Understanding_ the_Cleaning_Process_for_Automatic_Stencil_Printers.pdf - 第18页
Glue Binders • Synthet ic f iber s found in paper usually are polyester or r ayon. • In gener al, about 30% of the pap er’s w eight is found in binder s. • These paper s have a har der sur f ace, lower t ensile strength,…
Wiper Paper
• “Printers are only as good as the material that you put into it” – the same can be applied to the wiper
• Using low-cost paper directly influences the wiper ability to clean the stencil
• In general, there are two types of papers used in stencil wiping: papers made with synthetic fibers held
together with glues (called binders), and papers made from a mix of natural and synthetic fibers that do not
use glue.
• The papers ability to absorb both the solder and solvents reflects on the cleanliness of the stencil
Understanding the Cleaning Process for Automatic Stencil Printers
Glue Binders
• Synthetic fibers found in paper usually are polyester or rayon.
• In general, about 30% of the paper’s weight is found in binders.
• These papers have a harder surface, lower tensile strength, absorb less contamination and are less expensive than glue-less versions.
• Cross-section microphotograph of polyester paper made
with binders, enlarged 200 times.
• The fibers are coated with glue, making surfaces hard and unable to
absorb contamination.
• Most empty space in the wipe has been filled with binders, reducing the
ability to pick up solder paste.
Understanding the Cleaning Process for Automatic Stencil Printers
Hydro-Entangling
• Some paper is made using a process called “hydro-entangling”
• This process involves laying raw fibers of polyester and cellulose onto a conveyor belt and intertwining the fibers with high-pressure jets
of water
• Heat and pressure then are used to dry the slurry into the proper configuration
• Lacking glue, hydro-entangled papers have a softer feel
• They are more absorbent, thicker and stronger than ordinary paper
• The flat, rough cellulose fibers (thin, top layer) are highly absorbent, but
weak and prone to lifting
• The rounder polyester fibers (middle and bottom) provide structural
strength and open space to pick up solder paste
Understanding the Cleaning Process for Automatic Stencil Printers