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Monday, September 29, 2014

A story from the testing lab: Scott-bond

One time I was visiting a customer facility with a Technidyne sales person. We were discussing their biggest challenges and opportunities in the future. While we were there, we had a conversation with the Technical Director. He seemed very distracted. Finally, he asked if we knew anything about Scott Bond testing. {Internal bond strength (Scott-type) according to TAPPI T569 measures the energy required to rapidly delaminate a sheet-type specimen.}

We are certainly not experts on Scott Bond, but we thought we would try to help. We went to the test lab and watched as paper samples came down from the machine floor for testing.  The samples were prepared and tested for a variety of properties as we talked to the Technical Director. He explained that in the last week, the Scott Bond test values were always lower at then end of the first shift each day.  This was resulting in increased chemical and mechanical costs in the pulping process to get the bond strength back up to the specification.  The Director, also, had retrained all the testers and were confident that everyone was using the same sample preparation and testing procedure.  We watched the tester prepare the samples and then test them on the Scott Bond instrument.

We asked that the tester continue to prepare and test samples while we watched. Finally, it struck us. We asked the tester to wash his hands and prepare the next sample WITHOUT getting some potato chips out of the bag and eating them before he handled the sample and tape.  When we said this, everyone stopped for a moment. The tester proceeded to wash his hands as we asked and then prepared the sample and tested it. The values jumped back up to the expected values that were received before noon that day and every other day.

No one could believe how simple the solution to the problem was. The operator, after eating lunch, would bring his potato chips from the lunch room and eat some before each test sequence. The grease from the chips reduced the tack of the tape to the samples.  This resulted in lower internal bond numbers after lunch each day.

Simple audits of your testing practices and operator processes can result in more efficient testing and more reliable data....do it.




Friday, September 26, 2014

Meet our Lab Manager: Nick Riggs


Nick Riggs has joined Technidyne as the Manager of Technical Lab Services. Nick has 23 years of experience in the Graphic Arts and Allied Industries. He has worked in graphic arts and design, ink manufacturing and research and development, printing technologies, plastics and flexible packaging design, development, engineering, testing and analysis, process management, quality control and regulatory compliance. His broad experiences in the industry will help Technidyne leverage our expertise in in analysis and process control within the paper and pulp industries as well as develop new markets for our unique products.

If you have any questions about Technidyne's calibration standards or testing service, feel free to contact Nick directly at nickr@technidyne.com.

Monday, September 22, 2014

Is anything truly non-fluorescent?



In the Paper Industry, we often measure fluorescence as the fluorescent component of brightness.  The instrument makes a brightness measurement which includes the effect of optical brighteners by using a calibrated UV Level (UV-included).  The instrument then makes a brightness measurement with a UV-cutoff filter in place to eliminate the effect of the optical brighteners (UV-excluded).  The resulting difference (UV-included minus UV-excluded) is identified as the Fluorescent Component of brightness.  Things that can effect this result are the raw material, processing that may physically alter the raw material (e.g. refining) and additives to the sample.




Generally, samples with a fluorescent component of 0.25 or less are considered to contain no optical brighteners.  This value is used in some specifications to: 1) prevent optical brightening agents from coming into contact with food, or 2) maintain a contrast between substrate and inks.  Fluorescent component can measure above 0.00, but less than 0.25 due to intrinsic fluorescence (from virgin fibers) and due to limitations in the repeatability and reproducibility of the instrumentation.




Therefore, it is common for samples to have a fluorescent component above zero, and still be classified as non-fluorescent.

Monday, September 15, 2014

Why have multiple ranges of calibration standards?

Whether it is a balance, caliper, brightness, tensile, moisture, consistency meter, many people calibrate equipment to only one range of measurement.  This is simple, however, it does not verify that their calibration is correct over a range.  It may be as simple as a zero-range in addition to another range, but the more ranges that we can verify the better.

As TAPPI Test Method T 452 (Brightness of pulp, paper and paperboard) states:
  • "Obtain reflectance standards at monthly intervals and calibrate the test instrument with them as soon as they are received."
  • "Check the test instrument readings at least monthly against the assigned values of all the standards."
Graph 1 - Good Calibration
Notice that it says to check instrument readings against the assigned values of ALL the standards. This is to ensure that their is proper linearity in the calibration.

In Graph 1, the calibration was performed with the 70-range standard. Then it was compared against the other standards at the different points e.g. 50, 60, 80 and 90. It is right on all of these points. This verifies calibration across a large range.

Graph 2 - Bad Calibration Using 70-range
In Graph 2, the calibration was again performed with the 70-range standard. Then it was compared against the other standards at the different points e.g. 50, 60, 80 and 90. It only matches at the 70-range point. The measured values show a linear response, but it is off at every range other than the 70.

Graph 3 - Bad Calibration Using 80-range
Many customers will choose to do the primary calibration in the range in which they normally measure.  In Graph 3, the calibration was performed with the 80-range standard. Then it was compared against the other standards at the different points e.g. 50, 60, 70 and 90. It only matches at the 80-range point. The measured values show a linear response, however, it does not match at any range other than 80.

