Super Air Wipes Help a Swiss CNC Machine to be More Accurate

Precision Required

As machined parts require tighter tolerances, machine shops are starting to look at Swiss-type CNC machines.  These types of machines are extremely accurate and very fast in producing small parts.  But in order to reach that level of accuracy, the bar stock may have to be pre-treated by a centerless grinder.

Our customer was using Swiss-type CNC machines with guide bushings to produce a very tight-tolerance part.  Because they were using guide bushings, the outside diameter of the bar stock had to be smooth and concentric.  This helps to reduce any vibration when machining.  A centerless grinder was used to accomplish this.  The bar stock that they used was 10 feet long and it was placed into a bar feeder.  They had to grind the bar to an outer diameter of 30mm with a surface finish of 32Ra.  As they were loading the bar stock, they noticed that the surface finish was scuffed and marred.  This was enough to affect the machining process and not meet the tolerance standard.

As they reviewed the possible causes, they found that after the bar was ground, some grinding remnants were sticking to the outside of the bar.  As the rods were leaving the grinder and placed onto a roller-type conveyor, the oily film and metal shavings were sticking to the rollers.  This would scrape and mark the rods as they traveled along the conveyor toward the Swiss-type machining center.  As an attempt to remove this debris, they attached two copper tubes to blow compressed air onto the top and bottom of the bar.   Not only was this loud and inefficient, it was not effective.  They still had a dirty line along the sides of the rod that remained.  They contacted EXAIR to see if we could help them with this dilemma.

In order to get a consistent blow-off force around the entire circumference of the rod, EXAIR Air Wipes were engineered to be an ideal solution for this kind of problem.  I recommended the model 2482 Standard Air Wipe Kit.  The Standard Air Wipe is designed to blow compressed air in a 360 degree flow pattern.  This air pattern is directed at a 30 degree angle toward the center to blow the debris off of the bar stock.  The Coanda effect maximizes the entrainment of ambient air into the compressed air.  This makes the unit very efficient and powerful.  The model 2482 Standard Air Wipe has an I.D. of 2” (51mm) which gives it enough clearance for the 30mm bar stock.  It can be mounted easily near the exit of the centerless grinder to keep the grinding remnants inside the machine.  The kit includes a filter, regulator, and shim set.  The filter will remove contaminants from the compressed air system to keep from introducing any new grime and to keep the inside of the Air Wipe clean and functional.  The shim set and regulator provide the ability to adjust the air to the ideal force level and remove any debris from the surface of the bar.

Standard Air Wipe with Shim Set

As they removed their home-made copper tubes and attached the Standard Air Wipe, they noticed some great improvements.  The dark lines of debris previously along the sides of the bar stock were gone.  The surface was clean around the entire circumference of the bar.  The customer also noticed that the Standard Air Wipe was much quieter than their home-made solution, as it only has a decibel rating of 77 dBA.  As an added benefit, the Standard Air Wipe was using much less compressed air than the copper tubes.  This is due to its design to maximize the amplification ratio.  With more of the “free” ambient air than the compressed air being moved over the target area, it will save money in compressed air usage.  The ROI could be less than four months.

If you have any items that need to have a 360 degree blowing pattern, you can contact an Application Engineer at EXAIR to see if a Standard Air Wipe could work for you.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb
Picture: External-Micrometer-Screw-Gauge by Emilian Robert Vicol.  Creative Commons license

Super Air Wipe Cools, Cleans and Dries Extruded Shapes

We have many customers that use the manufacturing process of extrusion to make their various type of products.  EXAIR has an Intelligent Compressed Air Product that works very well with these processes to provide a drying, blowoff and cooling function.

Many types of products are produced via the process of extrusion, which is to shape (as metal or plastic) by forcing through a die.  There are many advantages to the extrusion process, including it being a continuous operation, it runs at high speeds, is good for high volume and low production costs, as well as many other factors.

The extrusion process typically requires heating of the metal billet or melting of the plastic to a high enough temperature to allow it to flow and be shaped as it it forced through the die. After the product has passed through the die and has been shaped it must be cooled and this is usually achieved by passing the it through a water bath.  Once the material has been cooled, it needs to be dried to remove the moisture, before the extrusion enters the next stage of processing, like getting cut to length or printed upon.

