How to choose the sand material of the automatic sandblasting machine for burr treatment?

Guide for sand material selection of automatic sandblasting machine for burr treatment

First, the selection of core judgment basis

Hardness of workpiece material; 2. The size of burr removal and processing efficiency; 3. Requirements for surface roughness of workpiece; 4. Whether the workpiece is allowed to be scratched or deformed; 5. Subsequent processes of workpiece (electroplating, anode, spraying and assembly); 6. Cycle life and cost of equipment.

Second, the commonly used sand classification, applicable scenes (for deburring)

1. Plastic sand (nylon sand/resin sand)-the first choice for soft deburring.

Low hardness, no damage to the substrate, no scratch, suitable for precision plastics, injection molded parts, die-casting aluminum parts, connector 3C electronic burrs, injection molding line.

Advantages: only flash burr is removed, without changing the original luster and size of the workpiece, and it can be recycled.

Disadvantages: low hardness and slow removal speed of thick and hard burrs; High temperature workpieces cannot be used.

2. Glass beads (glass sand)-slight burrs+matte beautification

Soft impact force, used for slight burr and scale removal of stainless steel and aluminum parts, and at the same time for matte wire drawing effect.

Application: Small burrs of metal stamping parts, aluminum alloy shells and decorative parts do not produce deep scratches.

Not applicable: thick and hard burr, extremely low removal efficiency.

3. Brown corundum (alumina sand)-the mainstream of general metal deburring.

Moderate to high hardness, strong cutting power, high cost performance, common for carbon steel, cast iron, stainless steel and zinc alloy.

Application: Quick removal of thick flash and burr of die-casting aluminum, stamping hardware and machined parts.

Disadvantages: it will form a uniform coarse texture on the surface of the workpiece, which is not recommended if the workpiece needs a high-gloss appearance.

4. White corundum (high-purity alumina)-precision metal finishing deburring.

High purity, less micropowder, clean burr removal and better surface roughness than brown corundum.

Application: precision molds, aviation aluminum parts, stainless steel precision parts, anode pretreatment deburring.

Advantages: less impurities, not easy to produce blackening and pollution of the workpiece, suitable for high-end products.

5. Stainless steel shot/stainless steel sand-high-strength, thick burr and large stamping flash.

Metal sand, with strong impact, is suitable for thick iron plate, cast steel, heavy burr and oxide layer of large hardware.

Caution: Use soft aluminum and magnesium parts with caution, which may easily cause deformation and deep dents.

6. Silicon carbide (green silicon carbide/black silicon carbide)-deburring of superhard materials.

The hardness is the highest, and it is specially used for fine burrs of cemented carbide, ceramics, graphite and hardened steel.

The cost is on the high side, and generally only precision hard workpieces are selected.

Three, according to the industry workpiece rapid selection scheme

3C Electronic, plastic injection molded parts and connectors: nylon plastic sand (not damaging the plastic, only cleaning the burrs of the mold).

Aluminum alloy die casting, mobile phone middle frame and aluminum shell: white corundum/fine glass beads (deburring and even matte surface)

Ordinary hardware, stamping iron parts, zinc alloy: brown corundum (high efficiency and low cost to remove thick flash)

Stainless steel precision parts and medical device accessories: white corundum fine sand with fine surface and no blackening.

Cemented carbide, ceramics and graphite parts: silicon carbide.

Heavy burr of large cast steel and thick iron plate: stainless steel shot.

Four, sand particle size selection rules

The larger the particle size number, the finer the sand particles; The smaller the number, the coarser the sand.

Coarse burr and thick flash: coarse sand (16 #–60 #) with large cutting force and high efficiency;

Fine and precise burr, appearance: fine sand (80 #–200 #) with fine surface;

Ultra-thin and deformable workpiece: give priority to fine soft sand to reduce impact deformation.

Five, the use of key points for attention

Do not mix two kinds of sand with different materials, which will cause confusion of surface effect and decrease of cleaning efficiency;

Long-term circulation of sand will break into fine powder, and the dust will increase and the deburring ability will decrease, so it needs to be screened and replaced regularly;

Processing oxidizable metals such as aluminum and magnesium to avoid the accumulation of a large amount of metal sand and prevent the risk of spontaneous combustion of dust;

Follow-up electroplating/anodizing of the workpiece: white corundum and glass beads are preferred to reduce embedded impurities on the surface of the workpiece;

Corundum and stainless steel sand are strictly prohibited for soft workpieces (plastic and thin aluminum sheets), which are easy to puncture and scratch.