A multitude of difficulties has pushed the SME sector and medium-sized contract manufacturers in the German machine tool industry into times of trouble. The global impact of the coronavirus pandemic taking the lead, the reasons are diverse such as structural changes in the automotive industry, fluctuating order intake, rising production costs, decreasing batch sizes, unqualified labour and price pressure from low-wage countries, and trade policy conflicts.
These difficult times, however, allow an opportunity to reinvent with solutions such as automation in machine tool manufacturing to emerge from the crisis. After all, it is a universal fact that automation can significantly increase the availability and flexibility of production facilities and compensate for a shortage of skilled workers.
Reaping the benefits of automation
From medium-sized contract manufacturers to OEMs, the machine tool manufacturing industry is beginning to realise that automation is a practical solution. These days, automated processes are commonplace in factories that produce machine tools.
For instance, metal and plastics cutters, who produce small and medium batch sizes, are keenly interested in the Stuttgart-based company SHERPA Robotics’ latest launch, a camera-controlled robot cell, the SherpaLoader®. It has been specially designed for loading and unloading CNC machines.
Depending on the specific process, stations are integrated into the loading process: Pre-stamping, turning (for processing the second side), measuring (for quality assurance) and marking (for ISO 9001-compliant traceability). This allows for effective automated processes.
The SherpaLoader® is an automated process that has also proven beneficial to large-scale manufacturers of machine tools because it offers high-quality and complex full automation to their processing machines. For manufacturers of smaller batch sizes and small to medium-sized customers who do not have an in-house solution in their portfolio, a strategic partnership with SHERPA Robotics allows them to offer their customers flexible automation ‘from a single source’.
Loading robots with 3D vision systems
Automated systems like the SherpaLoader® make the loading process very simple. The system is placed in front of the production machine using a lift truck and the corresponding loading medium, eg, table trolleys or pallets.
These systems eliminate the setup effort necessary with conventional techniques, such as the raw parts to be processed are no longer prepared using laser-cut sheet metal templates.
This is because the 3D vision system of the loading robot automatically detects the randomly deposited raw parts, picks them up and feeds them into the clamping system of the CNC machine. Then, after machining, the robot removes the finished workpieces from the CNC machine and places them back on the loading medium.
These processes maximise the spindle time, speeding up processes like pick-up and deposit of new and finished workpieces ‘in parallel’ to the machining time, ie, during the ongoing machining by the CNC machine.
Even the most advanced loading robot is unreliable if it does not have the right gripping technology. For increasing the efficiency of industrial production processes, gripping technologies now hold central ground, especially for the SherpaLoader®. To deliver a gripping technology of the highest quality and that is reliable, SHERPA Robotics chose the gripper specialist Zimmer Group from Rheinau.
They rely on the 2-jaw parallel grippers of the GPP5000 series and 3-jaw centric grippers of the GPD5000 series. The grippers of the 5000 series are highly robust, universally applicable pneumatic grippers that offer high gripping forces with short cycle times and boast a high level of exchange accuracy.
“The decisive factors for us in choosing Zimmer grippers were reliable gripping of a wide variety of workpieces and conditions, as well as the guaranteed freedom from maintenance of 30 million cycles. For a CNC automation application, this is equivalent to a lifetime warranty,” says Dr Eike Langenberg, Co-founder, SHERPA Robotics.
The GPP/GPD5000 series of grippers, which recently won IF and Red Dot Design Awards, currently make up the premium line at Zimmer Group with a robust, hard-coated steel-in-steel profile slot guide. As a result, they have virtually unbeatable robustness and very high gripping forces. The GPP/GPD5000 are also insensitive to overload, which benefits the SherpaLoader® in its work with an extremely high variance of workpieces under sometimes adverse operating conditions.
The grippers’ specially coated gripper jaws, low coefficient of friction, and exemplary emergency running properties ensure that the grippers - as mentioned above - can handle 30 million cycles without maintenance. Such continuous performance is possible because the gripper jaws are equipped with lubrication pockets for a reliable lubricant supply.
The developers have also used a double wiper for sealing the prismatic guides. The outer sealing lip wipes off dirt and dust, while the inner sealing lip ensures that the grease supply is maintained over the entire service life. With this double seal, the grippers have a tightness class of IP64 - a value that competitor products can only achieve with additional protectors, if at all.