Shot blasting machines may use one or a multitude of turbines positioned in such a way that the abrasive blast pattern covers the entire surface of the material
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CYM – 1 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar TECHNI CAL BROCHURE General Introduction to Shot Blasting Shot Blasting is a surface treatment process using high velocity steel abrasive. Shot blasting is method through which it is possible to obtain excellent cleaning and surface preparation for secondary finishing operations. Shot blasting is commonly used for: The cleaning of iron, steel, non – cast parts, forgings, etc. Mechanical cleaning of sheets, rods, coils, wire, etc. Shot peening to alter mech anical properties (increasing resistance to fatigue for springs, gears, etc.) Preparing surfaces to be painted, coated, etc. In general shot blasting concentrates abrasive particles at high speed (65 – 110 m/second) in a controlled manner at the material th ereby removing surface contaminates due to the abrasive impact. shot. This method remains in use today for cleaning metal frames and weldments.
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CYM – 2 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar Shot blast production lines, both manual and automated systems, became possible with the introduction of centrifugal wheel blast machines. The system of shot blasting by centrifugal wheel is more productive than by compressed air and achieves a better more uniform su rface finish. The criteria used for selecting the type of shot blasting system depends on the size and shape of the parts, the condition of the surface to be cleaned, final surface finish specification and overall process required. Shot blasting systems ar e comprised of 6 basic subsystems : 1. Abrasive delivery method: o By Compressed Air. o By Centrifugal turbines. 2. Abrasive recovery and cleaning. 3. Dust collection. 4. Blast Cabinet. 5. Part movement and support system. 6. Controls and instrumentation.
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CYM – 3 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar Abrasive delivery method: There are two ways of accelerating the steel shot: By compressed air: This system is suitable for lower production applications where maximum flexibility is needed. These systems are very flexible in that the shot can be delivered horizontally thr ough a rubber hose and nozzle assembly. This enables uses in finishing operations of steel frames and weldments thereby replacing hand tools. Because of this, an air blasting machine for a production line is expensive compared to the centrifugal wheel blas ting machine. For example to deliver shot at a rate of 1100 kg per minute a 1650 Hp compressor and 33 workers are needed using 10 mm diameter nozzles delivering 6.5 kg/cm2. On the other hand the same task using centrifugal wheel turbines only requires a t otal of 100 Hp distributed to between one or a multitude of turbines housed in the same machine. Only one or two operators are needed for such a shotblasting machine.
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CYM – 4 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar By centrifugal turbine: Centrifugal wheel blasting is the more common blast cleaning technique as well as the most economical and environmentally friendly method. The turbine delivers abrasive shot by centrifugal force in a specific and controlled direction, speed and quantity. Function of the turbine is similar to that of a fan or centrifugal pump. Shot blasting machines may use one or a multitude of turbines positioned in such a way that the abrasive blast pattern covers the entire surface of the material to be shot cleaned. The shape and size of the parts determine the number of turbines used in a machine. Power of the turbine motor is based on degree of cleaning needed and throughout speed of the material.
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CYM – 5 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar 2. Abrasive Recovery and cleaning system . Recirculation and cleaning the abrasive shot is required to maintain a consistent cleaning operation. In conventional shot blasting equipment after the shot hits the part the abrasive falls into the collection hopper under the machine. The shot is then carried by gravity o r screw conveyor to a bucket elevator. The elevator carries the shot, removed oxides and other contaminates to an air wash separator located in the upper portion of the machine. A combination of baffles, strainers and plates separate these contaminates whi ch are ineffective during the shot blast operation. The cleaned abrasive is contained in an upper hopper (feeding – box) and is subsequently fed into the shot turbine by gravity. The recirculating and cleaning capacity of the abrasive in each machine is related to the shot blasting power used for the turbines. An incorrectly sized system will cause premature wear to the machine and decrease overall shot blasting effectiveness and shot consumption . 3. Blast Cabine t The machine cabinet contains dust and abrasive. A machine mounted dust collector, reduces air pressure inside the machine thereby preventing dust from escaping into the shop environment. Material access openings in the entrance and exit of the shot blaster must be designed and protected to prevent abrasive spillage. Cabinets are built from low carbon steel with an inner shell made of abrasive resistant materials including high strength alloy plates and thick rubber compounds. In the areas t hat are subject to direct high velocity shot, alloy steel plates (64 RC hardness) are used which have much more abrasion resistance than other more commonly used materials like manganese steel.
