Pad printing head is the core component of pad printing process, its quality directly affects printing results and production efficiency. Many enterprises encounter various defect problems during head making and use, such as bubbles pinholes, blurred patterns, head cracking, short life, poor ink pickup etc., repeated adjustment still cannot solve, seriously affecting production schedule and product quality. Shenzhen Hongyejie Technology Co., Ltd. Hongye Silicone, with nearly 20 years of
Pad Printing Silicone R&D and application experience, systematically analyzes causes and solutions for common pad printing head defects, helping enterprises quickly locate problems and effectively solve defects.
Bubbles and Pinholes Defect
Bubbles and pinholes are the most common pad defects, showing as internal or surface bubbles in the head, causing pinhole pattern missing during printing. There are four main causes: first, air entrainment during stirring, too fast stirring speed or stirring rod leaving rubber surface causes air entrainment. Second, improper pouring method, pouring from high altitude causes impact bubbles. Third, insufficient degassing, not enough vacuum time or no vacuum equipment with insufficient natural degassing time. Fourth, dusty mold or accumulated release agent, bubbles attaching to mold surface.
Solutions: Stir at moderate speed, keep stirring rod submerged below rubber surface to avoid air entrainment. When pouring, slowly pour from one side of the mold, let rubber flow naturally to fill, do not pour directly from high altitude. If vacuum equipment available, degas at negative 0.09MPa for 2 to 3 minutes until no more bubbles rise, release pressure and re vacuum if necessary. Without vacuum equipment, let sit 5 to 10 minutes for natural bubble rise, or gently sweep rubber surface with low temperature heat gun to help bubble break. Thoroughly clean mold before use, apply thin and uniform release agent without accumulation.
Blurred Patterns and Edge Bleeding
Blurred patterns and edge bleeding show as unclear printed patterns, hairy edges or bleeding, detail loss. Main causes: first, pad hardness too high or too low, too high hardness causes insufficient contact with product surface, too low hardness causes excessive deformation leading to pattern distortion. Second, oil or dust on pad surface affecting ink transfer. Third, improper ink viscosity, too thin or too thick both affect printing results. Fourth, pad used too long with surface aging, degraded ink pickup and transfer performance. Fifth, improper printing pressure and speed parameters.
Solutions: Select appropriate hardness pad based on product shape, flat and slightly curved products choose medium high hardness like Hongye HY-902 or HY-912, large curved surfaces choose ultra soft Hongye HY-916. Clean pad surface with alcohol before use to remove oil and dust. Adjust ink viscosity, add appropriate amount of thinner based on ink type and printing environment to achieve best transfer viscosity. Replace pad when surface aging, do not force use. Adjust printing pressure and speed, moderate uniform pressure, stable speed, find best parameter combination through test printing.
Pad Cracking and Short Service Life
Pad cracking and short service life show as surface cracks, chipping, pieces falling off after certain use time, service life significantly lower than expected. Main causes: first, excessive component B ratio, pad too hard and brittle, easy to crack. Second, curing temperature too high or time too long, pad aging and embrittlement. Third, many bubbles during making, internal defects causing stress concentration and easy cracking. Fourth, improper cleaning during use, strong solvent repeated wiping corroding pad surface. Fifth, product has sharp edges or burrs scratching pad surface during printing.
Solutions: Strictly weigh A and B components at accurate 100:2 ratio, do not arbitrarily increase component B ratio, excessive B causes brittle pad and shortened life. Curing temperature not exceeding 100°C, moderate curing time, do not over cure. Fully degas during making to reduce internal bubble defects and improve overall pad strength. When cleaning pad, gently remove residual ink with clean nonwoven cloth or tape, do not repeatedly wipe with strong solvents like acetone, toluene. If product has sharp edges or burrs, polish first to avoid scratching pad during printing. Choose high wear model like Hongye HY-902 to significantly extend pad service life.
Poor Ink Pickup and Incomplete Transfer
Poor ink pickup and incomplete transfer show as incomplete pattern when taking ink from plate, or ink remaining on pad with incomplete pattern transfer to product. Main causes: first, release agent residue on pad surface affecting ink adhesion. Second, new pad not fully conditioned, surface performance not stabilized. Third, improper plate etching depth, too deep or too shallow both affect ink pickup. Fourth, improper ink drying speed, too fast or too slow affecting transfer. Fifth, environment temperature humidity too high or too low affecting ink performance.
Solutions: Thoroughly clean new pad surface with alcohol before use to remove release agent residue. Before first use, do 10 to 20 test prints on waste paper to fully condition pad surface and reach stable state before formal production. Check plate etching depth, adjust etching parameters based on pattern fineness and ink type, generally fine lines etch shallower, large solid area etch deeper. Adjust ink drying speed, add appropriate slow drying or fast drying agent to achieve best transfer state on pad surface. Control environment temperature at 20 to 28°C, relative humidity 40 to 60 percent, avoid extreme temperature humidity environment.
Hongye Silicone Defect Troubleshooting Technical Support
Hongye Silicone has focused on
liquid silicone for over 20 years, providing full series pad printing silicone products and professional technical support for various industries. The company has a professional technical service team with average industry experience over 10 years, providing full process technical support from pad making to printing debugging, including defect troubleshooting, making process optimization, printing parameter debugging, ink matching suggestions etc., helping enterprises quickly solve pad defect problems, improve printing quality and production efficiency. Hongye also provides 1kg trial kits for enterprises to test before bulk purchase. As the pad printing industry continues to develop with higher requirements for pad quality and printing precision, Hongye Silicone will continue R&D and innovation to provide higher quality pad printing silicone products and professional technical services for all industries.
Shenzhen Hong Ye Jie Technology Co., Ltd
