How to choose an appropriate automatic sandblasting machine for surface treatment of electronic product shell?

Guide for selection of automatic sandblasting machine for electronic product shell

(Applicable: plastic, aluminum alloy and magnesium alloy housings such as mobile phones/tablets/notebooks/headphones/smart wear)

First, look at the material first, and directly set the model.

Aluminum alloy/magnesium alloy shell (most common)

Requirements: remove the knife marks, matte, sand blasting evenly, no sand marks, and no hole plugging.

Recommended: rotary automatic sandblasting machine/translational reciprocating automatic sandblasting machine.

Abrasive: glass beads, ceramic sand, stainless steel balls.

Plastic casing such as PC/ABS.

Requirements: matte effect, no damage to the substrate, no indentation and no whitening.

Recommended: low-pressure automatic sandblasting machine and wet sandblasting machine.

Abrasive: resin sand, fine glass beads.

Stainless steel middle frame/small piece

Requirements: Pretreatment, derusting and even matte before drawing.

Recommended: crawler or translational automatic sandblasting machine.

Second, choose the structure according to the output (determine the efficiency)

1. Small batch, multi-model, quick model change.

Model: multi-station turntable automatic sandblasting machine (8/12/16 station)

Advantages: small floor space, uniform sandblasting, and suitable for special-shaped surfaces.

Suitable for: small and medium-sized electronics factories, mold factories, proofing and mass production.

2. Mass, standardized shell

Model: pass-through/translation reciprocating automatic sandblasting machine (assembly line)

Advantages: continuous production, high efficiency and less labor.

Suitable for: large-scale foundry with a monthly output of hundreds of thousands of pieces.

3. Precision appearance parts and high dust-free requirements.

Model: wet automatic sandblasting machine (water-sand mixing)

Advantages: almost no dust, fine surface and no dust pollution.

Suitable for: high-end mobile phone case and wearable device case.

Third, how to choose the key configuration (determine the appearance effect)

1. Number and layout of spray guns

Flat shell: 4-8 guns are sprayed up and down.

Curved surface/3D shell: multi-angle spray gun+rotary fixture

Key points: the spray gun can be numerically controlled to adjust the angle and distance, so as to ensure that there is no dead angle and no negative and positive surface.

2. Sandblasting pressure control (electronic shell is the most important)

Aluminum alloy: 0.3–0.6 MPa low pressure.

Plastics: 0.2–0.4 MPa ultra-low pressure.

Must be selected: variable frequency voltage regulation and pressure stabilization system, sand marks and bright spots will appear when the pressure fluctuates.

3. Abrasive automatic circulation system

Configuration: cyclone separator+dust removal box+screening machine

Function: automatically separate broken sand and dust, ensure uniform sand material and avoid surface pitting and scratches.

4. Dust removal and environmental protection

Required for electronics factory: pulse bag dust removal+filter element secondary dust removal.

There are dust-free requirements in the workshop: choose closed+negative pressure dust removal to prevent dust diffusion.

Four, precision and appearance control points

Repetitive consistency

Fixture positioning accuracy is 0.1 mm.

Servo motor is used to move the spray gun to avoid manual adjustment difference.

Avoid common defects

Sand marks/pits: the sand is too coarse, the pressure is too high, and the spray gun shakes.

Local overspray/overspray: incorrect angle and insufficient stroke.

Hole plugging/burr: the distance of the spray gun is too close and the fixture is not covered.

Surface roughness control

Before anodizing: Ra 1.0-2.0

Before spraying/baking: Ra 1.6-3.2

Direct matte appearance: Ra 0.8-1.6

Five, the simplest selection comparison table

form

Product Type Recommended Abrasive Pressure

Glass bead/ceramic sand 0.3–0.5 MPa of automatic sand blasting machine for middle frame/back cover of mobile phone.

0.4–0.6 MPa of translational ceramic sand for notebook shell.

TWS earphone shell small turntable fine glass beads 0.2–0.4 MPa

Low-pressure fine adjustment of ultra-fine resin sand by high-end precision appearance wet automatic sandblasting machine

Sixth, buy a pit.

Don't choose a simple open sandblasting machine to save money, because the appearance consistency of the electronic shell is poor.

The spray gun must be adjustable by numerical control, not only by manual adjustment.

It must be automatically sorted with abrasive, and the broken sand will directly discard the appearance parts.

Electronic factories give priority to the closed low-dust type, otherwise the dust in the workshop will be difficult to manage.

Seven, a word summary

Preferred selection of electronic product shell: small batch and multiple models → standardization of rotary automatic sandblasting machine in large batch → high-end precision appearance of pass-through assembly line sandblasting machine → core of wet low-pressure sandblasting machine: pressure stability, numerical control of spray gun, abrasive separation and dust removal in place.