Screen Printing Scraper

Screen printing squeegee is an indispensable and important tool in the screen printing process. The following is a detailed introduction to it:

Definition and Function:
A screen printing scraper is a rubber or plastic blade with a handle, used to press ink onto the substrate through a screen. Its main functions include:
Transfer the ink to the substrate through the screen.
Scrape off the excess ink on the screen.
Keep the wire mesh in contact with the substrate.
It can print on substrates of different shapes.

Material:
Polyurethane: Polyurethane scrapers have excellent elasticity and wear resistance and are one of the most commonly used materials. Its hardness range is from 55 degrees to 90 degrees.
Nylon: Nylon scrapers are relatively soft and suitable for printing fine patterns.
Metal: Metal scrapers have high hardness and are suitable for large-area printing.
Composite materials: Some new types of composite material scrapers are also gradually being applied, which combine the advantages of multiple materials.

Hardness:
Low-hardness scraper (55A-65A) : Suitable for printing fine patterns, it can better adapt to substrates of different shapes.
Medium hardness scraper (66A-75A) : Suitable for general printing requirements.
High-hardness squeegee (75A and above) : Suitable for large-area printing, it can better push the ink into the screen and transfer it to the substrate.

Shape and size:
Shape: The shapes of the scraper include flat edges and pointed edges, etc. The flat-mouthed scraper is suitable for uniform application over large areas, while the pointed-mouthed scraper is ideal for fine handling of detailed parts.
Size: The size of the scraper should be selected based on the printing area and the shape of the substrate. Large-sized scrapers can better remove excess ink, but they may not meet the requirements of various shaped substrates.

Usage skills:
Angle: It is very important to keep the Angle of the scraper correct. Generally, the recommended Angle range is between 45° and 60°.
Pressure: The applied pressure should be moderate. Excessive pressure can cause ink accumulation, affecting the printing effect. Insufficient pressure may result in the ink not being transferred completely.
Speed: Moving the scraper at a constant speed can ensure that the ink is evenly distributed and avoid the formation of streaks or other flaws.

Maintenance and upkeep:
Cleaning: The scraper should be cleaned immediately after each use to prevent the ink from drying up and causing damage to the scraper.
Inspection: Regularly check if there is any wear on the edge of the scraper and replace it in time to maintain the best printing condition.

Selection suggestions:
Select the material and hardness based on the printing requirements: If high-precision printing effects are needed, polyurethane or metal squeegee with higher hardness should be chosen. For the printing of fine patterns, nylon or soft polyurethane squeegee can be chosen.
Consider the shape and material of the substrate: For substrates of different shapes and materials, it is necessary to select the appropriate hardness and shape of the scraper to ensure the printing effect.
When choosing a squeegee, it is also necessary to take into account both printing efficiency and cost comprehensively. For instance, metal scrapers are durable but relatively expensive, while polyurethane scrapers are more economical and practical.