Assembly supply

Published on: November 3, 2015 / Update from: April 24, 2021 - Author: Konrad Wolfenstein

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Deliver small components efficiently

Whether companies from the automotive and manufacturing industry, electrical engineering, oil & gas or medical technology: This solution is aimed at medium-sized companies and corporations with series production and a wide variety of variants. For all of these companies, the smooth provision of spare parts on the production lines is of utmost importance. However, the lack of space that prevails in many companies often stands in the way of this.

The parts are often stored further away in shelving or high-bay warehouses and transported to the assembly line when called. At first glance, this is a cost-saving technology, but it requires long distances and a lot of personnel. In addition, it proves to be quite inflexible when the product range changes and is not optimal in terms of the accuracy of access.

The alternative is to convert to an automated delivery system that delivers the required small parts effectively and precisely. For such low-volume items, AKL are often considered the first choice. These are mostly aimed at extensive ranges with 4,000 or more containers. This is also the disadvantage of these systems, as due to their size they usually do not fit in the immediate vicinity of the assembly lines and thus lengthen the travel times for the goods.

Picking on the assembly line

We are therefore looking for a model that is compact enough to be placed in limited spaces and that also picks the required items reliably and quickly. The following comparison illustrates the advantages of such a solution, using the Vertical Buffer Module called LR 35 recently introduced by the intralogistics manufacturer Kardex Remstar as an example.

The system is an automated vertical buffer and picking warehouse for storing small parts in containers and trays. It differs from a classic AKL in that it has a significantly higher picking performance with up to 250 double cycles per hour. Due to its design, it only requires around a third of the energy consumption of conventional AKL.

The payload per shelf is 35kg. The device accommodates AKL-compatible containers with external dimensions of up to 600x400mm and up to 640x440mm. A mix of different sizes and heights is possible. Due to its small device width (from 1.92m) and height (from 2.5m), it can be placed comparatively close to an assembly line, which minimizes travel times compared to larger AKL.

Order picking with conventional rack storage vs. automated system

Initial situation

In shelving or pallet racking, production components are often stored in container types of different sizes, which leads to unfavorable storage space occupancy because the shelves are not used optimally in terms of both depth and height.
Filling levels of 60 to 70 percent are the rule rather than the exception. When called off, the orders are processed one after the other, meaning the order pickers have to visit a large part of the storage locations, possibly the same ones several times in quick succession. In addition to long distances and the resulting slow preparation times, there is a risk of incorrect picking, for example due to reading errors or the accidental removal of items from a neighboring storage location.

Effects

This type of picking is time-consuming and complex. This means that assembly orders have to be provided with a long lead time so that consistent production can take place. Incorrectly picked orders also lead to delays in the entire process and thus to significant costs - if not completely incorrect parts are installed.

If new production parts are stored, this usually leads to complex and time-consuming rearrangements in the shelves. In addition, the entire picking process is physically demanding and unergonomic for the employees (long distances, heavy loads, bending, lifting).

To address this problem, the static storage systems in the warehouse can be replaced by automated, dynamic devices. Due to the manageable dimensions of the small Vertical Buffer Module, the parts can be stored close to assembly, from where the order containers are transported via conveyor technology directly to the assembly stations as soon as they are requested. The small components can also be stored in container types with different dimensions, which optimizes the storage volume used.

The automation and direct connection of the new storage device to the assembly ensure that the personnel requirement for picking is reduced. The required items are provided to the picker automatically and ergonomically according to the “goods to person” principle. In this way, the order picker's walking distances are reduced to a minimum, the health aspect of the work is promoted and at the same time the speed is increased. The risk of packing errors is also reduced many times over thanks to automatic provision. To further increase precision, each order container is assigned a put-to-light display.

The optical displays at the removal opening ensure error-free and quick picking. Additional picking information played via a display shows the order picker exactly from which storage location which item is to be picked and in what quantity. The order picker grabs the required parts from the container and confirms the removal using an acknowledgment button, which is attached directly to the removal opening. At the same time, the picking cart already shows which order container the removed item belongs to. The order picker places the goods in the designated order container and confirms this on the put-to-light display. If the same article is required for several orders in a batch, the employee removes the total quantity of the article and distributes it to the corresponding order containers according to the specified quantities. Software-controlled batch picking reduces machine travel for storage devices to a minimum.

If an order from the batch has been completely picked, the employee is visually informed of this, which they simply have to confirm at the push of a button. The order container is now ready for further processing in assembly. If minimum stocks are reached during the picking process, the vertical buffer warehouse management software informs the customer's higher-level merchandise management system. Items are stored parallel to the picking process at the manual operating opening or at the conveyor technology connection. It takes place in the same way as outsourcing, only in the opposite direction.