# How to Measure Paper considering Variation and Humidity

#### mjpanicali

##### Registered
Paper is a critical component of our product with the variation and humidity of the paper being key inputs into our setup. There are some assumptions made during the setup but if the assumptions are wrong, the process is not optimal.

We are looking for ideas on how best measure a huge roll of paper for thickness of individual sheets as well as its humidity. Any ideas?

#### Marc

##### Hunkered Down for the Duration
Staff member
I can't personally help, but you might want to let people here know what your dimensions, variance and tolerances are.

#### mjpanicali

##### Registered
Paper used in electrical power application (as part of bushing condenser). The problem is the thickness of the paper and its moisture content impacts the winding process around the conductor. Even variation inside the specification causes waste by having the operator dial the process in for every roll entering the winder.

I would normally say measure by weight of the roll and calculate the paper thickness; however, the paper isn't necessarily dry. Not to mention, the cardboard tube in the center will have variation and same problem with moisture content changing its weight..

Super Moderator

#### mjpanicali

##### Registered
Thanks for the feedback. I'll take a look. I finally dug through a few layers of specifications and found the paper spec. One of our options is: .100 mm +/- .005 mm. the rolls are 120mm ID and 1000mm OD (max)...weight is 2700kg. The challenge is measuring a single sheet of paper to that level of accuracy. We are investigating taking a core and measuring multiple layers with some simple math.

#### normzone

Trusted Information Resource
Well, I don't envy you this one. It's all very doable in theory, but it brings new meaning to the phrase " Well, it looks simple on paper, but ... "

#### howste

##### Thaumaturge
Super Moderator
Well, I don't envy you this one. It's all very doable in theory, but it brings new meaning to the phrase " Well, it looks simple on paper, but ... "

#### Rambo

##### Registered
Are you wanting to measure the paper thickness as it's being wound up on this roll? Is this heavy weight paper?

We make a thin-walled product in some of our processes-- I have considered measuring the thickness with air gaging as the material moves over a mill roller in the calendaring machine (36" wide). I considered using a series of ports across this web to get several measurement points (using calipers, only the edges could be measured). I haven't moved forward with it, because current methods seem to be sufficient, given the application and tolerances.

Of course a solution like this isn't portable/hand-held, but if you're looking to measure the product as it is being wound, you might look at it. My concept isn't perfect-- the variation in the roll itself and its orientation is going to add into the measurement error. Porosity of the paper might be a challenge, too, using air.

#### David-D

##### Involved In Discussions
What is your underlying concern on the paper thickness? Is it roll-to-roll variation or within-roll variation? If the paper is consistent within a roll, but you're concerned about how this roll's thickness will affect performance/manufacturing, then your problem is "easier" in that you only need to measure at the outside and you can stack multiple layers, measure together, and divide (using a micrometer). Hopefully you can then adjust your process parameters accordingly (or control your input requirement more tightly). If you're concerned about variation within the paper roll, that's more difficult, especially since I assume you're feeding it at high speeds and don't want to stop periodically to measure (and change you're tension, etc).

If you need fast in-process measurement, that's going to be tough - perhaps some sort of laser micrometer? Perhaps some sort of laser and detector to measure attenuation thru the paper?

Good luck,

David

#### David-D

##### Involved In Discussions
So I just did some quick math and you said your spec tolerance is +/- 0.005 mm which would equate to a bit tighter than +/-0.0002 inches. That means for a single sheet, it is asking a lot (too much) from a standard micrometer which might be +/-0.0001" and completely invalidates calipers. I'd also assessume that measurement area and force probably affect good measurements. You might want to see of there is an "official" industry standard on how to do the measurement and if it is specified for a single sheet or multiple at once.

