What are the current trends in regard to cases and subracks? If we take a closer look at what is currently happening in this area, one word comes up again and again: individuality. This relates to the functionality, construction, dimensions, appearance and also to accompanying service options. Martin Traut, product manager for subracks and cases at Pentair - Schroff GmbH, and David Martin, managing director at Pentair - Schroff UK, explain
Various manufacturers offer cases and subracks as catalogue items. These off-the-shelf products offer the user certain advantages - they are easy to order, are delivered fast and offer better value for money than customised products. Nevertheless, the proportion of off-the-shelf products to individualised products has shifted significantly towards the individualised. And this adaptation should of course be affordable. In the past, modifications to off-the-shelf products for particular conditions and requirements in an application or requirements for a particular look were often carried out by the customer himself. In the course of the concentration of capacity and the focusing by businesses on their core competences, however, the customisation of cases and subracks is now increasingly becoming the task of the manufacturer. This customisation incurs additional costs for the manufacturer that must ultimately be borne by the customer. The extent of these extra costs is determined largely by the use of appropriate development concepts and by the scope of the off-the-shelf product portfolios.
If emphasis is given to allowing a high level of modification and flexibility of off-the-shelf products from the development stage, these products can often already cover some 90% of all requirements. In this situation the benefits of standard products are thus combined with those of custom solutions.
Such a concept, demonstrated by the example of subracks, shows the advantages obtained. Because the demands for use are different from one market segment and application to another, it is important that customers are able to order subracks in different versions. If these modular subracks are based on a product platform, they can be fitted with different off-the-shelf components to create a range of different products on a unified basis. They can thus be configured for varying requirements concerning dimensions, price structure, and also static and dynamic loading levels such as shock and vibration resistance, electromagnetic interference shielding and individual internal mounting options.
A standard subrack consists of at least two side panels and four horizontal profiles, the horizontal rails. Suitable additional accessories include cover plates that fit over the board cage, front panels, rear hoods, guide rails and various parts for internal fittings. The basic EMC shielding may for example be easy to retrofit, depending on the customer’s requirements, and there are various EMC gasketing concepts available for the front panels (textile or stainless steel gaskets). Subracks of this type can be individually configured if so required by the customer. The high level of versatility of these modular 19” units and the wide range of components mean great flexibility in design and construction.
Cases constructed according to the same principle, i.e. as a product platform, also allow a high degree of flexibility and keep costs down for the user.
Another trend for cases is the constantly increasing level of miniaturisation of the electronics. Thus, in addition to the established 19” market, there is now also a growing market for non-modular applications. A simple ‘box’ to accommodate a motherboard, a large PCB or an ARM module (Fig. 2) are now the subject of regular inquiries. Small cases of this type also offer solutions for holding non-standardised PCBs for various applications in industry, railroad systems, measurement and instrumentation, security applications, medical technology, energy systems and communications and network technology. In particular in the area of embedded systems, so-called computer-on-module (COM) solutions, for example, can thus be constructed. Here again, well-designed development concepts pay off for offering flexibility in terms of case shape, dimensions and fixing options effectively as standard.
More service options
Overall, customers of cases and subracks are making increasing demands for extra services related to the product. As fewer and fewer electronics manufacturers can afford their own mechanics division, requests for particular modifications, machining or even complete assembly of cases and subracks are growing constantly. Help during and simplification of the ordering process are also a recurring theme. What is necessary in order to construct cases and subracks on an individualised basis, i.e. a very extensive range of off-the-shelf component options, can be a stressful experience when ordering.
To simplify ordering for the customer, some manufacturers also offer subracks as pre-defined kits. These kits are created to satisfy the commonest customer requirements for specific areas of application. By specifying the required dimensions (W x H x D) and the intended application or area of use, e.g. CompactPCI applications with rear I/O or measurement and instrumentation or a ruggedised application, customers can then order the complete product with a single order number. The kit thus ordered contains all the components and some pre-installed parts (e.g. threaded inserts, EMC gaskets and hole or insulation strips). Consequently, the customer can be sure that all the necessary components are included. No more extra waiting time for forgotten parts or items not yet received by us. These pre-configured subrack versions cover all common market requirements, from the simple off-the-shelf version through to high-end subrack models.
Everything ready fitted
More and more customers are also seeking time and cost savings on their own premises with regard to assembly and thus do not order their cases or subracks as kits but rather expect them to be supplied fully assembled. This may range from assembling the mechanical, electrical and electronic components through to fitting additional customer elements supplied to the case or subrack manufacturer by the customer. The customer is then supplied with the fully assembled subrack or case including all accessory parts such as guide rails, mounting plates, backplanes, power supply units, socket strips, fans and fan trays, etc. He thus saves a substantial amount of time as there is no need to study any assembly instructions and can continue with his core tasks once the product has been received.
Wide variety of modifications
The commonest modifications requested by customers as customisations of the off-the-shelf product include different height, width or depth dimensions, drilled holes for lamps, LEDs and switches, cut-outs for connectors, consoles, and special colours. Such modifications also affect the design and processing of the front panels of a 19” subrack or case. These must normally be individually designed and manufactured for each application. A broad spectrum of off-the-shelf front panels and plug-in units with a wide range of dimensions and various finishes and versions further facilitate customisation at an affordable cost. Particularly for building prototypes, pre-production or small production runs, it is often essential to carry out the machining in just a few days, so that any corrections or modifications can be made quickly. The bottom line here is speed of manufacture and fast delivery.
Provision of CAD data
Today it almost goes without saying CAD data should be provided for electronics developers and designers. It can be a real boon if, in addition to the 2D or 3D CAD data for the off-the-shelf product, there is also the possibility e.g. of integrating the desired modifications directly into the customer’s design from tool and components libraries, with pre-defined cut-outs for standardized Sub-D and coax connectors - with counter bores, face milling, etc.
Generally, simple online access to off-the-shelf products is assured, and 2D and 3D product data can be downloaded from here. Now the customer can mark any desired mechanical processing, such as different cut-outs, directly into the file on his own CAD system. Some providers also offer support to customers for this graphical editing of the CAD file. In this case, component drawings may include component mounting limits that show the designer what areas are available for use without any conflict with the 19” standard.
Customisation, and the need for support and services, will continue to grow in the coming years. Only through constant observation of the market and close contact with customers can such developments be detected in good time and successfully implemented.