What Is Vapor Degreasing?
Condensing the vapours of solvents on the surface of the item that is being cleaned is the first step in the degreasing process known as vapour degreasing. The procedure does not call for the use of any water or scrubbing at any point. Instead, solvent vapours are used in the vapor-degreasing machine to clean and remove contaminants from the parts. During the manufacturing process, this process is used to clean a variety of materials, including plastic, glass, metal, gold, and ceramics, among other things.
The Vapor Degreaser Design
One particular variety of still is known as a vapour degreaser. The degreaser reduces a cleaning solution to vapours and fumes by heating it to boiling. This is its most basic function. Because warm vapours are lighter (less dense), they rise upwards in the machine; however, a layer of refrigeration that creates a temperature inversion prevents them from escaping because it traps them. After that, the vapours turn back into liquid form and are reintroduced into the cleaning machine so that they can be used again. The fundamental operation of the system is depicted in the schematic that can be found below. In the rinse sump, there is never any old cleaning fluid to be found. When more recently freshly-distilled cleaning fluid is cycled back into the system through the cooling coils, it is always cycled back to the rinse sump. The rinse sump will eventually overflow into the boil sump, which is where the bulk of the cleaning will take place.
Important point to understand, and in contrast to cleaning with water, the cleaning fluid does not degrade over time. It may be reused hundreds or even thousands of times due to the fact that the cleaning fluid is continually being repurified and recycled. This results in vapour degreasing being extremely accessible financially. It is essential to keep in mind that the term “boiling” does not denote a significant amount of heat. The majority of MicroCare, Opteon, Vertrel, and Bromothane cleaning fluids boil at relatively low temperatures, typically ranging anywhere from 40 degrees Celsius (105 degrees Fahrenheit) to 65 degrees Celsius (165 degrees Fahrenheit) depending on the formulation. Temperatures that are lower not only make the workplace safer for workers but also reduce the amount of energy used. In point of fact, the majority of modern vapour degreasers require no more than 25 amps to function. There are, as you might anticipate, dozens of variations and improvements on this very simple process, such as the addition of ultrasonics, but all of those enhancements are essentially the same thing.
How does Vapor Degreasing work?
A vapour degreaser is comprised of two tanks, which are referred to as sumps, a metal basket, and bands of cooling coils in its most fundamental configuration. In the first sump, known as the boil sump, the solvent is heated to boiling, and in the second sump, known as the rinse sump, the solvent distillate is collected. Here is where you can view the vapour degreasing solvents that we have available for purchase. The components can be immersed in a boil sump and subjected to additional agitation with high-frequency ultrasonic waves as a secondary cleaning method. During this step of the procedure, the components are arranged in a metal basket, which is then lowered into the machine. The basket stays elevated above the boiling solvent while staying positioned below the cooling coils. The solvent goes through the boiling process in the vapour degreaser. The vapours of the solvent rise, but they are unable to leave the machine because they are blocked from doing so by a layer.
After that, the vapour dissolves any contaminants that were on the surface of the parts where it has condensed. The soils are removed along with the solvent as it drips off the objects in question. Because this is a closed-loop process, the solvent goes through numerous iterations of the cycling process. The vapours travel upward into the cold trap, where they first condense into a liquid before returning to the rinse sump at a lower level. After that, the contents of the rinse sump make their way into the boil sump. It is possible to prevent cross-contamination of both the parts and the rinse sump by ensuring that the soil is contained within the boil sump and does not travel with the vapour. Those who are used to wearing glasses will be comfortable with this procedure. It takes place when a person goes from being in a hot environment to being in a cool room immediately afterward. On the inside, a fog will form because the air outside is warmer and more humid.
A vapour degreaser offers a number of advantages, including the following:
- Highly Effective Cleaning: Vapor degreasers and the solvents they use are capable of easily removing almost any kind of contamination, including waxes, heavy greases, and oils of varying viscosities.
- Versatile Cleaning: Vapor degreasers and the special solvents they use are able to easily penetrate and manoeuvre around even the tiniest of parts, even those with extremely close clearances, resulting in flawlessly clean contours and components.
- Speedy Cleaning: Since vapour degreasers have very short cleaning cycles, even a modest batch machine can usually outperform an in-line water cleaning system that costs two or three times as much.
- No Entrapment: Because the solvents evaporate so quickly, it is simple to remove the vapours from designs that contain complex shapes, deep holes, blind vias, and other elements in which slow-drying solvents would either be unable to clean or could become trapped. Because of this, costs are reduced while quality is maintained.
- No Water Spots: Vapor degreasers are ideal for cleaning optics and other super-critical applications because they never leave behind any water spots, whereas water frequently leaves behind unacceptable water spots.
- Broad Materials Compatibility: Since there is no high pressure spraying involved, the temperatures are kept low, and the cleaning cycles are kept to a minimum, solvents and vapour degreasers are excellent choices for use with the majority of the components.
