Saati TQM Glasses Helps to Identify Danger Zones

08 April 2023: Can using yellow safelights through screen making area improve reclaim results ? – 100%. Failure to use safe light wavelengths results in some pre-exposure of the emulsion layer and a ‘fogging’ of the image areas. Underexposure is then applied to try and keep the fine detail open for printing, but with the penalty of under-cured stencil, which is not only less durable, it also reacts with ink and solvent cleaners that will fuse resins onto the mesh. These stains cannot be easily removed during reclaim and may require the use of caustic haze remover to restore the screen or suffer ghost images.

Emulsions are very sensitive to actinic light and this means UV and blue light. Many artificial lights, even so-called UV-safe lights emit strong blue wave lengths that correspond to the maximum sensitivity of most emulsions. Daylight entering from open doors or unshielded windows is even worse. So how can you be sure your lights are safe ?

TQM blue safe-light glasses from SAATI are an easy-to-use tool. Simply wear them on a walk-through of your screen making area to identify any areas where light safe conditions do not exist. Yellow light sources will appear dark. Blue and white light sources are visible.

Take for example a stencil developing area that has two lighting systems. At left there is standard lighting and at right amber bulbs only. Seen through SAATI TQM Glasses, the standard bulbs will produce a lot of blue light that exposes any emulsion that isn’t fully developed. The same area with only amber light sources is revealed to be safe for both coated stencils and stencils that have already been exposed but not yet developed.

Exclusively yellow light sources must be installed at every station in stencil preparation where you coat your screens, drying and storage areas, on the way to exposure, the actual exposure area, even when using DLE systems like CST or SAATI LTS, on the way to stencil developing and the developing area.

Don’t turn a blind eye to a problem that won’t go away. Take further control of your screen making process with this low-cost QC tool and ensure the integrity of your screen making areas for the best printed results.

Contact SAATI if you want to buy quality control tools from a global leader in screen printing, active since 1935, if you are seeking screen making technical advice and if you want to buy other products combining technologies to create entire screen making product packages.

www.saati.com