Metallizing in general
Metallizing is an anti-corrosion treatment where molten metal is sprayed at high speed onto the surface to be protected. For the best anticorrosion result, a 99.9% pure zinc wire or an alloy of 85% zinc and 15% aluminum is preferable to use.
The zinc-aluminum alloy instantly solidifies upon contact with the steel surface and creates a coating that protects the steel through the means of insulation and anodal sacrificial process. As a result of this electrochemical process, the less noble metal, in this case zinc and aluminum, will corrode instead of the steel.
This process is very suitable for an automatic treatment with robots. The metallization process itself is hazardous because of the creation of a high percentage of dust consisting of zinc and aluminum which cannot be transferred to the steel surface. This dust is potential flammable and can create a risk of explosion under very special circumstances. We see a great tendency towards robots taking over the metallization work to avoid personal involvement.
Metallizing large offshore tower sections with robotic solutions
The off-shore wind energy production is speeding up around the world. The world needs green energy more than ever and that is of course something we are aware of in Clemco Denmark. During the last many years we have provided automated robotic solutions for surface treatments of wind turbines, tower sections, hubs, generator platforms and other off shore wind components. The market for our kinds of robots is driven by the high demand for wind energy, but is also an indicator for the fact, that it can easily pay off investing in a robotic solution for surface treatment and coating.
The robots are becoming more and more popular within surface treatment in the wind turbine off-shore industry. When a customer is investing in and installing a robotic solution, then the benefits and advantages are quickly clear to him, and then, we have observed, the customer wants to expand with additional robots; either at other of their factories or in relation with new projects. This is partly because of the advantages a robotic surface treatment brings, but also, that we in Clemco Denmark, can provide an advanced robotic solution for surface treatment at a market price that pays off quickly.
Our metallization equipment for robotic solutions
The metallizing equipment can be controlled with all important process parameters to ensure a very consistent layer thickness and transfer efficiency. The spray pattern can be controlled from a circular spray fan to an elliptical shape. This (in situ) change in the spray fan geometry is very usable to avoid excessive masking of areas that do not need zinc/aluminum coating.
The performance of the equipment varies from 800 Amps to 1500 Amps and can handle zinc/aluminum metallizing wires from 2,5 mm to 4,0 mm in diameter. It is possible to achieve a coating performance of up to 150 m2 pr. hour depending on the current strength and the layer thickness needed.
Spray programs can easily be copied, duplicated and transferred to other robotic programs and it is also possible to define separate spray parameters for start and stop of the spraying process to perform a perfect zinc/aluminum layer structure.
Our robotic equipment
In relation to the choice of robots, we have chosen to cooperate with the robotic company ABB. ABB has a large selection of very different robots, and one of the reasons why we have chosen to cooperate with ABB is that the programming itself is very uncomplicated and easy, and it is possible to make simulations off-line before uploading the program to the robot.
We have chosen a 6-axis robotic solution which we have expanded with 3 more axes, so that you can program a total of 9 axes for shot blasting steel structures measuring more than 6 meters in length and typically weigh 20-25 tons, so in terms of workpiece sizes we are on the heavy side.
Our 9-axis robotic gantry solution is entirely self-developed in Clemco Denmark, and many resources have been used during the design phase, an we are of course happy that our customers, counting the largest manufacturers of steel structures in the world, have received our robotic solutions so well.
Programming the robot
Before installing the robot with the customer, we have pre-configured robotic programs corresponding to the surface treatment that the robot is intended to perform on a given steel workpiece at this specific customer.
We know, in advance, the geometry and surface requirements of the steel structures to be cleaned and all possible parameters which are important for correct robotic programming. That makes it possible for us to work with the programming before the robot is installed.
Clemco Denmark has a very talented team to perform robotic programming, and in terms of development and technical capability, our designers and engineers have been working with automation solutions and robotic systems within surface treatment for more than 15 years.
When the robotic solution is installed, we send our programming team to the site. They set up the programs for the robot, they make it up and running, they fine-tune it in terms of item sizes, distances, layer thickness and speed. When the robot is ready to perform “wet spray” we always suggest our customers a training period together with our technicians and programmers, before the customer takes over the full operation of the plant.