Cold Gun Aircoolant Systems Eliminate Mist & Breathing Problems In Machine Shops

Some machine tool operations require flood coolant. Not only does the liquid remove heat of friction from the tool and the work piece, it also provides lubrication that the cutting of some materials require. For other machining operations, mist coolant removes heat, provides a measure of lubricity, and minimizes (to a degree) the volume of liquid used in a flood coolant application.

This high speed photograph illustrates how flood coolant gets atomized by a machine cutting tool.

Whether you flood or mist liquid right onto a tool cutting metal, some of it’s going airborne. CNC machines are oftentimes equipped with collection systems for coolant mist, and it’s not unusual to see ambient mist collectors installed in machine shops to take care of the mist that escapes individual machines.

These mist collectors play an essential role in these facilities, as there are considerable health risks associated with exposure to these fluids, both oil- and water-based. In the U.S., the National Institutes of Health (NIH) compiles & analyzes risks associated with skin contact & inhalation of metalworking fluids. The National Institute for Occupational Safety and Health (NIOSH) has comprehensive recommendations of limitations on exposure to them. In England, the Health & Safety Executive agency likewise published a document geared toward helping machine shops and their employees work safely with them.

Speaking of NIOSH, they strategize a Hierarchy of Controls that can be applied to most any industrial process:

Elimination of the hazard isn’t always possible, but when it is, it’s the most effective option.

While mist collectors (Engineering Controls) are reasonably effective (and essential in the large number of applications where metalworking fluids are necessary), there are still a fair amount of applications where liquid coolant CAN be eliminated. For those applications, consider the EXAIR Cold Gun Aircoolant Systems.

Cold Guns not only eliminate messy and potentially hazardous liquid coolants, but also have been proven to improve cutting tool life.

Using Vortex Tube technology, EXAIR Cold Guns generate cold air flow from a supply of compressed air, instantly & on demand, with no moving parts to wear or electrical components to burn out. They’re safe, quiet, effective, and install in minutes, using a built-in bar magnet and 1/4 NPT compressed air connection.

Both Standard & High Power Systems come with Filter Separators, and are available with Single or Dual Point Hose Kits.

We know we can’t replace liquid coolant in every machining application, but if you’d like to explore elimination of it in your processes, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Next Level Customer Service

I recently spoke with a customer who is a casting / machining manufacturer.  They had an automated cell that was finish machining a feature on a cast aluminum part then placing it on a conveyor belt for an operator to pick up and continue processing.

The parts were placed 3 pieces wide per row and the conveyor would index with every three parts.   The operator would pick three pieces up and transfer them to another station during the machining time.  These parts were carrying residual machining coolant and debris onto the outbound conveyor.

The operator would blow them off with a handheld blow gun and all the coolant and chips would generally end up on the floor in the area causing a slip hazard.  The focus of the project is to eliminate the safety hazards and leave the parts as clean as possible for the inspection and further process.

The metal parts were positioned similar to the parts I placed in the mock up picture below.  The conveyor the customer has is an open mesh conveyor so the process will work better than if it was a solid belt like in the mock up.

The bulk of the concern from the customer was the outside of the part and they stated that anything to blow out the internal is a bonus.  The objective is to get as much coolant off as possible.   For that we recommended they span the conveyor with a Super Air Knife Kit to blow all the parts off at once.  This is mounted closely in the mock up because the customer had space restrictions.

The Super Air Knife Kit with Universal Air Knife Mounting System will firmly mount the knife over the parts and leave adjustment if needed.

The model 1103 Mini Super Air Nozzles with Stay Set Hoses of various lengths easily bend into place and hold their positioning for the side hole on each part.

Then, because the parts are always placed in the same location with the same orientation we can locate the ID hole with a Mini Super Air Nozzle on a Stay Set Hose of varying length to reach each set of parts as they come through.  Once I had the idea and the products in place I delivered the customer  a quote and dimensional CAD file for each part.

Another recommendation was to use a regulator and filter to control just the knife then operate the three nozzles off their own regulator and filter so that the forces between the two can be varied and the performance of the other is not effected.  Accompanying the models were installation sheets for each item as well.   Followed by the pictures of this mock up for their application.

Needless to say the customer was amazed that we would go to such lengths just to give them more assurance than our 30 day guarantee.  They were extremely thankful and are pleased we shipped from stock and met their installation window.

If you are looking for a creative solution, next level customer service, same day product availability, or just a nice human to talk to about compressed air, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

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

Cold Gun Provides Cooling For CNC Router

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This CNC needs a way to cool the drill and blow away chips created during machining

Precision control with CNC’s means we can achieve a near-identical output in product dimensions and quality.  And, it also means we can create an identical problem every time the machine is used.

Case in point, the CNC shown above is used to machine a 5mm piece of aluminum, but was plagued with problems preventing it from performing to its full potential.  The problem, was that when the machine would plunge into the aluminum, the plunging speed would produce excessive heat leading to a deterioration in performance and quality.  The temporary solution for such a condition is to slow down the machining speeds, but this reduces the efficiency and throughput of the machine.

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A Cold Gun can install directly onto this machine, providing cooling and light chip removal as needed

The real solution for this type of condition is to provide some sort of cooling for the drill head, and if possible, a means to remove the chips and debris from the machining area as well.  Fortunately, both of these are possible through the use of a Cold Gun Aircoolant System.

A Cold Gun in this application will provide cold air at temperatures below freezing to cool the drill, and the airflow from the Cold Gun will simultaneously clear the small chips and debris from the machining area.  And, these improvements to the application keep the workspace completely dry.  There’s no need to add a coolant collection system or to create additional work through cleaning coolant from the machined pieces once they’re complete.

If you have an application in need of a dry-cooling solution, or if you’d like to explore the possibility of removing liquid cooling from your CNC, contact an EXAIR Application Engineer.  We’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE