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Shop Solutions: No Fine Too Small for Sustainable Filtration System

Cobra Metal Works was started 17 years ago by owner Anton Hirsch to manufacture safety-related components for air bags for the automotive industry. Today, the company’s manufacturing capability has grown to include more than 150 pieces of precision machining equipment, including 11 Hydromat’s (mostly EPIC CNC models and three legacy machines), 12 six-spindle screw machines, and CNC multispindle five-axis and seven-axis turning lathes.

Its product mix has grown in step with a resurgent automotive industry, leading the company to be featured as one of the “Survive to Thrive” companies at IMTS 2012.

“Until about two years ago, most of our products, 90% of our production, went into air bags. We’ve since diversified over the last couple of years into manufacturing fuel injector components, emission parts, and steering components for the automotive industry,” said Hirsch.

To meet its customers’ requirements, Cobra Metal Works receives as much as 40,000 lb (18,143 kg) of material a day for processing including steel, aluminum, brass, titanium, and high-temp alloys. The company has QS-9000 and ISO/TS 16949:2002 registrations and has an active Six Sigma program with project goals of eliminating chips, improving machining efficiencies, reducing cycle time, and eliminating waste.

The machining objectives identified by its Six Sigma program for its high-volume precision production led Cobra Metal Works to look for coolant filtration systems that would minimize downtime for its high-volume production machines. “The biggest challenge we have is to get the most uptime that you can get out of each machine,” said Hirsch. “One of the issues we had with traditional chip conveyor filtration systems is that chips and sludge had a tendency to get into the bottom of the tank. We would have to frequently pull the tank, clean out the sludge and grime that had accumulated, and then refill the machine so it could go back into production,” said Hirsch.

JKI’s HydroClean sustainable filtration system removes fines ranging from sub 80 µm to below 10 µ/m in size from high-volume machining on a Hydromat EPIC CNC at Cobra Metal Works.

Hirsch learned about JK Industries sustainable filtration systems at IMTS. “The JKI sustainable filtration system completely removes chips and micro fines from the coolant so that we don’t get accumulation that leads to excessive downtime to shut off units and clean them out,” said Hirsch. Machines that would normally have to be cleaned out multiple times throughout the year are now completing their first year of production without cleanings, and the coolant and tanks are still very clean.

“Our sustainable filtration systems enable shops to switch from machining one metal to machining another without having to change the coolant system and our systems work on water-soluble and straight oil cutting fluids,” said Keith Urban, inventor of the HydroClean coolant filtration system and president, JK Industries LLC (Warren, MI). “Metals include aluminum, cast iron, titanium, steel, and exotic metals like beryllium. Shops that are doing production machining with stand-alone machining centers constantly face sumps that fill with solids. These solids degrade coolant, are circulated in the coolant back into the machining environment and cause problems with tool life, build up on pallets and fixtures, tolerance issues, finish issues, premature machine fatigue on spindles, way covers, and ballscrews, and spoiled coolant. Our products are guaranteed to remove all those issues, creating a sustainable environment for coolant so that coolants will last at least one year guaranteed,” said Urban.

JKI sustainable filtration systems feature a patented five-stage process for handling coolant and chips that maintains clean coolant in the tanks all the time, separating out everything down to the smallest micron-sized fines. This process eliminates settling of solids and is sized to remove more dirt than can be introduced by the cutting process which results in consistent coolant clarity throughout the year. 

The first two stages of filtration are similar to conventional offerings in which a hinge belt conveyor removes larger chips before sending coolant to a secondary self-cleaning 50/80 µm filter.  Fines larger than 50/80 µm are continuously removed by means of a rotating stainless steel filter element and drag style conveyor. The fines are discharged into the same hopper with the larger chips from the hinge belt.

Here is where the JK system takes a different approach. The third stage of filtration pumps the coolant from the clean side of the second stage 50/80 µm filter through a JK centrifugal separator which concentrates the remaining super fines into a low flow stream. “These fines range in size from sub 80 µm to below 10 µm and can be as much by volume as 30% of the stock removed from the part. These fines are what accumulate as sludge in the tanks on convevtional systems  and cause big problems for the process. Most of our clients show us quality graphs that spike like saw teeth and coincide with changing the coolant and cleaning the sumps on other brand systems,” said Urban. 

The JK separator concentrates these fines into a low flow rate that feeds a high-capacity cartridge filter (fourth stage) which traps them and holds up to 2 cubic feet of sludge before needing to be changed. This filter change frequency can vary from once every three weeks to once every three months depending on the type of operation. The coolant discharge from this filter is very clean typically <8ppm @10 µm, and is used to feed high pressure coolant through the tool.                     

Before: an old tank at Cobra Metal Works after four months of machining using traditional chip conveyor filtration systems.After: JKI’s HydroClean tank after one year of machining with the JKI sustainable filtration system in operation.

The final and crucial fifth step in the JK system uses the coolant that exits the clean side of the centrifugal separator to keep the entire coolant tank circulation high and clean. This is achieved by piping the coolant from the separator into the JK tank cleaner package that is engineered to keep solids from settling in the tank and provides excellent circulation of the coolant. This also keeps the coolant oxygen levels up helping to prevent bacteria from colonizing or growing, thereby stabilizing the pH levels and keeping the emulsion stable.

“One of the aspects of the JKI filtration units that stands out is with the filtration we get down to very fine microns of filtration, and we’re able to run smaller coolant-through drills for the injector manufacturing that we weren’t able to use before. It was always an issue that lines would clog up with chips and fine particles,” said Hirsch.

“Also, the JKI filtration systems equipment isn’t as cumbersome as traditional high-pressure coolant pumps that are added to the machines,” said Hirsch. “Adding equipment to traditional chip conveyors as add-ons becomes very bulky and unattractive, takes up a lot of space, and doesn’t look that nice.”

“Chip evacuation is critical when drilling stainless steel or when running 24/7 machining aluminum with a high-pressure coolant pump,” said Hirsch."We bought the machine with a JKI system on the machine right off the bat and we were getting really good tool life on the drilling of stainless. We calculated that we realized a six to seven month payback per machine in terms of uptime.”

Cobra Metal Works is converting over from the conventional chip conveyors to the JKI units. “We’ve already converted the Hydromats and are now working on the six-spindle multispindle machines. Right now, each machine has its own unit, chip conveyor and high-pressure coolant for it and features localized sump side filtration.”

Cobra Metal Works’ diversification has put it squarely in line to benefit from the resurgence of the auto industry not only in North America, but also in Europe. “Right now the US is the low-cost country for precision production for the automotive industry, because of our use of automation and high-production machines,” said Hirsch. “A lot of European companies are calling us for quotes right now because of the favorable exchange rates.”

“We feel that integrating JKI systems into our manufacturing process will be one of the key elements to keeping our productivity high and our operations lean.” ME

For information from JK Industries LLC, go to www.jkindllc.com, or phone 586-620-5202.

 

This article was first published in the May 2014 edition of Manufacturing Engineering magazine. Click here for PDF


Published Date : 5/1/2014

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