutch) a rod trips and stops the air flow to the tool thus limiting the torque applied to the fastener. These clutches are highly accurate and since they shut off automatically when the proper torque is reached, they also prevent operators from influencing final torque applied to the fastener. In other words, the operators can't give the fastener "one last nudge for good measure." The final resting torque of the fastener is determined by the tool, not the operator. Here is a picture of a torque controlled clutch, (disregard the oil free blades text):



You can check out one of my all time favorite torque controlled screwdrivers at: http://www.intlairtool.com/products/Ingersoll-Rand-1RPMS1-Torque-Controlled-Assembly-Screwdriver.html

Now the negative (Con) aspect of clutch tools - Since the air flow to the tool and hence rotation of the bit is stopped abruptly by the activation of the mechanical clutch, a torque reaction (jarring motion) is produced at the end of the cycle which is transferred to the arms of the operators. This reaction can be harmful to the wrists and elbows, but can be prevented... More to come on this later...

Pulse Tools

A pulse tool combines the speed of an impact wrench with the repeatability and precision of a shut off clutch tool. However, in contrast to a spring, ball and cam type clutch tool, a pulse tool uses a hydraulic cylinder to amplify, regulate, and apply the torque generated by the air motor. This hydraulic cylinder is often referred to as the pulse unit. Not only does the pulse unit generate torque, but it also absorbs the torque reaction, noise, and vibration making it a highly ergonomic (but expensive) tool. Since a picture is worth a 1,000 words, here is a cutaway of a pulse tool...

Pulse tools are usually used for higher torque range applications which are measured in ft. lbs. (12 inch. lbs. in 1 ft. lb.). They are also very quiet and consume very little air (low CFM). IMPORTANT: Pulse tools are virtually reaction-less because the torque is applied to the fastener in a series of rapid starts and stops that are visually undetectable during use. Think of the second hand on a clock and the way it pauses before it moves to the next position... Now imagine this same motion at 8,000 RPM's and you have the method by which a pulse tool delivers torque! Here is an example of a high quality Ingersoll Rand Pulse Tool...

Check out a classic Ingersoll Rand pulse tool here

Torque Reaction Arms

Lastly, let's talk a minute about torque reaction arms... A torque reaction holds and supports a torque controlled clutch type screwdriver during operation. See the photo below:

Since a torque controlled screwdriver comes to an abrupt stop when the desired torque is reached (due to the clutch engaging), a torque reaction arm is used to absorb the transfer of torque (twisting force) before it reaches the arm of the operator. This in turn prevents injury associated with repetitive motion. Torque reaction arms also force the operator to follow the preset pattern/motion of the arm thus performing the assembly in a disciplined and ergonomic fashion. Torque reaction arms come in a variety of materials and configuration, but all share the same goal, which is to prevent injury to the operator caused by torque reaction and repetitive motion.

Selecting the Right Configuration

Sorry for that long winded explanation, but it was necessary... We are now ready to explain how to choose the right tool to get the assembly job done while adhering to proper ergonomics... As a rule of thumb, a clutch tool should be used with a torque reaction arm anytime there is a visible torque reaction noticeable when monitoring the operator perform a series of run downs.... Additionally, the operator should be questioned as to his or her comfort level after performing multiple cycles. See how they feel about 1/2 way into their shift and question multiple operators all the while assuring them that their input is contributing to plant wide increases in productivity. When in doubt however, implement a torque reaction arm. Some experts in the field will assert that a torque reaction arm be implemented only above certain levels of torque (i.e. - above 15 inch lbs.). However, we at International Air Tool have found that torque reactions vary greatly based on the type of joint (hard or soft) being assembled. While some operators may resist the implementation of torque reaction arms, assure them that it is for the benefit of their health as well as the overall well being of the business.

You might have already figured out that by design, pulse tools do not require torque reaction arms. While many plants prefer to implement a combination of clutch tools with torque arms due to lower costs, when possible, it is advisable to use pulse tools. Additionally, since the pulse tool requires no torque reaction arm, it reduces clutter and better supports a lean manufacturing environment. However, pulse tools are mainly offered in higher torque ranges because as you might have guessed, greater amounts of torque cause greater reactions and thus require a countermeasure to diffuse that torque. With borderline medium-low torque ranges i.e - 10 to 20 inch lbs., pulse tools are not typically offered and therefore, you will have to be vigilant and see whether a clutch tool and torque arm combination is required.

In summary, when working with a clutch tool, a torque reaction arm is always a good idea when there is any noticeable torque reaction present at the end of the run down. For higher torque applications, bypass the torque reaction arm entirely and streamline your process with a highly ergonomic and repeatable pulse tool. If you have questions regarding a specific application feel free to call our office during normal business hours or send an email to mark@intlairtool.com

Thanks for reading...

Mark Schieber