Innovative cutting cell takes a stronghold on industry and handicrafts - Robot saw for batch size 1
There is a global trend towards individualization, particularly in the furniture industry. The diversity of materials and versions knows no limits and has led to radical changes in series production in many sectors. The production of small batch sizes right down to 1 is becoming increasingly feasible for many manufacturers.
In order to provide the best possible support to users in industry and handicrafts, the engineers at HOMAG Plattenaufteiltechnik GmbH, formerly HOLZMA, embarked on the development of a pathbreaking cutting cell. The main focus of the machine designers is described by Uwe Elhaus, Head of Mechatronics at HOMAG Plattenaufteiltechnik: “An overriding development goal was to reconcile the hitherto diametrically opposed factors of individual part production and maximum output. This was only possible with cycle time-optimized full automation offering maximum flexibility. And that’s where we came to the subject of robots.”
In elaborate analyses, the mechanical engineers explored every possible alternative. Robot solutions quickly proved to be unbeatable in terms of flexibility and handling speed. Of all palletizing robots examined, the four-axis Yaskawa machines of the MPL series came closest to satisfying the existing requirement profile with regard to speed, availability, range, payload, etc. But collaboration was also an important aspect, as Dieter Pilz, HOMAG Group Director Strategic Sourcing, stresses: “The Yaskawa team focused fully on our project, invested a great deal of time and contributed a wealth of know-how prior to the final order placement.”
Fully automatic cutting process – unlimited recuts
The innovative HPS 320 flexTec robot saw caused quite a stir at its world premiere at ‘LIGNA 2015’. “A compact panel dividing centre that completes the individual cutting process fully automatically with only one saw and permits unlimited recuts with maximum cutting pattern layout flexibility – that is just what the market had been waiting for. The first orders were already received at the trade fair,” says Elhaus.
Since the HPS 320 flexTec can either be connected to an automatic storage area or integrated into complete industrial production lines, the client base includes representatives of both handicrafts and industry. Due to its intelligent modular design, the cutting cell can be configured according to the client’s needs and customized both in the flow of parts and performance.
The centrepiece of the HPS 320 flexTec in the version with a 3,200 millimetre cutting length is a fast Yaskawa MOTOMAN MPL300II palletizing robot. The saw with a cutting length of 4,300 millimetres features a MOTOMAN MPL500II with an even higher payload. Both four-axis robots have an identical range of 3,159 millimetres and take care of all part and strip handling. For this purpose, the robot lifts the strips after the initial longitudinal cut, rotates them and deposits them on the rear machine table or strip buffer for the second cut, the cross-section.
The same applies to recuts, for which the robot ensures correctly oriented feed-in of the parts. Fully automatic and flawless recuts are thus possible without limit. In the final phase, the robot deposits the finished parts on the automatic output roller conveyor or stacks them on pallets. “The two Yaskawa machines are the perfect robots for our system. They are powerful, proven in thousands of applications and operate with the highest level of availability. They are an optimum complement to our HOMAG machines,” says Pilz.
Know-how intensive gripper technology
Extensive experience has been invested in the development of the huge suction gripper that is responsible for parts handling. The large suction beam has more than 30 individually controlled activators, enabling it to pick off and position parts in the possible size range. “Only after elaborate simulations did we succeed in designing the suction beam for all conceivable positions in consideration of the robot’s range. The selection of workpieces to be picked up extends from a minimum of 240 x 80 millimetres to a maximum of 4,300 x 2,200 millimetres, a surface ratio of 1:500,” stresses Elhaus.
To guarantee the greatest possible reliability and fast operations, the vacuum is monitored by sensors. The parameters of the vacuum and panel weight are constantly set in relation to one another, and the robot’s speed is regulated as needed. These control algorithms run in the background without the need for intervention by the operator.
Practice has shown that the two systems – robot and saw – harmonize perfectly when it comes to cycle time. Thanks to the superb performance of the Yaskawa four-axis robot, the saw can demonstrate its full capabilities without the need for waiting times in robot handling. The optimum interplay of these two components makes for an outstanding output of up to 1,500 parts per shift.
Robot programming unnecessary
A further major advantage of the panel cutting centre is simple operation which eliminates the need for robot programming. The four-axis robot is completely integrated into the HPS 320 flexTec machine controls. Its gripper and movement patterns are automatically generated from the cutting pattern without the intervention of the operator. These patterns are conveniently created offline in the office by the HOMAG Schnitt Profi(t) optimization software . The data is transmitted to the system controls by mouse-click – that’s all that is necessary.
With the introduction of the HPS 320 flexTec, HOMAG has achieved a technological quantum leap for cutting single panels. The decisive advantages of this solution: thanks to robot handling, multiple recuts are now possible with only one saw. Multiple recuts used to require manual intervention, so maximum flexibility is the norm today – with fully automatic workflows.
In connected production lines the HPS 320 flexTec operates unmanned over long distances. In future this will also be possible with unconnected facilities, as proven by a new system variant that celebrated its premiere at ‘LIGNA 2017’. The robot can stack the finished parts on up to four lifting tables. In order to achieve stable stacking, it temporarily buffers parts. “Whether interlinked or not – this system revolutionizes batch size 1 production. It unites speed and flexibility in a completely new way,” says Elhaus.
Text: Ralf Högel
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