The specification of a fastener will be governed by a number of possibly conflicting factors. At the concept/design stage, the designer will consider the functionality of the components, environmental issues, life-cycle expectancy, how the assembly is to be held together and whether there is a need to disassemble it amongst other concerns. For the sake of simplicity and cost the first consideration is to see if standard fasteners can be used and check the current availability with suppliers.
Whilst International Standards will provide comprehensive information on things like fastener diameters, lengths, materials etc., we should not assume that the entire range listed in a particular Standard will be available from stock as standard product range – so even "standard" fasteners may require specialist sourcing and supply arrangements.
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Consideration of standards is of course vital and can be difficult without guidance from an experienced team - the following are common examples:
• International Organisation for Standardisation (ISO) – ISO Metric Threads
• Deutches Institut für Normung (DIN) – ISO Metric Threads
• American National Standards Institute (ANSI) – Unified National and Metric Threads
• British Standards Institution (BSI) – ISO Metric, Unified National and British Threads.
Reference to these international standards will provide detailed specifications for thread tolerances and other information on the geometry of fastener threads while considerations of other configuration requirements can be integrated in the final design.
Drive types will need to be considered where quantity, speed, torque requirements and cost can be defining factors, differentiating between slotted, Phillips, Pozi and Torx to name a few well-known variants.
The team at Challenge Europe can offer guidance on material selection based on cost, product strength characteristics, environmental and corrosion-resistance requirements, application of the fastened joint. They will of course include steel; stainless steel – Austenitic, Ferritic or Martensitic; plus, brass, bronze, aluminium, copper and plastics of many sorts.
The actual manufacturing processes, heat treatments or annealing processes involved in the production of a suitable fastener will very likely have a profound influence on the quality and longevity of the final assembly and so form part of consideration in the service package.
Once the sourcing is confirmed only then can supply chain issues be addressed such as stocking, importing, batch sizes, delivery, e.g. using JIT, Lineside supply, VMI, Kanban or other protocols.
For more information visit www.challenge-europe.co.uk.
