The ideal picking model

O picking refers to the order picking activity in the storage area, considering mix and quantities of products requested in the purchase order. It is one of the most important activities within a warehouse, representing 30 to 40% of the labor cost, depending on the type of business. The model of picking most suitable for the operation depends on a series of variables such as: size of the picking units (pallets, layers of pallets, boxes, fractional boxes or items), number of orders shipped per day, variety of items, time interval available for the picking an order, products handled (weight, shape, degree of fragility, etc.), tolerance for picking errors, and available budget.

Figure 1 – Drivers used to define the degree of complexity of the operation

Source: ILOS

Regarding the place of execution of the picking, it can be done directly in the area where the products are stored (pickers to parts) or there may be a dedicated area for order assembly activity (parts to pickers). Each model serves a different context:

pickers to parts

The advantage of this model is that there is no need for an area reserved for separating orders, leaving more space for storing products. On the other hand, this model presents a greater need for displacement and a lower speed of picking, since the operator needs to pick up the products from their storage addresses at each order assembly. O pickers to parts It is indicated for a small variety of items, with a low level of fractionation and a small number of separate orders per day.

parts to pickers

In this model, order picking consists of two major steps. Before effectively assembling the orders with the composition of the requested products, a “pull” of the products that will compose a set of orders is carried out. The big benefit of order consolidation is reduced travel. For this, it is necessary to reserve an area to temporarily store the products that were “pulled” from the stock and another area where the orders will be assembled. In addition to displacement reduction, another advantage of this model is the higher speed of picking and the downside is the need to reserve valuable warehouse space for the activity. O parts to pickers It is suitable for operations with a large variety of items, small size of picking units, large numbers of orders and the need for speed.

Another way of classifying the picking according to the organization of activity among operators, with three main types: picking discreet, picking per lot and picking per zone.

Picking discreet

No picking discreet each operator collects one order at a time, item by item, being applied to high volume picking units and high ratio between: SKU's per order/ SKU's in stock. This type of organization has a number of advantages, mainly because it is the simplest, adapting perfectly when all documentation is on paper. The risk of errors in the activity is reduced, as there is only one document for each product picking order. However, it is the least productive procedure, as the operator must complete the entire picking order, the displacement time is much longer than in other procedures.

Picking by Batch

No picking per batch, each operator collects a group of orders jointly. By working with several orders per collection, with products common to several orders, this type of procedure has a productivity gain in relation to the others. However, it is only indicated when the products are mostly collected in fractional quantities (not in boxes), and when the orders have few different products and small volumes. The productivity gain is due to the reduction of operators' transit time. A negative point of this procedure is its greater complexity and its need to use severe measurements to minimize the risk of errors. Such measurements can be made using current technological solutions

Picking by Zone

No picking by zone the warehouse is divided into zones and each operator is associated with a set of items. This method is ideal for large storage areas, a wide variety of products and products that require different handling or packaging methods. Its advantage is that it allows different handling equipment to be used and its disadvantage is the difficulty of balancing the workload between different zones.

Figure 2 - Work organization methods in the picking activity

Source: ILOS

After deciding which model picking is most suitable for the company's operation, if the picking will be done in the storage area (pickers to parts) or if there will be a pre-separation for an area reserved for picking (parts to pickers), if each operator collects one order at a time (picking discrete), one set of orders at a time (picking per batch) or if each operator is responsible for a set of products (picking by zone), the next step is to define the most adequate structure to support the operation. flow rack, stations picking, picking by voice, electronic collector, picking by light, dynamic station, carousel, mini load, conveyor systems, sorter, checkweigher, a-frame, robots of picking, are some of the existing systems and technologies to make the order picking activity more productive and accurate. But this is the topic for a next post.

References:
'https://ilos.com.br/web/estrategias-de-picking-na-armazenagem/