Sand Blasting – Precise and Flexible

Sand blasting uses compressed air as the main power to spray irregular abrasives at high speed onto the workpiece surface. Its core positioning is cleaning + precise roughening, with additional deburring functions. It is a critical pretreatment process for subsequent spraying and electroplating.

The power can be flexibly adjusted: the air pressure for pressure-feed sand blasting is 0.5–0.7 MPa, and for suction-feed blasting is 0.3–0.5 MPa. High-pressure water-assisted blasting (wet blasting) can be used in some scenarios. Media include sharp-edged irregular abrasives such as quartz sand, brown fused alumina, and eco-friendly walnut shells. Particle size is selected based on surface roughness requirements; G120–G80 grit is recommended for Sa2.5 rust removal grade.

Its main purpose is to thoroughly remove oil, old coatings, and rust from the workpiece surface, precisely control surface roughness, and improve the adhesion of subsequent coatings. It can also be used for art engraving and matte treatment of electronic products.

It is suitable for small-batch, multi-variety, and complex-shaped precision workpieces, such as molds, thin-walled aluminum parts, and local rust removal on ship sections. It is more friendly to soft metals and thin sheets to avoid deformation, and complies with the GB/T 8923.1 rust removal grade standard.

Shot Peening – Precise and Focused

Similar to sand blasting in power form, shot peening uses compressed air or small centrifugal force to spray round shots at high speed onto the workpiece surface. It focuses primarily on surface strengthening and is suitable for local treatment of complex areas.

The power is flexibly adjustable, allowing precise control of the spray angle and velocity of shots, making it suitable for complex inner cavities and corners that cannot be covered by shot blasting. The media, consistent with those used in shot blasting, are round shots with a diameter of 0.1–2.0 mm. They have smooth surfaces, do not excessively scratch the workpiece, and are recyclable.

Its main function is to increase surface hardness, fatigue strength, and wear resistance through work hardening, while also providing stress correction and deburring. Its cleaning effect is weaker than sand blasting.

Applicable scenarios include local strengthening of key load-bearing components such as automotive gears, aviation parts, and bearings. Note that workpieces with surface oil must be degreased in advance to avoid contaminating shots and affecting results.

Shot Blasting – Batch and Efficient

Shot blasting uses mechanical centrifugal force as the core power. A high-speed rotating impeller (blast wheel) hurls round shots at high speed onto the workpiece surface. It focuses on high-efficiency batch cleaning + surface strengthening, features a high degree of automation, and is the preferred choice for large-scale production.

In terms of power, the impeller speed can reach 1500–3000 r/min, and the initial shot velocity is up to 100 m/s. It does not rely on an air compressor and offers a higher energy efficiency ratio than the other two processes in long-term use, with efficiency more than 30% higher than manual sand blasting. Media are round, edge-free shots, commonly cast steel shots or stainless steel shots, with a diameter of 0.8–2.5 mm. They can be recycled hundreds of times, with only regular replenishment required (replenishment ≤ 10% of total volume).

Its main function is to batch remove oxide scale, molding sand, and rust from castings and forgings, while increasing surface hardness and fatigue resistance through work hardening and relieving internal stress.

Applicable scenarios are mainly large quantities of regular workpieces, such as steel plates, wind turbine towers, and automotive chassis parts. It can be combined with automated conveyor lines for continuous production, complying with JB/T 8355 equipment standards and GB/T 8923.1 rust removal grade standard.

1. Power Source Differences

• Sand Blasting: Mainly powered by compressed air, with adjustable air pressure to suit different precision requirements.
• Shot Peening: Similar power to sand blasting; uses compressed air or small centrifugal force for precise control.
• Shot Blasting: Relies on centrifugal force from the impeller (mechanical power), no air compressor needed, with more stable and powerful power.

2. Core Purpose Differences

• Sand Blasting: Core functions are surface cleaning and precise roughening as pretreatment for spraying and electroplating, with deburring.
• Shot Peening: Core function is local surface strengthening to improve hardness and fatigue resistance; cleaning effect is relatively weak.
• Shot Blasting: Core functions are batch removal of rust and oxide scale, plus overall surface strengthening, emphasizing high efficiency.

3. Media Characteristics Differences

• Sand Blasting: Uses irregular, sharp-edged abrasives (quartz sand, brown fused alumina, etc.), non-recyclable.
• Shot Peening: Uses round shots with smooth surfaces that do not scratch workpieces excessively; recyclable.
• Shot Blasting: Same round media as shot peening (cast steel shots, stainless steel shots, etc.), with high recycling efficiency.

4. Applicable Scenario Differences

• Sand Blasting: Suitable for small-batch, multi-variety, complex precision workpieces (molds, thin-walled aluminum parts).
• Shot Peening: Suitable for complex inner cavities and corners unreachable by shot blasting, mostly for key load-bearing parts (automotive gears).
• Shot Blasting: Suitable for large-scale production of regular workpieces (steel plates, wind turbine towers), compatible with automated production lines.

5. Environmental and Cost Differences

• Sand Blasting: Generates large amounts of dust; non-recyclable abrasives lead to relatively high long-term cost.
• Shot Peening: Moderate dust generation; recyclable shots, cost between sand blasting and shot blasting.
• Shot Blasting: Fully enclosed equipment with low dust; high media recycling rate, lowest long-term cost.