Developing Standard Operating Procedures, Part 2: The Screen Department
Without consistency in screenmaking, you'll find that your profits also will become intermittent. Learn how to bring repeatability to this crucial prepress function.
Identifying and implementing standard operating procedures in the screenmaking department is easy. But maintaining those standards, especially when production picks up, is quite difficult. Failure to adhere to standard procedures in the screen room can lead to issues such as too few screens to maintain production, downtime on press due to screen-quality problems, and a total loss of production efficiency throughout the workflow. In this month's installment, we'll look at the procedures needed to ensure the consistency of the screens that reach your production floor.
Standards for screenmaking
Standard operating procedures in the screen department are intended to facilitate consistent and repeatable results and, in turn, maximize the efficiency of the textile screen-printing operation as a whole. The following information will give you the basics needed to implement solid screenmaking procedures within your facility. The first part of setting up standard procedures is to identify the production flow of screens through the department. The cycle in most facilities involves screen reclaiming, degreasing, and drying; screen coating and drying; exposure; washout and drying; touch-up; taping; printing; and cleaning.
Once you've identified these steps according to your own routines, you can begin to develop the individual procedures to ensure that each step is executed in the same manner for every screen that passes through the department. The following sections discuss basic procedures that should be employed to ensure consistent screen quality. These are general procedural recommendations, and the guidelines that best fit your facility may vary based on the type of screens you use and the dedication of employees to the standardized process. The desired result here is to produce the highest quality screens and be capable of reproducing such screens from run to run. You also should set the procedures up so that if your employees follow them closely, they'll be able to deliver quality results again and again.
Screens will inevitably require degreasing, whether they're new or broken in, and used screens coming from the screen-cleaning area require reclaiming before they're degreased. In order to establish a system of quality and consistency, you need to start at the top of the process. In this case, it's reclaiming. Again, the template you use when setting up your procedures will vary based on your facility's activities.
Make sure that you remove all residual plastisol or other ink from the screen/stencil area, as well as the screen frame, before you reclaim the screen. If you find any ink remaining, return the screen to the cleaning area. Once all ink is removed, apply the screen-reclaiming agent to the entire stencil area of the screen as described by the manufacturer's recommendations. (This aspect of the process is predetermined and should be described in detail for the procedure based on the reclaiming chemistry you use.) Allow the reclaiming agent to reside on the stencil for a minimum amount of time. Using a pressure washer, begin stripping the stencil from the mesh, starting at the top and working your way to the bottom of the screen. Once pressure washing is complete, inspect the screen for residual stencil material and remove any you find. Ensure that the frame also is thoroughly washed and free of any residual reclaiming chemicals on both the front and back. Once you've completed these steps, move the screen to the drying cabinet. rnrn
Keep in mind that newly reclaimed screens should not be stored in the same drying cabinet as freshly coated screens. Newly reclaimed screens will introduce excessive moisture into the drying environment and could adversely affect the quality of the freshly coated screens. A simple solution is to use separate drying cabinets. This is an example of how the amount of detail built into your procedures can give employees ways to accurately and consistently carry out their responsibilities in the process.
If your facility uses retensionable frames, you must include a procedure that addresses measuring and retensioning every screen that comes from degreasing and reclaiming. Doing so ensures that a fresh, high-quality screen is available for every production cycle. I've seen many facilities bypass this procedure, but measuring and retensioning builds the greatest degree of quality into the screens. Every screen should be checked according to the standard reclaiming procedure to ensure that the mesh is retaining its required tension. Most facilities will allow for