Pad Printing Head Hardness Selection Guide How to Choose Right Hardness for Different Product Shapes

Pad printing head hardness is one of the key factors affecting printing quality. Many enterprises encounter problems like blurred patterns, incomplete transfer, edge bleeding and short pad life in pad printing production, and the root cause is often improper pad hardness selection. Different product shapes require different hardness pads to achieve best printing results. Too high hardness cannot conform to curved surfaces, too low hardness causes pattern deformation. Shenzhen Hongyejie Technology Co., Ltd. Hongye Silicone, with nearly 20 years of Pad Printing Silicone R&D and application experience, introduces pad printing head hardness selection principles in detail, helping enterprises select correctly.

Flat and Slightly Curved Products Choose Medium High Hardness

Flat and slightly curved products are the most common type in pad printing, including stationery, tools, electronic product housings, remote controls, buttons, hardware parts etc. Product surfaces are basically flat or only slightly curved, printing area is relatively large, requiring high pattern clarity and pad wear resistance.

These products are suitable for medium high hardness pads, recommended 25 to 28 Shore A. Hongye HY-912 (25A) and HY-902 (28A) are both ideal choices. Medium high hardness pads have firm rubber, sharp clear pattern edges, high printing precision, plus good wear resistance and long service life, suitable for mass continuous production. Too low hardness pads used on flat products cause excessive pad deformation, leading to pattern deformation and edge bleeding, plus poor wear resistance and short life. For high volume high frequency flat products, recommend Hongye HY-902 high wear model with 28A hardness, tensile strength ≥4.0MPa and tear strength ≥18kN/m, long pad life effectively reducing replacement frequency and overall cost.

Slightly Curved Surface Products Choose General Medium Hardness

Slightly curved surface products include pen barrels, rulers, cylindrical cosmetic bottles, small figurine faces, small toy accessories etc. Product surfaces have certain curvature but not too large, pads need moderate deformation to conform but cannot be too soft causing pattern deformation.

These products are suitable for general medium hardness pads, recommended 23 to 25 Shore A. Hongye HY-901 (23A) and HY-912 (25A) are both suitable. Medium hardness pads balance conformability and pattern stability, can moderately deform to conform to slightly curved surfaces while maintaining clear pattern without deformation. Hongye HY-912 multi color eco friendly general purpose model at 25A, RoHS and REACH certified, multiple colors with stable batch quality, is ideal for slightly curved products, especially for export enterprises. Hongye HY-901 economy model at 23A, affordable and easy to operate, suitable for domestic sales and cost sensitive enterprises. For slightly curved products, too high hardness causes insufficient edge contact and incomplete transfer, while too low hardness causes pattern deformation. Medium hardness is the best balance point.

Large Curved Surface Products Choose Ultra Soft Low Hardness

Large curved surface products include spherical toys, oval figurines, humanoid dolls, animal shaped toys, large curved cosmetic bottle bodies etc. Product surfaces have large curvature, pads need significant deformation to fully conform, standard hardness pads cannot make complete contact with curved surfaces, causing incomplete pattern transfer, partial missing print and blurred edges.

These products must use ultra soft low hardness pads, recommended 16 to 20 Shore A. Hongye HY-916 ultra soft model at 16A is the lowest hardness and strongest deformation model among four series, with elongation ≥400 percent. The soft elastic rubber can fully deform and wrap large curved surfaces during pressing, making complete contact with product surface and ensuring complete pattern transfer. HY-916 ultra soft model specifically solves large curved surface printing difficulties. Whether it is spherical toy surface, humanoid figurine face and body, or animal shaped irregular surface, it conforms well with clear complete patterns. For large curved products, using standard hardness pads inevitably causes partial missing pattern and blurred edges, only ultra soft pads can solve this problem.

Irregular and Deep Concave Products Choose Custom Ultra Soft Model

Irregular and deep concave products include irregular perfume bottles, craft ornaments, deep concave gifts, irregular promotional items etc. Product surface shapes are complex with deep concave areas, protrusions and large curvature changes, printing difficulty is highest, standard hardness and standard shape pads often cannot meet requirements.

These products need custom pads based on specific shapes. For hardness, recommend ultra soft model below 16A, contact Hongye technical support for custom lower hardness formula. Pad shape also needs special design based on product irregular surface, ensuring pads can reach into deep concave areas, conform around protrusions and adapt to curvature changes. Based on Hongye HY-916 ultra soft model, custom hardness 10 to 16A special formulas can be developed to meet extreme irregular product printing needs. Meanwhile need to 配合 adjust printing pressure, speed, pad stroke and other parameters, find best process through repeated trial printing. Hongye technical team can provide on site technical support to help enterprises solve irregular product printing difficulties.

Common Misconceptions and Precautions in Hardness Selection

Many enterprises have misconceptions in pad hardness selection. Common ones include: first, thinking higher hardness is better, actually too high hardness cannot conform to curved surfaces, only suitable for flat products. Second, thinking softer is better, actually too low hardness causes pattern deformation, poor wear resistance and short life, only suitable for large curved surfaces. Third, using one pad for all products, different shape products should use different hardness pads to achieve best results. Fourth, only looking at hardness ignoring other performance, tensile strength, tear strength, elongation and other indicators are equally important, affecting pad service life and printing results.

The correct approach is to select corresponding hardness pad based on product shape. Flat products use medium high hardness, slightly curved use medium hardness, large curved use ultra soft hardness, irregular products use custom ultra soft model. Also consider production volume, eco certification, color and other factors to select the most suitable model. Hongye Silicone provides four models including HY-901 economy (23A), HY-902 high wear (28A), HY-912 eco friendly general (25A) and HY-916 ultra soft (16A), covering all application scenarios from flat to large curved surfaces. Enterprises can select based on product characteristics, or contact technical support for professional selection advice.

Hongye Silicone Selection Technical Support