Use Of Portable Wet Blasting Machine In Manufacturing
I. Introduction:
Manufacturing is a vast field across multiple industries such as automobiles, machine tools, metallurgy, chemicals, steel etc and can range from small scale to huge complex machinery involving the use of expensive industrial equipment and infrastructure. Manufacturing companies aim to minimize unit production costs and cut down on capital expenditure by running their machinery as long as possible and as high capacity as demand permits. However, this results in a significant amount of wear and tear of equipment. Therefore, companies must conduct frequent maintenance and keep the equipment in good condition to increase asset longevity. Most machinery is built from metal which requires surface preparation prior to installation as well as regular maintenance to keep in good condition. This could involve surface cleaning, surface preparation for painting or powder coating, stripping of corrosion, stripping of mill scales on the metal surface, removing burrs and sharp corners from machined components, and similar works.
This article will provide insight into asset maintenance, asset remediation and extending asset longevity in the manufacturing industry. This will include details on the current types of problems faced in this industry, such as corrosion, oil spills, dirt, and oxidation.. Wet abrasive blasting could be an optimal environmentally solution to asset maintenance in many cases.
II. Demands of the Manufacturing Industry
Pre-production needs: Most machinery is made from steel and has some form of coating on it to increase its longevity. Surface preparation is critical for the coating to adhere to the surface and as the old adage goes ‘A coating is only as good as the quality of its surface preparation’. Once steel is produced and before it can be coated and used in infrastructure or machinery manufacture, the thin layer of mill scale needs to be removed. The surface also needs to be etched to create a suitable profile on which the protective coating can adhere. Manufacturing components and machinery are often very expensive and therefore buyers expect premium quality and the finish to be of high quality requiring a good protective coating.
Routine maintenance: Manufacturing is a heavy-duty, highly demanding industry, and machines are put through a high amount of wear and tear during production and therefore, maintenance is required regularly to improve the longevity of these expensive machineries. Corrosion is a multi-billion dollar problem in the manufacturing industry due to the susceptibility of steel to moisture and chlorides. In addition, there is often a large buildup of surface contaminants, such as oil and grease that need to be cleaned before the machine can be repainted.
A quick and effective method of maintenance is required to minimize the time in which production is halted.
III. Manufacturing in Various Industries
Manufacturing plays a vital role in the economy of many industrialised nations and is an industry that is supported by the governments due to the spin off benefits it has to other industries.
1. Foundry:
In a foundry, small or large castings are manufactured by melting metal, poured into a mold and allowed to cool. The castings taken out from the mold have runners and risers and tend to be uneven and are cut off using a hand fettler, cutting machine, or other methods. Most castings need an even or textured surface finish for painting, powder coating, or other coatings.
Small and medium-sized castings are finished using tumbling, shot blasting, or sandblasting cabinets with built-in enclosures. The big and heavy castings that cannot be accommodated in these facilities are completed using alternative methods such as grinding, fettling, sanding, and sandblasting. Dry and wet sandblasting cabinets are an effective solution depending on the finish desired as they provide a quick, clean and more environmentally friendly option.
2. Metallurgy:
Metallurgy or the manufacture of metals involves the processing of ores to separate the metals they contain and combining metals with other materials to create alloys. These alloys must then go through a range of finishing processes such as deburring, coating, shot peening, and welding. Wet blasting plays an important role in ensuring sharp edges are removed (deburred) and the surface is etched in preparation for coating.
3. Fabrication
After the fabrication of large metal components like the body of machines, chassis of a truck, trailer components and similar items, the metal surfaces needs to be prepared for painting. The different processes available for surface preparation are manual grinding/sanding, high-pressure washing, chemical cleaning, and sandblasting. The manual processes are slow and require precise skill to achieve the required surface finish. Chemical cleaning is quick and cheap but can be hazardous to the operators and the environment. Dry sandblasting is efficient and the media can be easily reused whereas wet abrasive sandblasting is portable and can be done without a blast booth or containment facilities.
4. Manufacture of machine tools
Steel guards on machine tools are made from hot-drawn steel sheets which has mill scale on the surface. that needs to be removed as preparation of the surface for painting or powder coating. In addition, it is necessary to remove burrs and sharp edges from these forgings, or CNC cut components. Manual processes can be time consuming and sandblasting using a soft abrasive media is an efficient process to deburr and etch the surface for the protective coating to adhere.
5. Chemical plants and refineries
Chemical plants and refineries use tanks, valves, pipes, and pumps made from stainless steel for handling acids, salts, and other chemicals that cause the steel to corrode over a period of time.
Chemical plants and refineries use insulation over carbon and low alloy steel pipes for hot and cold lines. Moisture seeps into the insulation initiating corrosion of the pipes over a period. This is a serious problem commonly known as corrosion under insulation (CUI). The corroded pipelines are reconditioned by removing the insulation, sandblasting the corrosion from the pipe, recoating the pipe, and insulating once again. In addition, the seam welds in the pipelines need to be inspected from time to time for leaks. The protective coating over the welds is stripped off through sandblasting and repainted..
It is common to have the factory and warehouse floors painted with chemically resistant epoxy or urethane flooring and line marked with paint. However, the coating deteriorates and wears out over time. The easiest way to remove epoxy coating from flooring is through wet abrasive blasting. The process is dustless and does not pose a safety risk to employees.
6. Reconditioning and Refurbishing
With protracted use, engines may require reconditioning and the work involves stripping the engine, cleaning the engine block, engine head, transmission parts, refurbishing all the parts, and then reassembling with the required new parts. Abrasive blasting can be used to clean the parts and thereby extend the useful life of the equipment.
