The secret of 'fully automatic' screen printing machine revealed

Okay, the printing working principle of a fully automatic screen printing machine (fully automatic screen printing machine) can be broken down into two parts: core principles and automated workflow.

1. Core printing principle: using 'template' for selective penetration

The core principle of screen printing has not changed since ancient times. It can be summarized as follows: through a screen with a hollow pattern, the ink can only penetrate into the substrate from the transparent part of the screen under the squeeze of the scraper, thereby forming a pattern.

This process mainly relies on the following key components:

1. Silk screen version:

This is the 'template' for printing. It is made by stretching a layer of extremely fine mesh (silk in the past, now mostly nylon, polyester or stainless steel mesh) on a metal or wooden mesh frame.

Through the photosensitive platemaking process on the screen, the mesh in the non-graphic and text parts (areas that do not need to be printed) is blocked by photosensitive glue, while the mesh in the graphic and text parts remains transparent.

2. Ink:

There are many types of screen printing inks that can be adapted to various materials such as plastics, metals, glass, textiles, and circuit boards.

3. Scraper:

It is usually a rectangular rubber strip installed on the scraper base. It has two functions:

Filling and Smoothing: It fills the graphic holes of the screen with ink before moving.

Transfer: When moving, the screen is pressed against the substrate by applying downward pressure, and like a shovel, the ink is squeezed through the transparent mesh onto the surface of the substrate.

4. Ink return knife:

Usually a piece of metal or plastic. Its function is to evenly scrape the ink back to the starting position after the scraper completes a printing stroke to prepare for the next printing, while ensuring that the graphic and text parts of the screen are filled with ink again.

Simply put, the core principle is like using a piece of cardboard with holes to spray paint on the wall. Only the holes will be stained with paint. The silk screen printing machine makes this action highly precise and automated.

2. Complete workflow of fully automatic screen printing machine

'Fully automatic' means that the entire process from feeding, positioning, printing to receiving does not require manual intervention and is completed automatically by the machine. A typical work cycle is as follows:

Step 1: Feeding and positioning

Feeding: The automatic feeding mechanism (such as manipulator, conveyor belt, vibrating plate, etc.) accurately transports the substrate to be printed (such as plastic parts, glass sheets, circuit boards, etc.) to the designated position on the printing platform.

Positioning: The platform is usually equipped with precision positioning devices (such as clamps, positioning pins) to ensure that each product is in the exact same position. Some machines will also use a visual positioning system to identify the product position through cameras and make fine adjustments to ensure absolutely accurate alignment.

Step 2: Screen drop

The screen assembly (including screen, scraper and return knife) fixed above the machine is driven by a cylinder or servo motor to vertically drop to a preset height that maintains a small gap (screen distance) with the substrate.

Step 3: Scratching and ink return (a reciprocating motion)

Stage 1 - Scratching: The scraper is lowered and a preset pressure is applied. The scraper then moves from one end of the screen to the other. During the movement, it squeezes the ink through the transparent graphic mesh on the screen, and the ink is transferred to the substrate below.

Second stage - ink return: After the scraping is completed, the scraper is lifted and returned to the starting position. At the same time, the ink return knife descends, and in the process of returning, the ink is evenly spread on the screen, covering the graphic area and preparing for the next printing.

Step 4: Screen rising and demoulding

After printing is completed, the entire screen assembly is lifted upwards. Due to the certain viscosity of the ink and the slight tension between the screen and the substrate (thanks to the preset mesh distance), the screen will 'peel' off the substrate, leaving a clear and smooth ink layer. This process is called 'demoulding' and is critical to print quality.

Step 5: Receiving and curing

Material collection: The printing platform lowers or the conveyor belt starts to remove the printed products. An automatic receiving mechanism (such as a robot or another conveyor belt) takes away the product and simultaneously feeds in the next product to be printed.

Curing: The removed product is usually immediately sent to an online curing unit, such as an ultraviolet curing tunnel oven or a hot air drying oven, so that the ink can quickly dry and solidify within seconds to minutes, completing the entire printing process.

Summary and features

The working principle of the fully automatic screen printing machine can be summarized as:

Precise cyclic feeding is achieved through an automated mechanism → precise alignment of the screen and substrate → the scraper squeezes the ink through the graphic holes of the screen to complete the transfer → screen peeling → product collection and instant curing.

Main advantages:

High efficiency: The cycle speed is extremely fast and thousands of products can be produced per hour.

High consistency: Automation eliminates the human factor and ensures identical print quality for every product.

Strong adaptability: can print on flat, curved and irregular surfaces.

Thick ink layer: The printed patterns are bright in color, strong in hiding power and good in durability (such as road signs and home appliance panels).

Because of these characteristics, fully automatic screen printing machines are widely used in high-volume, high-quality industrial printing fields such as electronic products (such as circuit boards, keyboards, panels), glass bottles, plastic containers, textiles, and automobile dashboards.