How To Choose The Right Style & Size Vacuum Cup

When you are using vacuum to pick and place different objects, how do you know which style vacuum cup and size you need?  EXAIR offer’s (3) different styles of vacuum cups in a variety of sizes to cover a wide variety of applications.

The first is the round cup, they are suited to smooth, flat surfaces.  They grip and release quickly, hold their shape with frequent use, and grip well when used with vertical loads.  Also, round cups are offered with cleats for a better gripping power when the load is heavy.  Vacuum Cups with cleats provide extra rigidity that lends itself to heavy loads.  The extra rigidity prevents the cup from peeling away or deforming when a heavy load is required.

Large Round Cleated Vacuum Cup
Round Cup With Cleats

Next we have the Oval Cup, they provide the most gripping power due to their larger surface area.  They naturally lend themselves to heavier loads.  They are ideal for flat rigid sheet materials such as wood, glass, cardboard and composites.

Oval cup
Oval Cups Provide The Most Vacuum Which Make Them Ideal For Heavy Loads Due To Their Larger Contact Area

Last but not least we have the Bellows Cup, they are best suited for curved, uneven or textured surfaces.  The bellows or more accurately called “convolutions”, provide a collapsible area that allows the cup to quickly compress when it contacts the surface of item to be moved.  Please know that the grip/release time is greater due the the larger internal volume of the cup.

bellows cup
Bellows Cup Are Excellent For Uneven Or Textured Surfaces, However They Longer Pick-Up & Release Times

Here is an example: If we want to pick up a sheet of glass that weighs 20 lbs, what size vacuum cup(s) do we need?  Fortunately we have published charts in our catalog with the math already completed, but this is how we arrived at the answer.  Using the formula below:

Cup Diameter Formula

D = Cup Diameter
W = Weight of item
N = Factor of safety ( We recommend a safety factor of 2 for horizontal lifting and 4 for vertical lifting).  For this exercise we will use a safety factor of 4.
U = # of cups (Remember it takes a minimum of 3 points to make a plane)
V = Vacuum level (psi) – Exair Porous E-Vac’s are rated to 21″ HG, Non – Porous 27″ HG and the Adjustable E-Vac 25″ HG.   (Each inch of HG equals .491154 PSI)
π = 3.14159
μ = Vertical surface friction coefficient (.5 for typical non-porous materials such as metal, glass, stone, etc..)

Cup Diameter Formula Solved

The calculated diameter is 2.26″ so we would choose the next standard size which is 2.5″ diameter.

When you are looking for Vacuum Cup application assistance or expert advice on safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you!

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
Visit us on the Web
Follow me on Twitter
Like us on Facebook

Thinking Outside of the Box

Over the years of working at EXAIR, I have spoken to thousands of customers. The applications we discuss can run the full range that is showcased in the Solutions section of our website. It is always fun to approach applications when we have to think outside of the box for a solution. Throughout the Application Engineering department, our level of experience here combined with the customer’s knowledge of their setup, sometimes results in a solution that is not straightforward. Sometimes, we have to think outside of the box.

What kind of application may we have encountered where the obvious solution wasn’t the one that worked? One of the best applications that came to mind for me is when a customer was attempting to lift/pick up a very porous piece of filter media like the pre-filter from a Heavy Duty HEPA Vac. This material is extremely lightweight and porous. When hearing from a customer, I want to pick this material up, my mind quickly goes to the E-Vac Vacuum generators which are used to generate vacuum to operate suction cups.

In-Line E Vac picking up a block of cut extrusion.

With this material however, the vacuum flow needed is quite extensive and there is another product which is going to be a more efficient use of compressed air. That product, the Super Air Amplifier. As you can see in the photo below, a 2″ Super Air Amplifier easily lifts the porous material and because the suction side is a nominal hose size a hose can easily be attached if needed. The image shows a single amplifier lifting a larger sheet from a bench, these could be organized in an array like suction cups to pick materials up.

Model 120022 – 2″ Super Air Amplifier picking up a porous pre-filter material.

The moral of the story is to keep an open mind for solutions, while one path will always work other paths may become a more efficient manner. These solutions don’t always fit inside a box nice and neat. The Super Air Amplifier fit this because the amount of air entrained is tremendous and can easily be utilized to pull low vacuum force/high flow applications. This is very similar to fume evacuation which would be a “normal” application for the Super Air Amplifier.