The EXAIR Super Air Wipe is ideal for blowoff, drying, cleaning and cooling of continuous materials such as extrusions, pipe, cable and more.

saw_2-2

The Super Air Wipe has a split design which offers easy clamping around the surface of the material, eliminating the need for threading. All Super Air Wipe models include stainless steel screws and shims.  Stainless Steel wire braided hose which is plumbed to each half, is included on sizes up to 4″ to simplify installation and plumbing. Aluminum models are rated to 400°F and the stainless steel models for temperatures up to 800°F.  Models are available in size from 1/2″ to 11″ Throat Diameters.

The Super Air Wipe provides a uniform, 360° air stream that is ideal for drying and cooling of extruded materials.

To discuss your application and how an EXAIR Super Air Wipe can benefit you extrusion process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Twitter: @EXAIR_BB

Consider these Variables When Choosing Compressed Air Pipe Size

Here on the EXAIR blog we discuss pressure drops, correct plumbing, pipe sizing, and friction losses within your piping system from time to time.   We will generally even give recommendations on what size piping to use.  These are the variables that you will want to consider when selecting a piping size that will suit your need and give the ability to expand if needed.

The variables to know for a new piping run are as follows.

  • Flow Rate (SCFM) of demand side (products needing the supplied compressed air)
  • System Pressure (psig) – Safe operating pressure that will account for pressure drops.
  • Minimum Operating Pressure Allowed (psig) – Lowest pressure permitted by any demand side point of use product.
  • Total Length of Piping System (feet)
  • Piping Cost ($)
  • Installation Cost ($)
  • Operational Hours ( hr.)
  • Electical Costs ($/kwh)
  • Project Life (years) – Is there a planned expansion?

An equation can be used to calculate the diameter of pipe required for a known flow rate and allowable pressure drop.   The equation is shown below.

A = (144 x Q x Pa) / (V x 60 x (Pd + Pa)
Where:
A = Cross-Sectional are of the pipe bore. (sq. in.).
Q = Flow rate (cubic ft. / min of free air)
Pa = Prevailing atmospheric absolute pressure (psia)
Pd  = Compressor discharge gauge pressure (psig)
V = Design pipe velocity ( ft/sec)

If all of these variables are not known, there are also reference charts which will eliminate the variables needed to total flow rate required for the system, as well as the total length of the piping. The chart shown below was taken from EXAIR’s Knowledge Base.

Piping
Airflow Through 1/4″ Shed. 40 Pipe

Once the piping size is selected to meet the needs of the system the future potential of expansion should be taken into account and anticipated for.   If no expansion is planned, simply take your length of pipe and start looking at your cost per foot and installation costs.    If expansions are planned and known, consider supplying the equipment now and accounting for it if the additional capital expenditure is acceptable at this point.

The benefits to having properly sized compressed air lines for the entire facility and for the long term expansion goals makes life easier.   When production is increased, or when new machinery is added there is not a need to re-engineer the entire system in order to get enough capacity to that last machine.   If the main compressed air system is undersized then optimal performance for the facility will never be achieved.   By not taking the above variables into consideration or just using what is cheapest is simply setting the system up for failure and inefficiencies.   All of these considerations lead to an optimized compressed air system which leads to a sustainable utility.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

There’s More Than 1 Way To Blow Some Air

Just today I spoke with a customer who is threading the ends of pipes and needs to blow the coolant and chips out of the threads.   The pipes range from 4″ to 9 – 5/8″ Diameters.  They are all threaded then fed into a trough and pushed down line to the next operation.

PEO ACWA
A machine with an out-feed roller conveyor similar to the pipe threading machine mentioned.

The photo above is not the exact machine but you can see where if this was used to process piping the different diameter pipes would all sit at the same level.  One option could be to use a Super Air Wipe  for this application but then the smaller diameters would not pass through the center of the Air Wipe, instead they would pass through the bottom half of the airflow which may not give optimal performance. Instead, I suggested to use 4 of our 6″ Super Air Knife kits and 2 of our Electronic Flow Control units.

