Choosing the Right Critical Cleaning Method

Q: We want to implement long-term critical cleaning applications, but there are so many products out there with varying information. How do we make the right choice?

A: Successful cleaning methods are critical to ensure components work as they should. Within the product finishing industry, metal cleaning is paramount. Metal components must be perfectly clean prior to painting, plating, welding or subsequent processing. The optimal metal-cleaning process needs to dissolve or displace common contaminants without damaging substrates.

So how do you find an efficient method? Develop a cleaning “scorecard” to help you evaluate cleaning processes.

First “score” your cleaning methods. When choosing a cleaning process, many companies only consider the cost of a machine or a drum of solvent, believing the lowest-priced machine or the cheapest cost per liter to be the most important factor. A cleaning scorecard focuses on the total cost per part cleaned. 

In scoring a long-term cleaning method, worker health and safety, and environmental regulations also must be a priority and should influence your choices. Regulatory laws are continually changing, making the selection of cleaning fluids limited and the risks of making an incorrect choice high. Decision-makers need to take this into consideration and invest in cleaning methods that have long-term stability.

Consider cleaning capacity. Don’t look at equipment by its physical size, consider its production or cleaning capacity. How many units can be cleaned per hour or day? Alternatively, estimate the total surface area of all the parts to be cleaned. It is important to remember that some components may need to be cleaned by different methods. If they are intricate or fragile, you may need different cleaning processes.

Once a cleaning capacity “score” has been determined, look at the technology. A vapor degreaser, for example, is good for efficient, high-volume cleaning, but it is larger and more expensive than other methods like benchtop cleaning machines, which are slow, but small and cheap.

Look for consistent cleaning. A vital calculation to consider is the consistency of the cleaning process. It is important to understand the value of a simple, consistent and sustainable cleaning method, as better cleaning will play a key role in a method’s final score.

When it comes to consistent cleaning, the use of solvents scores highly against processes like aqueous cleaning. The benefits of vapor degreasing are clear, as it is a simple process that uses sophisticated, “low-boiling” chemistry to remove contamination. Another huge advantage is the reduction in analytical work required to ensure cleaning is effective. Aqueous systems require engineers to consistently monitor results to ensure they are within operating parameters. Solvent cleaning, however, saves on this cost implication, minimizing production costs, while meeting all critical cleaning requirements.

Try before you buy. Once you have assigned scores and found the best possible equipment for your production needs, test this technology. Ask the equipment manufacturers to run trials. Request sample reports on the cleaning process, solvents, temperatures, times and results to ensure the system performs to your specification.

It is important to then calculate the average productivity of the system in terms of assemblies per hour. This is crucial to estimating the cost per part cleaned, as operational and labor expenses are usually tabulated as hourly costs.

Look at the cycle times to give an average throughput score. This is defined as the duration of one complete cleaning cycle, including loading and unloading.

Compare total cleaning costs from each machine, including the cost to purchase and set up the machine, as well as consumables like water, solvent and electricity. Recalculate the figures into one standard unit of measure to come up with the total cost per part cleaned.

Don’t forget operating costs. After you have determined the throughput score, work out operating costs like “drag-out,” for example. This is the loss of cleaning solvent that becomes trapped in, on or around clean parts as they move through the system. High-boiling solvents like water and hydrocarbons are prone to high drag-out losses, but the chemicals are relatively cheap. Low-boiling solvents can minimize drag-out, but are more expensive.

Reduce drag-out by incorporating equipment that takes this into consideration. New vapor degreasers use extra refrigeration, superheat and hoists to reduce losses and save money. Aqueous systems use air knives and extra drying chambers, which reduce drag-out but are costly on utility usage.

Also remember to account for hidden costs like labor and maintenance. Automated equipment is thought to save time on labor, but also consider the technicians performing inspection, re-cleaning and drying of parts. Maintenance costs can also vary. Machines like aqueous systems include many moving parts and processes, from water treatment and recycling to the alkaline additives used to boost cleaning power that leave residue—all of this must be maintained.

Vapor systems will require filters to be replaced and the solvent in the degreaser to be boiled down and removed. However, when properly designed, equipped and configured, vapor systems outperform the cleaning efficiency of any other cleaning technology.

Scorecard Checklist

To sum up, remember it is the total cost-per-part-cleaned, that is important. Design your cleaning scorecard around these important calculations to find the cleaning process that works effectively for your needs:

1. Ensure products adhere to regulative scrutiny.
2. Consider your cleaning requirements and how they may change. Average those requirements into a daily or hourly rate of required throughput.
3. Compare different cleaning technologies. Send part samples to the equipment makers so they can prove the ability of their systems to clean the components to your specifications.
4. Examine upfront capital costs, including everything from floor space and installation costs, to energy, solvent and labor costs.
5. Determine if the cleaning is consistent. Do you have clean components every time?
6. Convert all the cost data into a performance index of total cost per part cleaned.
7. Select the option that minimizes this total cost per part cleaned.

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Mike Jones is vice president at MicroCare Corp. Visit microcare.com.