How to prevent barré and shade variations within the end fabric
PRISMA's unique OffColor feature
Producing substandard yarn leads to costly complaints and lowers the profitability of a spinning mill. It is therefore even more important to carry out clever quality control that ensures quality yarns and does not compromise efficiency. PRISMA is exactly the right solution. Unique technology combined with clever software ensures maximum profitability for every spinning mill.
One important quality aspect is the consistent color of the yarn to prevent barré and shade variation within the end fabric. Such defects can occur due to errors in the spinning preparation process:
- Bobbins with different colors or shades get mixed-up due to human error, especially on round magazine by manual bobbin loading
- Roving’s are mixed up and incorrectly attached to the spinning machine, or sliver cans are mixed up at the draw frames
- Bobbins contain several color shades due to blend variations or deviations during the spinning preparation process in the mill
- Insufficient cleaning of machines during lot changes, leads to clearly different colors or color shade faults
PRISMA’s RGB sensor technology enables the most accurate recognition and classification of shade and glossiness differences in any type of yarn color or blend. The optional feature OffColor completes the unique technology by detecting color variations. As the OffColor feature is cleverly combined with the two textile alarms, Bobbin startup alarm and Length limit alarm, PRISMA offers the most efficient color variation detection.
PRISMA provides the fastest detection of faulty bobbins on the market with its Bobbin startup alarm. It detects bobbins with the wrong color immediately after the bobbin change, within the first wound 11 to 20m. With a 50m observation length for color deviations, PRISMA ensures the removal of any color fault with one single cut. If a color deviation exceeds a customizable length, the Length limit alarm is activated. The Length limit alarm ensures those long faults are suctioned completely and an immediate alarm signal is sent to the winding machine to eject the faulty bobbin.
In summary, PRISMA provides the following benefits in color variation detection:
- Clears color variations at the highest level while maintaining the efficiency of the winding machine
- Complete quality control on color faults
- Prevents color strips and color variation within the end fabric
- Avoids cost-intensive complaints from downstream processes
- Fastest detection of mixed-up and faulty bobbins
- Fewer cuts, splice cycles and energy consumption in color variation detection
Settings
After opening the OffColor matrix, the curve can be set according to the spinner’s needs using the simple touch operation. During monitoring the dark events are shown in the upper part of the matrix, while the bright events are shown in the lower part of the matrix.
In the cut history, the parameters of the detected faults, like length and intensity can be viewed at any time for every sensing head.
First verification of the setting with faulty sample bobbins:
- Produce bobbins with wrong color, use these freshly produced bobbins as comparison.
- Check where the faulty sample bobbins are getting classified at the single winding position. Use the automatic bobbin change for this.
- Adjust and finetune your clearing curve until the faulty bobbin is always detected and the good bobbin is processed.
Second verification of the setting with Testmode:
Use the Testmode to verify OffColor cuts in the normal winding process.
Field Studies
The following 2 studies demonstrate the unique possibilities of the OffColor feature.
Study 1:
The study took place in the field with a Ne 120 with two different cotton varieties. With a close look, the fine shade difference is visible by holding the bobbins next to each other.
The parameters were set for the darker yarn, 100% Pima cotton, and after some running time with this yarn, the bright yarn was started with similar settings. The brighter yarn got detected in OffColor bright classes marked in blue.
The fault specifications are listed in the last cut history.
Study 2:
The study took place in the field on a Ne 100 with two different cotton varieties. With a close look, the fine shade difference is visible by holding the bobbins next to each other.
A sample bobbin made up of two different bobbins with shade variations was prepared with these two different bobbins and the shade variation was visible under the UV light.
The parameters were set for the brighter yarn (cotton blend 30% / 70%) and after some running time with this yarn, the bright yarn was started with similar settings. The darker yarn got detected in OffColor dark classes marked in blue.
The fault specifications are listed in the last cut history.