Compressed air is the basis for successful automation. This form of energy can be used in many ways and combines speed, power as well as low weight. However, the cost to generate it is relatively high, as electrical energy must be converted for this purpose via several efficiency losses. Even though the compressed air-less factory is merely mentioned as a buzzword for a trend, technological alternatives are needed right now to make vacuum automation independent of the compressed air hose.
«The aim is not to replace compressed air-based ejector systems for vacuum generation. We want to create alternatives that reduce energy consumption and still function when no or too little compressed air is available,» explains Dr. Kurt Schmalz, managing partner of J. Schmalz GmbH. Possible scenarios include mobile robots or robot cells that operate in an area that is not connected to the compressed air system. In percentage terms, the vacuum generators consume very little energy compared to the entire plant.
Vacuum generator made small
The solution is purely electric vacuum generators that are so compact that they can also be mounted directly on the robot arm. Electric vacuum generators are nothing new: «We have long had electric pumps and blowers on offer that operators use in automated and manual handling when high suction flow rates are required. However, these are too large and too heavy for use on a robot arm,» explains Dr. Kurt Schmalz. Schmalz has therefore expanded its portfolio of electric vacuum generators in the direction of smaller and lighter designs and introduced the first cobot pump, the ECBPi, in 2016. This is an electric vacuum generator and mechanical gripper interface to the robot in one. «We were pioneers in vacuum automation with this,» comments the managing partner. The challenge: In addition to vacuum generation, Schmalz also had to implement the airless depositing function in a very confined space. The solution for the fast depositing of the workpiece is called: ventilation instead of blowing off.
Even more compact is the new ECBPMi cobot pump, which is designed for handling small parts of airtight objects. «The lightweight end-of-arm components are ideal for cobots and lightweight robots. They do not require compressed air, which means they can also be used on autonomous transport vehicles,» says Dr. Kurt Schmalz, outlining one potential application. However, it is no longer just the small lightweight robots for which detaching from compressed air makes sense: With the trend towards sustainability and thus the demand for more efficient systems, the need for compressed air-independent vacuum automation has also increased for larger systems.
Compressed air offers several advantages: the high power density and the realizable operationally reliable functions in the pneumatic components. This makes them small in size, robust and fast. «If we look at our vacuum ejectors, which convert overpressure into vacuum almost optimally and can react adaptively to the handling process with their air saving function, we have powerful and efficient components with savings of up to 95 percent. However, the air saving functions cannot be used everywhere,» adds the expert.
«If the airless factory should come at some point, manufacturers of pneumatic components and handling technology will have to supply alternative products that function purely electrically. We are therefore pursuing a parallel strategy,» explains Dr. Kurt Schmalz. Following this strategy, Schmalz has now developed the GCPi electric vacuum generator: It is larger than the Cobot pump and joins the new electric vacuum generators in the existing portfolio. With the GCPi, Schmalz is breaking away from the previous standard of mounting the vacuum generator directly on the robot arm. Instead, the user mounts the powerful GCPi on the robot base so that it can supply several suction cups on the robot gripper from there. The challenge here is again the purely electrical detachment of the load. Schmalz has also integrated a ventilation function into the GCPi. Depending on the length of the hose to the suction cup, however, pressure equalization with the atmosphere can be delayed. In this case, the ventilation function can also be decoupled from the pump. «Here we have to change our perspective and think in terms of new system architectures,» says Dr. Kurt Schmalz.
That’s why Schmalz developed the LQE electric ventilation valve. «This is the real innovation. With it, we can continue to use larger vacuum generators centrally and still work decentrally in a highly dynamic manner – with very short set-down times. It has been shown that direct atmospheric venting is often even faster than active blow-off with compressed air,» clarifies Dr. Kurt Schmalz. The LQE ventilation valve offers even more advantages: It allows the lines to be pressurized with vacuum. When the valve opens, the vacuum on the gripper builds up immediately. «It is an intelligent valve that can also replicate the air saving function of our compact ejectors,» explains the managing partner. This additionally contributes to the energy efficiency of compressed air-free vacuum handling.
«Just because of vacuum handling, the compressed air is not switched off,» emphasizes Dr. Kurt Schmalz. If a connection is available, the ejector is a robust, efficient and powerful way to generate vacuum for automated handling. All issues of vacuum handling technology were thus considered solved until the question of sustainability came to the fore. «The industry has to fundamentally think about compressed air. Our task is to develop alternatives,» says the vacuum pioneer. Schmalz is taking the electrification route: an electric vacuum generator can be more sustainable – in terms of the overall system. «Regardless of whether with or without compressed air: we have the right solution in our portfolio for every application,» concludes Dr. Kurt Schmalz.
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