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CYM – 6 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar 4. Dust collector system Dust produced during shot blasti ng is withdrawn from the machinery cabinet and continuously recirculating abrasive by a dust collector. Typical dust collector design uses baffle filters or cartridges. The dust collector not only evacuates dust within the machine but also keeps the surrou nding area clean and dust free. Changes in airflow will reduce collector efficiency and therefore result in lower dust extraction, loss of the cleaning power, and contribute to dust in the immediate production area. A properly designed and sized dust colle ctor is therefore critical to the ongoing performance of the shot blasting System. 5. System for holding and transporting parts for shot blasting Handling and transporting parts through the shot blast process will depend on several factors. For materials in large quantities (brake, pulleys, screwdrivers, etc.) tumblast machines are used. For larger and heavier pieces, (motor blocks, bicycles frames, bunch – welded parts, etc.) spinner hanger machines are used. For the shot peening of gears and other special components, tables and multi tables machines are used. For cleaning pipes, plates, bars, wire continuous machines are used .
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CYM – 8 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar Blast Cleaning and Shot peening machines are widely used in different industries such as: Shipyards: o Cleaning and preparation of profiles and sheets surfaces before painting o Portable machines for the maintenance of ship hulls Automotive components: o Cleaning of gearboxes, mechanical transmissions, connecting rods, etc. o Shot peening of stabilizing bars, springs and elastics, gearboxes, pistons, connecting rods, etc for increasing fatigue resistance. o Cleaning and preparation of car and truck tires before painting. o Break shoes and clutches blasting o Cleaning of rectified engines components (blocks, pistons, etc). o Screw mechanical descaling from metric 3 before coating application Aviation: o Portable machines for rubber elimination and roughness restitution in airport tracks o Shot peening of airplane components tincrease fatigue resistance. o Airplane painting removal Bicycles and motor bikes: o Cleaning and preparation of bicycle frames, motorbikes and tires surface before painting. Rubber: o Cleaning and preparation of steel part surfaces before rubber application. Concrete, ceramics, marbles: o Blast for making non – slipping floors. o Artistic blasting. Coach builders: o Cleaning and preparation of truck coaches surfaces before painting. Denin Jeans: o Erosion of clothes (jeans).
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CYM – 9 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar Metallic structures and profiles: o Cleaning and preparation of steel sheets and profiles before painting. Iron foundry: o Remove foils from the framework. o Surface homogenization. o Melting of steel, iron, aluminum and bronze. o Cleaning and grit removal of melted parts. o Surface homogenization. Milk, Ref r igerating and Nutritional Industries: o Limpieza y preparación de superficies previal metalizad. Moldes: o Cleaning and preparation of surfaces of stainless steel parts for surface homogenization. Cleaning of painting systems (hooks): o Painting removal of part load hooks of painting systems. Metal working: o Cleaning and preparation of surfaces before being metalized. Moulds: o Cleaning of rubber, glass, aluminum extrusion moulds, etc. Me tallic furniture: o Cleaning and preparation of metallic furniture surfaces before painting. Metallurgical: o Cleaning and preparation of industrial machines before painting. Petroleum and gas: o Cleaning and preparation of surfaces of GLP, GNC gas cylinder and gas and petroleum stationary tanks before painting. o Cleaning and preparation of gas and petroleum bottles before painting. o Blasting and shot peening of petroleum pump rods. o Blasting of coupling union of pump rods before metal working.
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CYM – 10 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar Concrete floors: o Por table machines for the preparation of concrete industrial floors before coating. Iron and steel industries: o Mechanic descaling of round, hexagonal and square bars for wire drawing operation. o Mechanic descaling of coil rod. o Mechanic descaling of steel sheet s and iron hoops. o Mechanic descaling of tubes with and without rims. o Descaling of laminated levers by heating. o Blasting of lamination cylinders. Trains: o Cleaning and preparation of trains and wagons surfaces before painting. Metallic drums: o Cleaning and preparation of internal and external surfaces of metallic drums before painting. Heat treatments: o Cleaning and preparation of parts after heat treatments. Electric transformers: o Cleaning and preparation of surfaces of electric transformer before painting. Glass: o Grind glass. o Artistic blasting.
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CYM – 11 CYM MATERIALES SA www.cym .com.ar // info@cym .com.ar CYM MATERIALES S.A. Industrial Solutions Administrat i o n and factory Brig. Estanislao Lopez Nº 6 [S2108AIB] Soldini – Santa Fé – Argentina Tel: [54 – 341] 490 1100 | Fax: [54 – 341] 490 1366 E – mail: info@cym .com.ar www.cym .com.ar Metalcym Brasil Rua Mário Junquei ra da Silva nº 684 – Jd Eulina Campinas – SP – Brasil – CEP.13063 – 000 Tel: [55 – 19 ] 3242 – 9777 – Fax: [55 – 19 ] 3243 – 7236 E – mail: metalcym@metalcym.com.br www.metalcym.com.br
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