A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

adhesive		Glue for affixing the mesh to the screen printing frame. Mostly used are two component adhesives, but there are also rapid- and UV-glues available
antistatic		Mesh treatment that minimizes static charge generation and/or provides ”controlled” static charge dissipation.
bolting cloth (silk)		Mesh woven of twisted multifilament natural silk.
calendering		A process by which fabric or wire is passed through a pair of heavy cylinders to reduce mesh thickness
calendered screen printing mesh		One or double sided flattened screen printing mesh in order to reduce the ink volume.It is especially used for UV inks. SEFAR PET 1000 OSC are one side calendered.
capillary film		backing film coated with emulsion
copy		see exposing
copying unit		For exposure of the stencil. UV light sources should have an emission spectrum peak in the range of 350 to 420 nm.
degreasing		Before making a stencil, the mesh should be degreased with a suitable degreasing agent, unless it has a special surface treatment like e.g. SEFAR PET 1500. Please do not use household detergents!
direct emulsion		UV - sensitive Emulsion layer for screen printing stencils
exposing		Exposing the photosensitive layer (emulsion) to UV light. The uncovered areas will harden and become water insoluble. The unexposed areas remain water soluble and can be washed out with water.
exposure time		Time, the stencil is exposed to UV emission.
fabric geometry		see mesh geometry
fabric number		see mesh count
frame		The purpose of the frame is to hold the tensionned screen printing mesh. It has to be stable enough not to be deformed by the big forces of the highly stretched mesh and the printing process.
frame section		Beside the material (steel, aluminium), the profile and the cross section are crucial for the dimensional stability of screen printing frames. We distinguish between square- rectangular - and special sections.
half-tone		There are two different types of half-tone: Amplitude modulated rastering (AM): Resolution in a constant number of dots per area, the dot sizes are variable. Frequency modulated rastering (FM): The dots are as small as possible but the size is constant. The number of dots per area is variable.
half-tone printing		Printing of in halftone dots converted continuous-tone images, consisting of individual raster dots.
ink release		release of the ink from the stencil
ink volume, ink deposit dry		Ink deposit after drying resp. hardening of the ink in mm
mesh count		Mesh count means the number of threads ("Fn") per cm or inch (Fn/cm; Fn/inch)
mesh geomety		The mesh geometry describes all two- and three-dimensional aspects of the mesh structure. The basic factors in fabric geometry are mesh count and thread diameter.
mesh number		indication of number of threads per cm or inch and thread diameter
mesh tension gauge		Measuring and checking instrument to control the mesh tension. Modern Instruments operate electronically with digital display
mesh thickness		The mesh thickness is measured on the unstretched mesh in mm
off-contact		The off-contact is the distance between the screen and the substrate before printing, i. e. before the squeegee is pressing down the screen to the substrate.
one circuit stretching system		The one circuit stretching system works pneumatically and is equipped with one control circuit only for all clamps. It is used for screen printing frames with shanks up to approx. 150 cm (also see "two circuit stretching system").
open area		Sum of all mesh openings over the total mesh area "ao" in %. A mesh with an ao = 30.5% has an open ink permeable area of 30,5% and a closed, impervious area of 69,5%.
open mesh area		see "open area"
pneumatic stretching system		Pneumatic stretching systems are consisting of individual clamps and a central control unit. Depending on the system, they are operated with air pressure and one or two air control circuits. The number of clamps is depending on the frame size.
raster		see half-tone
raster ruling L/cm or L/pi		The raster ruling is indicated in lines resp. dots per cm or inch. In screen printing, rasters between 5 L/cm till max. 48 L/cm can be printed, depending on the mesh used. Guideline: the smallest dot must have a minimal diameter of two threads and one mesh opening.
register		1: Exact congruence between original (e.g. diapositive) and the printed image 2: Multi colour printing: exact congruence between originals of the various colours and their printed images (colour register) 3: Exact congruence of images at the beginning and the end of a print run, or between intermediate printings.
sawtoothing		The edges of printed lines and areas are spiky. Main reason: coating thickness too small, and/or RZ value too high
screen printing frame		Aluminium and steel are the mostly used materials for screen printing frames. Aluminium frames are less heavy and easier to handle but to give a comparable strength to steel , the cross sectional area must be enlarged. See also 'frame'
screen printing moiré		interference between mesh and halftone dia positive
squeegee		The squeegee fills the mesh openings with ink and is pressing the stencil onto the substrate. The edge of the squeegee blade, the squeegee pressure, the angle as well as the material and hardness have an important influence on the printing result.
squeegee side		The side of the mesh resp. stencil directed toward the squeegee.
squeegee angle		Angle from the screen, in which the squeegee is fixed. The common angle is 75°.
squeegee pressure		The squeege is pressing the stencil onto the substrate. The pressure should be as low as possible.
step exposure		The step exposure is a methode of determining the optimum exposure time. It depends on the characteristics of the photo emulsion, the mesh, the overall thickness, the light source and the distance between the lamp and the screen.
stretching system		Stretching systems are used for stretching the screen printing mesh before glueing it onto a frame. We distinguish between: - mech. stretching systems - pneumatic stretching systems
Tensocheck 100		Digital tension measuring instrument from Sefar
theoretical ink volume Vth		Calculated Value of the ink volume "Vth" from open area ("ao") in % and the mesh thickness "D" in mm: Vth = ao x D/100
thread diameter		The thread diameter resp. thread thickness is specified as nominal value, referring to the diameter of the raw and unwoven thread in mm.
two circuit stretching system		A two circuit stretching system works pneumatically and is equipped with two independent air circuit controls, one each for the the parallel frame shanks. It is used for frames with shanks exceeding 150 cm (see also "one circuit stretching system")
undercutting		Light rays striking the white fibres of the mesh are reflected and scatter under the edges of the film. Light is also conducted through the fibres leading to yet more undercutting. Result: unsharp edges, colour shifts. Sefar yellow dyed mesh prevents undercutting.