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Tuesday, October 17, 2017

Lab Management Trends: Data Management

The quality control laboratories in manufacturing environments are continuing to evolve. Most of us

can remember the typical QC lab:
  • Purchased instruments
  • Full-time employees to operate instruments
  • Employees calibrated and maintained the instruments
  • Each test was performed on dedicated instruments
  • Data was logged in a physical book
  • Physical data book was rarely looked at (usually only when a customer complaint was being reviewed)
So many of these old ways of doing things have changed or have totally disappeared over the last 10-20 years.

Automated Testing
Laboratory equipment was purchased for each individual test for many years. If an end-use customer

required some specific test parameter or requirement, the equipment was purchased.  Full-time employees were hired and trained on the calibration, operation and maintenance of each piece of test equipment. Several testers on each shift sat in the lab. They prepared samples for testing after each turn up or batch. Each tester would run a series of tests on the samples that were prepared.

That system and process has changed dramatically for many organizations. It is continuing to evolve around the globe for others.  Most have automated all or at least part of their laboratories. Automation gives more data in a much shorter amount of time. CD, MD, top and bottom measurements can be made in a manner of seconds with automated equipment. At the same time, the real variation in the system can be seen because the automated testing removes any effect of the tester. Many know that testers can effect the results by manually changing data, accidentally entering the wrong data, searching for the best data by manipulating the sample, accidentally damaging the sample, etc. Automated testing removes these factors from the data and provides significantly more detailed information more quickly and electronically.

Big Box vs. Modular Automated Testing

If the decision is made to automate, there are different approaches available. The big-box automation is where a large, fixed-size system is purchased with a significant cost for the "bed" and at the same time any number of tests (usually 1-8) are purchased at the same time. The cost is usually quite high (US$500k to over US$1M) and depends on the specific tests and the total number of modules. In many instances modifications to the existing laboratory are required to accommodate the size (10 ft. x 3 ft. x 5 ft.) of the device. This is an additional expense. Ongoing preventative maintenance and service work is quite high (US$30k+ per year).

Technidyne PROFILE/Plus
modular automated system
In the case of modular automated testing, each test has the same footprint (11 in. x 15 in. x 24 in.) and the modules are priced slightly higher than a normal stand alone instrument because they have the feed mechanism and software for automation built-in. The cost is usually quite reasonable (US$15k to US$350k) and as the big-box system, depends on the specific tests and the total number of modules. However, there is no need to modify the existing laboratory to accommodate the modular automated testing system. Ongoing preventative maintenance and service work is much lower than the big-box and is based on the number of modules in the system.

Choice of big-box automation, modular automation or stand alone testing equipment for lab varies with different factors. Understanding these factors helps in deciding which path to take with equipment. Some factors and the rationale behind it at different scenarios are given below.

A. Ability to get ROI/payback:

  • If the estimated cost of the equipment is high but there are a number of people that can be replaced through automation, and the ROI/payback can be achieved quickly (less than a year), the purchase of a big-box or modular automated system is suggested
  • A modular automated system is the best option when an older automated system is being replaced. This is the case when the bigger dollar figure of a big-box system is going to make ROI/payback difficult over a 1-3 year period of time.
  • When personnel reductions are not possible or practical, and smaller operational efficiencies will be achieved through automation, a modular automated system is preferred to get ROI/payback one piece at a time (6 months - 1 year per module).
  • If budgets do not allow for large expenditures at one point in time, but it does allow for smaller purchases each year, a modular automated system or stand alone testing would make sense.

    B. Tenure of equipment usage:

    • If the expected usage of the equipment is more than three years and its frequency of usage is high, big-box or modular automated testing is suggested, provided the need to upgrade the equipment is low.
    • If the expected usage of the equipment is less than three years or the product mix/grade structure of the facility is likely to change in the future acquisition of a modular system is suggested.
    • Stand alone testing is preferred if the equipment will be used for a short term and its frequency of usage is low.

    C. Need to upgrade:

    • Regulations and technology developments will require upgrading lab equipment regularly. High-end equipment that involves high technology is subjected to a high rate of change in technology, which results in regular upgrades.
    • It is preferable to acquire equipment with a low to moderate need for upgrades through big-box or modular automated testing, as acquiring equipment with high upgrade requirements could result in owning obsolete equipment.
    • It is preferable to procure equipment associated with frequent technological changes and frequent upgrades in a modular automated testing system or stand alone, as it is easier to upgrade and avoids owning a big-box system with obsolete equipment.
    • Stand alone equipment is suitable for all types of users irrespective of the industry or size of the company when the technology is changing frequently and there is a need for constant upgrading of the equipment.

