Screen Printing - June/July 2012 - (Page 24)
Boosting Garment-Printing Efﬁciency
Use the following tips to control the variables most commonly encountered in garment screen printing.
Dawn M. Hohl-Nowlin
liminating problems and managing variables in garment screen printing lead to real improvement in quality and efficiency. This article focuses on five top culprits that slow the process down: screen tension, stencil exposure, stencil drying, squeegee quality, and flash curing.
Screen Tension Screen printing is next to impossible to control without proper and consistent screen tension. To deal with tension at all, you need to use a calibrated tensionmeter as part of a daily routine of managing tension on screens. Tension should be measured on every screen every time you stretch, retension, or pick out a screen to enter into the production cycle. Higher tension levels produce better print results, improve registra24 SCREENPRINTING
tion, and increase production speeds. Appropriate tension levels for a particular mesh count and thread diameter vary based on the fabric strength, frame type, and—in some cases— stretching device. Most meshes used for garment printing can be tensioned easily to 25 N/cm and higher. Tension should not be considered a goal unto itself. Choose tensions that that can be consistently achieved and maintained given your shop’s conditions. High-tension screens have less resistance to knocks and pokes and will break more easily, and therefore need to be handled with more care. Off-contact distances must be reduced when higher screen tensions are introduced to the press. Failure to lower off-contact accordingly can result in the mesh breaking on press. When raising tension levels, it is a good idea to increase op-
erating tension gradually, and establish timely communication with the pressroom so appropriate adjustments are made. Screen-tension uniformity refers to consistent tension within one screen. Maintaining tension uniformity is important for preventing image distortion and registration problems. Uneven warp and weft tension can create inconsistent registration, unpredictable ink deposit, and destructive moiré. For best results, variations should be within ±1.0 N/cm. Tension measurements should be taken in at least five places on the screen. This is known as a five-point measurement method. To establish your measurement locations, divide the screen into four equal quadrants, each with a corner joining at the center (Figure 1). Measurements are taken in the center of the four quadrants and in the center of
Table of Contents for the Digital Edition of Screen Printing - June/July 2012
Screen Printing - June/july 2012
Digital vs. Screen and the Dilemma of Process Improvement
Step Up Your Game With Team Wear
Boosting Garment-Printing Efficiency
What Printers Think About Rip Software
Direct-to-Garment Site Preparation and the Environment
Screen Printing - June/July 2012