 

2 - 110006 - 6" Aluminum Super Air Knives coupled together w/  a 110900 SAK Connector Kit
2 – 110006 – 6″ Aluminum Super Air Knives coupled together w/ a 110900 SAK Connector Kit

I  suggested that we make two pairs of knives for this blowoff setup by coupling two of the 6″ Super Air Knives together.  Once they are coupled together like is shown above, we could mount the two coupled air knives vertically along the trough and blowing at a 45° angle toward the center of the conveyor.  The plumbing of the two bottom knives will be to one EFC while the top two knives will be plumbed to the other.    The sensors will then be set up at two different heights, lower knives to sense the bottom of the pipe and the upper knife sensor will be set just above the bottom 6″ knife.

The reason for using 4 – 6″ Super Air Knives and 2 EFCs instead of 2 – 12″ Super Air Knives and 1 EFC is to save the most compressed air possible.   By enabling them to turn the top two 6″ Super Air Knives off automatically when they are running below a 6″ diameter pipe.  Then when a larger pipe is processed the top knives will also kick on with the lower knives and provide a uniform blowoff of the product.

So if you have multiple sizes of product being processed on the same line and don’t think any one solution will work, contact us and see if we can’t come up with our own recipe.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Machine image courtesy PEO ACWA Creative Commons

 

Super Air Wipe Blows Electric Resistance Welded Pipe Clean During Manufacture

SAW pipe
Super Air Wipe Blows Off Pipe

A manufacturer of Electric Resistance Welded (ERW) pipes contact us recently. They were trying to make improvements to an existing pipe mill where pipes of diameters 3-1/2” up to 8-5/8” diameter are being processed. They had previously used our Super Air Wipe product on a smaller line that produced pipe in the 2-3/8” to 3-1/2” outside diameter range with great success. So, they wanted to know what we had that could blow off the outside diameter of their large product.

It so happens that EXAIR produces the Super Air Wipe product up to 11 inch inside diameter. With such a size, the Super Air Wipe has capability to blow off and cool pipes up to about 10 inch diameter. This capability was well within the need for our customer.

Previously, the customer had been using a series of open pipes that terminated into a ring around their product to blow off coolant used during the final phases of production. This solution was extremely loud and used a large volume of air which ran continuously while the mill was in operation. Also, the finish produced was not quite as consistent as the customer wanted. The inconsistent velocity between the home made “nozzles” caused lines to form on the pipe’s outer surface finish that were not appealing.

The Super Air Wipe was able to harness the compressed air into a more manageable flow with even velocity all the way round the outside of the pipe. The sound level dropped considerably, the flow rate dropped down to a much more reasonable level for the customer and the visual quality of their final product had no lines as before.

The pipes produced at this particular facility were used in the oil and gas industry. However, any application where pipes, hoses, tubes and any other round forms need to be blown off or cooled with air create good opportunity to take advantage of the features that an EXAIR Super Air Wipe bring to the application.

Neal Raker, International Sales Manager
nealraker@exair.com

Back At Ya!

This may not be big news as it happens almost every month.  EXAIR is continuing to grow our product line and this time it is something we have never done before.  This new EXAIR Engineered Solution doesn’t blow debris away, instead, it all comes back towards you.   Why would you want this you ask?  What does this new-fangled contraption look like?  Both of those questions will be answered below.

To answer the first question, why would you ever want debris to come back at you?  Well, this isn’t for just blowing any part or area out, this nozzle has been designed for a special purpose – to blow out pipes, tubes, extrusions, and even some blind holes or pockets.   This is ideal when working on a piping system that you may need to clean out and don’t want to push debris further into the system.   It is a quick and easy way to clean out chips from a saw cut operation for tubing or extrusion.  The nozzle could even be used to clean out cylinders or crank shaft openings on engine blocks.

So what is the name of this new nozzle and what does it look like?

What does it look like already!
What does it look like already!