David

How to measure severity if my product is designed for emergency use and failure would result in death? ISO 14971 - Medical Device Risk Management 9
Looking for a third party to calibrate our measure equipment - South Carolina General Measurement Device and Calibration Topics 6
Validity / outcomes measure for custom made medical device ISO 13485:2016 - Medical Device Quality Management Systems 2
Performance specification as a Risk Control Measure, EN 14971 ISO 14971 - Medical Device Risk Management 7
KPIs or Metrics to Measure a New Complaint Handling Process 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 5
Torque fractional unit of measure; cN-m or N-cm? General Measurement Device and Calibration Topics 2
ISO 9001 5.1.1 - How to measure System effectiveness ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
How to measure a Critical Characteristic that is a Basic Dimension Misc. Quality Assurance and Business Systems Related Topics 6
Can we use pin gauges to measure an accurate Cpk ? Capability, Accuracy and Stability - Processes, Machines, etc. 9
Best criteria to measure Corrective Action effectiveness - Poor Maintenance ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 10
How to measure straightness on a HEX Long Bar Manufacturing and Related Processes 7
Measurement Method Challenge - Measure feature #91 Inspection, Prints (Drawings), Testing, Sampling and Related Topics 9
Measure 3 times, for calibration report? Customer Owned Reference Standard General Measurement Device and Calibration Topics 4
Informational The ANSM decides, as a precautionary measure, to withdraw from the market macrotextured breast implants and breast implants with polyurethane-coated s Medical Device and FDA Regulations and Standards News 0
Informational Health Canada advises Allergan of its intent to suspend its licences for Biocell breast implants as a precautionary measure Medical Device and FDA Regulations and Standards News 0
SI 13 - Not Every Process Requires an Efficiency Measure IATF 16949 - Automotive Quality Systems Standard 1
NPR Metric - What if Customer has relaxed measure? TL 9000 Telecommunications Standard and QuEST 1
Tape Measure, the right device for 2 or 3 decimals accuracy on prints General Measurement Device and Calibration Topics 8
How do we document and measure a service we do not provide? IATF 16949 - Automotive Quality Systems Standard 1
M For a Type 1 Gage R&R I want to use 1 unit and measure it 30 times Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
Advice/recommendations for equipment to measure a soft pvc tube - Optical Measuring? General Measurement Device and Calibration Topics 4
R Height gauge to measure short hard to access heights General Measurement Device and Calibration Topics 3
D Proper Tool to Measure Wall Thickness (ISO 3611 - Micrometers) Manufacturing and Related Processes 7
S Quality Measure for Engineering Services Misc. Quality Assurance and Business Systems Related Topics 1
A What are methods and tools to measure Workload analysis ? Human Factors and Ergonomics in Engineering 1
M How do I measure variation in my process ? Capability, Accuracy and Stability - Processes, Machines, etc. 3
J How to measure process quality? Is DPPM the correct metric? Capability, Accuracy and Stability - Processes, Machines, etc. 5
M Micrometer Anvil Placement to measure the diameter of Steel Wires Measurement Uncertainty (MU) 6
S Where to Get SPC Training to Measure our Processes? Training - Internal, External, Online and Distance Learning 12
A question on Measurement System Analysis - Stability to measure got Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
Measure Twice, Cut Once: The French Railroad Snafu World News 18
S Measure water activity for fresh raw chicken meat and giblets Food Safety - ISO 22000, HACCP (21 CFR 120) 1
O Metrology Devices to Measure the Basic Dimensions of Plastic Specimens General Measurement Device and Calibration Topics 6
How to Measure Paint Thickness for an Enclosure Manufacturing and Related Processes 5
C Chamfer Measurements - Do you measure the height and width or the hypotenuse? Manufacturing and Related Processes 15
Repeatability in MSA - Is repeatability a measure of Location Error Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
How can I measure three true positions? GD&T basic question General Measurement Device and Calibration Topics 5
V How to use a Calibration Certificate in Uncertainty Calculation for a Test Measure Measurement Uncertainty (MU) 13
R How do companies measure QC Productivity? Quality Manager and Management Related Issues 3
V How to measure radius without radius gages APQP and PPAP 4
A Device to measure "Straightness & Deformation" of a metal that's under water Manufacturing and Related Processes 4
M How to measure effectiveness and efficiency of the established QMS as Auditors ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 14
F Specification for how to measure lengths of hose assemblies Various Other Specifications, Standards, and related Requirements 1
P MSA requirements for Systems that Measure Process Parameters Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
J How to Measure Chamfer Angles Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
J How to measure Loosening and Tightening Torque (VDA 5 - MSA) Quality Tools, Improvement and Analysis 5
C Measurement System to measure Hole Diameters, True Positions, Surface Profiles, etc General Measurement Device and Calibration Topics 4
J How to measure effectiveness of the Metrology Process General Measurement Device and Calibration Topics 5
How to Measure Effectiveness of the Design Validation Process? Design and Development of Products and Processes 7
N The right method to Measure and Evaluate a Flatness Callout Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1