What is shot blasting machine?

Shot blasting machine is a processing technology that steel balls are blasted in a high speed and impacted on surfaces of objects in a high speed. Compared with other processing technologies, the shot blasting machine is more rapid and efficient and can partially keep the casting process after being stamped.

Shot blasting machine can also be used for removing burrs, membranes and rust, which may partially affect the integrity, appearance or definition of objects. The shot blasting machine can remove dirt on the surfaces for a part of paint coating and provide a surface profile used for adding coating adhesion to achieve a purpose of strengthening the workpieces.

Application range:

1.Surface cleaning

The shot blasting machine is firstly applied for cast steel, surface sand burning of iron castings and removal of oxide skins in foundry industry.

Almost all steel castings, gray castings, malleable steel castings, nodular iron castings and the like are subjected to blasting process. This is not only for removing oxide skins and burnt-on sand on the casting surfaces, but also it is an indispensible process for the casting quality pre-checking. For example, the large gas turbine shell bodies must be subjected to strict shot blasting before non-destructively being inspected to assure the reliability of the inspection result. During the general casting production, shot blasting is an essential process for finding the casting surface defects, such as subcutaneous blowholes, slag blowholes, burnt-on sand, cold shut and peeling. In addition to shot blasting of surfaces of non-ferrous castings, such as aluminium alloy and copper alloy, removing oxide skins and finding surface defects of castings, the main purpose is to remove burrs of die castings through steel balls, achieve a decorative surface quality and a comprehensive effect. In the metallurgical steel production, the blast ball or acid pickling is a mechanical or chemical combination process of removing phosphorus skins to ensure that high efficiency is achieved in the mass production of steel. During the production of other alloy steel plates and strips, such as silicon steel sheets or stainless steel sheets, shot blasting or acid pickling must be processed after being annealed in the cold rolling process to ensure the surface roughness and thickness precision of the surfaces of cold-rolled steel plates.

2.Workpiece strengthening

According to the modern metal strength theory, the main direction of enhancing metal strength is to increase dislocation density insides the metal. It is proved by practice that shot blasting is an effective process for increasing metal dislocation structures. For the workpieces that can not be further strengthened through phase transformation hardening (such as martensite quenching) or based on phase transformation hardening, shot blasting is of great significance. It is required that the components and parts in aviation, aerospace industry, automobile, tractors and the like are of light weights, but the need for the reliability is increasingly high. An important process measure is to adopt the shot blasting process to improve the strength and the fatigue strength of the components.

Shot blasting machine types

1.Rotary drum type shot blasting machine

Rotary drum type shot blasting machine mainly blasts the blast balls onto the continuous tumbling workpieces in the drum to achieve a purpose of cleaning the workpieces and belongs to the scope of foundry machinery. The drum type shot blasting machine is applicable for cleaning, derusting, descaling and surface strengthening of the castings and forgings under 15 kg in various industries. The rotary drum type shot blasting machine is suitable for cleaning all kinds of castings and forgings that are not susceptible to damages and scratches and it is an ideal equipment for cleaning residual sands and oxide skins of workpiece surfaces in a small-scale heat treatment workshop. The rotary drum type shot blasting machine is mainly composed of a drum, a separator, a blast wheel, an elevator, a gear motor and the like.

2.Tumble belt type shot blasting machine

Tumble belt type shot blasting machine is suitable for surface derusting or shot blasting of various kinds of medium and large batch workpieces and belongs to the scope of casting machinery. The workpieces must be the castings and heat treatment parts under 150kg/unit which are not susceptible to damages. The tumble belt type shot blasting machine can be used independently or can be used with a wiring. The workpieces are automatically put into a rubber tumble belt type drum, the operators press ��Run�� button, then the door of blast chamber is automatically closed, the shot blasting begins and the tumble belts are continuously tumbled; The efficient and powerful blast wheel blasts the blast balls onto the tumbling workpiece surface in a high speed and the workpieces can be thoroughly and uniformly cleaned; the steel balls are flown into a spiral conveyor through holes on the tumble belts, conveyed to a bucket elevator, elevated to a separator through the bucket elevator and stored for standby after being separated. When the shot blasting is over, the door of the blast chamber is automatically opened, the tumble belts are reversed and the workpieces are unloaded. The tumble belt type shot blasting machine is applied for cleaning and polishing the die castings, precision castings, precision forging and the like. The tumble belt type shot blasting machine is also applied for removing the surface scales of thermal treatment parts, castings and forgings, strengthening the springs, derusting and preprocessing the fasteners.

