In-Line Metal Cleaning for Cold Heading Operations

Cold heading is one of the most competitively costproduction rates are increased. The automation also
driven metal forming industries. Large volumes ofdecreases labor time for the operators. The addition
parts are produced against paper-thin margins,of a drying stage obviously creates drier parts than
causing cold headers to re-evaluate their methods ofthe agitated dip tanks.
processing parts constantly, always looking forThere are negatives with the rotating basket system.
cheaper and faster alternatives.The transfer system used to transport the baskets
The parts cleaning system is one of the commonlyis sensitive to wear. All the parts in the system rely
evaluated areas of production. This system isupon each other, meaning weakness or variation in
charged with removing the large amounts of soilone component will generate problems for the rest
residue left over from the forming process.and impede the cleaning process. In addition, the
Companies are on the look out for the most efficientparts travel out of the baths in a manner similar to
way to remove this residue and dry the part.the agitated dip tanks, opening up the possibility of
The most effective cleaning method for cold headingre-contamination.
operations is to use a hermetically sealed solventBaskets on Standard Belt Conveyor
cleaning system. This system will remove all oils andThis process employs a standard multiple stage belt
chips from even the tightest deep threads, then willwasher. Parts are loaded into baskets, and
dry the part completely in a single batch cycle. Thistransferred to the washer via hand, gravity roller,
style system must be done in large batches though inpowered roller, or a pick and place gantry. The pump
order to contain the solvent vapors within thesprays the part in a 360-degree fashion. The major
system.advantage of this method is that the parts are not
For those manufacturers looking to clean theirbrought up through a soil layer, eliminating the threat
product in single piece or continuous flow as part of aof recontamination.
multi operation manufacturing line, there areHowever, parts are still placed in baskets on top of
alternatives. Three of the common cleaningeach other. The inside of the stack is not guaranteed
processes are cylinder loaded baskets for agitateda consistent impingement of fluid spray.
dip tanks, rotary baskets, and baskets on a standardExamining these options demonstrates the limited
belt conveyor.capabilities of a washer. It must automatically and
Hand-Loaded Agitation Tankscontinuously transfer parts to, in, and from the
With this system, a basket of parts are cylinder pushwasher. It needs multiple mechanical action and
loaded from an indexing conveyor onto a gratedcleaner to lift soil. The operation must not drag parts
shelf. The shelf lowers in a steel tank. A pump orback through the soil. Every part must be exposed
ultrasonic transducer agitates the tank, and the actionto the cleaning, and they must be dry when
of the chemistry's surfactant combined with thecomplete. Also, the inventory of dirty parts must be
multiple mechanical actions of the pump/ultrasoniclimited. The longer they sit, the harder they are to
waves or the lifting and lowering into the solutionclean.
breaks the surface tension of the soil on the parts.Rotary Auger Drum
There are few benefits and several disadvantages toThe Rotary Auger Drum System can achieve each
this system. The dual mechanical action may beof these goals better than the three previous
effective in removing soil. However, the parts havesystems. This style forgoes the basket, and provides
to be raised through the tank to be removed froma continuous flow of parts through each stage. An
the system, which exposes them to theauger style fin rotates with the drum to drive parts
contamination that was just removed.one at a time through the various cleaning stages.
Water does not break the surface tension of the soilThe main advantage of this system is the ability to
as well as a solvent does so cleaning is not asclean parts at the speed they are introduced to the
effective. Part layering in the basket shields thesystem, limiting dirty inventory. The parts are not
middle layers of parts from the beneficial mechanicalre-contaminated at any point in the system. There is
cleaning action. In addition, the parts exit the machineless labor involved, because the system has little or
wet instead of dry.no operator interface. The footprint of the machine
Rotating Basket Systemis small as well, since it only needs to wash one small
This system is similar to the agitated dip tank incollection of parts at a time. The entire part is
function, but with an additional mechanical action ofexposed continuously and consistently to the cleaning
turning the basket over. Rotating systems areprocess, unlike in basket systems, and then is able to
relatively simple operations. They send fluid fromdry once clean.
different tanks to a single process area and then dryThrough the use of "in-process" fluid treatment, the
the parts in the same area. They can be largeamount of soil in the washer can be controlled via in
systems, using a series of multiple dip tanks andline particulate filtration and oil removal devices. This is
complex material handling designs that transfer thea necessary addition to the machine or else it will
parts.become saturated and inefficient.
Benefits of this system are more numerous than theThe best way to control the wash process is by
agitated dip tank. The multiple mechanical actionscontinuously washing a few parts at once, using
(spinning, pump spray, and ultrasonic) in conjunctionmultiple actions and clean water. The rotary auger
with an aggressive chemical surfactant packagedrum is the best option for this, and will help a
remove the soil. When a sophisticated, automatedcompany maintain their high output and quality.
material-handling system is included in the design