Product handling in (high quality) manufacturing industry
In the manufacturing industry, product handling is a necessary part of the manufacturing process. In the supply of raw materials, the processing of material into parts and products and the transport of these products to the next step in the chain.
At some companies, the entire (handling) process has already been automated, while others still do everything manually – often as a conscious choice! The degree of automation in product handling is highly dependent on the end product of the manufacturing company. A company that mass-produces a single or a few type(s) of products will have a completely different handling requirement compared to a company that produces only a few (or unique) products per year. In practice, many manufacturing companies are somewhere in between.
In the high-quality manufacturing industry, such as the production of medical devices or consumer electronics, handling often involves small and/or vulnerable products. Picking up, carrying and moving must be done with great care so as not to damage products. We see that more and more companies are looking for sophisticated handling solutions. The number of standardised handling solutions on the market is growing rapidly. However, these solutions are often not sufficient for the high-quality manufacturing industry. A tailor-made solution can make a big difference in these companies.
Picking and placing
When a company has a handling issue, a distinction must be made between picking and placing and moving products. Picking and placing can be compared to how human fingers grip and release a product. The movement is then done with the wrist or arm. Movement is therefore separated from gripping, even in automated handling solutions.
First of all, picking and placing. The starting point for the design of the gripper, is the product itself: dimensions, mass, material density, surface and shape of the product are the most important. The way in which a product is supplied or must be removed also plays a major role. In addition, other requirements imposed on the solution are taken into account; speed, accuracy, longevity, control and environmental factors. With this in mind, the choice can then be made to use a mechanical gripper, a vacuum gripper or yet another type of gripper.
A mechanical gripper is usually literally a ‘gripper’ with a jaw that closes around the product. A mechanical gripper can, among other things, have a servo motor or can be pneumatically controlled. The advantage of a servo gripper is that it can sense and dose force, and can therefore adapt to the product. Opening and closing happens gradually, giving more control. A pneumatically controlled mechanical gripper grips in one go and is therefore a lot faster.
Vacuum grippers ensure minimally intensive contact with the product. The product is only touched on one side. For this, a product does not necessarily have to be flat and smooth. There are all kinds of solutions on the market to ‘suck up’ the most special shapes and materials. The depth and number of bellows in the suction cup ensure that the correct shape is picked up. The size of the vacuum suction cup and the vacuum generator coupled to it determines the amount of force and thus the weight that can be carried.
In the manufacturing industry we see many multiple grippers. These grippers are designed in such a way that they can grip multiple products at the same time. Multifunctional grippers are also widely used. Several functions are then combined on a single gripper. It is quite possible that both mechanical and vacuum solutions are present. Think of a grab that must be able to pick up different products. The gripper can have a mechanical gripper on one side to pick up product A and on the other side a suction cup for product B. Especially with agile industrial robots, we often see that grippers are designed and used multifunctionally. By means of an exchange system on the robot, it is also possible to exchange different grippers during the process.
When the product is firmly gripped, it can be moved. This transportation is performed with actuators, often referred to as axes in mechanical engineering. An industrial robot is essentially no more than a collection of axes in order to create great freedom of movement. Actuators can move grippers, but also move product carriers, such as loose products in trays or fixed products in carriers.
In special machine building we see that a choice is almost always made between a pneumatic or an electric actuator or a combination of these. The trade-off between these two controls is based on a number of characteristics of both types of actuators. A pneumatic actuator is often more compact, cheaper, more resistant to shocks and lighter in weight. Compressed air is applied to move the actuator. An electric actuator (usually equipped with a servo motor), on the other hand, is often easier to program and control and has a higher accuracy with a more controlled movement. In general, when choosing the right actuator, pneumatics are more efficient at shorter distances, greater force required and longer cycle times, and servo-electric is a better match for longer distances, lower force requirements and shorter cycle times.
Tackling a handling challenge with a tailor-made solution can lead to surprising insights. During the design and development process, the surrounding production steps are examined and, if necessary, also optimised. This can lead to an overall improved production process. In addition, automated handling improves the production process by increasing the speed, flexibility and quality of the process. In addition, automated handling offers the possibility to generate and collect more data about the production process.
A smart solution that is frequently used is the use of an IO link. This means you only have one physical cable that carries both data and power. The IO-link controls sensors in the handling solution and keeps track of parameters of these sensors. The advantage of an IO-link sensor is that the sensor can measure the distance to a product and distinguish between the size of objects. This is in contrast to a normal sensor that can only detect and report a presence/absence. Due to the amount of data and the statuses of sensors that the IO-link keeps track of, it is possible to predict the maintenance of certain processes.
Connectivity with the rest of the production process and the option to control the installation from a distance also offer new possibilities. This way, we are in the middle of the fourth industrial revolution to produce more efficiently, more flexibly and zero-defect.