    D. Frequency of usage:

    • It is preferable to acquire big-box or modular automated equipment for medium to high frequency of usage tests, as return on equipment is high because the cost of the equipment is spread over the hundreds or thousands of tests.
    • Even if the test frequency is high for up to 4 or 5 tests, if there are very few tests that require a high frequency and others are low frequency, modular automated testing
    • Stand alone testing is preferred for equipment that is used less frequently or by ad-hoc requests. Acquiring equipment for temporary usage incurs more cost and less return.
    • If equipment is going to be used very infrequently, paying for testing by the manufacturer or a testing lab has become an option.
    E. Correlated data:
    • Big-box automated systems do not have all tests according to the applicable international testing standards, therefore, correlations are used for many tests.
    • Modular automated systems offer standard testing just like stand alone equipment.
    Automation has become a normal part of today's testing laboratories. There are many factors that can help determine what version of system is best for your situation. Careful consideration must be given to determine how to bring the benefits of fast testing with more relevant data (MD, CD, top, bottom) to the production facility.

    Other topics in blog posts:

    • Procurement
    • Data Management
    • Outsourcing

    Contact me with  your observations related to Data Management.

    Monday, September 25, 2017

    Smoothness (Roughness) in the Paper Industry

    One of our most popular posts has returned. Please contact us at our website for additional information and assistance. Also, email us, if you have questions or ideas for other posts.

    The terms “smoothness” and “roughness” are generally well understood as far as a dictionary meaning goes; however, the use of the terms in test methods is sometimes confusing. In the title of a test method, the term “smoothness” is used when an increasing number is correlates with a smoother surface measurement. An example of this would be the Bekk method, where a smoother surface requires more time for a given volume of air to leak across the surface. Since the reporting for Bekk smoothness is in units of time (seconds), a surface that measures 500 Bekk seconds is smoother than a surface that measures 200 Bekk seconds. If the Bekk instrument was originally configured to report in Bekk flow, which is the reciprocal of Bekk time, then the test methods would categorize it as a Bekk roughness tester.

    The two most common instruments that directly report airflow across the surface are the Sheffield and Bendtsen methods. A rougher surface causes higher airflow; therefore these instruments are designated as roughness testers. The Parker Print Surf method is also a roughness tester; however, the reporting (in microns roughness) is a function of the cube root of the measured air flow. In the last few decades, the zeitgeist has been to accurately name the test methods in accordance with the function and not to continue using the manufacturer’s earlier assigned name, if it was not technically correct.

    The Papermaking Process:

    There are several manufacturing processes that shape a continuous web and wind the product on a roll. When metallic materials are plastically deformed through a series of roll nips, the end product is quite uniform, due to the malleable properties of the materials. The modulus of elasticity is quite high for metallic materials, as compared to that of paper. Metallic materials leave a roll nip substantially the same thickness as the roll gap, with a surface finish somewhat equal to the roll finish.

    By comparison, paper is extremely compressible. There are numerous voids in paper, including the presence of air within the fibers, which resemble small capillary tubes. In the calendering process, the nips are loaded to a certain nip pressure, “pli”, or pounds per linear inch. The resulting distance between the mating roll surfaces is primarily a function of the nip loading, the compressibility of the paper and the deformation of the roll surfaces. The mechanical action in the nip imparts a smoother surface on the paper, and there is a decrease in the thickness of the web after it is calendered. Further, there is a difference in the stacking height of such calendered papers, due to both the thickness reduction, and the way in which rough surfaces stack together. The properties that affect stacking height are surface roughness, compressibility, and stack

    When building a reel, the highest priority is to wind a uniform roll, as a roll with ridges and valleys will give a perceived value of poor quality, and also there can be runnability issues with such rolls.

