Save Money, Improve Your Cleaning Process

The storm clouds are gathering. “How much is this new cleaning system going to cost me?” bellows the plant manager. “We have to lower the defect rate,” grumbles the production manager. Your old cleaning system is on its last legs and your boss, the plant manager, has put lucky you in charge of cleaning and process change. To top it off, given the challenging economic climate, you must justify costs. With the competitive atmosphere, you have to show superior precision cleaning performance. You need what we call a Cleaning Process Change Management System (CPCMS).

Why Clean?

We question everything in the manufacturing process, starting with the need to clean. This may seem surprising, considering our line of work, but one of the first things we consider is what the manufacturer is trying to accomplish in the cleaning step. Any step may be a critical cleaning step, or it may be totally unnecessary. Cleaning encompasses: removing the soils of interest; minimizing undesirable surface contamination; and achieving the appropriate surface qualities and properties.

Step back; take a dispassionate look at your entire manufacturing process. A cleaning step may have been introduced to remove a specific lubricant; the lubricant may no longer be used, so the cleaning step may no longer be necessary. While you should not eliminate cleaning steps without careful consideration, excessive cleaning can slow the process, contaminate the surface and potentially produce surface damage.

Where do you need to clean? In what timeframe do you need to clean? Cleaning promptly can save time and money, because with time, soils tend to become more adherent. A simple, effective dip process immediately after machining may be more critical to achieving the appropriate surface or product than the $500,000-plus cleaning system you planned to purchase.

Avoid Linear Thinking

After you have eliminated the unneeded, counterproductive cleaning steps and after you have set up simple cleaning processes, perhaps a costly investment in capital equipment is still looming in the background. Before petitioning the boss to invest in six- to seven-digit capital equipment, coordinate the cleaning process by considering the benefits and limitations of cleaning agents and cleaning equipment as part of the same thought process. This may seem contrary to the Archetypal Engineer’s Law of Linear Thinking, but let us explain.

There are two prevailing scenarios of linear thought in cleaning process evaluation. Both waste time and money:
Scenario 1: Pick the cleaning agent; the cleaning equipment will magically appear.
Scenario 2: Pick the cleaning equipment; any cleaning agent will work.

The first group puts forth copious effort sorting through, testing and eliminating cleaning agents. They may do extensive dip testing, and then check visually and even use analytical testing to see if soils appear to be removed. They may have eliminated entire categories of cleaning chemistries based on real or perceived safety and environmental concerns. There may be a series of arbitrary litmus tests. After evaluating hundreds of potential cleaning agents, the winning product is announced and the search for cleaning equipment begins. Uh oh! The cleaning equipment takes up an inordinate amount of floor space. The rework rate soars, because the dip testing did not correctly emulate process conditions. Waste stream management costs skyrocket. Time and money are wasted; the new cleaning process has to be revisited.

Fans of cleaning equipment may purchase a system out of a catalogue, assuming that the technology of cleaning, the cleaning force, time, temperature and automation are all that is needed. It is not unheard of for engineering teams to specify custom equipment in minute detail—order the equipment, get it in house and only then attempt to find a cleaning agent. Second uh oh! There may be limited cleaning agent choices and the cleaning agents may not remove the soils of interest. The selected automation system may not be appropriate to the process; in order to automate a cleaning system, you have to understand the requirements. Perhaps the cleaning system uses cleaning agents that must be controlled in terms of worker safety, community exposure or environmental considerations such as air emissions or water usage. If the bells and whistles in the cleaning system do not include the appropriate engineering controls, it may have limited utility.

Multi-Task

Since both scenarios tend to be costly and unsuccessful, multitasking really is the best way to go. Multitasking means planning the project so that you alternate between exploring cleaning agents and exploring cleaning equipment.

Educate yourself about cleaning agents. Determine what cleaning agents are likely to remove the soils of interest. Understand the solvency and wettability characteristics of your cleaning agents. Determine the nature of the residue; cleaning agent residue may compromise the next step in the process and/or compromise product performance. If the product has medical or pharmaceutical applications or any applications involving the FDA, ignoring the residue of process fluids and cleaning agent on or in the product can have catastrophic implications. Consider materials compatibility and corrosion issues (the impact of the cleaning agent on your substrates). Consider the safety and environmental implications of adopting the cleaning agent.

Consider all of the above factors in the context of the cleaning system. Even a mild-mannered aqueous product could potentially erode the product surface with enough ultrasonic cleaning force. Even a “regulatorally challenged” cleaning solvent can be well controlled and successfully used in the appropriate cleaning system. Where aqueous cleaners seem promising but water supply and/or environmental regulations restrict water usage, consider closed-loop systems rather than summarily dismissing the aqueous cleaning agent under consideration.

Analyze the part to determine what type of cleaning system will best match your cleaning
requirements. For example, with products having blind holes and complex geometries, line-of-sight-cleaning, as in an aqueous cabinet washer or in-line spray cleaner, is not likely to provide adequate soil removal. In fact in such cases, line of sight cleaning using organic solvent may not adequately remove soils. Consider the fixturing; how will the components be positioned so that the cleaning agents properly contact the surfaces to be cleaned (Figure 1).

Trust but Verify Vendor Claims

In the CPCMS program, allow time for comparison among vendors and for testing. Look for product support. Product data sheets and even MSDS for cleaning agents are often not informative. They all seem to indicate that the product will work well. At best, you may be able to spot phrases like “light duty” degreaser, an indication that the product is not likely to work for heavy soil loading but may be less likely to attack the substrate. Sometimes direct conversations with technical representatives of the vendor yields useful information. This is not always the case; compare vendors in terms of appropriate product offerings.

