What are SMDs?
“Surface-mounted device” (SMD) is a term from the electronics industry. SMDs are extremely compact and a result of the increasing miniaturization of electronic components. In contrast to conventional components, SMDs are glued directly onto the surface of the printed circuit board and then soldered rather than plugged into them, or hardwired. This eliminates the need for elaborate drilling on the PCBs, which is necessary with conventional components. The small size of the SMDs has led to ever lighter base products for the electronics industry which can be manufactured at steadily reduced costs.
After their production, SMD components are usually transported in belts which are wrapped onto reels. At the start of manufacture, trolleys – so-called feeders – supply these reels to the pick and place machines for production. Larger SMD components are often put into plastic sticks or onto small pallets, the so-called trays. While trays can be placed directly into the pick and place machines, the sticks also require feeders.
Afterwards, the circuit boards to be populated pass several stations where the robots put the required SMD component onto the board and “glue it on.”
The output SMDs needed for the manufacture of electronic components are usually ordered, shipped, and stored in large numbers, so a sufficient quantity of them is in stock when production starts. Once production is finished, SMDs not needed are
- put back in stock
- kept ready for the next production
Picking the feeders with SMD reels efficiently is crucial for populating the PCBs error-free. The central aim is to achieve productive and cost-efficient upstream and downstream processes – for example putting the SMD reels into and removing them from storage, placing them onto feeders, and restocking excess material after the population order. Retrofitting the SMD lines quickly without losing time and material is another factor. To this end the different storage and retrieval systems – such as vertical carousels and storage lifts – are equipped with user-specific software which controls the usage of the SMD reels.
The principle of interim storage of electronic parts such as SMD components in the direct vicinity of the population lines is an increasingly important customer requirement. It results from optimized material flow with ever shorter setup and downtimes, and requires the continuous traceability of the SMDs by the in-house ERP systems.
When it comes to warehousing these parts, customers want complete solutions that not only give them the necessary hardware (the racking) but also let them monitor and control the complex SMD production and enable them to subject their SMD stock to a permanent inventory.
The software within a package which records the data about where the stored items are moved and keeps track of the stock as well as the period of use of the SMD components plays an important role in this. The allocation of the material to the pertinent production order is also documented. The system recognizes the availability of components for the current orders and reserves the quantity needed. Any shortages are promptly reported and reordered or again requested from the main store.
In sum, the customer requirements are:
- permanent inventory control
- better picking accuracy
- need-based storage of the components
- reduction of space requirements
- optimization of access times
- greater safety and ergonomics for the staff at the workplace