 

The EXAIR Model 1006SS - Back Blow Nozzle
The EXAIR Model 1006SS – Back Blow Nozzle

This is it, the EXAIR model 1006SS Back Blow Nozzle.   The nozzle features a 1/4″ FNPT air inlet, a 3/4″ O.D. to fit into piping, extrusion, or holes, and two flats which allow for the use of a 5/8″ wrench to install the nozzle.   The nozzle is constructed of 316 Stainless Steel, utilizes  22 SCFM when operated at 80 psig, gives off 80 dBA and is designed for use with 7/8″ to 4″ I.D. pipe, tube, or holes.

The unit will also be available on our Safety Air Guns with Chip Shields to offer cleaning excellence and protection for the operators.  Like all of the stock EXAIR products, this is available with our 30 day guarantee.   So if you are not sure whether this nozzle will work on your application, give us a call, get one in, and put it through the paces.   If the Back Blow nozzle doesn’t meet your needs, simply let us know within 30 days from the date of purchase and we will take it back and provide you full credit.

If you want to discuss this nozzle or any other compressed air application, don’t hesitate to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Finger Face – Tsahl Levent-Levl , Creative Commons License, Some Rights Reserved

 

 

 

A (Sample) Lexicon For Compressed Air

Every industry and different technical subject matter comes with it’s own lexicon of terms or vocabulary words.  More often than not, when speaking to an Application Engineer here at EXAIR you are going to hear words within our lexicon. The list I have compiled below is merely a sampling to help translate some terms that we forget not everyone knows.  Some of these are merely acronyms that get thrown around a good amount.

SCFM – Standard Cubic Feet per Minute – This is the unit we use to represent the volumetric flow rate of compressed gas that has already been corrected to standardized conditions of pressure and temperature.

PSIG – Pounds per square inch gauge – This is the unit which we use to represent the operating inlet pressure of the device.  When requesting this, we generally are looking for a pressure gauge to be installed directly on the inlet to the device with no other form of restrictions between the two.  For the most part, catalog consumption values are given in SCFM at 80 psig.  The main exception to that rule are the Vortex Tube based products.

Compressed Air – This is a utility that most industrial manufacturing facilities have available to them.   It is regular, atmospheric air which has been compressed by an air compressor to a higher pressure than atmospheric.  Generally speaking, compressed air systems will be at a range of 85-120 psig.

OSHA – Occupational Safety and Health Administration – This is the main federal agency that enforces two of the major conformance standards that EXAIR products meet or exceed.

29 CFR- 1910.95 (a) – Maximum allowable noise level exposure.  The great majority of EXAIR products meet or exceed this safety standard, our largest Super Air Nozzles
1910.242 (b) – This is the standard which states compressed air blow off devices cannot exceed 30 psig of dead end pressure.  This means, if the exit point of the air can be blocked the operating pressure must be below 30 psig.  The reason for this standard is to prevent air embolism which can be fatal.  All EXAIR products meet or exceed this standard by having multiple orifice discharge.

Coanda Effect – This is the effect that numerous EXAIR products utilize to amplify and entrain ambient air.   The Coanda effect is when a fluid jet (stream of compressed air) tends to be attracted to a nearby surface.  This principle was found by a Romanian aerodynamics pioneer, Henri Coandᾰ.  The picture below shows a Super Air Amplifier blowing a foam ball into the air and suspending it due to the Coanda effect on the surface of the ball.

A Super Air Amplifier's air stream causes a foam ball to be suspended in mid air thanks to the Coandᾰ effect.
A Super Air Amplifier’s air stream causes a foam ball to be suspended in mid air thanks to the Coandᾰ effect.

Rigid Pipe or Hard Pipe – This is the term we will often use when discussing the compressed air line that can be used to support and supply certain EXAIR products.  Generally we are referring to a Schedule 40 steel pipe, Type L copper line, stainless steel tube, or any form of pressure rated hard pipe that can be used for supplying compressed air.

Plenum – the state or a space in which a gas, usually air, is contained at pressure greater than atmospheric pressure. Many of our products feature a plenum chamber. 

Again, this list is only a sample of the terminology you will hear us use when discussing compressed air applications.  If there are any other air/compressed air/fluid dynamic terms you may be unsure of, please contact us.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF