Make stencils for screen printing
Overview
This standard is for pre press operators preparing and processing stencils for screen printing
This standard covers:
- selecting and preparing the appropriate mesh
- transferring images to stencils using film **or by direct etching
- processing stencils
It includes:
- identifying the mesh type and frame size
- selecting and preparing the frame
- stretching the mesh (when necessary) and checking the tension
- checking the condition of mesh material
- degreasing mesh material (when necessary)
- applying and drying emulsion or use pre emulsion mesh
- positioning the photo-positive or use the appropriate file
- exposing, developing and drying the stencil
When working with stencils it is important to make sure that the positive films match with artwork elements and the correct exposure values to produce required stencil characteristics are:
- complete
- sharp and clean
- the required resolution
Performance criteria
You must be able to:
Prepare mesh and frame
- check the job details you have are complete
- identify and select appropriate mesh types and frame sizes for each job
- check that the tension of mesh on the frame meets job requirements, stretching it yourself where required
- check that new or used mesh is in a suitable condition for use in accordance with organisational procedures
- prepare mesh so that it is in the appropriate state to accept the stencil, roughening it and degreasing it in accordance with organisational procedures where required
- report when the frame or mesh is no longer suitable for use in accordance with organisational procedures
**Process screen printing stencils
**
7. check that the job details you have are complete
8. check that photo-positives are fit for use
9. apply emulsion to the screen and dry it in line with procedures where required
10. position photo-positives on screens and confirm that exposure is sufficient to suit stencil systems
11. develop stencils using water at the appropriate temperature and pressure in accordance with organisational procedures
12. dry stencils at the appropriate temperature, checking that drying is even over the entire surface, in accordance with organisational procedures
Knowledge and Understanding
You need to know and understand:
- how to identify the machine to be used
- how to select the frame
- how to identify the required mesh material
- why it is important that reclaimed mesh is free from stains and ghost images and how to confirm this
- why pre-treatment is necessary for new screen meshes and how to select treatments
- how to treat mesh material
- why it is necessary to degrease the screen mesh and how to do this
- how to check that stencil residue has been completely removed from reclaimed screens
- the health and safety requirements when using chemicals and what personal protective equipment to use
- to whom to report unsuitable frames and meshes
- the methods to use in the production of the different types of stencil
- how to select the type of stencil to use
- how the stencil type affects the quality of print
- the materials available for the production of stencils
- what safe light conditions are
- how to determine the resolving power of materials
- why it is important to position the photo-positive correctly and how the machine affects positioning
- how to achieve the optimum exposure
- the effects of under- and over-exposure
- how the condition of the stencil affects the printed image
- what the critical parameters of the stencil are