When it comes to evaluating particle residues remaining on parts after manufacturing, the “go to” is often particle counting.  Particles remaining on parts after normal manufacturing operations are collected using a secondary, more aggressive washing method.  Collected particles are then tallied by size, number and, in some cases, type and probable origin as a measure …

The post Millipore Testing – Evaluation by Particle Counting appeared first on CTG Technical Blog.

In a very early blog written in 2011 I talked about the “Scotch” tape test for cleanliness.  At that time I did not address quantification of the results other than as a visual assessment.  In addition to evaluating general cleanliness, this technique is being found particularly applicable when determining the cleanliness of substrates that “shed” …

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As I was writing the recent post about gravimetric Millipore testing it occurred to me that I was trying to boil a good-sized part of a 180+ page document into 500 or so words.  It also occurred to me that many people don’t have the time for or interest in reading endless pages of specifications …

The post Gravimetric Contaminant Testing Flow Chart appeared first on CTG Technical Blog.

Millipore testing is all about evaluating cleanliness based on the presence of particles or other solid, non-soluble contaminants.  In general, it can not be used to detect the presence of hydrocarbons or other contaminants which will be solubilized in the extraction process.  The results of Millipore testing are generally expressed by weight using gravimetric analysis …

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“Millipore” testing evaluates cleanliness by extracting particulate contamination from a surface and then either weighing or counting and quantifying the collected particles to assess the cleanliness achieved by a prior cleaning means.  The first step in either case is to collect and prepare for analysis any particulate residue remaining on the surface after pervious cleaning.  …

The post Millipore Specifications Update – Extraction and Sample Preparation appeared first on CTG Technical Blog.

Once in a while a question comes up that I can’t think my way through.  Here is one.  Within an insulated system there is air passing over a heat source that constantly produces a certain number of BTU’s per hour.  In the process, the air is heated from the inlet temperature to an elevated temperature …

The post Special Edition – Mind Tweezer appeared first on CTG Technical Blog.

Thank you to all of you who responded to my plea for insight regarding Millipore testing using particle counting methodology.  Your input has given me some direction and insight into your experiences with this method.  Anyone else who would like to chime in is more than welcome.  Respond in the comments section below or email …

The post Thank You! appeared first on CTG Technical Blog.

It would make sense that variations in the aluminum foil used for testing in the foil test for ultrasonic performance could have a bearing on the outcome of the test.  Most people use standard “grocery store” aluminum foil for testing because it is inexpensive and widely available.  So let’s talk about that first.  The most …

The post Foil Test – Foil Variabilities appeared first on CTG Technical Blog.

I just spent a couple of hours re-reading several of the ISO specifications related to “Millipore” testing including ISO16232-3 and -7.   I put the word Millipore in quotes here because although these are normally called Millipore specifications, none of them mentions the word Millipore.  (Millipore happens to be the name of a company that developed …

The post Millipore Testing – Help! appeared first on CTG Technical Blog.

After three + months of sheltering in place, things are slowly returning to the “new normal” here in New York state which is where I write this blog.  We all know all too well what’s been going on around the world over the past several months so I’m not going to belabor those details here.  …

The post Welcome Back! appeared first on CTG Technical Blog.

Task At Hand – In a previous blog I declared that I am not a fan of the aluminum foil test for evaluating ultrasonic performance.  I question its validity and relevance on a number of fronts.  If my purpose here is to question my own skepticism, then I guess I should probably define the factors …

The post Aluminum Foil Test for Ultrasonic Performance – Potential Problems appeared first on CTG Technical Blog.

Until recently, I was only able to theorize about the mechanism involved in the perforation of aluminum foil by ultrasonic cavitation.  I no longer have to theorize! My theory had always been that perforation of aluminum foil was due to the repeated flexing of aluminum foil as cavitation implosions occurring on opposite sides of the foil …

The post Aluminum Foil Test – Foil Perforation Mechanism appeared first on CTG Technical Blog.

