During the past year, Valk Welding supplied four new robot installations to the company Van Hool in Lier, Belgium, Europe’s largest manufacturer of busses and industrial ve¬hicles.
During the past year, Valk Welding supplied four new robot installations to the company Van Hool in Lier, Belgium, Europe’s largest manufacturer of busses and industrial vehicles. Van Hool has been a client of Valk Welding for many years and is extremely satisfied with the supplied products and services. From the beginning we considered how we could maximise the yield of the new robots. We talked with Mario Discart of Van Hool about the measures he and his colleagues had taken to make the robots as productive as possible.
During the initial phases, Mario spent much time on analysing the company’s own operating processes. He even wrote a programme that enabled him to read out the parameters for all the robots in order to compare their performances. On the basis of this information he was able to chart the non-productive elements of the welding process.
Changing drums costs time
As these robots are placed on a conveyor, changing drums turned out to be extremely time consuming. The robot needed to be stopped and sometimes needed to be manoeuvred by hand to a position where the drums could be placed near the robot on the platform. Then the drums needed to be hoisted over the jig with all the corresponding dangers. A production stop of one hour was no exception when it came to changing a drum of welding wire.
The PFA offers relief
The Pneumatic Feed Assist from Wire Wizard offered the opportunity to solve a number of time-consuming activities in one go. With the option to work with a wire cable of 30 metres or more, it became possible to place the drums outside the installation. The wire cable did not need to be brought to the robot with a hanging construction, but could go into the carrier together with the other cables that lead to the robot arm.
Quick longitudinal movement
As many products are welded, all three robots were placed on a conveyor. Mario Discart, “As the drums are no longer on the conveyor carriage with the robot, the carriage is much lighter and can manoeuvre much faster. You no longer need to bring 250kg, or in the case of two drums 500kg, to running speed and then apply the brakes. The carriage can also be made lighter and therefore cheaper, and the wear and tear of the conveyor is significantly lower.”
Less wear and tear
As the wire is pushed into the outside bend of the wire cable by the PFA unit, the wire in the wire cable has no friction. Mario Discart, “This means there is minimum wear and tear of the cable and no material is scraped from the wire, so there is less contamination too. The wire motor also has a reduced load with the PFA unit, as the wire is fed to the end of the wire cable and can be pulled out without using power.”
For stainless steel to
Van Hool works on the new installations with a wire-exchange system that enables them to switch between steel and stainless steel. Stainless steel presents no problem to the PFA unit. As the wear and tear is minimal, the wire cables for the stainless steel wire have a hard-steel internal liner.
Mario Discart and his colleagues have optimised the plants and the PFA units even further. There are trolleys to put the drums on and they have their fixed place near the cell. The cone with the PFA unit is mounted on a vertical strip on the wall, so it can be moved up when the drums are changed. The PFA unit is also used to insert new wire; it pulls the wire extremely quickly through the wire cable to the wire motor. All in all, a small investment has achieved major improvements that ensure structural time gains and costs savings.
Benefits of using PFA units for Van Hool:
• Drums can be changed faster - previously 1 hour, now 10 minutes.
• No more dangerous and risky hoisting of drums.
• The carriage of the longitudinal guide with the robot on it is much lighter and can manoeuvre much faster.
• The longitudinal guide has a reduced load and is less susceptible to wear and tear.
• The wire motor of the robot has virtually no load, and the wire spools last much longer.
• It is much easier to control the position of the welding wire in the drum.
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