Shoe Industry Revolution: The Next 90% Traditional Shoe Production Lines Are Dominated By Robots.

The footwear assembly line has always been very traditional and highly labor intensive, especially in the shoe last / production stage of footwear manufacturing technology. The new technology, especially process automation and robotics, shows that the organization of this shoemaking stage has innovative methods. Robots are attracting more and more attention in various manufacturing fields, especially in some countries where labor costs are rising rapidly, including China.

Based on this, this paper discusses the footwear robot used for making shoes with a shoe upper and a bonding outsole to illustrate how the assembly line's organization is affected by the robot and how the structure of the manufacturing system changes.

Our focus will be Footwear assembly (Manufacturing) production lines, but this does not mean that other departments do not use robots. In the past and recently, experiments on robots were carried out in the completion of operations. People's ideas have promoted robots to be used for sewing tasks (3D sewn complex shoe geometry structures) and laser marking.

There are still huge room for development in these areas, but at present, we are still in the stage of applied research, and it takes time to see the emergence of the first batch of industrial applications. On the contrary, for manufacturing operations, we already have some implementation examples currently in production and new ideas discussed in this analysis.

In investigating the current and future applications of robots for shoemaking, we can understand many different ways of robot operation:

1. Robot operated end effector

Such a plan involves fixing a specific end effector (optimized for tasks to be executed, sometimes using multiple tools to set up layouts, installing two tools on the same end effector), and fixing it to the robot wrist, installing the shoes that need to be processed on the special support (when the robot is part of the automation system, usually conveying the pallet of shoes) and reliably fixing the shoes when the robot performs the processing task.

　 2. Robots operate footwear.

The second option is to install a special clamping mechanism into the robot wrist, and use clips to hold the shoes from the given location in the space (usually shoes mounted on the pallet and in front of the robot) to grasp the shoes (or preferably grasp the shoe last by installing metal connecting plates on them) and move the shoes to one or more active workstations (each workstation performs a specific task or part of the task).

In this case, the robot must also follow the predefined path movement that is programmed in a way similar to the previous situation (each specific task or sub task trajectory to be executed).

Robots only perform pickup and placement operations, which may be the most innovative solution, so the lack of implementation examples in this area is not surprising. In this case, the robot does not carry out any "activity" tasks on the shoes, but transplants the shoes that need to be processed from one station to another. This may be the most "human God integration" way of using robots, that is, the tasks performed by robots are very similar to the tasks performed by the operators (picking up shoes from the conveyor and putting them into any type of automatic machines or transferring shoes from one machine to another). These operations are typical picking and placing tasks, which belong to the typical operation field of robots. We can make full use of its sensitivity and speed. Transporters and machines or machines and machines or even man-machine tasks are the tasks we can imagine in the final scene of shoemaking robots.

If these are the ways in which robots can perform footwear operations, we can now understand how these methods are actually applied to typical manufacturing lines based on robots. To this end, we must consider two factors: the robot itself in all possible schemes, and how the footwear is transferred from one workstation to another workstation, namely, which way of transmission is adopted.

These two elements work together and work mode to achieve some typical ones. Operation plan 。

　　 1. Robot + conveyor production line (mixed)

The key element of the scheme is the transmitter, which is quite common in all shoe factories.

In this typical setup, the conveyor transmits shoe last, footwear semi-finished products and components in an annular fashion; depending on the specific manufacturing sequence and production target of the production line, machines and workstations are distributed along the ring (or other shapes). The robot unit can conveniently "integrate" in this layout, usually can replace one or more workers manual operation (such as rough or adhesive), is the use of special CNC shoe machine alternative.

However, the transmission system directly interacting with it does not really serve specific robot units for a given machining task. In fact, the operator operates two elements of the production system, making it an independent part of the manual task connection, and usually completes the conveyor. footwear Transmission for processing in robot unit.

ANZANI and ROBOT SYSTEM (robot systems) have demonstrated the interesting development of this concept at the SIMAC exhibition. The solutions put forward by the two companies are based on traditional conveyor production lines with multiple stacking discs. Stacking discs are equipped with special fixtures. When the shoe last moves from one workstation to another on the production line, the fixture can fix the shoe last. A specific index mechanism is used to stop the shoe last and clamp it reliably in a specific workstation. The robot workstation performs footwear processing tasks (such as shoe bottom or side roughing); a very basic intelligent conveyors for simple conveyors; and a more inexpensive solution than the complex and expensive stacked disk production line.