    The process control systems in use today have a strong history of development around basis weight, moisture, and caliper (thickness) control. Basis weight and thickness variations can cause the calendering action to be different across the web. When a web has reasonably uniform basis weight, but has caliper uniformity problems, a process control system can make very small, but effective adjustments to the calender stack to build a level roll. Such adjustments may affect the smoothness profile, but generally there are no on-line sensors that provide such feedback. When a CD strip from a reel is run through a profiling smoothness tester, there are generally regions of high and low smoothness values that show up at the same places, reel strip after reel strip. When the smoothness values fall within the accepted limits, there is generally no concern in fixing the problem. The astute production manager will observe such trends, and take action before the measurements reach upper or lower control limits.

    There is an interrelationship among roughness, porosity, and optical formation measurements. Those regions that are calendered the heaviest will be smoother, denser, and will have lower opacity than the adjacent regions that are calendered lightly. Local variations in opacity will show up as having poor formation on optical formation testers. A rough surface will absorb more ink, and that same rough surface will be more porous, as it received less calendering action. The more porous region will also absorb more ink into its interstices. When printers correlate poor printing with poor formation, perhaps it is the roughness and porosity variations that are the culprits, and the formation tester is one additional piece of test equipment that verifies the root of the problem. These formation problems occur on a small scale, smaller than what a basis weight process control system will discriminate. Formation problems are perhaps quite detectable by analyzing the standard deviation of porosity and roughness measurements within a small region. The roughness and porosity variations caused by fiber flocs are much smaller than the test area of either the roughness or porosity measuring heads. There can be other reasons for high standard deviations, such as non-uniform sizing, which may also be caused by the localized absorbency properties in the region of fiber flocs.

    The Printing Process:
    One of the most important reasons for measuring and controlling surface smoothness is for print quality. For the contacting-type printing processes, the ink film will transfer to a paper surface upon physical contact. When the voids in the paper surface are deep enough prevent such contact, ink will not transfer to the low spots, and non-uniform ink transfer causes poor print quality. When the ink film is adjusted to achieve satisfactory print density on the rough areas of a web, the same ink film may be too heavy to achieve optimum print quality on the smoother portions, perhaps causing mottle and other problems.

    Xerography Processes:
    There are many reasons why the manufacturers of photocopy machines have target ranges for Sheffield roughness. A xerographic machine needs optimum paper surface properties for reliable sheet feeding, image transfer, and image fix. The fix level decreases as the Sheffield roughness increases, as it affects toner adhesion. Print density loss is observed as roughness increases. There also can be image problems with papers that are too smooth. Toner particles can be flattened and appear as larger dots, thus increasing the perception of the background. Rougher papers produce less background. With regards to paper handling, smoother papers are less stiff for a given basis weight. Smoother papers increase “electrostatic tacking” in the image transfer process. The coefficient of friction decreases with increasing roughness, a factor that is important in sheet transfer operations. The Sheffield roughness properties are carefully specified for the
    electrostatic copier printing process.

    Inkjet printing:
    Similar to the photocopy machines, inkjet printers have paper handling requirements. The method in which a single sheet is transferred from the supply stack generally relies upon the friction differences in paper-to-rubber versus paper-to-paper in a stack. In recent years, there has been development work on optimizing 2-sided surface roughness for ink jet printers. The printing surface was manufactured to be smooth for image quality and the back side was rough in order to facilitate paper feeding and also to avoid excessive contact with a freshly-printed surface as printed sheets are successively stacked in the printer tray.

    The Parker Print Surf test:
    The Parker Print Surf tester was one of the first roughness testers that featured both quick test results and a digital display. Since it had those desired features, it showed up in applications where test conditions had no relevance to the nip loading for which the PPS was designed. The PPS loading was designed to replicate the conditions of offset, gravure, and letterpress printing processes; where the operator could select 0.5 mPa, 1.0 mPa or 2.0 mPa loading. The theory was that paper under test should be subjected to the same compression loads found in a printing process.

    The Sheffield test:
    The xerography and inkjet processes are common examples of processes where the PPS tester does not replicate the loading factors. The Sheffield test subjects the paper to loading pressures of 0.09 mPa at zero Sheffield units, and 0.154 mPa at 400 Sheffield units. The reason for the nonconstant loading is related to the design of the air system, and the “hovercraft effect” of the variable pressure between the measurement lands. When the PPS instrument is set to measure at the lowest loading pressure, it is still about 4 to 5 times higher than the Sheffield loading.