If single-point calibration is used and there is no means to verify the linearity of the measurement, we may run into a situation like Graph 2 or 3. In these cases the instrument responds in a linear manner, but the calibration is not correct.  This could be due to a number of other issues such as spectral response, failing electronics or failing optics, to name a few.

Graph 4 - Bad Calibration with Non-linear Response
If the instrument is responding poorly enough, the values could be questionable even over a very tight range around the calibration range. If we calibrated to the 80-range, but were measuring in the high 80's, the values may not be reliable. 

Also, as seen in Graph 4, the calibration was performed with the 80-range standard. Then it was compared against the other ranges.  This example shows a non-linear response. This would not be seen if only the 80- and 50-range standards were measured.

ALWAYS use more than one range to verify your measuring devices. If you see responses like those in Graphs 2, 3 and 4:
   1. Recalibrate you device
   2. Get fresh calibration standards (or get them recertified)
   3. Contact a factory-certified service technician for support

Friday, September 12, 2014

Passing the Torch in the United Kingdom

Technidyne has established a new sales and service agent in the United Kingdom, AML Instruments.  Technidyne had been represented by Carisbrooke Instrument Services and principal, Roger Tringham since 2001.

AML Instruments
AML Instruments is a family owned and run calibration & instrument company, centrally based near Lincoln. They pride themselves on providing outstanding customer care and service at all times.  Since  the acquisition of Carisbrooke Instrument Services Limited, AML are now the only and official U.K. Representative for Technidyne Corporation and Roll Test Oy. They also sell, service and calibrate the Ohaus, Hanatek, Rhopoint, Integra, REA, RDM, Grip Engineering and Amecal ranges.



We are very pleased to bring AML into Technidyne's worldwide family of representatives.

Find the Technidyne Agent in your part of the world.

Monday, September 8, 2014

Lamp Life: Why does my instrument's lamp have to be changed so often?

Quartz Tungsten Halogen (QTH) Lamp
Very often customers question how often they should change their lamps.  We tell our customers to change QTH (quartz-tungsten-halogen) lamps in their S-4, Micro S-5, BNL-3, TB-1 and Micro TB-1C instruments every 3 months. Over the years we have noticed three things that start to happen to the lamps at the 3 month time frame.

1) The UV level of the lamp degrades as the lamp ages.  The UV level will start dropping faster at the 3 month period of time which will effect readings on any product with optical brighteners.

2) The instrument will start having minor stability issues. The repeatability and reproducibility is reduced due to the degradation in the lamp.
 

3) The spectral response from the lamp changes which will affect the response of the instrument to reflectance measurements at different wavelengths.  This may affect color values, brightness and/or opacity which are all measured at specific wavelengths.

All of these are due to degradation in the lamp over time.  By replacing the lamp on a regular basis and recalibrating the instrument, the customer should not see any large shifts in their readings.

There are two options available to users:

1) Make sure to change lamps in the instruments at least every 3 months.  The small cost of a QTH lamp is far less than the cost of a customer claim or return.

Xenon power pack & bulb
2) In cases where the instrument is a diffuse geometry (TB-1 or Micro TB-1C), use a Color Touch spectrophotometer instead of a colorimeter. The Color Touch uses a xenon lamp which is filtered to achieve the different UV levels necessary for optical measurements. The xenon lamp will last for 5-20 years (depending on usage).

PS - Don't be fooled in to thinking that xenon lamps need to be changed on an annual basis. They have a lot of UV energy. Even over years of use the UV level of a xenon lamp will be high enough to prevent the issues described above.  If your instrument manufacturer suggests that the xenon lamp be changed in a period less than 5 years, ask why and ask to see data showing the degradation in the lamp.

Thursday, September 4, 2014

From Jerry Popson (Chairman and founder)



To All Technidyne Employees and Retirees,

At the luncheon a couple of weeks ago celebrating the 40th anniversary of Technidyne Corporation I was blindsided by my son, Todd, who proceeded to put me on the spot and ask me several questions (interrogated me) about the early days of Technidyne. Even though I was surprised it turned out to be great fun to reminisce about the old days. I was shocked that I was able to remember that far back (more than two weeks) but I enjoyed the exercise.

Only after the party was over did I remember that I forgot to thank all those who were responsible for our 40 years of success. These days it is rare for a small high-tech company, especially for a family owned company, to operate successfully for two generations over a period of 40 years. No company can be great without having great employees and I feel that we have been very blessed with great, hard working, and loyal people.

I want to express my deep appreciation to all of you who had a hand in the establishment and continued success of Technidyne. Many people have told me that Technidyne is a SPECIAL company and I couldn’t agree more. Success through integrity and hard work is hard to come by now days but you have all made it happen. Let’s make it another 40 years, except that if I’m still around for that celebration, you will have to strap me onto the stool.

Jerry Popson