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Texturing, through chemical penetration, creates various patterns on metal surfaces, such as stripes, images, wood grain, leather grain, silk, HANDS, HN3D, and more. This process includes sandblasting, which directly sprays glass sand onto the metal surface.

In general, it encompasses: various plastic mold textures (leather, wood, fabric, 3D), patterns on the exterior of electronic devices (TVs, computers, phones, automobiles, motorcycles, air conditioners, refrigerators), roller textures, shoe soles patterns, stainless steel, die-casting mold etching, embossed logos, patterns, and sandblasting.

The shallowest etching depth is 2?m, commonly used on acrylic display windows to prevent glare. The deepest etching is 3mm, imitating marble, often used on bathroom tiles. Precision plastic mold texturing, also known as mold etching, is widely used due to its low cost, rich effects, and fast processing.

What is Precision Plastic Mold Texturing?

Precision plastic mold texturing is a surface treatment process for molds, also known as mold etching or mold engraving.

Principle of Precision Plastic Mold Texturing

It involves using chemical solutions (like hydrochloric acid, and sodium cyanide) to react with the mold’s steel surface, controlling the reaction to achieve various effects.

Development of Etching

As more plastic products fill our lives, people started preferring them not to look like “plastic.” Therefore, etching techniques for mold decoration became popular.

Initial Stage: Masking molding defects with rough textures.

Mid Stage: Diverse textures, extensive use of single-layer leather, and wood grain textures.

Current Stage: Application of 3D geometric textures. With the progress of time, product ID has become an essential part, demanding higher quality. Laser technology with 0.01mm precision is widely applied in texture fields, making patterns more refined and realistic, enhancing product perfection.

Purpose of Mold Texturing

1. Enhances the aesthetic quality of plastic parts, giving them varied or new designs.

2. Improves product appearance by covering defects like sink marks and weld lines.

3. Increases surface hardness after mold texturing and sandblasting, preventing scratches.

4. Provides anti-slip and good tactile feel, creates matte surfaces to prevent glare, and reduces eye fatigue.

Selection of Materials for Textured Molds

Typically, materials like NAK80, SKD61, 8407, and S136 are chosen.

NAK80 (36-38 degrees): Good etching effect, easily etched in one attempt but prone to rust and wear, generally lasts 30,000 molds.

SKD61 (48-50 degrees): Longer etching lifespan, can be etched in two attempts, commonly lasts 100,000 molds.

8407 or S136 (50-52 degrees): Good etching effect, high mold hardness, 2 times successful etching, generally lasts 200,000 molds.

Types of Mold Texturing

Texturing includes many types: stone, sand, leather, wood, fabric, 3D textures, patterns for electronic device housings, shoe sole textures, stainless steel, die-casting mold etching, embossed logos, and sandblasting.

The most common textures in mold industries are stone and sand textures, especially sandblasting, often used on tool equipment.

Stone Texture

Sand Texture

Mold Texturing Process

Currently, there are two types of texturing: chemical texturing and laser texturing.

Chemical Texturing Process:

Degreasing and Cleaning → Masking → Chemical Inspection → Surface Treatment → Printing Treatment → Repair Treatment → Chemical Etching → Surface Treatment → QC → Rust Prevention → Packaging

1. Degreasing and Cleaning the Mold

Method and Effect:

Use a special mold cleaner to remove oil and impurities from the mold surface.

Common Defects:

• Oil residue on the surface, which can prevent uniform chemical etching.
• Difficulty in adhering protective tape to the mold.

Mirror Surface Protection:

After cleaning, immediately protect surfaces with special requirements. Generally, after cleaning, spray a layer of black paint on mirror surfaces to protect against rust and scratches.

2. Masking the Mold

Method and Effect:

Use special tape to mask areas that do not require etching, typically applying at least three layers. After masking, seal the boundary of the textured area with wax and clean the textured surface again.

Common Defects:

• Uneven boundary lines between the textured and non-textured areas.
• Poor adhesion, leading to over-etching.

Mold Optimization:

When the boundary between the textured and non-textured areas is a radius, keep the radius as small as possible, generally not exceeding R0.5mm.

3. Chemical Inspection

Method and Effect:

Soak the masked mold in a chemical solution for a few seconds. The unmasked surfaces will be chemically corroded by 0.01~0.02mm and appear black.

Common Defects:

• Inconsistent material or hardness.
• Sand holes.
• Welding marks.

These defects will show different depths and colors.

