What is Wet No.4 & HL Brushing Machine Line?

A Wet No.4 & HL Brushing Machine Line is a stainless steel surface finishing line that uses grinding liquid, coolant or water-based medium during abrasive brushing. It produces No.4 fine satin finish and HL long Hairline finish with better cooling and cleaner surface quality compared with dry processing.

The line usually includes feeding, wet grinding/brushing, liquid filtration and recycling, cleaning, drying, optional protective film laminating and output/recoiling sections.

Product Overview

The LEBON Wet No.4 & HL Brushing Machine Line is designed for high-quality wet grinding and brushing of stainless steel sheets, plates and coils. It uses abrasive belts or brushing rollers together with grinding liquid or coolant to produce uniform No.4 satin brushed finish and HL / Hairline finish.

Compared with dry processing, the wet brushing system provides better cooling, lower dust, smoother surface texture and reduced risk of burning marks or surface discoloration. The line can be equipped with feeding, wet grinding and brushing units, grinding liquid filtration and recycling system, cleaning, drying and optional protective film laminating sections.

With stable material feeding, adjustable brushing pressure, variable line speed and accurate belt tracking, the machine helps achieve straight grain direction, consistent surface quality and efficient production. It is widely used for decorative stainless steel sheets, elevator panels, home appliance panels, kitchen equipment, architectural wall panels and high-end interior metal surface finishing applications.

Key Features

• Produces both No.4 satin brushed finish and HL / Hairline finish

• Wet brushing design with grinding liquid or coolant for better surface quality

• Suitable for stainless steel sheets, plates and coils

• High-speed abrasive belt or brushing roller system for efficient surface finishing

• Adjustable brushing pressure for different material thicknesses and finish requirements

• Variable feeding speed to control No.4 and HL surface texture

• Stable belt tracking system to prevent belt deviation marks and uneven grain lines

• Multiple abrasive grit options for No.4 fine brushing and HL Hairline finishing

• Grinding liquid supply system helps reduce heat, dust and surface burning marks

• Filtration and recycling system reduces grinding liquid waste and operating cost

• Cleaning and drying unit removes oil, residue, dust and water marks after brushing

• Stable feeding system ensures straight grain direction and consistent surface finish

• Optional protective film laminating system after surface finishing

• PLC and inverter control system for easy operation and stable speed adjustment

• Customizable working width, thickness range, brushing units and production layout

• Ideal for decorative stainless steel, elevator panels, appliance panels, kitchen equipment and architectural metal applications

Working Process

1. Material Feeding

The stainless steel sheet, plate or coil is fed into the brushing line through the conveyor system. Stable feeding keeps the material flat and ensures straight grain direction during processing.

2. Surface Pre-Grinding

High-speed abrasive belts lightly grind the stainless steel surface to remove minor scratches, oxide marks and surface defects. This prepares the material for No.4 or HL finishing.

3. Wet No.4 Brushing

For No.4 finish, abrasive belts create a fine and uniform satin brushed texture. Grinding liquid or coolant is supplied during brushing to reduce heat, control dust and improve surface smoothness.

4. Wet HL / Hairline Finishing

For HL finish, the machine creates long, straight and continuous Hairline lines. The final line effect is controlled by abrasive grit, brushing pressure, belt tracking accuracy and feeding speed.

5. Grinding Liquid Filtration and Recycling

Used grinding liquid is collected, filtered and recycled for reuse. This helps reduce waste, lower operating cost and maintain stable brushing performance.

6. Surface Cleaning

After wet brushing, the stainless steel surface is cleaned to remove grinding liquid, oil, dust, abrasive residue and metal particles.

7. Drying Section

The cleaned surface passes through the drying unit to remove moisture and prevent water marks on the finished No.4 or HL surface.

8. Protective Film Laminating

If required, a protective film is applied to the finished surface to prevent scratches during handling, cutting, transportation and further processing.

9. Finished Surface Output

The final stainless steel surface has a uniform No.4 satin finish or long straight HL Hairline finish, suitable for decorative panels, elevator interiors, appliance panels and architectural applications.

Applications

• Stainless steel decorative sheets

• Elevator panels and cabin interiors

• Home appliance panels

• Kitchen equipment panels

• Architectural wall and ceiling panels

• Stainless steel doors and frames

• Interior decoration materials

• Hotel and commercial decoration panels

• Furniture and display fixture panels

• Appliance shell and cover panels

• Escalator side panels

• Commercial kitchen and restaurant equipment

• Signage and advertising boards

• Metal cabinets, worktops and countertops

• Pre-treatment before coating, laminating or further processing

• High-quality No.4 satin and HL Hairline stainless steel surface finishing

Quality Controll

Surface Uniformity Check

The finished surface should have a uniform No.4 satin or HL Hairline texture across the full sheet or coil width. There should be no obvious dark/light difference, patchy areas or uneven brushing marks.

Grain Direction Check

The brushing lines should be straight, continuous and consistent along the processing direction. For HL finish, the line texture should be long and fine; for No.4 finish, the texture should be even and satin-like.

Surface Defect Inspection

The finished material should be free from deep scratches, belt deviation marks, vibration marks, roller marks, burning marks, oil stains, water marks and visible surface defects.

Roughness Control

Surface roughness can be controlled by abrasive grit, brushing pressure, belt speed and feeding speed. Typical reference values:

• No.4 finish: around Ra 0.4–0.8 μm

• HL finish: around Ra 0.2–0.6 μm
  Actual values can be adjusted according to customer sample and application requirements.

Abrasive Belt Control

The abrasive belt should be checked regularly for wear, damage, clogging or uneven cutting. Worn belts may cause unstable grain, scratches or poor surface consistency.

Wet System Control

Grinding liquid or coolant should be supplied evenly during brushing. Liquid concentration, flow rate and filtration condition should be checked to prevent overheating, burning marks and surface contamination.

Cleaning and Drying Check

After wet brushing, the surface must be fully cleaned and dried. The finished material should have no grinding residue, coolant marks, water stains or remaining metal particles.

Film Laminating Check

If protective film is applied, the film should be flat and firmly attached. There should be no bubbles, wrinkles, dust particles or scratches under the film.

Dimension and Feeding Check

Material thickness, width and flatness should be checked before production. Stable feeding and tension control help avoid sheet deviation, vibration lines and uneven brushing texture.

Final Sample Approval

Before mass production, one sample should be tested and approved by the customer or quality team. After approval, the same belt grit, pressure, speed and wet-system settings should be maintained for stable production quality.