More cleanliness than in the restoration of Rembrandt’s The Night Watch: Armageddon or reality?
Smartphones not working. Electric cars stationary. Hospital equipment not functioning. Internet down. It sounds like a scene from an Armageddon film. This really could happen if (chemical) contamination happens during the production of mission-critical parts and systems. CoreDux implements an innovative solution to eliminate these risks saving time and headaches.
“As a company, how do you really know whether the supplied system-critical parts are free of hydrocarbon and other organic contamination?”, asks Process Engineer Gijs Linders from CoreDux. He knows the answer from years of experience in the business. Answers which were not actually satisfactory…
Losing time through external analysis
“We design and manufacture ‘mission-critical’ gas and liquid transport systems. We do this for the manufacturing process of microchip wafers in the semi-conductor industry and for manufacturers in the rocket, satellite, aircraft and automotive world. During production, we always cleaned the systems to the highest possible level. Afterwards, we packed the hose systems in a double vacuum; for complete security. What often happened next? Clients would get an external laboratory to analyse the contamination, which takes a few working days”. An expensive, time-consuming and unnecessary ‘solution’, Gijs now knows.
Plug and play
Gijs and his colleagues are always looking for ways to innovate for their customers. Due to the extra lab phase concerning the cleanliness process they were contemplating a solution that would tackle this in one go. The result? A revolution for the chain integration in the field of cleaning and validation for cleanliness levels. “We were able to get the systems totally free from organic contamination with guaranteed certainty”. Now they carry the label of CoreDux TOC approved, which means the systems are completely free from Total Organic Contamination. This means companies now have the ability to unpack and install systems in the cleanroom without any worries. It’s just plug and play”.
Almost less than nothing
CoreDux has been working since 2007 on the control of chemical contamination, among others in its own ambient air, the so-called Airborne Molecular Contamination (AMC). The organic hydrocarbons present are a particular risk for many companies and products and an important cause of chemical pollution. Until the breakthrough that is now in place … “Our cleaning process now has the right parameters and steps to get products to the desired level of cleanliness both inside and out. We now have ambient air under control to an extent that the measurements are below the detection limit. This means there is little or no measurable contamination”.
Gas and absorption
How did they achieve these results? “Via a special sampling installation among other things. We flushed very pure gas through the artery systems, which are the hose systems for liquid and gas transportation. At the end, the gas arrived at a sample tube filled with absorption material, which functions like a kind of sponge. The gas pushed along any contamination such as hydrocarbon. The tube with the absorption material then collected and trapped the substance. This is how Total Organic Contamination is measured”, explains Gijs.
Better than Rembrandt’s famous painting ‘The Night Watch’
The next step in the cleaning and validation process was: correctly pushing the collected sample from the tube to the analysis equipment.
“This equipment includes a thermal desorption unit and capillary gas chromatography. The units work with unprecedented precision and speed. You can also see this method used during strict environmental measurements for air and soil, detection of explosives and laboratory technology for the pharmaceutical industry”.
The restoration of ‘The Night Watch’ painting is currently also undertaken using such equipment. It is used to accurately determine which paint and varnish Rembrandt used at the time to know which cleaning products are suitable. “We have the capability to measure hose systems far more accurately during validation. In fact, up to tenths of a nanogram!”.
Hundreds per week
Measuring this accurately is also achievable for other situations. However, companies usually need much larger quantities to be processed simultaneously. This is often where it goes wrong. “Many companies work with larger sub-assemblies and modules for small numbers; we are now able to perform hundreds of validations per week. When you perform such sensitive measurements on a large scale, you will face many challenges in stabilizing the measurements and therefore maintaining the detection limits. Think of stabilizing and automating the sampling process”, explains the Process Engineer.
Trial and error
An intensive process of development, trial, error and optimization comes before the solution for the stabilization and automation. “We have been working on this since 2007. That’s when we built our first cleanroom with a self-manufactured air handling unit for the quality of the air”.
