Continuous Cleaning System For Machined Parts

Virtually all precision machined part manufacturers require a method of cleaning their parts prior to shipment to their customers. And because many machine shops cut with oil, parts cleaning is usually a complicated multi-step process.

Many shops use a batch processing system that accumulates a quantity of machined parts and then runs them through a cleaning system. Batch processing has been successfully applied in screw machine shops for many years.

Sometimes, however, the batching of parts can cause damage to delicate workpiece features. Agitation, necessary to separate batched parts, can result in a higher than desired incidence of damaged, hence scrap, workpieces.

Cecil Manufacturing Inc. (Rochester, New York) has developed a continuous cleaning system that eliminates damage to delicate workpieces. The system is called CECIL and stands for Continuous Efficient Cleaning In Line. The name Cecil originated because of its serpentine conveyor system. According to Bob Brinkman, president, "it looked like Cecil the sea serpent, which was a cartoon character from the 1960s."

The concept and design of the Cecil cleaning system was developed in order to improve the quality of output for the screw machine and other manufacturing industries. The company commissioned a team to design a product that would effectively clean these machined parts while minimizing handling time, thereby resulting in "ding free" parts that would bring increased value to their customers. As the first Cecil was produced and tested within the screw machine industry, a noticeable improvement in part quality was achieved.

The Cecil cleaning system is designed and built on two fundamental concepts: 1) moving parts directly and continuously from a parts manufacturing machine, through a cleaning process, and into a packaging process with minimal manual intervention and 2) completing this process with no part to part contact, which may damage high precision parts and make them unusable to customers.

Cecil uses a conveyor system to transport parts single file from the machining process to the cleaning tanks. The system can be customized using from one to four tank cleaning stations to achieve specific cleaning goals, which may include de-oiling, chip removal, rust inhibiting, and so on. The process is very effective with deep blind holes and hard to clean sensitive parts.

At the front of the cleaning line, an initial air blow can be used to remove a great deal of the contaminants from the part and the conveyor belt. Surface oil and some loose chips are cleared from the parts. These are then deposited into a drip pan and can flow back into the production machine for recycling.

In a standard three-tank system, the part continues on a conveyor at an incline until it is dropped into a part transfer mechanism. Once transferred, the part travels along the conveyor and is spray washed, then immersed into an aqueous washing solution where ultrasonic cleaning is used to clean blind holes and difficult to reach part features.

The part remains in the first wash tank for approximately 15 seconds. This wash tank holds 75 gallons of wash solution and is temperature controlled to 150 degrees. The time the part is in the wash tank is determined by the speed of the conveyor, which is adjustable from 3 to 9 feet per minute to reflect the screw machine production rate.

The part then comes out of the washing solutions and is subjected to additional spray cleaning. Next, the part is transferred to a second conveyor and may pass through an air knife in order to minimize drag out of the wash tank solution.

At the second tank, the part is submerged again into 165-degree water for approximately 15 seconds. The part is then transferred onto the last conveyor and into the final rinse tank, where it is submerged into 180-degree water for another 15 seconds (approximately).

When the part comes out of the final rinse tank, it may be dried using a variety of methods with the most common one being a blow-off system. The movement from each of the three tanks is on separate conveyor chains, which helps eliminate contamination from one tank to another as the part moves along the chain. Once the part is clean, it is then transferred from the conveyor into the desired container for packaging and shipping.

A standard three tank Cecil parts cleaning system measures approximately 16 feet long and 3 feet wide. If needed, custom tank configurations may be designed in order to accommodate work cells and a variety of footprints. The system is cast on rollers for mobility in the job shop and may be placed adjacent to most any machining process.

The system represents another choice for shops looking to solve a problem with damaged workpieces caused by cleaning. With continuous operation, it is also relatively free of operator intervention for shops looking to extend their unattended or lightly attended production hours.