If you’ve heard of ultrasonic cleaning you’ve probably heard of the aluminum foil test.  The practice of putting a piece of aluminum foil into an ultrasonically activated tank of water probably began as a novelty demonstration.  The holes produced in the aluminum foil by the collapse of cavitation bubbles at least showed that something interesting …

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It was in 1962 during my junior year in high school when my chemistry teacher, Mr. McBain, described an unusual phenomenon related to a specific element.  At the time, I think it was more intended as a test question to see who had studied their notes.     I recently witnessed this phenomenon for the first …

The post What Is It? appeared first on CTG Technical Blog.

Liquid level sensors are used to indicate liquid level by sensing the presence of a liquid using several different means. The “float” type sensor is the one that probably comes to mind first for most of us.  The float valve in a toilet tank is a prime example. In the case of the toilet, a …

The post Liquid Level Sensors – Floats appeared first on CTG Technical Blog.

Drying is the last and often a critical part of a cleaning process.  In many cases it is also the most time and energy consuming.  It is often the most difficult part of the process to specify and control.  Although there are several drying technologies available, blowing with hot air is simple and by far …

The post Hot Air Drying – Tips and Pitfalls appeared first on CTG Technical Blog.

Using the right amount of chemistry is important to successful industrial cleaning.  Since there is no standard convention for expressing the amount of chemistry to use, it sometimes takes a little effort to sort things out.  Chemistry is supplied in either liquid or powder form with several different conventions for each.  Let’s look at liquids …

The post How Much Chemistry – Liquid appeared first on CTG Technical Blog.

With its well-deserved credentials for chemical resistance and durability, stainless steel and particularly 316 grade stainless steel is a “go to” for the fabrication of ultrasonic cleaning tanks.  Although it performs well in most applications, there are still those where stainless steel has its limitations.  Stainless steel achieves its “stainless” characteristic by developing a very …

The post Stainless Steel Compatibility appeared first on CTG Technical Blog.

The term “near field” is not new to ultrasonic cleaning.  In general, it refers to cleaning parts in near proximity to the ultrasound source.  It is well known that increasing ultrasonic power density can produce improved cleaning results in many cases.  Increasing power density can be accomplished by reducing the size of the cleaning vessel to …

The post Ultrasonics – Near Field and BEYOND! appeared first on CTG Technical Blog.

If you are squeamish about electricity or don’t care about electricity you may want to skip this one.  But we’re going to talk about some things at are pretty neat, central to the world of electronics and downright cool if you’d like to stick around. Recent blogs have talked about resistors, capacitors and inductors which, …

The post Reactive Electronic Components and Phase Angle appeared first on CTG Technical Blog.

Just about everyone celebrates a holiday at this time of year.  I celebrate Christmas.  This year, my wife and I will be spending the first part of the holiday season break with our daughter, her husband and their son in Frisco, TX.   Then it’s on to Ellicott City, MD to visit our son, daughter-in-law and …

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The blog Ultrasonics – Ultrasonic Generators – Power Control discussed several ways in which the power delivery of ultrasonic generators can be varied.  One of the ways is by modulating the amplitude while another is through the use of time proportioning or duty cycle modulation.   There are other ways as well, but these are the …

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The purpose of fuses is relatively easy to grasp. A fuse interrupts a circuit (turns off) if the current flow (amps) is more than expected or more than the circuit components including wires etc. can safely handle. High current is usually the result of a short circuit, the failure of a device connected to the …

The post A Fuse is a Fuse? – Not Quite! appeared first on CTG Technical Blog.

My recent blog, Are Ultrasonic Power Ratings Real?, prompted a response from my friend and colleague William Puskas.  Some of you may know Bill as the “Father of Sweep” as he was the first to implement frequency sweeping technology in ultrasonic cleaning equipment decades ago.  He is also the author of a significant number of …

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Nearly anyone who has been involved in the procurement of an ultrasonic cleaning system has come head to head with watts of ultrasonic power issues.  Variations of an order of magnitude or more are common in ultrasonic watts ratings from competitors selling equipment of otherwise similar size and capacity.  Despite the discrepancies, I don’t believe anyone …

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“Millipore” testing is a popular way of quantifying part cleanliness today.  What is generally not known, however, is that it is far from an absolute standard and, in fact, can be very misleading even if “properly” applied.  Part of this may be due to the genesis and heritage of Millipore testing.  At its inception, Millipore …

The post Thoughts About Millipore Testing appeared first on CTG Technical Blog.

