Cellular Parts Cleaning for Kaizen Conformity

ITW Highland, a deep draw stamping manufacturer in Waterbury, CT, is one manufacturer that’s fully risen to the changing face of manufacturing in the United States: The company has adopted and implemented a range of Kaizen practices, including cellular manufacturing, KanBan and other other techniques, as a means to improve processes, product, and response to dynamic customer requirements. Its various manufacturing cells now improve workflow, while they easily adapt and reconfigure for whatever job is at hand. Concurrent process improvements yield superior parts with fewer rejects.

However, these modular changes have dictated that new methods for secondary processes, including parts cleaning, must now be employed. Highland’s large, inline systems are inappropriate for a significant amount of the cellular work going through the plant. While these cleaning system workhorses still do the job for which they were designed decades ago, a new, lean, cellular cleaning approach is required for much of today’s, (and even more of tomorrow’s) volume.

In 2006, the company began investigating cellular, precision cleaning systems. After preliminary review, the field was narrowed to the Lean Clean 360 four-basket system from Jenfab (Jensen Fabricating Engineers, Inc.) and a similarly-sized, precision cleaning system from Ransohoff.  ITW Highland settled on the Lean Clean 360-4 Rotating Basket Cellular Washer as the best system for its requirements.

Rob Weber, Business Unit Manager for Highland, said: “The Lean Clean 360 offers especially rugged, robust mechanical construction and superior drying cycles. Its anticipated, long life and faster, better drying were the primary factors in the decision.”

The JENFAB Super Dryer™ fan recirculates 6,000 Cubic Feet per Minute (CFM) of hot air onto the parts as they rotate past several high velocity air slots. The high volume of air blowing through the parts evaporates water quickly, at lower temperatures and reduced energy consumption than with high-pressure blow-offs.  All of the air in the chamber is recirculated, over 150 times per minute, past the heating elements and back through the parts.  The heater is activated only as needed to maintain the temperature set point.  This method saves more than 75% of the energy required by high-pressure blow-offs, for savings of several thousand dollars per year.  Since the air is constantly recirculated, less moisture is discharged into the room than with high pressure blow off.

“Other, major considerations were its efficient oil filtration, Jenfab’s experience with stamping environments similar to ours and the system’s ease of maintenance” he added. ITW’s current maintenance schedule includes a weekly scrub-down, filter change and chip basket cleaning. Since the Jenfab system is designed so that filters and baskets are easily accessed, removed and replaced, it’s a major time-saver with higher throughput and reduced maintenance frequency.  Jenfab’s high-efficiency, coalescing oil removal system and large, 300 gallon tank capacity also reduce chemical maintenance intervals.

The Lean Clean 360-4 rotating basket cleaning system employs ergonomic, waist-high loading: Baskets do not have to be lowered into, or lifted out of, the cleaning chamber. The system cleans parts with spray, immersion, ultrasonics and high-pressure, submerged turbulation. Baskets are rotated 360 degrees in solution to submerge all parts and expose all surfaces to both an immersion wash and a powerful submerged spray.

The selected machine processes four baskets, side by side, per cycle. Its small footprint (8’ 6’ x 9’) requires minimal floor space and lends itself to cellular configuration. However, its simultaneous processing of four baskets ensures considerable throughput for its size. Jenfab also makes single, double and eight-basket models for differing requirements.

The process chamber is comprised of 11 gauge 304 stainless steel, with a 110 gallon capacity. Its V-shaped bottom is pitched from three sides for complete, 100% drainage and chip removal. Fresh filtered solution is directed at the parts at 180 GPM and 50 PSI as they rotate.  The solution is continually recirculated, filtered and delivered through high pressure, submerged jets.  The entire volume of the cleaning chamber is turned over nearly twice a minute.  This fast, recirculating turnover rate scrubs the parts clean while it flushes away chips, soils and oils. Fresh, clean solution is constantly in contact with the parts.

The Lean Clean 360 at ITW Highland is capable of meeting and exceeding precision cleaning specifications with its ultrasonic cleaning option. A 25 KHZ (40 KHZ available) piezoelectric ultrasonic resonating transducer is installed in the process chamber. The tube resonator is a unique, omni-directional ultrasonic device, designed to uniformly disperse ultrasonic cavitation into the parts as the baskets rotate or articulate. Rotation within this ultrasonic field assures that the full power of ultrasonic energy reaches all of the parts. Rocking in solution (an exclusive Jenfab feature) offers even longer contact time with the ultrasonic action.

Installation was quick and easy, since all of utility connections are single point. Upon spotting, minimal time is required to connect utilities. With prior utility or soft drops, the Lean Clean was operational in less than six hours. Standard Allen Bradley Micro Logix PLC controls made start-up and programming relatively uncomplicated.

ITW Highland manufactures a large volume of automotive components. In addition to its second tier automotive customers, the company serves a line of commercial customers, including valve and appliance manufacturers. Specifications for cleanliness are to the particulate level for parts such as automotive fuel injectors. Typically, residual particulate extracted from a designated number of sample pieces is weighed to a customer specification. The company plans to accommodate even tighter specifications, to the micron level, in the future.

Both Rob & Karl Knightly, the company’s automation technician, had experience with Jenfab systems in previous manufacturing environments. In fact, ITW Highland also has several, older, inline Jenfab systems, which are still doing the job for which they were designed. Other ITW Business Units, including Drawform, Ramset and Paslode, also have Jenfab cleaning systems installed. Between the new Lean Clean 360 and these older parts cleaning systems, ITW Highland processes an average of a half-million parts per day. The new, Lean Clean 360 machine is currently used on one shift, but, Highland intends to add a second shift. Some of its currently out-sourced cleaning will be brought in-house, once customer PPAP qualifications and validation results are approved. At that time, ITW Highland will add a second Jenfab Lean Clean 360.