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Monday, November 24, 2014

A Story from the Testing Lab: Can Opacity be sided?


It is possible to achieve a measured opacity on one side of a sheet of paper which is different than the measured opacity on the other side of the same sheet.  Differences are usually very small e.g. 0.5% or less from one side to the other.  However, there are instances when the values could be as different as 2.0%.  This normally occurs in papers which are heavily coated only on one side.

The most commonly used methods for the measurement of opacity address this issue slightly differently:

TAPPI T 425, Opacity of paper (15/d geometry, illuminant A/2°, 89% reflectance backing and paper backing)
There is a note in the Procedure section that says, "Usually neither the side nor direction of the grain of the paper makes any significant difference. If either effect exceeds 0.2, report each side and/or direction separately."

TAPPI T 519, Diffuse opacity of paper (d/0 paper backing)
The method instructs measurements to be made on the felt side and then the wire side.  The report section says, "If the measured opacity from each side differs by 0.5% or more, report the opacity for each side separately."

ISO 2471, Paper and board - Determination of opacity (paper backing) - Diffuse reflectance method
The procedure actually includes directions to measure both sides.  There are instructions to "Calculate the mean opacity for each side and the standard deviation.  If the differences between the two means are greater than 0,2%, the sides should be identified and the results reported separately.  If the difference is equal to or less than 0,2%, the overall average shall be reported."

Thursday, November 20, 2014

New Training Facility

Our new training room at Technidyne has been getting a lot of use since its completion earlier this year.  Technidyne employee training and customer training is performed in this newly created space.

In August, Ilka Mustonen from ACA Systems led a training session on the new RoQ (roll hardness) as well as the Permi (on-line porosity) and ACAV A2 & A4 (coating and pigment runnability).  In October, Alex Gruner from Emtec and AFG did a training session on their products including the TSA (tissue softness), CAS (charge analyzer), FPA (fiber potential) and DFA (dynamic filtration).

In December, we have customers from Neenah Paper receiving training on their new PROFILE/Plus automated testing system.

Technidyne is exploring new opportunities to offer training to customers and agents. Let us know if you have ideas via email.

Thanks to Leslie Lewis & Associates and Upton Pry for making this a great facility.

Monday, November 17, 2014

A Story from the Testing Lab: Routine Maintenance

It only takes one quality claim or customer return to pay for years worth of routine maintenance on your laboratory or on-line instrumentation.

Technidyne has offered Preventative Maintenance (PM) on its instruments since 1985.  This is similar to routine maintenance on your car to make sure it runs well and for years to come.  During a PM visit the instrument 'current' state is checked, the instrument has routine maintenance performed (cleaning, checking voltages, etc.). Finally, the instrument is calibrated and rechecked for its 'as left' data.  Also, during PM visits general maintenance questions can be asked and features can be demonstrated.   

How often do you have routine maintenance done on your car? Most manufacturers recommend that
you change your oil and rotate your tires every 5,000 miles. If you are like me, you stretch that into 7,000 miles.

How often do you have routine maintenance done on your lab or on-line instrumentation? If you have your instruments checked once a year, that amounts to maintenance after 326,509 miles of paper have been made (on a machine running at 1000 meters/minute). Even if you have routine maintenance every quarter, that amounts to maintenance after over 75,000 miles of paper have been produced.

It only takes one quality claim or customer return to pay for years worth of routine maintenance on your laboratory or on-line instrumentation.

Thursday, November 13, 2014

Technidyne Thanksgiving Lunch

Pitch-in Lunch
Thanksgiving isn't for 2 weeks in the US, however, we celebrated today at Technidyne. It was a fun time filled with great food, camaraderie, games and laughter.  Thanks to the Technidyne staff for making everyone enjoy working together.  Here are some photos of the fun.

Bill unveiling his BINGO prize
Lance studying the board trying to decide which ornament represents each employee

Monday, November 10, 2014

A Story from the Test Lab: Calibration & Maintenance Frequency

Let's say a mill has 2 paper machines that use the same test lab. Each machine has a turn up every 30 minutes.  Each turn up requires that a given property be measured manually at 2 locations across the machine. At each location only 1 measurement is made due to time constraints. If the value is very far off specification it will be retested. All of this occurs every day, month and year.  The instrument normally only goes through a complete primary calibration procedure once a month.  Therefore, there are 4,320 manual tests performed per month (between primary calibrations). If Preventative Maintenance service personnel visits one time per year, there are 51,840 manual tests between routine maintenance visits.

If automated testing equipment is being used, the system is programmed to make 10 measurements across the test strip.  This means 21,600 automated tests are performed per month (between primary calibrations).  That means if service personnel visits only one time per year, there are 259,200 automated tests between routine maintenance visits.

In this example, there are 5 times more tests between primary calibrations and between Preventative Maintenance visitsIt is unrealistic to think that even equipment designed for MORE usage is going to require 5 times LESS routine maintenance.  Even if Preventative Maintenance were increased to four times per year, we would be expecting the equipment to perform for a longer period of time between tune-ups based on the number of measurements.

If you increase the volume of testing with automated testing (or through some other means) consider increasing the frequency of checking calibration and scheduled routing Preventative Maintenance.

Monday, November 3, 2014

A Story from the Testing Lab: What is 100% on the ISO Brightness Scale?

Liquid-cooled Zeiss Elrepho
The original diffuse brightness tester, the Zeiss Elrepho, was introduced in 1953 by Carl Zeiss Company of Oberkochen, West Germany. The Elrepho (ELectro-REcording PHOtometer) with its integrating sphere (diffuse) geometry originally used magnesium oxide as the basis for the 100% brightness point just like the GE Brightness Instrument (directional geometry, TAPPI T452). This was chosen since it was the 'whitest' substance available at the time. Since magnesium oxide was very unstable and yellows over a relatively short period of time the basis for setting the 100% brightness point was changed from the reflectance of magnesium oxide to absolute reflectance which is a more theoretical 100% point in the mid-1960's.  This scale change caused all brightness readings to go down i.e. a pulp previously measured at 60% brightness might now read 58.5%.

Measurement on Color Touch
In the early 1970's, a gloss trap was included in the integrating sphere to exclude the specular gloss component.  The insertion of a gloss trap is an attempt to minimize the effect of surface reflectance, leaving only intrinsic brightness to be measured.  Brightness values may be lower by up to 2% due to the inclusion of a gloss trap.

These changes which occurred over a decade resulted in brightness values for the ISO Brightness instrument scale to go down over 2%.  Since that time ISO has developed a more rigorous process for maintaining this absolute reflectance 100% brightness calibration point. This 100% point is considered the perfectly reflecting diffuser.  Standardizing Laboratories transfer this calibration from the perfectly reflecting diffuser to the Authorized Laboratories.  Then Authorized Laboratories transfer this calibration to end-users of the instruments via paper standards which are issued on a monthly or quarterly subscription basis to allow brightness tester users to maintain close agreement with the perfectly reflecting diffuser.

ISO Standard 2469, which was based on the Zeiss Elrepho, was adopted by ISO in 1973.  TAPPI T525 is identical to ISO 2469 and ISO 2470-1 (ISO Brightness). Subsequently, brightness testers conforming to ISO 2469 have been manufactured by Datacolor, AutoElrepho, Minolta and Technidyne Corporation.