- Planet-friendly Cleaning: Because they only require a small amount of electricity and do not require the use of water, vapour degreasers are very kind to the environment.
- Lowest Cost-Per-Part-Cleaned: Both the purchase and use of vapour degreasers are very economical options. A contemporary degreaser can reduce the amount of solvent needed to just a few pennies or dollars per day.
What are the most basic steps involved in running a vapour degreaser?
The vapour degreaser is prepared for the first step of the solvent cleaning process by having the solvent poured into it. Next, decide what temperature you want the solvent to reach and make the necessary adjustments. This temperature varies depending on the solvent that you choose, as various solvents have varying temperatures at which they boil. The ultimate objective is to bring the solvent to a boil, which will cause it to change into a gas.
Turn on the vapour degreaser once the appropriate temperature has been established so that both the heating element and the cooling coils can begin operating. After the vapour degreaser has reached the appropriate temperature and the solvent has begun to boil, you will be able to begin the process of cleaning the components.
The final steps can either be automated or completed by hand, depending on your preference. Place the things to be cleaned in a metal basket, and then gradually lower the basket into the gaseous atmosphere, which is above the boiling solvent and beneath the cooling coils. It will clean the objects in the gaseous environment. Give the solvent’s vapour time to adhere to the components and form condensation there. You carefully remove the basket out of the vapour degreaser, leaving the components clean and dry. This is due to the solvent dripping off the components and returning to the boiling solvent.
Is vapor degreasing safe?
Vapor degreasing, like the vast majority of other industrial processes, is not inherently dangerous as long as appropriate safety protocols are adhered to. Ventilation is one of the factors that should be given the utmost attention in this regard. It is strongly suggested that an underfloor ventilation system be put in place. Additionally, you should always use personal protection equipment, and you should consult the safety data sheet that is included with the shipment of your solvent for specific handling and application instructions.
What exactly is meant by the term “ultrasonic degreasing”?
Vapor degreasing may also be followed by an additional step known as ultrasonic degreasing. It is utilised in the event that oil and flux are still present on parts after the basket has been removed from the gaseous atmosphere of the vapour degreaser. In the vapour degreaser, a separate reservoir houses a liquid solvent as well as a component that generates micro vibrations in the liquid solvent. These vibrations are used to clean the surface of the component. When the basket containing the parts is completely submerged in this tank, the ultrasonic vibrations function in a manner that is analogous to scrubbing, thereby assisting in the removal of contaminants from the parts. When you have finished holding the components in the ultrasonic degreasing tank for the allotted amount of time, carefully lift the basket into the air and then slowly lift the components out of the tank in the same manner that you would have done if you had not used the ultrasonic degreasing tank.
What Operational Checks Are Important When Installing A New Vapor Degreaser?
Check for leaks in the solvent – Leaks can occur almost anywhere the solvent travels, including the lines, pumps (including system seals and gaskets), and the water/solvent separator. Check for leaks in the solvent containment system. Leaks can occur in the sumps, return troughs, and wand. There is a risk of leaking wherever there are welds or canister bolts (like in the water separator), so take extra precautions. In addition to the system for the solvent, the refrigeration system needs to be checked from the compressor, all the way through the discharge line, and then back to the compressor via the suction line.
Check that the cooling system is operating as it should. The refrigeration system needs to have its leaks checked, but it also needs to have its operation checked to ensure that not only is it cooling, but that it is also able to operate adequately to handle the heat load that is generated during the condensation of the hot vapours. Check that the heating system can maintain the temperatures set at its set points. It is important to check that the heating system is operational and that it can maintain the temperatures set at its set points. This can be accomplished by contrasting the results with those obtained from a second thermometer. Verification is also required for temperature overloads in safety zones.
Check the frequencies of the ultrasonics – The ultrasonics (transducers) need to have their frequencies checked to ensure they are accurate. Checking the rating on the transducers is an easy way to ensure that you have the right type of cleaner (or that you ordered the right cleaner) for the type of cleaning that you intend to do in the future. Ultrasonic cleaning is typically done in the frequency range of 20 to 80 kHz, but the frequency can go as high as approximately 130 kHz. In general, the lower frequencies are utilised for the cleaning of large parts, whereas the higher frequencies are utilised for more precise cleaning applications, such as the cleaning of extremely minute or highly complex geometrically shaped parts. There is a possibility that some units contain more than one transducer. You have the option of installing these on the interior of the home or on the exterior of the home, attached to the sump (typically the wall but also the bottom plate).
Test wand operation – The functionality of the wand should be evaluated, including whether the mechanism it employs activates and when it shuts off. The vast majority of the time, the power is turned on by means of a foot switch pedal.