3.Hook type shot blasting machine

Hook type shot blasting machine is a standard model type. The diameter of work cylinder of the standard model type is 900-1300mm, the height is 1300-2200mm. The standard model type is provided with 2-7 blast wheels and can load a maximum of 10000kg.The hook type shot blasting machine is quite high in production efficiency and flexibility and convenient to operate;  the whole blasting process can be completed only by loading the workpieces to-be-processed on the machine, pressing the start button and waiting for a very short time (generally 5-7 minutes). When the shot blasting is over, all the dust and residual particles are removed. The hook type shot blasting machine is mainly used for the surfaces of various kinds of medium and large castings, forgings, welding parts and thermal treatment parts, including fragile and out-of-shape workpieces.

4.Rotary table shot blasting machine

The rotary table shot blasting machine is mainly suitable for blasting surfaces of small and medium workpieces. The equipment of this specification is applied for engine connecting rods, gears, diaphragm springs and the like and can be widely used in casting industry and automobile manufacturing industry. The rotary table shot blasting machine has the characteristics of being high in production efficiency, good in sealing effect, compact in structure, convenient to load and unload parts and high in technical content.

5.Roller conveyor shot blasting machine

Roller conveyor shot blasting machine is a multifunctional steel preparation line for blasting welding structural members, H-steel, structural steel, net racks and steel plates. The blast wheels are arranged as a multi-angle structure and the blades on the blast wheels are the most advanced in the world. An intensive abrasive beam is blasted in a high speed and impacted on each portion of the steel in an original state which is subjected to three-dimensional and all-around cleaning, therefore the corrosion layer, welding slag, oxide skin and its dirt on each surface of the steel can be rapidly removed. In this way, a clean surface with a certain roughness can be achieved, the adhesive force of surfaces of paint films and steel is increased, the fatigue resistance performance and the corrosion resistance performance of the steel are enhanced, the inherent quality of the steel is improved and the service life is prolonged. A major functional component of the machine is a cleaning chamber which comprises an indoor conveyor roller, a feeding and discharging conveyor roller, a blasting wheel, an abrasive cycling system (including an elevator, a separator, a vertical and transverse spiral conveyor, an abrasive recovery mechanism and an abrasive feeding pipeline) sweeping mechanism, dust removal components, electrical control components and the like.

7.Wire mesh belt  type shot blasting machine

Wire mesh belt type shot blasting machine mainly clean plate-shaped parts, sheet-shaped parts, castings, machine bodies, structural parts and the like. The mesh belt type shot blasting machine can apply powerful shot blasting on steel and casting surfaces in an original state and remove rusty scale, welding slag and oxide skin to make the metallic luster of the surfaces be uniform, and thereby improving the painting quality and anticorrosion effect of steel. The mesh belt type shot blasting machine is mainly used for automobile, aerospace, railway and machinery manufacturing industries. The designed and fabricated metal continuous mesh belt type blast wheel allows parts to pass by in an automatic and continuous mode and be subjected to shot blasting in many directions. Hub type blast wheel can maximize the shot blasting efficiency and can avoid damaging the part surfaces caused by mutual collision of the parts.

Derusting grade

National standard GB8923��88 ��Steel surface finish grade and derusting grade before coating�� divides the shot blasting machine derusting grade into four levels, representing by letters ��Sa��.

Sa1 Mild blasting or blast derusting. There is no visible grease or dirt on steel surfaces and there is no loosely attached oxide skin, rust, paint coating and the like

Sa2 Thorough blasting or blast derusting. There should be no visible grease, dirt, oxide skin, rust and the like on the steel surface, they should be essentially removed and the residues should be firmly attached. Blast dents, which are formed after blasting, are uniformly arranged on the steel surfaces. The anti-sliding coefficient reaches 0.35��0.45

Sa2.5 Very thorough blasting or blast derusting. There should be no visible grease, dirt, oxide skin, rust, paint coating and the like on the steel surface. Any residual traces should be dot-shaped or stripe-shaped color stains. Blast dents, which are formed after blasting, are uniformly arranged on the steel surfaces. The anti-sliding coefficient reaches 0.45��0.5

Sa3 Blasting for making steel surface be clean or blast derusting. There should be no visible grease, dirt, oxide skin, rust, paint coating and the like on the steel surface. The surface should appear a uniform metallic luster.