ASTM D 1907 yarn linear density testing depends on selecting the right testing option, which depends on the customer’s scouring and conditioning requirements. Sample conditioning, reeling tension, skein length, calibrated weighing, and final calculations are the main steps for getting the right results.
How to Select a Suitable ASTM D1907 Test Method?
The testing options of ASTM D1907 or D1907 M mainly depend on the type of fiber, its composition, moisture, finish applied on its surface, and the required mass.
Because the results may be based on conditioned mass, oven-dry mass, and commercially adjusted mass by manufacturers. That is why, the testing options must be selected according to specifications provided by the customer and supplier.
Major Difference Among 7 options of ASTM D1907 Testing
- Testing of unscoured, conditioned yarn which is mainly used for cotton spun yarns.
- Testing of unscoured oven-dry mass yarn. It measures the oven-dry mass without removing the finishing treatments.
- This option includes oven-dry yarn, and its moisture is adjusted for commercial use.
- This type includes scoured and conditioned yarn testing after removing extractable materials.
- Testing of scoured oven-dry yarn, which measures the dry mass of cleaned yarn.
- Testing of scoured oven-dry yarn, but its moisture is adjusted commercially.
- Lastly, testing of scoured oven-dry yarn with commercially adjusted moisture but with extra allowance for finishing treatments.
So, from option 1 to 6 the main difference is in moisture either the yarn is scoured or unscoured. The last option also provides extra allowance for finishing treatments.
Types of Yarn Suitable for Testing and Their Limitations
For cotton spun yarns, option 1 will be considered. Options 6 and 7 are usually considered for testing filament type yarns and wool yarns. If the yarn stretches by more than 5% under the specified tension, then testing must be done according to the agreement of the customer and supplier, such as adjustments in reeling tension.
This standard is mainly suitable for testing finer yarns having a count more than 2000 Tex. While for testing coarser yarn, specified reeling conditions may be used.
Effect of Sample Conditioning and Treatment on Final Results
When to Choose Conditioned, Oven Dried, or Scoured Yarn?
The testing of conditioned yarns is basically done under specified laboratory testing conditions, which include finishes and moisture in that state. Testing of oven-dried yarn is done after complete removal of moisture from the yarn, so we can find differences in results after removing moisture.
The scoured yarns include removal of natural impurities like waxes, oils, and sizing materials before conditioning and drying. Therefore, all textile laboratories should select a suitable ASTM D1907 test method according to buyer and supplier agreements and specifications for testing.
If we compare different samples of yarns that are treated differently, it can lead to incorrect results and misguide the customer.
Effect of Moisture and Extra Allowances for Treatment on Yarn Results
The measured mass is the actual final mass tested under specific conditions. The commercially adjusted moisture yarns adjust the oven-dry mass according to their agreed moisture percentage. The extra allowances may include some finishing treatment or other factors.
Therefore, laboratories must test the linear density of actual oven-dried yarns and commercially adjusted moisture yarns. The final testing reports must include finishing treatments, percentage of moisture regain, extra allowances, calculation formulas, and units.
It would be a wrong technique to compare the results of adjusted yarns with untreated yarn measurements.
Which Testing Equipment is Required for ASTM D1907 Test?
Which Testing Equipment is Required for ASTM D1907 Test?Requirements for a wrap reel, Weight Balance, oven, and Scouring Facilities?
All the options of the ASTM D1907 test require a wrapping reel for making skeins of yarn and a weight balance to measure the correct mass of yarn. Options 1 and 4 required conditioning, with scouring required for option 4 only.
Options 2 and 5 required an oven, and options 3 and 6 need calculation due to commercially adjusted moisture. For option 7, we require an oven, scouring, and calculation for commercial adjustments. The wrapping reel is used only for making skeins of yarn, and the weight balance is used to calculate the mass of yarn.
The accuracy of the weighing balance must be high, and moisture-sensitive samples must be handled carefully before weighing.
Selection of YG B086C or YG B086AC Wrap Reel Tester
For routine testing of yarn linear density, the Wrap Reel/Yarn Length Tester YG B086C is suitable equipment that provides proper tension control during testing.
The Wrap Reel Machine YG(B)086AC contains an electronic-based sensor that automatically controls tension during testing and provides real-time monitoring.
This improves the testing accuracy and repeatability, mainly for stretch yarns. While some checking requirements are needed for both testers, such as wrapping reel circumference, Length of skein, and winding tension, etc.
On the other hand, the Electronic Scale WT0200 balance must be properly calibrated and verified against the laboratory procedure of ASTM D1907.
How Textile Laboratories Can Improve ASTM D1907 Test Accuracy and Reporting?
Which Testing Measurements, Calculations, and Reporting Details Are Important?
The accurate yarn linear density is mainly measured by using accurate yarn skein length and mass. The basic formula is mass in grams multiplied by 1000 and divided by the length of yarn in meters.
For example, a skein of yarn having length 100 meters and weight 2.5 grams has a linear density of 25 Tex. Laboratories must confirm the required skein length and calculation basis.
The testing records must include mass, skein length, type of equipment used, calibration record, and commercial adjustments. The main chances of error can come from improper balance reading, improper winding tension, improper scouring, and drying.
Main Difference Between ASTM D1907 and ISO 2060
Both testing standards include the skein method for measuring yarn linear density and have seven testing options.
The main difference between these methods is that, the ASTM D1907 covers the yarn testing having density less than 5% under specific tension while, the ISO 2060 1994 contains a limit of 0.5% stretching under specific tension.
Laboratories must check the tension of the reel, sample preparation, conditioning, and calculation.
Conclusion
The selection of a correct ASTM D1907 testing option is very important to generate accurate and repeatable results. Some laboratory errors can also minimize the accuracy of results, such as incorrect sample preparation and conditioning and improper tension, etc.
Laboratories must have suitable equipment and facilities for sample preparation, oven drying, and calculation for commercial adjustments.
For a complete testing setup, you must have a suitable wrapping reel, weighing balance, and moisture control and treatments. This improves the testing accuracy and consistency.
FAQS
Can a wrapping reel cover all seven testing options of ASTM D1907?
A wrap reel makes skeins of yarn only. We require additional facilities and equipment for conditioning, oven drying, and scouring.
How to check that 0.01 g weighing balance is appropriate for ASTM D1907 testing?
Before selecting a weighing balance, you must check the sample weight range, required level of accuracy, calibration, and other specified requirements.
When to select YGB 086AC instead of YGB 086C?
You should select Wrap Reel YG(B)086AC when you require electronic tension control for accurate testing and to improve repeatability, mainly for stretch yarns.
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