Forming Fabric General Flashcards
What are the raw materials used in forming fabric?
Polyester and polyamide.
Need Polyamide for durability!!
Polyester is stiffer
Why is polyamide used in forming fabrics?
For durability
What is the roll of forming fabric
Dewatering, Retention and Transportation
No marks, high dry content and good formation. Stable, clean, predictable `
What direction is the warp yarn
Machine Direction
What direction is the weft yarn
Cross direction
What yarn is cross direction
Weft
What yarn is machine direction
Warp
What does SSB stand for? (Forming Fabric)
Sheet support binder fabric
Why was SSB forming fabric developed?
Designed so we can have two distinct sides. A fine paper side and a coarse wear side without impacting either side.
Fine top for good retention and contact points
Bottom for wear resistance
What is SSB forming fabric
Binding yarn in CD goes into paper side then into warp so it acts as sheet support as well as binding to the wear side
What is yarn count
2 values
nMD = number of MD yarns in cm
nCD = number of CD yarns in cm
What is T count
Its nMD + nCD
nMD = number of MD yarns in cm
nCD = number of CD yarns in cm
What is SP count
Support count
It is number of yarn knuckles that support the paper web in 1/cm2
What do FSI and DI stand for
Fibre support index and drainage index
What are the benefits of SSB fabric?
Sheet support binder
More stable and even profile
Higher wear potential
Higher fibre support - better retention and smoothness
What does a lower FSI mean in forming fabrics?
Means a coarser fabric which means water can exit faster
What are the different caliper values examined on forming fabrics?
Total caliper
Critical caliper - when MD yarns start to wear
Wear margin caliper between CD yarn to MD yarn
What is void volume in forming fabrics?
Free space inside the fabric
Do we want a high or low void volume in forming fabrics?
Ideally want low, because the more water we carry inside the more chance of misting… But we need to balance this with durability - compromise
What is a shaft count
Number of MD yarns until a weave pattern repeats itself.
Number of yarns known as shed
What is polishing?
Fine grinding to smooth topography and give better guiding - but this is very rare.
