Cleaning during initial fabrication and final assembly is an imperative for most products. While many manufacturers correctly opt for the consistency, control, oversight, and economy associated with in-house critical cleaning, using a contract cleaning facility can be a valid, cost-effective option.
Why might you consider contract cleaning?
Perhaps you are rapidly ramping up production and do not have the immediate capability to handle required throughput. Conversely, you might have very small, short-term production runs of highly critical components where specialized cleaning equipment is required but investment in capital equipment is not warranted. The physical dimensions of some products may make in-house cleaning impractical. Local regulatory constraints may make adding a cleaning process inadvisable. Perhaps you have designed a new product and, while you never intend to ramp up to full-scale production, it is desirable to demonstrate capability to potential buyers. The cleaning issue may not even be in-house; you may have a favored supplier that fabricates the parts superlatively but cannot achieve acceptable cleanliness.
Investing the effort in choosing the right contract cleaning facility can result in a mutually profitable and productive partnership. Here are a few pivotal steps to minimize headaches and maximize return on your efforts.
Choosing a contract cleaning facility
Be sure that the contract facility knows your expectations and—especially if you are not the final assemblers—understands the expectations of your customer. Communicate your criteria for a clean part in writing to assure that a suitable cleaning process is available and to avoid either under-cleaning or over-cleaning. Under-cleaning can result in decreased yield or, worse, in catastrophic product failure. The consequences of over-cleaning include higher costs and damage to critical components. Whether or not you (or your customer) are required to follow a specific cleaning process, you must demonstrate acceptability of the final component or product. Can the contract cleaner you are considering support clearly-defined cleaning processes? Can they validate surface cleanliness and/or surface properties? Ask the cleaning provider for customer references; better yet, contact the references yourself.
Conduct an initial evaluation and inspection of the contract facility. While it is possible to start with conference calls and documentation, conduct a site visit. Look for experience, intelligence, and professionalism on the part of management and technicians. Experience in your arena of manufacturing, including familiarity with the expectations of your customers and of your peers, is a plus.
Your visual observations and impressions are invaluable. Assess the overall cleanliness and housekeeping of the facility, both in and out of the cleanroom. Ask to observe the manner in which cleaning processes are conducted. If your product is your baby, think of critical cleaning as analogous to bathing your baby. Does the behavior of employees inspire care and confidence?
If you are part of a supply chain, gaining familiarity with the processes and the facility of your cleaning provider and being able to explain your rationale for choosing the contract cleaner is likely to help with acceptance by your customer.
Setting the groundwork
Agree on a process and get the cleaning process parameters in writing. Make sure the paper trail includes details of cleaning parameters (e.g. ultrasonic parameters, time, temperature, cleaning chemistry, including concentration). Be sure to specify rinsing and drying requirements. For solvent processes, specify the specific solvent and solvent quality, as well as the process parameters. Process baths have to be monitored; understand the monitoring protocols, determine that they are acceptable, and then get them in writing. Keep in mind that product from other customers may negatively impact the quality and contamination level of process baths.
Conduct acceptance testing. Send the facility some test parts to clean, preferably at least triplicates. Test a typical component and an example of one that typifies the greatest cleaning challenge. If the cleaning facility also performs tests for cleaning efficacy, have them include such test results. You will then need to essentially double the experiment, providing enough parts that cleanliness verification can be determined by a third party.
Finally, to avoid recontamination, it is essential to determine, agree on, and document procedures for parts/components handling both before and after cleaning.
The ball is always in your court
Whether you do the cleaning yourself or have someone else do it for you, it is your responsibility to ensure that the task is done properly and effectively. Therefore, even if you do not “do it yourself,” it is highly recommended that you invest the time to understand the critical cleaning processes that you need, the rationale for cleaning, the cleanliness standards, and the appropriate surface characteristics.
Barbara Kanegsberg and Ed Kanegsberg (the Cleaning Lady and the Rocket Scientist) are independent consultants in critical and precision cleaning, surface preparation, and contamination control. They are the editors of The Handbook for Critical Cleaning, Second Ed., CRC Press. Contact: firstname.lastname@example.org
This article appeared in the October 2012 issue of Controlled Environments.