We made an article on robotic bending before but because we like this topic we would like to make a new one. Maybe we will repeat some thoughts but probably you can even do something new from it. Let us start from the beginning.
The robotic bending on the press brake is the process where the operator is replaced by the robot for the function of holding the parts, positioning the parts, feeding the parts, and taking them away after the bending. We will not discuss in this topic other possible functions like changing the bending tools by the robot because this function is also presented but not so widely used.
The press brake with the installed robot is usually called a “robotic bending cell”. The robot takes the main operator function: take a plate from the batch, perform the right positioning with the special inclined table, then feed it into the press brake and position it where necessary. After the bending process robot moves the final part to another place for putting into the batch and removal from a robotic cell in the future.
The robot completely replaces the operator but for sure the operator should be presented for necessary programming, main control, bringing in the plates to be bent, and removing the bent parts away. Meanwhile, because it is not a constant job it is more reasonable to call it control and programming plus material handling functions. Anyway in this mode even one operator can control several bending cells and also do other necessary jobs so it is a great boost for personnel functions at the factory.
There is a general advantage of robotic bending and it is very big – the complete automation process and the possibility to work in the mode 24/7 without any limits, stops, pauses with high productivity and optimal precision. Robots cannot be tired and they cannot lose concentration during the last hours of the work shift which usually leads to mistakes. Also, the sheet metal parts could be medium weight or heavy – it is a big problem for the operator to handle them all the time and it is not a problem for the robot based on their possible payloads and capacities. So the main advantage of robot bending is the same as any robotic production cell in the industry – making the functions faster, precisely, and with big productivity.
The second advantage of a robot is not typical but interesting – better to call it construction advantage. Usually operator should position the part according to the position of the back gauge of the press brake as the necessary assistance. If we are talking about the robot it can position the part based on its program made. In this way, the position of the back gauge is not so important compared to human functioning. So in this case during the planning of the composition of the robotic bending cell, the expensive back gauge with 6 axes for example could be ignored and replaced with a more simple one. This allows for saving some costs for investment into the equipment. To tell the truth, theoretically, the press brake could be even without the back gauge completely if we are talking about standard sheet metal parts and not very precise tolerances.
We would like to underline one more advantage of robotic cells which is not clear to everybody. Automatic bending brings the factory to a new level, a high-technology process, completely digital and effective. It is a positive picture for any investors and customers, with great modern equipment, completely safe and eco-friendly for the environment. We want to say that almost all modern robots are free of service so they do not require ordinary maintenance for functioning.
Well, all marketing information will not tell you but there are disadvantages of robotic bending as well and we would like to specify them. Maybe it helps anybody to make the right choice and to study the picture completely.
At first – the investment part. Installation of a robotic bending cell is much and much more expensive than just installation of a press brake and inviting the operator to bend it. And we are not talking about the conditions where the robot is a necessary choice (for example for heavy parts). We are talking about economic efficiency and realistic return of the investments from the robot so it will be not left as just an expensive toy. The main reason to bend with the robot is a high quantity of completely equal production to bring more speed to the process of one or two types of parts.
Moreover completely contrary will be the situation if there are medium or low volumes of equal parts and the assortment is quite big – finally the robot will have a necessity for continuous reprogramming, new setup, and the production effect will be low.
Also, robots have a lot of limitations. To handle the part robot has to have a special holder or fixator. Usually, it is a holding device with suction caps to take a part or it is the mechanical gripper like a fork to clamp the piece from the edge. Small parts, holes, formings, and complicated geometry can make robotic bending very hard to realize or even impossible because of the impossibility of clamping.
Usually, the supply of robotic cells from the machine tool supplier or robotic integrator (the company that makes different solutions based on industrial robots) is completely connected with the production program and development of holders and grippers. All parts of robotic cells could be universal like positioning tables, positioners of pieces, safety devices, etc. but the holders should work exactly with your parts, otherwise, there is no reason to purchase the robotic cell. Also, robots as you can imagine are limited with functions.
So manufacturers of robotic cells implement additional robots like separate ones to change bending tools. On one side the robot is quite a universal tool that could be installed for a lot of functions to do with the proper auxiliary equipment and programming. From the other side robotic functionality should be as simple as possible – in this case, it will provide the maximum efficiency. The operator can change the tooling in minutes but if you make it automatic for the robotic cell you should re-set up the complete process.
One more story – the operator’s role is to make a manual bending process on the machine. Contrary to robotic bending – imagine if there are no part control functions or machine vision and the robot makes a complete batch completely defective due to the mistake. The operator can make a mistake in 2-3 first pieces to stop but improper programming of the robot could lead to much bigger problems.
In the end should be noted that all automatic production is based on country and average salary so compared to operator’s costs the replacement with a robot could be much more effective and profitable in rich countries with big salaries. Anyway, the robotic bending process and automatic robotic bending cell today is one of the parts of Industry 4.0 and represents the modern technology situation. And it is also just beautiful and very attractive to watch, that is why you will find so many robots at industrial exhibitions of machine tools.