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Reducing measurement uncertainty or test variability is at the heart of what L&W Autoline 400 provides the modern paper mill. In today's competitive market place, costs have been cut to the bone. The largest potential for cost savings now comes from incremental changes in the paper making process. To achieve these cost savings an accurate measurement of the process is required.
It has long been recognised that the traditional system of manually gathering and testing paper samples can produce unacceptable levels of measurement uncertainty. L&W Autoline users report significant reductions in test variation. This reliability improvement, combined with quick access to test results, allow the paper maker to shift production targets, and achieve more consistent performance. This is where the potential for savings can be found.
L&W Autoline has been able to greatly reduce or even eliminate traditional sources of variation in paper testing, such as:
– Operator and instrument variation. Unlike using individual bench top instruments for testing, an automated paper testing system requires no operator involvement and no specialised skills. Thus, differences in lab results related to tester changes or different operating techniques can be completely avoided. With the automated paper testing system, the operator simply inserts the sample and is done. The sample strip is automatically fed through the device and tested accordingly.
– Sample Preparation. Sample preparation is one of the most important and often overlooked areas of testing variation. Manually cutting samples from a jumbo reel is difficult to duplicate from reel to reel, much less from operator to operator. Improperly cut samples from the reel can affect how the individual test pieces are prepared as well as the orientation of the sample in the test instrument. When using a Profile Sample Cutter, samples are collected the same way every time, ensuring consistency and less variability.
– Testing in the true MD and CD direction. Manually cutting samples from the reel and again cutting the individual test pieces presents another opportunity for variation. If samples are not cut straight, you cannot test in the true MD and CD direction every time. Not testing in the true MD and CD direction will introduce variations as well as lowering test results. With the Profile Sample Cutter, the samples are cut in the true CD direction. Precise feeding of the sample ensures that the automated paper testing system will test in the true MD and CD direction every time.
– Same Position Testing. Not testing in the same position on the reel every time could simply be showing position variations, rather than an actual quality problem. Contrarily, this fault could also be hiding existing or developing problems. L&W Autoline 400 utilizes a precise feeding mechanism, to ensure it will measure in exactly the same position every time. This also facilitates long-term comparisons of a particular cross machine position in order to analyse MD variations.
– Increasing the number of data points. Increasing the number of positions tested makes the average of those measurements statistically more reliable. With automated paper testing systems testing volume is dramatically increased compared to manual testing. It is possible to test every property, every reel, every time. Customers typically test 20 positions across the complete reel width.
Financial benefits
How do L&W Autolines actually make money for their owners? By allowing for tighter controls, optimizing testing procedures and lowering overall costs.
Users of these systems have been able to benefit by optimizing process operating conditions, lowering customer complaints and retaining or expanding market share. The speed, accuracy, and frequency of measurements allow the papermaker to make short-term process improvements and long-term process changes in order to reduce variability and produce a consistent, high quality product.
This type of automation also represents a fundamental change, or paradigm shift, in attitudes both towards the work place and the role of employees. Highly skilled personnel no longer need to carry out repetitious and routine functions. This type of work can now be performed more cost effectively by machines, leaving technicians more time to concentrate on process and quality improvement, rather than measurement and data collection.
We have seen that by increasing the reliability of the testing it is possible to shift the target and therefore there is a huge potential to save money. Other possible benefits have been listed below:
Increased productivity results
- Speed increase on dryer-limited grades
- Weight decrease (when sold by area or strength)
- Less downgraded product Reduced grade change losses
- Reduced start up time
- Reduced breaks
Improved quality
- Improved market share
- Reduced customer complaints
- Preservation of existing market share
- Reduced machine direction variability
- Reduced cross-direction variability
Reduced costs
- Reduced steam costs per ton
- Reduced fibre usage
- Total weight increase (when sold by weight)
- Substitution of recycle for virgin fibre
- Substitution of fillers for fibre
- Decreased chemical additive costs
- Reduced refining
- Reduced freight costs
- Manpower optimization
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