　 2. Fully automated robot production line (based on pallets)

We can identify a number of distinctive elements that represent the first-class technology of such specific implementation.

The number of robots on the production line can be compared with the number of special shoe making machines (CNC or manual), and can even surpass. Robots are used in typical manufacturing operations and some initial steps in the completion phase.

A pallet based conveyor system is specially designed for all kinds of robot workstations. The system integrates some thermal adjustment units (heat setting machine and cooler) and a certain number of specific design machines and fixtures to complete the unfinished manufacturing sequences and steps of robots or special machines.

The computer is used to monitor the entire manufacturing process (mobile pallet, monitoring the processing cycle, tracking batches of production lines, managing various automatic machines), allowing the high level control process itself and the best use of robots distributed along the production line.

There are still a number of operators on the production line (relatively high number), but they mainly carry out the most detailed and demanding production process tasks (which we can call "value-added tasks") or maintain the production line at the target processing rate.

Perhaps the situation is not always so complex and comprehensive to cover the entire manufacturing and completion stage. However, there are already such examples in the market; it is not devoted to producing relatively simple low cost footwear, but also to produce footwear that requires high quality standards. These solutions are not without problems and technical bottlenecks, such as tight layout and impossible handling of the same production line footwear with significant manufacturing cycle differences.

3. Conveyor production line + robot equipment.

Although some development activities are under way, there is no practical application of this final structure. In this scheme, the advantages of the robot being able to work quickly and pick and place flexibly are fully utilized.

For example, consider the most modern conveyor system, which integrates all the most important heating units, surrounded by all kinds of first-class high-tech machines. If we exclude the number of operations, no matter what the technical level of the machine is used, we still need to provide operators (value-added tasks). For many other operations, the role of the workers is only limited to loading and unloading machines. Ideally, this is a pick up and placement task that a robot can perform. For this purpose, we can set up a kind of setup, the robot operates in this setup, pick up shoes from the conveyor stack tray, place shoes on suitable automatic machines (for reshaping, roughing or bonding), and put the shoes back to the stacked disk at the end of the steps. Therefore, we can eliminate the non value-added task operators and reduce the number of relevant operators.

At this point, we must state that the situation we describe is a very theoretical scenario, for a variety of reasons. First of all, picking up unrestricted random placement shoes from mobile transmitters is obviously not an easy task unless we consider installing high-tech sensors for robots, such as optical systems. Secondly, the automation machines we know today do not achieve the same degree of automation as their names induce us to imagine. We still need workers to start and stop, monitor, and modify their operations when necessary.

In short, the machine design has not yet reached the level of unattended operation. Therefore, it is necessary to achieve certain development so that it can really work on its own. Therefore, it is not surprising that there is no such example of using robots in shoemaking at present. However, we believe that this solution is highly attractive, at least it represents a relatively simple upgrade of existing manufacturing lines, with limited investment (because the purchase price of modern machines is reduced) and has long-term potential for savings.

4. Robot equipment - no conveyor production line.

In this final structure, we may find answers to previous restrictions. It has been a long time since the workers are grouped into teams and the machines used are closely positioned in the Kanban unit (such as setup). Now, another motive has been found, which can perfectly match the manufacturing paradigm of "Lean Factory", emphasizing the central role of labor, ability and technology.

This is a valuable starting point for generating this idea, taking advantage of the full use of robots and their capabilities. The idea here is to use automated machines as far as possible to perform all the most relevant activities of footwear, such as shaping, roughing and bonding, using high-speed, lightweight and low-cost robots to handle all handling operations, and use full-time workers to perform most of the high value-added processing steps (shoe last, outsole treatment and similar work). The main feature of this extremely compact and compact setup is that there are no transmitters or other types of transmission systems (Kanban, etc.), and the operators are closely cooperating with robots, and have built-in buffering capability.

Do robots and automation really trigger the new industrial revolution in manufacturing?

Of course, a new system approach that meets the requirements of shoe manufacturers has arrived. Therefore, we expect to see more in the future: less single machine, more production systems, single processing tasks with less focus and more processing methods, so as to provide comprehensive solutions for specific production needs, less rigid systems and lighter solutions.