Watts of ultrasonic generator output power is one metric often used in the comparison of ultrasonic cleaning systems.  In a previous blog, I discussed the potential foibles of using watts of consumption as a measure of comparison as there is no standard for measuring the output of an ultrasonic generator.  But there are also other …

The post Are Ultrasonic Power Ratings In Watts Meaningful? appeared first on CTG Technical Blog.

More is better in some cases but when it comes to chemistry in industrial cleaning, using too much is costly and could indicate process problems as well. Cost – First, there is the obvious cost of using more chemistry.  Most aqueous cleaning chemistries range in price from $15 to $40 per gallon but may exceed …

The post Too Much Soap! appeared first on CTG Technical Blog.

I sometimes reflect the purpose of John’s Corner.  It’s really pretty simple – to help those who are interested in industrial cleaning to understand and make the best use of the existing industrial cleaning technology – but maybe it’s more. As most of you may know (it is no secret), I am a former employee …

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Both capacitors and inductors are “reactive” components.  Unlike resistors, capacitors and inductors store electricity on a short term basis but in different ways.  For me, the capacitor is a little easier to understand so let’s start with it. For all practical purposes, capacitors consist of two pieces of conductive material (think aluminum foil) separated by …

The post Electronic Components – Capacitor appeared first on CTG Technical Blog.

The purpose of a diode is to allow the flow of electrical current in only one direction.  The ability to control current flow is very useful in electronics applications.  Diodes have been around in one form or another for a long time.  In the days of vacuum tubes, a “diode” was a tube with a …

The post Electronic Components – Diode appeared first on CTG Technical Blog.

The lowly resistor is probably the electronic component that is most familiar to most of us.  Its one and only purpose is to limit the number of electrons that flow through a circuit. The “poorly conductive material” used in the vast majority of resistors is a mixture of carbon with various other “stuff” to hold …

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Inductors and capacitors both provide short term storage of electrical energy but in different ways and with different goals.  A capacitor physically stores electrons and acts as a source of voltage.  An inductor stores electrical current in a magnetic field and acts as a source of current. Although not present in all inductors, a core …

The post Electronic Components – Inductor appeared first on CTG Technical Blog.

In a previous blog, we talked about the effect that different waveforms have on RMS vs. Peak voltage.  Now we’re going to look at the ramifications of that when it comes to power consumption.  For purposes of discussion, we are going to use an old-fashioned light bulb with a filament – something that’s easier for most …

The post Power Variations Due to Alternating Current in a Light Bulb appeared first on CTG Technical Blog.

Over the years I have made tens if not hundreds of efforts to clarify the meaning of the term “power” as it applies to the capabilities of ultrasonic cleaning systems.  Despite these efforts, a functional means of rating the capability of ultrasonic cleaning systems is still undefined.  There are several conventions and declarations.  But in …

The post Watt? appeared first on CTG Technical Blog.

The blog A Little About RMS introduced the concept RMS (Root Mean Squared) as a way of expressing the equivalent effect of alternating current vs. direct current electricity in the power consumed by a resistive load.  Now would be an excellent time to read that one again before going ahead with this one.  As part …

The post What a Difference a Wave(shape) Makes appeared first on CTG Technical Blog.

Successful ultrasonic cleaning processes utilize a combination of mechanical action provided by the formation and implosion of cavitation bubbles and  chemistry that dissolves and/or promotes the wetting and transfer of mechanical energy to dislodge the contaminants to be removed.  The interactions and effects of chemistry on the ultrasonic process obviously exist but are not well …

The post The Effect of Physical Chemical Properties on Ultrasonic Performance appeared first on CTG Technical Blog.