in Vol. 20 - March Issue - Year 2019
Robotic Blasting for Excellent Performance and Maximum Safety
Fully automated blast cleaning of large die-cast engine blocks
Operators work comfortably within a control cabin or control room, where they are protected from the hazardous environment of the blasting chamber
Gantry robot equipped with a manipulator for blasting large components
Blasting robot with manipulator function for cleaning components in the mechanical engineering and equipment construction context
Blasting large-scale components is a painstaking process – and not entirely without its hazards.
Investing in specially designed blasting robots, however, makes this type of work not only quicker and safer but also less expensive. Their use also produces better-quality results.
In the field of surface engineering, blasting is the most common means of assuring that component surfaces possess the degree of cleanliness and pre-defined quality prior to painting or electrolytic coating. Similarly, blasting is the predominant means of removing residues from castings prior to further mechanical processing.
Yet, manual blasting is very tedious and difficult work that is harmful to the health of those performing it, as it exposes them to a high degree of physical stress, as well as noise and dust – particularly in the case of large components such as cranes, rail vehicles and the engine blocks of large ships.
Until now, automated blasting has mainly been performed with blast wheels and pressure-blasting equipment. However, the scope of application of these blasting techniques is limited to simple components of a certain type and size.
While multi-axis industrial robots with a large operating scope would be significantly better suited, their use is not practical due to the abrasive environment posed by blasting. Dust and blasting particles damage such equipment and impair both their functionality and service life. Although covers can provide better protection, they also restrict the operating scope of fixed industrial robots, so that components often have to be repositioned in the course of the blasting process. On the other hand, robots specially developed for blasting that are mounted on gantry bridges or wall rails meet all task requirements. Combined with a cabin, they can even be used to manipulate large or complexly-shaped work pieces during the blasting process.
The benefits of blasting robots
Above all, blasting robots are beneficial because they assure greater occupational safety. Operators work comfortably within a control cabin or control room, where they are protected from the hazardous environment of the blasting chamber.
As with many of today’s machines and devices, the blasting robot is operated and controlled with a joystick. The operator is housed in a control cabin or control room that is well insulated, fully climate-controlled, and slightly pressurized to prevent the ingress of noise and dust.
Meanwhile, blasting robots employed in series-production repeatedly perform their programmed work sequences, and thus reliably deliver consistent cleaning results. The blasting sequences are very easily programmed by means of a teach-in process, whereby the operator cleans the component once by manually operating the joystick.
As he or she does so, all of the system’s movements and functions are recorded in sequence to create a blasting program that can then be used to clean the next identical component. If blast-cleaning a given component once by manually operating the robot is not possible, programming can also be carried out with a portable handheld panel. In this case, the robots movements are recorded by means of a point-to-point process, which produces highly efficient blasting programs.
Offline programming is even more efficient, as it eliminates any need to interrupt production. Performed on a PC, offline programming consists of entering the component’s 3D data, as well as those of the blasting chamber, into special simulation programs. All of the robot’s movements are then simulated on the monitor with a 3D model to check for any possible collisions. At the same time, this technique enables cleaning processes to be optimized offline in terms of quality and duration, thereby significantly enhancing the cost-effectiveness of robotic blast cleaning.
Another major benefit of employing blasting robots is that they are inexhaustible, even at high output rates. Due to the powerful recoil forces caused by the blasting media exiting the nozzle at such high output rates, the nozzle diameters for handheld manual blasting at 6 to 7 bar cannot be more than 10 or 12 mm. Modern blasting robots, on the other hand, can utilize nozzles up to 19 mm in diameter at blasting pressures of up to 10 bar without any restrictions. This alone means that their blasting performance is many times greater than that of manual blasting, and can be increased by adding a second nozzle to the robot arm. In fact, even under basic conditions, a blasting robot can achieve performance capacities of over 200 m²/hour (ca. 2,150 sq ft per hour), while an average worker is unable to manage even 20 m²/hour (215 sq ft per hour). For many companies it is also becoming increasingly difficult to find personnel willing to perform such strenuous work under the given hazardous environmental conditions.
Fast and flexible component cleaning
Compared to other mechanical blasting techniques, blasting robots easily adapt to components of different shapes and sizes. Gantry-type robots, which feature up to 8 axes, are also able to move around the entire blasting chamber and treat areas that blast wheels and pressure blasting units would be unable to reach, and which would therefore need to be subsequently blasted by hand. The robots also perform other tasks in addition to blast cleaning. These include the use of compressed air to remove abrasive residues and dust from a component after blast cleaning. This allows the component to be available sooner for further processing, while freeing up the blasting chamber more quickly for more components, thereby further shortening overall processing cycles.
Since the early 1980s, Blastman Robotics has been applying innovative engineering ideas and the right choice of materials to the task of manufacturing highly durable robots specially designed for automated blast cleaning. In fact, some blast systems supplied by Blastman Robotics are still in operation after more than 20 years.
Abrasive materials used with blasting robots can vary, depending on the application. Everything from sharp-edged steel grit to aluminum oxide to garnet may be employed.
Blasting robots are the most efficient means of cleaning large components and surfaces. Their use is particularly cost-effective both in cases where manual blasting would be very time-consuming and in those that involve components which would otherwise require additional follow-up blasting by hand. Examples of such applications include blast cleaning passenger and freight cars, as these pieces feature many large and difficult-to-reach surfaces. Blast cleaning of their interior surfaces can be performed and completed according to specifications by guiding the robot arm through the car’s openings. Since such cars are typically produced in series, the automated functionality of blasting robots provides added benefits to manufacturers. Blastman Robotics has already supplied more than 80 fully automated blast cleaning robots to the rail vehicle industry alone.
Blasting robots are also the preferable means of removing build-up from die-cast components, such as rotor hubs for wind turbines and engine blocks for marine diesel engines. Such stubborn deposits are removed in a targeted manner with coarse steel grit at flow velocities of 200 m/s.
Other examples for the use of blasting robots include components from the commercial vehicle sector, such as excavators, cranes and trailers. Nowadays, however, blasting robots with manipulation capabilities are also being employed to process small quantities of individual parts and components for the construction industry, as well as for the mechanical engineering and equipment construction sectors, such as bridge segments and turbine housings. In addition, blasting robots operated within direct control cabins can be very flexibly employed in the processing of a diverse range of products. They are also ideally suited to dealing with the wide variety of surfaces that arise when repairing and reconditioning used components.
Blastman Robotics has an extensive portfolio of blast cleaning robots to suit individual applications. Depending on the number, shape and size of the components to be cleaned, they range from a simple five-axis blasting robot mounted on wall rails to an assimilated eight-axis gantry robot – which is able to reach every corner of even large blasting cabins.
In 2016 a majority shareholding in Blastman was acquired by Kaitai Company of Shandong China. The acquisition of Blastman compliments the product range manufactured by Kaitai, which is sold by The Airblast Group. The Airblast Group was acquired by Kaitai in 2012. Should you wish to receive further information concerning the Blastman range of products, please do not hesitate to contact us.