When a company needs to install a merge conveyor, there are a range of variables that make the decision a difficult one.

The need for a merge conveyor in a packaging line is itself enough to indicate a process with a very high degree of complexity and automation throughout.

Choosing the right merge conveyor means taking into account:

• how it protects the quality of the items;
• making sure the machines downstream work as intended;
• the efficiency of the entire packaging line.

It is clear therefore that mistakes could be critical.
The risk of ending up with an ineffective and obsolete packaging line is too high. That is why, whenever a client asks me which model is the best fit, I always start with a thorough analysis of their current operations, needs and expectations.

So, let’s start with a quick overview of these machines, explaining their purpose, their benefits and their limitations.

To start with, there are different types of merge conveyors, but the majority fall into one of two broad categories: mechanical (or buffer) merges and dynamic merges.

Buffer merges

This product is equipped with “gates” at the entry lanes that remain closed until the convergence area is free, at which point they let the items through one after the other.

This is a simple and cost-effective solution that works as long as two conditions are met:

• the items must be able to withstand the pressure during the buffering phase;
• the downstream machines must be able to receive the items in a convoy without being triggered to do so.

The first point is related to the integrity of the items, and essentially means that it is appropriate only for boxes, trays and products stacked in tight packaging.

The second point requires greater detail.
As they leave the merge, the items are touching each other, or very close to it, but the speed of the conveyor belt is the same as it would be with products that space out the items with one item’s worth of space between one and the next.
The average productivity of the line doesn’t change, but when the convoy arrives downstream, the machine’s productivity at that moment is doubled.

That is why the machine must be able to manage the flow, otherwise it is necessary to regulate the flow with one conveyor belt to increase the speed and another to decrease it after the merge; however, this solution is naturally bulkier, with two more motors and a more complicated logic controller.

Dynamic merges

When handling items that cannot be buffered for fear of overlap (generally pillow pouch or flowpack packaging) or damage caused by excessive pressure or because downstream machines need the items to arrive at a regular frequency and with a certain distance between one item and the next, then it becomes necessary to install a dynamic system.

A dynamic belt merge is a scalable system consisting of a series of modulating conveyor belts that increase or decrease the speed of the items as they come through, ensuring enough space to avoid a situation where two items reach the convergence point at the same time.

With these devices, the products are always handled one at a time, thereby avoiding having groups of items together and ensuring regular spacing. As the production pace increases, the number of modulators must also increase.

M.H. is an Italian brand with thirty years of experience with handling movement and logistics within production facilities in every sector of industry, with a range of solutions for buffer systems.

When it comes to dynamic merge conveyors, MH’s fastest system isthe HP dynamic system that can reach manufacturing of up to 600 ppm for 150mm flowpacks. Depending on the weight and packaging of the items, it is possible to use up to five phases of conveyors with brushless DC motor and vacuum suction to manage rapid acceleration.

Our wealth of experience means that M.H. is also able to support companies in optimising and streamlining their packaging lines with our innovative and technologically advanced solutions.

he first questions that we have to ask ourselves in these situations are: Are my packaging machines suited to this system? Can my goods be conveyed using this type of merge?

Buffer or mechanical merges are equipped with “gates” at the entry lanes that remain closed until the convergence area is free; once the gates have been opened, these release the products through one after the other.

If you want to find out more about our products or to discover how you can optimise your packaging process

It is necessary to insert a belt merge, which indicates that we’re working with a packaging line with a high degree of complexity and automation.
Process optimization is the goal, improving the packaging machine’s performance. But if you install the “wrong” system, you risk the opposite effect of having to contend with regular unplanned downtime.

When it comes to dynamic belt merges, we at MH have developed the HP dynamic system that can reach manufacturing of 600 ppm for 150mm flowpacks.

This system includes one-by-one timing of the items, created using a multi-belt system with independent power for each of the entry lanes. The machine’s control system enables oversight of the step between the packaging coming out of the system and ensures that the timing occurs without contact, removing the risk of jams, overlaps or damage.

