How to choose the surface treatment of aluminum parts and stainless steel parts when choosing sandblasting machine?

Guide for selection of sandblasting machine for aluminum and stainless steel parts

Core selection logic: aluminum soft low pressure light sandblasting, stainless steel hard medium high pressure iron pollution prevention; Small box, batch automatic, large open

First, distinguish the core differences of materials.

form

Material characteristics of workpiece: Taboo reference air pressure for sandblasting red line

Aluminum (aluminum alloy) HB60~100, soft and easy to sag, thin-walled and easy to deform, it is forbidden to use ordinary carbon steel sand/steel shot, and the high-pressure piercing deformation is 0.2 ~ 0.5 MPa.

Stainless steel (304/316) HRC 25 ~ 42, high hardness, avoid iron infiltration (iron ions will rust), and carbon steel abrasive and carbon steel shot blasting with 0.5 ~ 0.8 MPa can not be used.

Second, the selection of three types of sandblasting machines (suction/pressure delivery/full automatic)

1. Suction type (negative pressure siphon) → priority 【 small batch of aluminum parts and precision small stainless steel parts 】

Application: small pieces of hardware, aluminum shell, stainless steel precision fittings, proofing/small batch (daily output < 500 pieces)

Standard for aluminum parts: closed box suction sandblasting machine with pressure regulating valve (lower limit of 0.2MPa), cyclone sand recovery+pulse dust removal, abrasive: glass beads/ceramic sand/fine stainless steel balls (0.2~0.3mm).

Small stainless steel parts: the same model, abrasive: glass beads/white corundum, to prevent carbon steel sand from mixing with contaminated workpieces.

Advantages: low cost, soft sand production and fine pressure regulation; Disadvantages: low efficiency (2 ~ 3m2/h), not suitable for mass production.

2. Pressure-feeding type (pressure tank) → priority 【 stainless steel batch, rough descaling of aluminum parts, large parts 】

Application: stainless steel plate/pipe fittings, aluminum profiles are oxidized in large quantities, and welding spots are removed from welded parts.

Stainless steel press: pressure 0.5~0.7MPa, abrasive: brown corundum/stainless steel balls/glass beads; The internal guard plate and hopper of the equipment are lined with stainless steel, which is isolated from iron dust pollution, pulse dust removal and high-precision sand separation (recovery rate ≥92%).

Aluminum parts press-feeder: equipped with precision pressure reducing valve with locking upper limit of 0.5MPa, fine nozzle, spherical abrasive (ceramic sand/stainless steel shot 0.3~0.6mm), and 30 ~ 60 inclined sandblasting anti-dent aluminum materials.

Advantages: the efficiency is 2~3 times that of suction type, and the recycling rate of sand is high; Disadvantages: the purchase cost is high, and it needs to match the high-power air compressor.

3. Fully automatic sandblasting machine (rotary table/conveying through type) → mass production (aluminum die castings, stainless steel stamping parts)

Rotary table automatic machine: the disc rotates and feeds, which is suitable for small and medium-sized standard parts, aluminum low-voltage module and stainless steel medium-voltage module with double pressure regulating system, and one machine can be used for two products.

Pass-through conveyor: aluminum profiles and stainless steel strip plates pass through the machine continuously, and the pressure is regulated by sections: stainless steel in the feeding section is deoxidized by high pressure, and aluminum parts in the discharging section are matte treated by low pressure.

Third, the abrasive matching selection (key selection, wrong damaged parts/rust)

Special abrasive for aluminum parts (from fine to coarse treatment)

Mirror matte: glass beads (120~300 mesh), no indentation, and metal color preservation.

Roughening before painting: ceramic sand 0.3~0.5mm, fine stainless steel balls, Ra 1.6 ~ 6.3 μ m.

Heavy oxide scale: fine white corundum with 80~120 meshes, and strictly controlled air pressure < ＜0.5MPa.

Special abrasive for stainless steel (ordinary carbon steel shot is strictly prohibited)

Decorative matte: glass beads/stainless steel pills, 304 pills are not iron-infiltrated, no rust spots.

Welding slag/oxide scale: 80~120 mesh brown corundum, quickly cleaned under medium and high pressure.

Four, according to the output-workpiece size quick selection table

Sporadic proofing, small parts (≤ 50 mm): 600 box suction sandblasting machine, aluminum/stainless steel universal, can be switched by changing sand material.

The daily output is 500~5000 standard small parts: rotary table automatic sandblasting machine, double pressure system and one-button switching of aluminum/stainless steel parameters.

Profile/strip plate: roller pass-through automatic feeding machine, with sectional pressure regulation.

Large-scale special-shaped parts and racks (can't be put into the box): mobile open pressure blasting machine, temporary low pressure adjustment for aluminum parts and medium pressure adjustment for stainless steel.

V. Required configuration of auxiliary machines

Air compressor: aluminum parts ≥0.6MPa for gas storage, stainless steel ≥0.8MPa for gas storage, and freeze drying+oil-water separator (water vapor will cause aluminum blackening and stainless steel watermark rust).

Dust removal: dry standard pulse filter cartridge dust removal (environmental protection standard); Wet sandblasting machine is optional for precision aluminum parts (no water stains, no dust, and aluminum is not easy to oxidize).

Nozzle: ceramic nozzle for aluminum parts (soft), boron carbide nozzle for stainless steel (wear-resistant and high-pressure resistant)

Six, one machine gives consideration to aluminum+stainless steel to save money

Choose adjustable pressure box pressure blasting machine:

Double limit of pressure regulating valve: 0.2~0.5MPa for aluminum lock and 0.5~0.7MPa for stainless steel.

Two sets of abrasive bins: ceramic sand for aluminum and corundum for stainless steel are stored separately, and they are stored in different areas to prevent iron pollution from mixed sand.