Analysis And Solution Sharing of Common Problems of Automated Screen Printing Machines And Pad Printing Machines

In the fields of industrial marking, product decoration and functional printing, fully automatic screen printing machines and pad printing machines have become core equipment on the production line with their high efficiency, high precision and stability. However, even highly automated equipment will encounter various technical problems in long-term operation. This article will systematically sort out the common faults, possible causes and solutions of the two major types of equipment to help you keep your production line running smoothly.

Part One: Frequently Asked Questions about Automatic Screen Printing Machines

A screen printing machine (screen printing machine) uses scraper pressure to transfer ink to the substrate through the graphic part of the screen.

Problem 1: Inaccurate printing position (overprint deviation)

Performance: Multi-color overprinting is not aligned, or the printing pattern is inconsistent with the position of the product.

Possible reasons:

1. Clamp problem: The clamp is worn, loose or the positioning pin is deviated; product placement is inconsistent.

2. Screen problem: The screen tension is uneven or loose due to aging; the screen frame is loose.

3. Mechanical problems: machine guide rails and bearings are worn; servo motor/stepper motor accuracy is inaccurate; synchronous belt is loose.

4. Calibration problems: The machine origin is offset; the vision positioning system (if any) is inaccurately calibrated or the lens is dirty.

Solution:

1. First check and tighten the clamp to ensure that the placement of each product is absolutely consistent.

2. Check the tension and fixation of the screen plate, and re-make the plate if necessary.

3. Perform machine reset and origin calibration, and perform color registration calibration again.

4. Check the transmission components, lubricate or replace worn parts.

Problem 2: Poor ink adhesion or poor penetration

Performance: The ink is easy to fall off, blurred or unclear.

Possible reasons:

1. Problems with the substrate: There is oil, dust or release agent on the surface; the material does not match the ink (such as PP/PE that is not treated).

2. Ink problems: Wrong ink model; improper ratio of additives (oil, water, curing agent); over-drying or expired ink.

3. Printing process problems: Insufficient squeegee pressure; Screen mesh selection is too high (the ink cannot pass through) or too low (the ink bleeds); Insufficient curing (insufficient UV energy or insufficient baking temperature/time).

Solution:

1. Clean the surface of the substrate and perform flame, corona or primer treatment if necessary.

2. Prepare the ink strictly according to the technical information and stir thoroughly.

3. Adjust the scraper angle (usually 60-75°) and pressure to ensure clear scraping.

4. Check the UV lamp power and cooling system, or calibrate the drying tunnel temperature.

Part 2: Frequently Asked Questions about Automatic Pad Printing Machines

The pad printing machine dips and transfers the pattern on the gravure plate to the irregular surface through a silicone head.

Problem 1: The printed pattern is incomplete or blurry

Performance: The pattern is missing ink, edges are missing, or the overall pattern is blurry.

Possible reasons:

1. Problems with the rubber head: The shape, hardness or size of the rubber head is improperly selected; the surface of the rubber head is damaged (pits, cracks) or stained with oil.

2. Ink and steel plate: The etching depth of the steel plate is insufficient or blocked; the ink is too dry or too thin; the scraper is worn and cannot scrape off the remaining ink on the surface of the steel plate.

3. Action settings: Improper setting of rubber head descent depth, ink dipping time, printing speed and pressure.

Solution:

1. Select the appropriate rubber head according to the curved surface shape of the product, and clean or replace the rubber head with a new one.

2. Check and clean the steel plate to ensure the etching depth is appropriate (usually 2-3 wires for a single color).

3. Adjust the ink thickness and replace the sharp scraper blade.

4. Finely adjust the action parameters of each section of the rubber head and optimize the trial printing.

Problem 2: The pattern has bubbles or pinholes

Performance: Small blank spots appear in the printed pattern.

Possible reasons:

Ink problem: too much air is mixed in when the ink is stirred; the ink itself has poor defoaming performance.

The rubber head and steel plate: The angle of the rubber head dipping in ink and landing is not good, and air is trapped; there are impurities on the etched surface of the steel plate.

Environmental issues: The air humidity in the workshop is high and the ink absorbs water.

Solution:

1. Stir the ink and let it stand for defoaming, or add a trace amount of defoaming agent.

2. Adjust the angle at which the rubber head contacts the steel plate so that it 'rolls' and dips in ink to avoid vertical slaps.

3. Keep the steel plate and ink pan clean, and control the temperature and humidity of the workshop.