Test movement robotics – Any movement robotics that have the capability to do so should have a check performed to ensure that they adhere to the programming guide in terms of time, distance, direction, correct stopping, and smooth operation (i.e. there is no binding of any type). Controls for electronic devices should be tested to ensure that they can be activated and deactivated in the appropriate manner. Controls for electronic devices include touch screens, dials, buttons, and switches, among other things.
How Do You Optimize a Vapor Degreaser Process?
Prior to beginning the optimization process, keep the following in mind:
- This step needs to be repeated for each individual component that you clean. This will assist you in developing standard operating procedures (SOPs) that your operators can adhere to.
- A component of this process is the creation of a unique programme to account for the various types of soil on the parts. For instance, you might be a contract manufacturer who uses a wide variety of solder pastes and fluxes depending on the specifications and call-outs provided by the company whose products you are producing.
- Determine, based on the construction of the parts, which of the many different options for cleaning you are able to use (or are unable to use), taking into account the sensitivity of the components. For example, what kinds of cleaning methods are acceptable to the client, such as immersion (in boiling or clean/cold sumps), ultrasonics, wand usage, and so on? Because of the sensitivity of the components, some customers may defer to your judgement regarding which method is the best and most effective, while others may inform you of what is not permitted or is not recommended. For instance, due to the sensitive nature of their frequency operation, RF components are typically unable to withstand the abrasion that is caused by an ultrasonic process.
We will use a simple PCB that needs to be defluxed as our example; there will be no restrictions regarding sensitive components. Assume, however, that the client has requested that there will be no immersions of any kind, such as vapour zone cleaning, but that the use of spray wands is acceptable. If you’re lucky, the company that makes your cleaning chemical has conducted cleaning tests on these test boards and given you a general guideline for cleaning only the vapour zone. Make your adjustments based on these default settings. In the event that this has not taken place, you will have to begin the process from the very beginning.
Step 1: Optimize for Maximum Condensation
- To ensure that the maximum amount of condensation has taken place, operate the test board using the typical vapour zone cycle time (when condensation stops, the part and the vapour have reached the same temperature and will be essentially dry).
- At this point, there will be no more cleaning. After completing the withdrawal procedure, remove the component and check it to ensure it is clean. If there is any flux residue left over, the cycle needs to be completed once more.
- Replace the component that was removed from the cold condenser so that the water can be cooled as effectively as possible. The target temperature difference between the component and the hot vapours should be as large as possible (record this length of time for future reference).
- Repeatedly put the component in the hot vapours, and this time make a recording (it will probably vary a bit from the first cycle).
- Proceed with the withdrawal procedure, and this time thoroughly examine the piece. If it satisfies the requirements for cleanliness, then you are finished. If not, you will need to continue the cycle until it is clean.
- Check that the procedure for cleaning the vapour zone is correct in accordance with your unique validation plan.
Step 2: Evaluate Supplemental Cleaning Steps
Test this in conjunction with the times that were recorded for the different vapour zone cycles. There were no restrictions on the use of wands.
- If you start by using the wand before the vapour zone cleaning, make sure to keep track of the amount of time you spend spraying and see if that makes a difference.
- To determine whether or not the cleaning is improved, try increasing the number of times the spray is applied before the vapour immersion. If this is not the case, begin shortening the times in order to find the optimal cleaning effect for the minimum amount of time.
- Additionally, try spraying the wand in the same way at the end of the vapour cycle times.
- Make a note of all of these different spray wand variations and times so that you can compile them later.
The purpose of this straightforward illustration is to illustrate how improving cleaning performance in a timely manner can be accomplished. As a result, this leads to an increase in throughput, a reduction in the amount of solvent lost, and efficient operation of the unit. Throw away any cleaning options or variables that don’t improve cleaning efficiency or cut down on the amount of time it takes to clean something after trying them. Return to previous steps of the experiment at regular intervals to recheck each option and variable until you are certain that the procedure is carrying out at its highest possible level of efficiency. Setting up your cleaning programmes or schedules can take a significant amount of time if you have a lot of different components and types of soil to deal with. This is something that should be obvious to you. However, once this process is complete, your employees will have a clear step-by-step recipe to follow regardless of the different parts or soils. When there is a new one added, the process of validating it has to be done again, and an addendum has to be made to the programme so that it can continue. Clear documentation of standard operating procedures (SOPs) enables a smoother transition of technicians as well as increased product consistency over time. Simply said, the “cleaning department” needs to confirm what, if any, modifications need to be made in order to account for this whenever there is a change in the process farther upstream. Your process team members will have the assurance that the cleaning method was verified in accordance with a stringent set of guidelines, and that as a consequence, the most effective method was selected to fulfil customer performance standards while optimising production time efficiency. The time invested in perfecting and documenting the procedure is time very well spent.
References
https://www.techspray.com/vapor-degreasing-the-quick-guide
https://www.microcare.com/en-US/Resources/Resource-Center/FAQs/How-Does-Vapor-Degreasing-Work