5 basic steps to identify and solve a NDT aqueous cleaning issue, and a troubleshooting guide with common problems and solutions
By David Geis, Product Manager
Cleaning parts using aqueous solutions are usually only one part of a much larger manufacturing process. When a problem arises in the process, technicians and engineers need to trace the source of the problem and determine the best solution.
Sometimes a problem will appear immediately after the step causing it. In those cases, troubleshooting can be simple and straightforward.
Other times, problems will only appear after several more processing steps. In these cases, tracing back the root causes can be difficult.
In this article, we outline 5 basic steps you can take to identify and resolve an issue with your aqueous cleaning system, and give you a list of common problems associated with water-based cleaners along with solutions for each.
5 Steps to Resolve an Aqueous NDT Cleaner Problem
Identify: Identify the stage in the process where the problem first becomes apparent. Closely observe that stage to find out what makes the problem visible.
Find the source: Starting with the identified stage where the problem becomes apparent, work backwards through the process and closely observe each stage to identify the source of the problem.
Monitor: When the stage causing the problem is found, monitor that stage to find out if the problem is transient, if it is periodic or if it is inherent to the process.
Dig deeper:
If the problem is transient or temporary, identify whether any materials or conditions have changed. Sometimes a simple change in material can introduce unforeseen problems.
If the problem is periodic or sporadic, observe the environment and nearby process stages. Sometimes seemingly unrelated operations can influence each other to create a problem.
If the problem appears to be inherent in the process stage, collect as much information as possible. Evaluate whether the problem can be eliminated by changing the stage where the problem originates, or by changing the stage where the problem becomes apparent. Determine whether subsequent process stages would be affected.
Take action: Based on the information you have, implement the best solution to the problem.
Common Problems with Aqueous Cleaning
If you have concerns or troubles with your process that are not covered in this list, please let us know so our experts can help you find the right solution to your cleaning issues.
Part is not clean (general)
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| Possible Causes |
Solutions |
| Cleaner concentration is too low |
Check cleaner concentration and adjust if necessary |
| Temperature is too low |
Check temperature controller and adjust if necessary |
| Parts are not cleaned for long enough |
Increase the time that the part is processed |
| Cleaning solution is loaded with too much soil |
Check soil levels. If necessary, dump cleaning solution and clean out reservoir to remove soil sediment. Refill with fresh cleaning solution |
| Parts are not rinsed enough |
Increase rinsing time. Increase flow of rinse water. Check rinse water for contamination. |
| Cleaner solution is not aggressive enough |
Switch to a higher pH, higher alkalinity cleaner, let us help you select the right Daraclean cleaner |
Part is not clean (hand scrubbing)
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| Possible Causes |
Solutions |
| Parts are not scrubbed enough |
Increase scrubbing action on part |
Part is not clean (soak tank, agitated tank, ultrasonic tank)
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| Possible Causes |
Solutions |
| Dirt is not being lifted off surface because ultrasonic power is too low |
Adjust ultrasonic power setting |
| Large particles not removed because ultrasonic frequency is too high |
Adjust ultrasonic frequency setting |
| Small particles not removed because ultrasonic frequency is too low |
Adjust ultrasonic frequency setting |
| Too many parts loaded in bath at one time |
Decrease number of parts processed at one time |
Part is not clean (spray washing)
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| Possible Causes |
Solutions |
| Too many parts being processed at one time |
Decrease number of parts processed at one time to allow more space |
| Parts are arranged so that spray is inconsistent |
Rearrange parts in basket |
Part surfaces are dark after cleaning
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| Possible Causes |
Solutions |
| Cleaner concentration is too high |
Check bath concentration and dilute if necessary |
| Bath temperature is too high |
Check bath temperature controller and adjust if necessary |
| Metal surface is being attacked by aggressive chemistry |
Switch to lower pH, l ower alkalinity cleaner solution |
| Switch to a solution with more corrosion inhibitors |
| Let us help you select the right Daraclean cleaner |
Parts have a rainbow pattern similar to heat burn
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| Possible Causes |
Solutions |
| Bath temperature is too high |
Check bath temperature controller and adjust if necessary |
| Dryer temperature is too high |
Check dryer temperature controller and adjust if necessary |
Part surfaces show pitting, but part surface is otherwise clean
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| Possible Causes |
Solutions |
| Metal surface is being attacked by aggressive chemistry |
Switch to lower pH, lower alkalinity cleaner solution |
| Switch to cleaner solution containing more corrosion inhibitors |
| Add low-concentration corrosion inhibitor to rinse water |
| Use a protective coat of machine oil for long-term parts storage |
| Let us help you select the right Daraclean cleaner |
Part surfaces have starburst pattern
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| Possible Causes |
Solutions |
| Part surface being damaged by ultrasonics |