    With the introduction of digital Sheffield testers in the late 1980’s, the Sheffield method maintained
    its prominence for these grades, at least in the USA. There are many regions of the world where the Bendtsen test is used; however, the correlation between Bendtsen and Sheffield for these grades is excellent. There are many grades where the Sheffield method gives more uniform results than Bendtsen; those grades being the higher basis weight and stiffer grades, where the Bendtsen deadweight is not heavy enough to fully flatten the sheet under test.

    Some of the other reasons for testing roughness are related to converting processes. The die-cut sheet feed in an envelope machine requires only one sheet at a time to be picked up and transferred, whereas multiple sheets will cause paper jams. The coefficient of friction between plies has a high correlation to Sheffield measurements.

    There are some applications where metallized films are applied to the surface of paper. The reflectance properties of the film can expose wire marks on the base sheet. This is another example where the gentle loading force of Sheffield test better replicates end use properties of the paper, as compared to the PPS test.

    Many plastic films are packaged in reams, like paper, for use in a photocopier to produce overhead projector transparencies. When the surfaces of the films are extremely smooth, there are static forces and cohesive forces that interfere with single sheet feeding. The manufacturers of such films generally create rough surfaces that enable an air film to exist between sheets. It iscommon to use Sheffield test results to control the process that generates the rough surface. Again, the PPS test would have measuring head loading that is excessive for this test.

    When selecting a test instrument for paper, it is important to understand the relationship between the end-use of the product and the physical test parameters of the instrument. A further requirement is to use a test where process control settings on a paper machine (or plastic web processing equipment) can be modified to optimize the final product for its intended end use. The old adage was “If you can’t control it, why measure it?” In today’s marketplace, the customer will be able to find a supplier who makes the product he wants.

    Tuesday, August 8, 2017

    Easier Calibration for Traditional Instruments

    From Lab Manager, Nick Riggs

    In 2015, Technidyne began offering large format calibration standards for Technidyne Technibrite instruments (TB-1 & Micro TB-1C) to:

    • improve calibration quality - by measuring all 5 points on the same sheet of paper
    • improve ease of use - no more shuffling 2" x 2" tabs
    This month, Technidyne is providing another improvement. After extensive testing and verification, we now have only three points for your calibration and verification routines. You obtain the same quality of calibration using our new 3-point calibration tabs and significantly reduce the time you need to spend calibrating and maintaining your instruments.

    Once you open your tabs, you'll notice the "F sheet" (felt side, measured sheet) has been reformatted to aid in your 3-point calibration. Instead of 5 measurement positions, you will see that the new measured positions have been circled and labeled 1, 2 & 3, as below:

    You will also notice that the traceability form has been updated. The data on the traceability form is now collected and reported automatically, which reduces the potential for human error in producing your calibration supplies. All the information from previous forms is still here, it’s just in a new format. As always, Technidyne is an ISO Level III Authorized Laboratory and calibration supplies for Technibrite™ instruments are still directly traceable to the National Research Council of Canada.

    If you have any questions regarding your new calibration standards, please feel free to contact us directly in the Lab, or reach out to your sales and service contacts. Email Nick

    Monday, July 24, 2017

    Technidyne's New Website

    Sometimes it just makes sense to shake things up! Please take a look at the new Technidyne website. 
    We hope it gives you more information at your fingertips with fewer 'clicks'. Here are some highlights:

    Besides an entire new look, the site also gives customers multiple ways to find the product they are searching for or need. They can drill down using menus for property or application. In addition, some key menu items lead them to the proper product.

    Customer interaction:
    We have expanded the ability for customers to communicate with us by implementing product inquiry and product support forms. When a customer utilizes one of these forms, a notification will be sent to the sales and/or service team for follow up. The product inquiry forms are designed with questions to focus the sales follow-up. The product support forms are designed with questions that will include serial number and other information a service person would need to make an informed follow-up.

    Mobile compatibility:

    The new site is compatible with mobile devices.

    These are just a few of the highlights. Let us know what you think and if there is additional information that would make your life easier. Website Comments Happy surfing!

    Thursday, June 15, 2017

    Technidyne Brings New Products to Market

    In the last two weeks, Technidyne has participated in Conferences in North America and Asia to show new products.

    Technidyne participated in PacWest, Whistler, BC, Canada last week. The small, table-top exhibit allowed Technidyne to showcase two new products that have particular importance in that pulp producing area - Color Touch QC and TEST/Plus ISO Brightness.