Calibration difficulty factor
Why was it so difficult to get the system reliable and accurate? “This was mainly due to calibration. The system contained a Flame Ionization Detector (FID) sensor. This flame converted the burned component into an electrical signal. We plotted this signal over time and delivered a chromatogram”.
“Every time there was a peak on the timeline, a component passed the sensor. Now you can imagine a flame changes due to typical combustion parameters. How clean the gasses are that you offer, has an influence on the burning efficiency. Do you take compressed air from a dirty compressor or do you place purifiers in these types of systems? This has a significant effect on the signal the FID sensor receives. This influence is exactly the reason we have to calibrate such a sensor or system”.
Calibrate during measurement
That is why the company now calibrates at the moment it offers a known quantity during a measurement. However there is a danger in this. “Calibrating with one concentration is extremely unreliable. This is why we opted for four concentrations and a repetition of three measurements per concentration. This is how the system makes an accurate conversion to the actual measured concentration”.
The Process Engineer chose for the current method the Tolueen component in a gas solution with a concentration of 1ppm. The reason: “We needed this low concentration to work with very low levels. After all, if we do standard measurements of tenths of nanograms, it makes no sense to calibrate the system with milligrams”. Gijs and his colleagues then looked at the calibration regarding the following: whether it was straightforward, repeatable and reproducible.
From pressure setting to Tedlar bag
The technicians encountered a few challenges whilst performing the aforementioned process. “We first connected a closable injection needle directly into the bottle, but that did not work. This turned out to cause an inaccurate pressure setting. And too much spreading”. After some trial and error, the team found improvement via a Tedlar bag with the calibration gas. “This Tedlar bag is an inert plastic bag which you fill with gas with virtually no pressure. Then you draw it up with the injection needle and inject it onto the sample tube for analysis”.
Working with the gas bag to repeat and copy the calibration proved to be much more reliable. However, the engineers still thought this was not satisfactory enough. “We opted for further automation of this process. This is why we built in a completely automatic system to further stabilize the loads. To prove it works, we performed a particularly extensive measurement system analysis (MSA). This showed the stability of the new set-up”.
Existing technology adapted
Equipment which already existed was used for the analyser. “Normally this measures concentrations and detection limits from a factor of 100 to much higher. We perfected the equipment to have the ability to work more accurately. Chemical filters, flow controllers, purifiers – we added them all, leaving nothing to chance”. And the old cleanroom from 2007? It was replaced a long time ago by one with the most advanced modern filters”.
Less time and costs
Now that it is also possible to keep the results stable for large numbers, Gijs thinks it is time to announce this. “Because this breakthrough will benefit companies. First of all in saving time. Secondly it will mean less costs and hassle. And with the absolute certainty your products are free from contamination”. The time reduction is mainly because there is no longer a waiting time for the results of the external laboratory.
The innovation delivered an extra benefit. “The knowledge of the contamination itself provides us with a wealth of information. Previously we would receive some figures back from the external lab, for example about the amount of hydrocarbon in the product. However, the whole validation and everything surrounding it was a black box for us. The fact we can now analyse ourselves also leads to an important source of information – process knowledge. Thanks to capillary gas chromatography, we now know exactly what is in the tested products”.
From effect to cause
As the engineers now have an understanding of what is in the products, it is easier to find the cause of any failure. “For example, do the measurements show too many chemical residues after we cleaned the products? Then we know we have not flushed enough. Furthermore, this knowledge also means we can better understand what is going on at a company. As a result, we translate their questions more specifically into this validation technique. If a client does not want a certain substance in their machine; we can now prove that it really is not there”.
Causes and effect
Manufacturers are pleased with this solution. “They are always working on risk reduction. Imagine if a hose system breaks on the Mars Lander due to pollution; eight years of work and billions of euros would be wasted…. And if the phones, cars, hospital equipment or satellites they make malfunction, a huge chain reaction would occur”.