7. Steel Mills and Fabrication
When stainless steel slabs are cold rolled into plates and sheets, the metal undergoes work hardening and needs intermediate annealing. The high-temperature annealing, unless done in an inert atmosphere, leads to the formation of an oxide scale on the surface. The oxide scale must be removed to keep the corrosion resistance property of the stainless steel intact. The oxide scale can be removed by a continuous chemical pickling process, but it can be hazardous. Alternately, multiple abrasive blasting nozzles can be positioned on an automated blasting line and the steel sheet gets blasted as it moves along on a conveyor belt.
I-beams and columns are also manufactured in steel mills for building steel structures in construction. These can be formed by hot rolling, cold rolling, or extrusion. Once the steel shapes are built, a special form of sandblasting known as shot blasting or shot peening is used to strengthen the steel and to prepare the surface for coating.
IV. Current Practices in the Manufacturing Industry
As described above, there are various methods of surface preparation used in manufacturing industries to strip corrosion, oxidation, coatings, removing burrs and sharp corners. They vary based on the type and scale of manufacturing and are summarized below.
- Chemicals – Different types of acids and chemicals are sometimes used in manufacturing to remove mill scale or rust. This can be a quick process but the fumes from the process and the risks in handling put the operators and the environment at risk due to the toxicity of these chemicals.
- Manual Grinding, Fettling, or Sanding processes are also used for surface cleaning and surface preparation. These processes are not safe due to the proximity of the operator to the resulting dust. They are also not efficient or suitable for large structures or components due to the extensive time and labour required. It is also hard to apply these processes to folded or curved parts where the surfaces are hard to reach. In addition, given the manual nature of the process, an uniform finish is difficult to achieve on multiple parts/large surfaces.
- Dry Sandblasting– In dry sandblasting, abrasive media is propelled on the surface with highly compressed air to remove paint, rust or oxidation. This is a highly efficient method that provides excellent results. Environmental and workplace safety laws require dry sandblasting to be performed inside a blast booth or the object to be covered in mesh to contain the arising dust. Operators are required to wear sufficient protective clothing and respiratory equipment with breathing apparatus while performing dry blasting.
- Wet Abrasive Sandblasting– The process is similar to dry sandblasting except that an additional element of water is added to the abrasive media and compressed air. The water is effective in suppressing the dust and in addition, it also provides a smooth feathered finish to the blasted surface.
V. Wet Blasting in Manufacturing
The wet abrasive blasting process also known as dustless blasting or vapour blasting or mist blasting has a few different variations based on the manufacturer of the equipment. The most efficient of these processes involves mixing water and abrasive media inside a pressurized blast tank and using compressed air to propel the slurry onto the surface being blasted. The impact of the force of the blast makes light work of removing the paint and coatings and achieves a smooth, feathered surface finish. This technique is similar to dry blasting but the additional element of water generates more impact and suppresses the dust. Steel and iron components have a layer of water on their surface after wet abrasive blasting and this can start flash rusting. If the wet blasted components are not taken up for painting immediately, they may be dried using clean compressed air to delay flash rusting. Also, the use of a rust inhibitor will provide protection against flash rusting for a period of up to 72 hours.
Advantages of Dustless blasting or portable wet blasting for surface cleaning and surface preparation needs in the manufacturing industry.
Within the sandblasting process, wet abrasive blasting provides even more benefits than dry sandblasting.
- Unlike dry sandblasting, wet blasting or vapour blasting is virtually dust free as approximately 95% of the dust is suppressed by the water molecules.
- Wet abrasive blasting does not require the use of a specialised sandblasting booth or the construction of containment barriers and can be performed anywhere in the open. It can also be done in high pedestrian traffic areas.
- Wet sandblasting provides a nice feathered finish between the blasted and non blasted areas.
- Unlike dry blasting, there is no heat generated in wet abrasive blasting and therefore thin substrates can also be blasted without the risk of warping.
- Wet blasting is truly portable and compact and can also be used on offshore rigs and on pipes and equipment in remote areas
- It can remove the high points and unevenness on large castings, the burr and smoothen the sharp edges on large-size machined castings, forgings, and metal fabrications and prepare the surface with a smooth finish or anchor profile for painting/coating.
- Can eliminate rust, oil, and mill scale which is common on the surface of steel components which have been recently manufactured.
- Surface contaminants such as rust and oil spots may be present in difficult-to-reach areas that can be removed only with acid dipping or wet sandblasting.
- Dustless blasting equipment is There is a wide range of abrasive media that can be used which can be used including sustainable options such as walnut shells, to specifically manufactured media such as glass beads and steel grit. This provides a wide range of options to match the surface profile required for different substrates.
VI. The RapidBlast Solution
The RapidBlastTM is the only Australian-made wet blasting machine and is manufactured and sold by Quantum Blast Australia. The Rapid BlastTM equipment is available in different sizes and can be tailored in different configurations and mounted on a purpose-built trailer or a truck to be fully mobile at a fraction of the cost of foreign-made alternatives. It is a versatile piece of equipment and very effective for surface cleaning and surface preparation. The RapidBlast provides a wide range of flexibility through a manual change of pressure. This can range from coarse blasting to remove thick paint, to delicate blasting of a can of coke without damaging the thin layer of aluminium.
For more information on RapidBlastTM wet blast machine and mobile units please visit Quantum Blast at https://quantumblast.com.au/.
Phone:1300822569 E-Mail:sales@quantumblast.com.au