Solutions:

• If the material or hardness differences are small, separate the etching and adjust the etching time.
• For small sand holes, fill them with wax before etching.
• If the difference in hardness is significant after welding, locally heat the welded area before etching.

Mold Optimization:

• Mark welding positions on the mold.
• Ensure the hardness difference between mold parts is less than HRC5.

4. Surface Treatment – Sand Washing

Method and Effect:

Use a spray gun to evenly spray sand particles on the corroded mold surface to remove the black oxide layer. After sand washing, the mold surface appears silvery white.

Common Defects:

Uneven sandblasting and incomplete cleaning lead to uneven etching.

5. Printing Treatment

A. Printing Patterns

Principle:

Use film to etch standard pattern plates (zinc), then evenly apply wax on the pattern plate. Use a press to transfer the pattern onto a special film to make wax paper. Apply the wax paper to the sand-washed mold surface to transfer the pattern onto the mold.

Applicable Scope:

Generally used for irregular pattern contours with no special requirements, such as leather patterns for automotive interiors.

B. Film

Method:

Make a film according to the pattern drawings, then attach the film to the mold as required, controlling the position of the film on the mold.

Applicable Scope:

Patterns with regular, clear contours (e.g., 3D textures).

C. Spray Pattern

Method:

Mix ink according to the pattern requirements (mainly adjusting the size of ink particles) and use a spray gun to evenly spray it on the mold surface requiring etching. Usually, test spray on white paper first.

Applicable Scope:

Patterns with no contour requirements (e.g., MT11010, MT11030).

6. Chemical Etching

Method:

• Soak the patterned, sprayed, or filmed mold in a prepared chemical solution.
• Corrode the bright parts of the mold. The etching depth mainly depends on the soaking time. The mold surface will appear black after etching. This process is similar to chemical inspection, with different chemical agents and soaking times.

7. Sandblasting

Method:

Use a spray gun to evenly spray sand particles on the corroded mold surface to remove the black oxide layer. After sandwashing, the mold surface appears silvery white.

Principle:

The sandblasting process is similar to sand washing but with different sand particle sizes. Under high-pressure air, the sand particles create small pits on the mold surface. The texture created by sandblasting does not last long.

Laser Texturing Process

1. Degreasing and Cleaning

2. Drawing

3. Sampling

4. Laser Processing

5. Gloss Treatment

6. QC

7. Rust Prevention

8. Packaging

Laser etching achieves various effects by using laser beams on the mold’s metal surface.

Below is a comparison of the advantages and disadvantages between chemical texturing and laser texturing.

Here’s the translated and formatted table in English:

Advantage Comparison	Chemical Texturing	Laser Texturing	Notes
Environmental Requirements	Uses chemical solutions, not eco-friendly	Does not use chemical solutions, eco-friendly	None
Precision and Stability	Poor precision, poor stability 1. Causes side etching and jagged edges 2. Cannot achieve repeatable and consistent processing	High precision, good stability 1. No side etching or jagged edges 2. Can achieve repeatable and consistent processing	None
Surface Quality	Rough, can only process 3~5 layers	Fine, can process 30~50 layers with a strong three-dimensional effect	None
Material Requirements	High requirements for mold materials	With low requirements for materials	Lasers can process various metals
Texture Adherence on Surface	Difficult to achieve on complex curves	It can be applied to curves, slopes, and spherical surfaces	None
Processing Range	Limited range	Limited by equipment processing range	None
Production Process	Long process route, large area required	Short process route, small area required	None
Other	None	Direct marking, extends mold life after laser surface treatment	None

Common Issues and Solutions in Texturing

Issues:

Rough cavity surfaces post-etching can cause mold sticking or adhesion, especially in areas with small draft angles, leading to ejection issues.

Solutions:

Polish the etched surface, reduce etching depth, and eliminate sharp angles to facilitate demolding. Apply mold release agents during production, and increase draft angles and ejector pins in problematic areas.

Requirements for Product Design with Texturing

• Greater texturing depth or height requires larger draft angles (typically 5-8 degrees).
• For areas with gloss, design artistic lines or embossed steps to prevent jagged edges at texture junctions.
• The shallowest etching depth is 2?m, the deepest is 3mm, based on visual and tactile requirements.
• The effect of texturing closely relates to mold material, which should be selected based on material choice.
• The texturing process cycle varies: simple spark textures take 1.5-2 days, horizontal/vertical/circular textures take 3-4 days, and complex patterns like diamond textures and deep textures take at least 5 days.

Showcasing Textured Injection Mold Products

Finally, we display some injection-molded products to illustrate the potential of texturing processes in creating unique products.