To control environmental and disposal costs, look for product stewardship and product support. A supplier of aqueous cleaners may claim that the product is biodegradable and either state or lead you to infer that spent cleaning agent can simply be put down the drain. Check with local regulators before you decide; the term biodegradable has somewhat indefinite connotations. Even if there is no problem in disposing of the cleaning agent itself, once metal and process soils have been added to the cleaning bath, the mixture may have to be treated as a hazardous waste. Some suppliers of organic solvents have programs to remove the spent solvent and even to redistill it for you. In the absence of such programs, a separate budgetary consideration will be needed for management of the spent solvent.

For capital equipment, be sure you are budgeting adequately. Check the equipment size and throughput and consider required scheduling in the production process. Allow a bit of growing room; after all, you are putting together a quality cleaning process. The benefits of an excellent cleaning process include a quality surface, a quality product and more business. Some equipment suppliers, perhaps fearful of sticker shock, size the equipment on the small side. You have to allow downtime for maintenance. Further, if the production flow is such that you must process, for example, 60 percent of the parts in a two-hour time frame, it can grossly disrupt production to purchase equipment using estimates based on running parts through the cleaning system at a constant rate over an eight-hour shift. In such a case, also look at your production flow to determine if steps can be taken to spread the throughput over a longer time, thus avoiding the need to purchase equipment that will be under-used most of the time.

When comparing equipment suppliers, ask for references, then, contact those references. Checking references is a cost-effective way to compare suppliers and to avoid investing in inappropriate equipment or in sub-optimal cleaning agents. The disparity between vendor claims and manufacturing experience can be astonishing. In some cases, you may find that a vendor claiming to have experience in building a particular type of cleaning equipment has actually had no experience. If you would be the recipient of the vendor’s first effort in a particular equipment design, please consider the ramifications. At least use the lack of experience as a negotiation tool.

On the flip side, very often, observing good performance expedites the selection process by providing a measure of confidence in terms of equipment ruggedness and product support.

Purchase Quality Products; Spend Appropriately

When first beginning work on new processes, we are often faced with harried managers demanding to know how to get the best bargains on cleaning agents and cleaning equipment.

The answer: be selective and buy quality. Consider the cost of using a cleaning agent, not just the initial cost. Consider dilution factors for aqueous cleaners. Consider the expected soil loading. In terms of cleaning equipment, look for ruggedness, reliability and adequate insulation.

Location, Location, Location

The cleaning equipment must mesh with the process; proper placement of cleaning equipment can impact the cost of the manufacturing process by either positively or negatively impacting process flow. This relates to the issue of selecting a single large cleaning system versus multiple small cell cleaning systems.

Floor space has value. It is critical to determine the floor space for your new process, including space to access and maintain the equipment. With estimated leasing costs in Southern California (Kanegsberg, 2001) ranging from $7.80 to $14.40 per square foot, and considering standard cleaning equipment, it becomes apparent that large footprint cleaning equipment costs money in floor space (Table 1). Many manufacturing facilities have limited floor space; so the space relative to the value of different manufacturing activities has to be considered.

Floor space becomes a particularly important consideration in cleanroom applications. For critical cleaning processes, it is often assumed that equipment should be placed in the cleanroom. However, cleanrooms are perhaps the most costly location in the manufacturing facility in terms of initial investment and maintenance. Cleaning equipment takes up a significant amount of space. Before placing cleaning equipment within the cleanroom, please consider that the cleaning equipment, if not configured properly to the task at hand, can be a significant source of contamination to adjacent processes.

Costs (and Benefits) of Planning

A Cleaning Process Change Management System involves some up-front costs, but it saves money over the course of the project and in day-to-day operation. In general, low levels of understanding and planning results in higher overall expenditures. Consider that automotive repair shops use inexpensive parts washers and would typically not set up a CPCMS. In those cases, studies indicate that, in contrast with forecasts by regulatory agencies, typical process conversion costs for solvent to aqueous conversion were on the order of $10,000 during the first year for small automotive shops (Kanegsberg and LeBlanc, 1999). Consider installation costs: 25 percent of capital equipment costs are a rule-of-thumb budgetary estimate (McChesney and Scapeliti, 2001).

Failed or sub-optimal cleaning processes are not published in journals; they are not announced at trade shows. Unfortunately, there are avoidable examples of equipment standing idle because it did not meet safety or environmental requirements, of higher than expected rework rates, of higher than expected costs for hazardous waste management. Some factors to consider when setting up your CPCMS are listed in Table 2 and a diagram of information flow is presented as Figure 2.

Cleaning is a critical part of manufacturing. To maintain competitiveness, if you are in charge of a cleaning process change, using CPCMS is essential, particularly in an era of economic challenges and vigorous international competition.


Barbara and Ed Kanegsberg, “The Cleaning Lady and the Rocket Scientist,” are independent consultants at BFK Solutions LLC (Pacific Palisades, CA). They are experts in critical and industrial cleaning and manufacturing processes. They can be reached at (310) 459-3614, or by visiting the Web site at www.bfksolutions.com.

References

1. B. Kanegsberg and C. Leblanc, “The Cost of Process Conversion,” Report to U.Mass
Lowell TURI, Proceedings, CleanTech’99, 1999.
2. B. Kanegsberg, “Costs of Cleaning,” CleanTech 2001, Rosemont, IL, 2001.
3. J. McChesney and J. Scapeliti, “Solvent Vapor Degreasing, Minimizing Waste Streams,” in Handbook for Critical Cleaning, Kanegsberg & Kanegsberg, ed, 2001.