Cleaning processes often offer significant potential for improvement when it comes to more reliable, economical and sustainable parts cleaning operations, according to Ecoclean. The first step is to perform a systematic process analysis, which also takes a close look at the upstream and downstream production steps.
In order to guarantee the quality of the subsequent stages of the process, to avoid defects and to guarantee the functionality of the final product, the constant cleanliness of the parts is a fundamental quality criterion. Increasingly strict or even modified cleanliness specifications must be met. In addition, requirements for speed, price, effectiveness and sustainability of the cleaning process are constantly rising. However, how well, fast and efficiently the cleaning work is carried out depends not only on the equipment, the process technology and the medium used, but also on factors relating to the cleaning process itself.
Systematic Process Analysis – Looking at The Big Picture
So what do you do if parts suddenly come out of the system stained, particle or thin film cleanliness specifications are no longer met, cleaned parts arrive at the customer corroded, or cleaning is too slow/too expensive? In the case of these and other problems, a systematic process analysis, such as that performed by the Ecoclean Academy at Ecoclean GmbH, can determine the root cause of the error. Cleaning experts not only focus on the actual cleaning process and equipment, but also evaluate the overall production environment. The slightest change in part, part or material spectrum, type of contamination, or modifications to upstream or downstream processes are enough to seriously degrade cleaning results.
Stains and Remnants of a Thin Layer on Parts
According to cleaning experts, a poor cleaning result or one that does not meet new higher requirements is a ‘classic’ reason to perform a process analysis. The first step is to identify the exact problem – are the thin film cleanliness specifications not met or are there spots on the parts?
If staining is the problem, one of the questions to ask is whether the amount and composition of the contaminants (treatment medium and other substances) have changed, or whether the ingredients and concentration of the cleaning medium are still appropriate. Other factors such as rinse water quality, bath treatment, process technology and process sequence as well as the drying stage are also carefully examined. These are additional influencing variables that play a role if thin film cleanliness results are unsatisfactory.
Failure to Meet Particle Purity Requirements
If the cleanliness analysis after the cleaning cycle shows that too many or too large particles are still attached to the parts, this may also be due to the cleaning program and process sequence used. Possible causes include residual particles in the work chamber or on the parts carriers, an inadequate filtration system, or a clogged filter. Sometimes the wrong choice of cleaning containers, such as perforated galvanized sheet metal crates, prevents efficient and reliable separation and removal of particles. This type of crate blocks the ultrasonic waves and prevents them from developing their full effect on the laundry. Likewise, the spray pressure does not reach the interior of the perforated crates. Compared to baskets made of round wire, an additional problem is that the cleaning medium does not drip as efficiently from these baskets. This may result in unwanted transfer of contaminants and/or cleaning chemicals. In any case, much longer and therefore more energy-intensive drying processes are required.
Another reason for a failed cleanliness check is often burrs still attached to the parts that come off when the parts are handled during the residual contamination check and then show up on the particulate filter. If these particles are examined under a microscope, it can be determined whether they are chips or burrs. If the latter is the case, upstream processes must be evaluated to determine where the irregularities occur and how they can be avoided. The purity of the particles can also be disturbed by magnetism that is “bought” with the raw materials or arises during the manufacturing process. Magnetism binds the chips to the parts and inhibits or prevents their removal during the cleaning process.
Handling Parts After Cleaning
However, the cleaning process is not finished when the parts leave the machine with the required level of cleanliness. To prevent recontamination or corrosion that can occur even with preserved or passivated parts, it is important to look at how the parts are handled after the cleaning step. The following questions must be answered: Where, how and for how long are the parts stored? How are they transported to the next processing step? What kind of packaging is needed for this? In addition, high cleanliness requirements often require processes such as internal transport, assembly or packaging to be carried out in a clean environment or clean room.
Cleaning process update
In addition to cleaning issues, modified cleaning programs can be an additional reason to perform a process analysis. The goal is usually to shorten the process time or improve the cleaning result. As always, analysis begins with documenting the actual condition, which includes checking process parameters, process sequence, and process times. Based on the results of the analysis, potential for improvement can be identified and appropriate measures determined. These may include upgrading the system, such as by retrofitting or upgrading ultrasound equipment.
It is essential that parts cleaning personnel participate in process analysis and optimization measures. Increasing staff awareness of cleanliness, as well as the capabilities of cleaning technology and the impact of parameter settings on the cleaning outcome, is a key factor. If there is a change of personnel, it is also important to pass on knowledge of how the cleaning system works and how, for example, bathroom treatment measures or regular maintenance of the cleaning system are carried out. Otherwise, problems that were fixed in the past may reoccur. Investing in the training and continuing education of cleaning staff is therefore a cornerstone to achieving reliable cleanliness requirements in an economical and sustainable way. Ecoclean Academy therefore combines process analysis with classic training courses.
For more information: www.ecoclean-group.net