Valk Welding: 2005

Valk Welding facilitated a double increase in output at JAC by optimizing their welding processes. With locations in Liège (B), Langres (F) and Heidelberg (D), JAC S.A. designs and builds industrial bakery equipment and bread-cutting machines.

The company wanted to improve both the quality and the output of its welding production and opted for a new welding system developed by Valk Welding. In so doing, JAC improved the quality of its products considerably and halved the production time for its frame assemblies. According to Peter Pittomvils, engineer and technical advisor at Valk Welding, the key to the success of this project lies in the optimization of the welding process.

4,000 Bread Machines Annually
JAC produces about 4,000 bread-cutting machines annually, making it one of the market leaders in the industry. The company invests continuously in new production technology in order to improve the quality and efficiency of its production processes. In recent years, large investments have been made in the modernization of the assembly line. Up to that point, the welding process had been a bottleneck in the company’s growth. By implementing one new robotic welding system, JAC consolidated the welding of both housings and cutting-blade frames into one process. Production turnarounds were greatly reduced economizing on one of two operators previously required. In addition, a problem involving buckled assembly frames had to be solved. JAC already had several years of experience working with welding robots supplied by another manufacturer. The company did not want to take any risks investing in a completely new robotic welding system. By employing an ingenious new concept, Valk Welding was able to differentiate itself from the competition and was eventually awarded the project. 


A pre-tack-welded housing is correctly positioned by a dual manipulator.

One Robot Serves Three Workcells
In order for one robotic welding system to assemble both the cutting-blade frames and housings, Valk Welding developed a system with two small stations and one large station with dual manipulators respectively. The stations are served by a track-mounted Panasonic VR welding robot. What was peculiar to this concept were the large station’s dual manipulators in which the pre-tack-welded housings were held. Using this dual-axis system, housings can be positioned in every orientation allowing for optimal access for the robot.

The previous welding process generated such high temperatures that frames used to buckle. This was solved by high-speed vertical-down welding.
 

The stations are served by a track-mounted Panasonic VR welding robot. All components can be assembled in one welding workcell.

Same Output in Half the Time
JAC wanted to consolidate the welding process of cutting-blade frames and housings into one system. In so doing, one operator is required as opposed to two for the previous system. Another condition was that the turnaround also had to be reduced. Valk Welding more than succeeded in this respect, doubling the output.

The increased output is mainly a result of the higher welding speeds that the Panasonic system permits. Peter Pittomvils, “At high speeds, the communication between the robot and the power source plays a major role. These two components are manufactured at one of Panasonic's factories and are optimally matched. The communication between robot and power source is many times faster than that between separate units working on a master-slave principle, as was previously the case at JAC. Furthermore, the system is faster as a result of shorter stop-start routines and we have succeeded in exploiting the benefits of vertical-down welding.

Vertical-Down Welding
Valk Welding succeeded in improving welding speeds by vertical-down welding the frames and housings, without compromising weld penetration. Peter Pittomvils, “What JAC achieved on its previous system in two shifts is now performed in a single shift. We have doubled the output. Traditional equipment is not suitable for vertical-down welding, since the welding arc is not stable enough and sufficient penetration can only be achieved at low speeds. This leads to high temperatures, which cause the seam to sag under the effect of gravity and results in sticking. Panasonic’s equipment allows the limits of what is technically feasible to be pushed ever farther. This equipment allows for a stable weld with sufficient penetration even at higher speeds. With the correct adjustments, sufficient penetration is guaranteed even at twice the usual speed.”

By vertical-down welding the seams, speeds could be doubled and final processing times reduced by 30%.

Buckled Frames Became a Thing of the Past
JAC was previously using aged equipment to weld the frames used to tension the cutting-blades. This meant that slower welding speeds were required to achieve adequate weld penetration. This generated high temperatures, which caused the frames to buckle. Frames even had to be pressed to re-straighten them after welding. Valk Welding therefore proposed a concept incorporating vertical-down welding of the frames. The frames are now welded at higher speeds, as are the housings, with the same degree of penetration, but with less heat generation. JAC now welds its frames at twice the speed without any buckling. This is a major profit factor for JAC.

After coating, complete, welded housings stand ready for final assembly.

In Liège, JAC employs 22 office workers, 56 shop-floor employees and 35 temporary staff members. The Liège plant covers 4,500 m2 (48,440 sq.ft.). For the past 15 years, JAC has had its own R&D unit, which has resulted in numerous new designs and models. Partly due to the modernization of the assembly line, JAC increased its production output in 2005 to 4,000 units.

JAC S.A.
B-4000 Liège
+32 (0)4 234 9870
www.jac-machines.com