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Selecting The Fastening Method Procedure and Calculator
Selecting Joining / Fastening Method Procedure and Calculator.
In order to select the most appropriate joining process, it is necessary to consider all processes available within the methodology. As technology specific selection criteria tend to be non transportable between domains, evaluating the merits of joining processes that are based on fundamentally dissimilar technologies requires a different approach. Differentiating between technology classes and process classes requires the comparison of specifically selected parameters. In order to evaluate a joint, consideration must be given to its functional, technical, spatial and economic requirements.
The joining process selection methodology is based on the same matrix approach used for Manufacturing Process Selection. Again, due to page size constraints and the number of processes to be detailed, each process has been assigned an identification code rather than using process names.
Things to know before using this tool:
- Obtain an estimate of the annum and total production quantity.
- Determine application engineering material types requirements.
- Determine whether the fastening process should be Permanent, Semi-Permanent, or Non-Permanent
Material type – Accounts for the compatibility of the parent material with the manufacturing process, and is therefore a key technical selection factor. A large proportion of the materials used in engineering manufacture have been included in the selection methodology, from ferrous alloys to precious metals.
Materials Included within calculator: Iron, Carbon Steel, Steel Tool & Alloy, Stainless Steel, Copper & Alloys, Aluminum & Allows, Magnesium & Alloys, ZInc & Alloys, Tin & Alloys, Nickel & Alloys, Titanium & Alloys, Thermoplastics, Thermosets, Fire Resistant Composites, Ceramics, Refractory Metals, and Precious Metals.
Production quantity per annum – The number of components to be produced to account for the economic feasibility of the manufacturing process. The quantities specified for selection purposes are in the ranges:
Very low volume = 1 - 100
Low volume = 100 - 1000
Medium volume = 1000 - 10 000
Medium to high volume = 10 000 - 100 000
High volume 100 000+
Preview: Selecting Joining / Fastening Method Procedure and Calculator
The following Joining / Fastening Method Calculators based on engineering material requirements are available (SEE BOTTOM OF WEBPAGE FOR PROCESS KEY CODE):
Calculator tools open in a new (popup) window
Joining Process selection Criteria:
Functional – Functional requirements define the working characteristics of the joint. The functional considerations for a joint are degree of permanence, load type and strength. Degree of permanence identifies whether a joint needs to be dismantled or not. In most cases the permanence of a joining process is independent of its technology class. Degree of permanence provides a suitable high-level selection criterion that is not reliant on detailed geometry. Load type and strength are often mutually dependent and can be influenced by the geometric characteristics of the joint interface. As joint design is dissimilar for different technology classes, it is difficult to use load type or strength as a universal selection criteria. However, these considerations must be taken into account when evaluating suitable joining processes for final selection when appropriate.
Technical – Specific needs of components to be joined are categorized by the joint’s technical requirements. The technical considerations for a joint are material type, joint design and operating temperature. Material type is selected based on parameters defined by the 28 Selecting candidate processes product’s operating environment such as corrosion resistance. The material type is relevant to all joining technologies because they need to be compatible. Joint design is often defined by the geometry. However, if joining is considered prior to detailed geometry, the selected process can influence the design. Due to the fundamental differences in joint configurations, it is not suitable as a selection criterion for non-technology specific selection. Operating temperature influences the performance of most joining processes, although it should be considered during material selection. While an important aspect, its effect varies for different joining technologies. Therefore, consideration of operating temperature is more appropriate during final selection.
Spatial – Geometric characteristics of the joint are accounted for by the spatial requirements. The spatial requirements identified are size, weight, geometry and material thickness. The size and weight of components to be joined is considered and determined when their material is selected. As the selection methodology is intended for use prior to the development of detailed geometry, using geometry as a selection criterion would be contradictory. Material thickness has already proven to be a successful criterion in other selection methodologies, and the suitability of joining processes is easily classified for different thicknesses of material.
Economics – The economics of joining processes aligns the design with the business needs of the product. Economic considerations can be split into two sections: tooling and product. Tooling refers to the ease of automation, availability of equipment, skill required, tooling requirements and cost. Product economics relate to production rates and quantity. These business considerations are driven by the product economics as they determine the need for tooling and its complexity, levels of automation and labor requirements. Production rate and quantity are very closely linked. They can both be used to determine the assembly speed and the need for and feasibility of automation. However, as the selection methodology is to be used in the early stages of product development it is more likely that quantity will be known from customer requirements or market demand.
||Functional requirements define the working characteristics of the joint.|
||Specific needs of components to be joined are categorized by a joints technical requirements.|
||Geometric characteristics of the joint are accounted for by the spatial requirements.|
||Other important issues not considered by the above groups.|
||The economics of joining processes aligns the design with the business needs of the product.|
Manufacturing Joining Process Key selection Matrix Codes
W1 Cold Welding (CW)
B1 Manual Torch Brazing
S1 Manual Torch Soldering
Mechanical Fastening Methods
F1 Solid Rivet
Manufacturing Process Selection, For Design to Manufacture:
K. G. Swift
Department of Engineering, University of Hull, UK
J. D. Booker
Department of Mechanical Engineering, University of Bristol, UK
Redford, A. (1994) Design for assembly. European Designer, Sept/Oct, 12–14.
Swift, K. G., Raines, M. and Booker, J. D. (1997) Design capability and the costs of failure. Proceedings of Institution of Mechanical Engineers, Part B, 211, 409–423.