overview
The quality of image demanded by today's screenprinting industry is becoming ever higher as screenprinters compete with emerging printing technologies. Whilst developments in screen-printing equipment, materials, inks and meshes mean that almost photographic print quality is achievable. These a dvancements in technology have exaggerated the problems caused by dust and static during the screenprinting process and can seriously affect yield and profitability.
Each colour print is critical and maintaining a high yield for multicolour printing (up to 20 colours in the Automotive industry) becomes a major challenge if the potential problem of dust and static is not addressed before the first colour print. The problem is equally troublesome in the screenprinting of electronic circuitry - membrane switches, facias, front panels and backlit displays. Dust, also, causes lost production time for the printer, due to the stoppages required to allow the operator to clean the screen.
Some users have experienced up to a 50% improvement in yield and reduced downtime, simply by using Teknek's contact Clean Machine products.
applications
To make a new screen, mesh is first stretched over a frame, emulsion is then coated onto the mesh. Artworks of the colour separations are exposed onto the emulsion using a UV light frame. The screen is subsequently washed, leaving the image on the screen. Dust trapped under the emulsion, or deposited onto the emulsion, either from the environment or from the artwork, can create defects during this 'image transfer' process. The accepted norm is then to 'touch up and redo' the screen (ie - to fill in the spots on the screen where dust has created pinholes in the exposed image), meaning extra time and effort is required before the screen is ready for production.
Using the DCR hand cleaning roller to manually clean the mesh before the emulsion is coated and at the UV exposure station can help remove all the dust and debris and dramatically reduce these defects and extra work.
When a direct image camera system is used for large-format screen manufacture, dust will be magnified with the rest of the image. The DCR hand roller and contact cleaning machines can be used to clean the artwork before it is used, removing dust to ensure clear imaging.
Dust in the screenprnting process can seriously affect the quality of the finished image. Teknek machines are used to clean the print stock immediately prior to printing (just-in-time cleaning).
Semi Automatic Machines
Four poster press, semi and ¾ automatic machines are designed to allow the screen to lift away vertically. The feed table is then moved to the loading position and the material is manually placed onto the table. The Teknek CH2 Clean Machine (Cleaning Head) for single-sided cleaning of the substrate immediately before printing. Improved efficiency (approx. 37%) and better yields / print quality result.
Reel to Reel Printing
Narrow web processing can involve many of the processes described in Converting, though generally, with a web width between 150mm (6") and 560mm (22"). Label printing using UV inks, are particularly susceptible to any dust on the product and the Narrow Web NW Series machine is specifically designed to fit into lines with space constraints.