If you want to discuss any point of use compressed air application with us, contact an Application Engineer and let us help you determine the solution your job needs.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

We Lift Things Up and Put Them Down (Part 2): EXAIR’s E-Vac Vacuum Generators

A few months ago, I wrote here on the EXAIR Blog about my wife and I competing in our very first powerlifting competition. It’s a long and tiring process training for months for one single day, but to see all of your hard work payoff on the platform come competition day makes it all worth it. After competing on Saturday, we were both back in the gym the following Monday morning getting ready for the next one. Memorial Day weekend we participated in the Rivercity Barbell MAYhem meet in Northern Kentucky, another trophy for my wife, and another 2nd place medal for me. I’m beginning to see a trend here…. The entire day didn’t go the way I wanted it to, but I was pleased with a strong finish: a 500lb deadlift on my 3rd attempt to end the day. Exactly what I had in mind on the drive home in early January after our first meet.

After a full, long day of lifting stuff up and putting it back down, I was definitely ready to hit the bed right upon getting home. I could’ve saved myself quite a bit of energy and exhaustion by using one of EXAIR’s E-Vac Vacuum Generators. Although I’m fairly certain that would end in a quick disqualification…  

EXAIR’s E-Vacs are designed to take the difficult part out of lifting, placing, clamping, and mounting across a wide variety of parts and materials. EXAIR offers two primary styles of E-Vacs to serve your needs: In-Line E-Vacs & our Adjustable E-Vacs

The In-Line E-Vacs are a single stage, cylindrical units that are compact and easy to mount right at the point of use. They can be held in place by threading directly onto a compressed air line, or by the use of a mounting clip. We offer styles for use with porous materials, such as paper or cardboard, with vacuum levels up to 21” Hg and vacuum flows up to 18.5 SCFM. For non-porous materials, such as glass, we offer units with vacuum levels up to 27” Hg and with vacuum flows up to 15.8 SCFM.

Adjustable E-Vac

For applications that may have varying weights and sizes, we offer a line of Adjustable E-Vacs as well. With the simple loosening of a locknut and turning the exhaust, you can increase and decrease both the level of vacuum and the vacuum flow. This style is also an excellent choice for applications where large particulate may be present and can pass through the vacuum. We offer (4) different models with adjustable vacuum up to 25” Hg and vacuum flows up to 81 SCFM.

No matter what it is you’re trying to pick up, EXAIR has an E-Vac suited to the task. For help in sizing the appropriate vacuum generator for your application, feel free to give us a call. Hopefully by then I’ve figured out how to win one of these competitions, and I’m sure I’ll have a trophy case full of ‘em for my wife.

Tyler Daniel

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

Additional Benefits To The Adjustable E-Vac Vacuum Generators

The EXAIR Adjustable E-Vacs are available in 4 different sizes to fit whatever your pick and place, vacuum holding, degassing, or vacuum evacuation process may call for. These units have been used in a multitude of applications and the Adjustable factor makes them versatile enough to fit a production line with changing needs.

These are all examples of how an E-Vac pick-and-place system is just a solenoid valve away from automation.

The Adjustable E-Vacs have a few benefits that may go unnoticed if one is not keen to exactly how they are constructed and function. This sets them apart from many vacuum generators. When dealing with vacuum generator applications such as pick and place, having a part that is always the same is easiest. This is not always the case. Sometimes it is not just the dimensions of the part that changes, sometimes the material changes or even the surface finish of the part. This is where the ability to change from a porous to non-porous vacuum generator is extremely helpful. Generally this means the material of the parts getting picked up will allow air flow through them (paper, cardboard, wood) or not (plastic, glass). A porous vacuum generator will pull more flow through the part material to hold the vacuum, a non-porous vacuum generator will pull less flow and achieve higher vacuum levels.

To better understand the difference between porous and non-porous, we’ve written about that. Check out Tyler Daniel’s blog on the difference between the two here. The beauty of the Adjustable E-Vac is that it can easily convert from porous to non-porous with a simple adjustment. This is a great feature for a job shop that may change materials they are cutting or engraving on their machines and need to adapt in a moments notice for the job at hand. This could also reduce the number of vacuum generator variances a store room may need to keep on hand for a series of production lines and help to reduce the chance an incorrect model is installed on a machine due to fewer variants.

Adjustable E-Vac

Another benefit which can be helpful in a production environment that has an E-Vac picking up dirty or debris ridden material is that the Adjustable E-Vacs can be disassembled and cleaned. Picking steel sheets off a laser cutter in order to remove the scrap that has a volume of spatter / dust can cause an accumulation of debris on the internals of any vacuum generator. By unscrewing the plug from the body the Adjustable E-Vac can be easily cleaned and all passageways maintained at a level to offer continual performance.

No matter what, the adjustability coupled with minimum components and fastener free disassembly of the unit are two great features that can help minimize machine downtime, lower number of parts kept on hand for machines, and ensure optimal performance no matter what the requirement is for the vacuum generator. If you would like to discuss further, please contact us.

Brian Farno
Application Engineer
@EXAIR_BF
BrianFarno@EXAIR.com