Throughout my career, I have often come across companies who make the mistake of underestimating the importance of the packaging line of their products dei loro prodotti.

The result: Reduced efficiency and the risk that machines may not work at maximum capacity, or worse still, grind to a halt.

These situations happen because someone erroneously thinks that product packaging requires buying the primary and, if necessary, secondary packaging machines and nothing more, failing to take into account the systems necessary to connect them.

There is an image that often comes to mind when I have to tackle this kind of problem: I think of the conveyor belts like the circulatory system that carries blood around the body and allows the different organs to function. Different packaging machines have to be connected to each other by an efficient “circulatory system” that is able to iron out any discrepancies that may exist between them.

Underestimating the importance of this “circulatory system” can result in production problems and delays.

When would we need a storage system?

There are two situations in which storage systems are critical:

• when we need to compensate for operating differences between two machines that are connected in series;
• when we need to regain productivity during micro-stops of downstream machines.

The first condition typically occurs when an intermittent machine is connected to a continuous one; for example, when an upstream machine produces product groups at regular intervals, while the downstream machine requires an ongoing flow of products equidistant from each other.

In the second case, on the other hand, we have start-ups and shut-downs of two machines that are incompatible with each other.

In these cases a buffer is a simple solution that requires a few metres of conveyor belt to regulate the flow and avoid regular stoppages in the production process.

As you can imagine, the efficiency gains are significant.

Which buffer to choose?

The choice of system depends on various considerations (including financial ones) but there are three variables that must be kept in mind:

• the operating method of the storage system;
• the available storage space;
• the recovery capacity.

It is only by carefully considering these factors that we can move to a rapid consideration of the investment in the purchase of a buffer.

How the buffer works

The buffer can either be LIFO(Last In First Out), in which, as the name suggests, the first product to enter the buffer is the last one to leave it, or FIFO (First In First Out), in which the first product into the buffer is the first one out.

Among FIFO systems, there is a choice of:

• machines that are external to the production line;
• machinery that keeps the product within the production line, gradually increasing the available transportation space. In the latter case, the product is fully traceable, and it is considered more of an advanced storage system rather than a buffer.

LIFO buffers are the cheaper and simpler models. They are particularly suited to non-perishable, with long expiry dates, that can wait a long time for final packaging.

FIFO systems, on the other hand, are recommended for fresh products that must pass through the packaging line within a limited time frame in order to retain their freshness. These machines are usually more complex and their price is often not far off that of the packaging machines themselves.

Storage space

The decision regarding the dimensions of the storage space is linked to the efficiency of the upstream and downstream packaging machines and the time it takes to bring them back online in cases of micro-stops. In cases of a longer stop caused by mechanical failure, it is unlikely that a system within the packaging line will be sufficient to avoid any interruption at all.

In most cases, the storage space can correspond to a production time of 2-5 minutes; obviously there may be situations in which the demand for storage is notably higher and in this case it is worth considering the cost-benefit analysis and the impact that the buffer’s presence might have on the time it takes to bring the packaging line back online.

Often, the long time to recover from a micro-stop is because the operator is unable to focus exclusively on fixing the problem, because the upstream products continue to arrive, with the potential for pressure and chaos along the line.
Real-world conditions have shown that the presence of a buffer can help to contain machine downtimes.

Another example might be whereproducts travel a long distance along the packaging line and the client wants the ability to fully empty them. In this case, the necessary space can rise to 20 minutes or more. Such situations are rare but can happen.

Recovery capacity

A properly sized packaging line requires a buffer that is able to recover the product during regular production. The downstream machine must also be able to work at a rate greater than its nominal one, usually 10%-20% faster.

The time for emptying the buffer depends on this recovery capacity.

For more information on this subject, I have published a video dedicated to choosing the right storage system.

M.H. is an Italian brand with thirty years of experience with handling movement and logistics within production facilities in every sector of industry. We offer dedicated solutions for LIFO and FIFO storage systems, tailored to the client’s needs.

Our wealth of experience and our innovative and technologically advanced solutions mean that M.H. is also able to support companies in optimizing and streamlining their packaging lines.