    Color Touch QC
    This instrument is specifically designed to meet the needs of long-time Technidyne Technibrite Micro TB-1C users. It provides the basic ISO brightness, color, fluorescence, opacity and whiteness data that those users depend on.

    TEST/Plus ISO Brightness
    This instrument is specifically designed to meet the needs of customers that only need ISO Brightness data. Pulp producers as well as others can quickly get the brightness data they need quickly.

    This week, Technidyne participated in WOW (World of Wipes), Nashville, TN, USA. This exhibit
    allowed Technidyne to showcase three products that have particular importance in the world of nonwovens -  Emtec Tissue Softness, Fiber Potential and Charge.

    Emtec Tissue Softness Analyzer (TSA)
    The TSA gathers all single relevant parameters which have an influence on the tissue softness - smoothness, compressibility, stiffness and “crumpleability“. Additionally it is possible to measure the elasticity and ball burst strength. The correlation of the measuring results to the subjective "hand feel" assessment is excellent.

    Emtec FPA touch!
    The knowledge of the fiber charge enables a correct and effective dosage of the charged chemical additives. The fiber adsorption of cationic starch, wet strength resin, and many other chemical aids can be easily measured with original samples on-site to optimize the dosage of chemicals in the wet end of the paper manufacturing process.

    Emtec CAS touch!
    Using standard techniques of titration, the CAS touch! determines cationic/anionic and acid/base demands of aqueous charge systems. Both, Streaming Potential (mV) and pH can be measured simultaneously, making it possible to easily determine isoelectric and flocculation points of a sample and examine the correlation between pH, titrant demand and streaming potential.
    Customer’s choice:
    The CAS touch! uses integrated high precision titrators, optionally with 1 or 2 titration systems (CAS-I touch!, CAS-II touch!), while also a version for use with external or hand titration is available to the customer (CAS-E touch!).

    Interest was so high at WOW that customers were still at the booth as others vendors were tearing down!
    Also, this week Technidyne participated in Propack Asia exhibit in Bangkok, Thailand. This exhibit allowed Technidyne to showcase the new TEST/Plus Caliper instrument.

    Technidyne's passion for customer satisfaction drives us to be the best in the world at developing economical and creative solutions.

    For additional information on any Technidyne, Emtec, Techpap and ACA products, please contact us.

    Wednesday, May 31, 2017

    From the Testing Lab: How does moisture affect brightness?

    The question was asked by a customer this week, "how does moisture affect brightness?"

    In this case the customer is making brightness pads, essentially a rough, wet handsheet. They have measured these for years. Now they are trying to use a wringer and microwave oven to dry the sheet to get a more accurate measurement of dry brightness.

    Here are the basic factors at play here:

    Moisture (water)
    In general, a wet sample will allow more light to transmit through and not be reflected, therefore, the brightness will be lower on a wet sample. The refractive index of water is similar to that of fibers. This is why there is less scattering (reflectance) and more transmittance.
    Light on dry sample: reflection, refraction and transmission
    Light on wet sample: reflection, refraction and HIGH transmission
    A simple test was run using a dry piece of paper. The paper was folded to get an infinite pad and measured on an ISO brightness instrument. The brightness was 82%. The same paper was wetted and measured. The brightness dropped to 60%. This was an extreme example, but it helps illustrate the point....more moisture = lower brightness.

    Filler content
    Fillers help increase scattering (reflection) and, therefore, increase brightness. If the filler content is very high, there will be fewer pores for water to fill. This will limit the amount of brightness loss due to moisture.

    Flatness of the sample
    A wet sample is more likely to bulge into the aperture which artificially increases the brightness slightly. Also, drying the sample can result in an uneven surface for measurement which can yield mixed results. Averaging a number of readings is the best approach.

    Over drying
    Drying a wet sample will increase the brightness. However, if a sample is dried in a microwave, it is very difficult to determine when the sample is dry enough and not over dried. Just like other items in a microwave, the paper sample will likely dry from the inside. Handsheets and pulp pads can often seem fine on the outside, yet be yellow or brown on the inside due to over drying. The fibers on the inside will essentially singe.

    The simple answer is that moisture will reduce brightness. The degree of reduced brightness is due in part to the factors described above.

    If you have other questions about best practices, lab audits, quality programs, calibration or maintenance, email our Service Manager.