Decrease ultrasonic power |
| Increase ultrasonic frequency |
Cleaning solution turns yellow or brown
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| Possible Causes |
Solutions |
| Bath temperature too high |
Check bath temperature controller and adjust as necessary |
| Cleaner concentration too high |
Check cleaner concentration |
| Cleaning solution oxidized over time |
Ambient air can cause certain cleaner formulations to oxidize and darken over time. This does not affect the usefulness or cleaning ability of the solution. |
| Cleaning solution loaded with too much emulsified oil |
Check soil levels. If necessary, dump cleaning solution and clean out reservoir to remove soil sediment. Refill with fresh cleaning solution. |
A film of oil develops on top of the cleaning solution
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| Possible Causes |
Solutions |
| Cleaner concentration too low |
Check cleaner concentration and adjust as necessary |
| Bath temperature too low |
Check bath temperature controller and adjust as necessary |
| Oil-phase de-foaming agent added |
If an oil-based de-foaming agent is in use, the film of oil on top of the solution is there to prevent the formation of foam |
| Oil loading in cleaner tank too high |
Check soil levels. If necessary, dump cleaning solution and clean out reservoir to remove soil sediment. Refill with fresh cleaning solution |
| Cleaner chemistry not compatible with soils being cleaned |
Switch to a different cleaner that is chemically compatible with the base material and soils being cleaned, let us help you select the right Daraclean cleaner |
Excessive foam
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| Possible Causes |
Solutions |
| Too much agitation |
Decrease agitation until foaming stops |
| Spray pressure and volume too high |
Check pressure and flow regulators and adjust if necessary |
| Recirculation pump cavitating |
Check condition of pump and check for flow blockage |
| Cleaner concentration too high |
Check cleaner concentration and adjust as necessary |
| Bath temperature too low |
Check bath temperature controller and adjust as necessary |
| Cleaner de-foaming agents used up |
Replenish de-foaming agents |
| Foaming soil or additive introduced to bath |
If soil is naturally foaming, a different cleaner formulation may be required, or additional de-foaming agents may need to be used, let us help you select the right Daraclean cleaner |
Parts have a film of oil when removed from the cleaning solution
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| Possible Causes |
Solutions |
| Parts not completely cleaned |
See above recommendations for Part is not clean |
| Oil loading of cleaner bath too high |
Check soil levels. If necessary, dump cleaning solution and clean out reservoir to remove soil sediment. Refill with fresh cleaning solution |
| Oil contamination of rinse water |
Check rinse water to make sure only clean water is used for parts rinsing |
| Parts have excessive grease or heavy oils before cleaning |
Add pre-cleaning step to remove excessive grease and heavy oil from parts |
| Cleaner chemistry not compatible with soils being cleaned |
Switch to a different cleaner that is chemically compatible with the base material and soils being cleaned, let us help you select the right Daraclean cleaner |
Parts have a white film or powdery residue
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| Possible Causes |
Solutions |
| Parts not sufficiently rinsed after cleaning |
Check rinse water to make sure only clean water is used for rinsing |
| Increase rinsing time or add second rinse stage |
| Increase rinse water flow or agitation in rinse tank. |
| Hard water scale forming on parts |
Install water conditioners on the processing line |
| Switch to a different cleaner that has better hard water tolerance, let us help you select the right Daraclean cleaner |
| Silicates precipitating on parts |
Switch to a different cleaner that does not use silicates, let us help you select the right Daraclean cleaner |
Excessive scale buildup on tank fixtures or heater
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Part surfaces appear grainy after cleaning
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| Possible Causes |
Solutions |
| Part is being etched by galvanic action between dissimilar metals |
Verify that all equipment and cleaning tanks are properly grounded. Verify that part baskets or fixturing are properly grounded |
| Part is being attacked by aggressive cleaner chemistry |
Switch to a cleaner that is compatible with the base metal of the parts, let us help you select the right Daraclean cleaner |
Color of alloy changes after cleaning
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| Possible Causes |
Solutions |
| Part is being anodized by galvanic action between dissimilar metals |
Verify that all equipment and cleaning tanks are properly grounded. Verify that part baskets or fixturing are properly grounded |
| Part is being attacked by aggressive cleaner chemistry |
Switch to a cleaner that is compatible with the base metal of the parts, let us help you select the right Daraclean cleaner |
Cleaner tank begins to rust at comers
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Cleaner system begins to leak
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| Possible Causes |
Solutions |
| Galvanic action is corroding metal of cleaner tank |
Verify that all equipment and cleaning tanks are properly grounded |
| Rubber gaskets and seals being attacked by oils removed from parts |
Verify all seals used in cleaning equipment are compatible with the oils and solvents being removed from parts at the temperatures being used |
| Let us help you determine the root cause and solution to advanced cleaning problems |
Do you have some other suggestions for how to troubleshoot NDT cleaners?
Share your knowledge with us in the comments section below.
