Are robots always the better solution for palletising?

Are robots always the better solution for palletising?

 

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2016/05: About robot palletising

Maarten van Leeuwen

Alvey is, let us admit it, not very well known for its robot solutions. Some people think we have something against them. This is not true. Others think we know little about them. This, also, is not true. In fact, we are engaged in robot projects at almost any point in time during the year. However, it is true that the majority of our projects are not robot projects. This article is about the pros and cons of robots, for palletising purposes.

When we study a new project, our internal general rule is to first see if it can be done with robots. Why? Simple. If it CAN be done with a robot, it is likely to be the cheapest solution. Also, we obviously do not make the robots: we buy them from ABB, Fanuc or Kuka. We make the gripper in the vast majority of the cases ourselves, but this is not a lot of work. It means our resources remain largely free to do other projects, which is great for throughput. And many customers love robots, as they are interesting and lively to look at while they are at work and yes, dear reader, sentiments DO matter in this world, no matter how many among us would like to deny it.

Another distinct advantage of robots is that they are inherently “multi-line”, meaning that they are likely to be capable to handle multiple packaging lines at the same time.

So robots are inexpensive, good for our business, fun to watch and can handle multiple packaging lines. Are there disadvantages? Yes there are, and this is the reason why the number we implement remains a minority.

First, of course, robots are limited to about 8 cycles a minute, depending on the configuration. That means it can move around and “do something” roughly 8 times a minute. Such as picking up a box and putting it on a pallet. Obviously, in many cases we can pick up more than one box, such as a row, or even a whole layer, in one cycle. However, palletising involves more than picking up boxes and putting them down. We need to pick the empty pallet, unless we have a conveyor for this – but this adds to costs. Often, there is a bottom sheet to put, and interlayer sheets, and possibly a top sheet. All this is eating into our cycles, and the more different things we need to pick up, the more complex the gripper gets.

Talking about the gripper, this needs to put the boxes down and go back. Depending on the type of the gripper and the pallet pattern, this often involves leaving some space in between the boxes, making for a – slightly – less stable pallet. If, in addition, the boxes are not perfect – such as we often see in deepfrozen potatoes and vegetables, the stability of the pallet becomes a challenge. The robot is programmed to move to all positions required given box dimensions. However, if box dimensions vary from one batch to another (for the same product) this may cause stacking quality and stability issues. If, in addition, we need clamping devices to stabilise the layer after forming, we start to get a fairly complex installation. So much so, that the cost advantages start to dwindle and a layer palletising machine starts to become the easier, and, ultimately, more cost effective solution.

A final disadvantage of robots is space. Once all safety, accessibility and peripheral issues are taken into account, they often tend to eat up a lot of space, which can be a challenge in existing factories, and in general is expensive in our part of the world.

Alvey is frequently asked to quote for projects with high-speed production lines, and, as you probably know, deepfreeze is one of our specialisations. As we have seen earlier, robots are typically not ideal for either situation.

This article relates to the topic in very broad terms. In reality, there are no clear and hard-cut answers. Each case is unique, and each case needs to be studied in detail. In the end of the day, it does not matter if we use robots or something else. What matters is that the customer gets an installation he is delighted with.

Maarten van Leeuwen
Group Managing Director

If you wish to react to this article, you can send us your feedback to club@alvey.be.

 

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    Are robots always the better solution for palletising?

    Are robots always the better solution for palletising?

     

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