Tài liệu Process Selection From Design to Manufacture P2 pdf

//SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 24 – [19–34/16] 13.5.2003 7:43PM . 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 ¼ 1–100 Low volume ¼ 100–1000 Medium volume ¼ 1000–10 000 Medium to high volume ¼ 10 000–100 000 High volume ¼ 100 000 þ All quantities. Due to page size constraints and the number of processes involved, each manufac- turing process has been assigned an identification code rather than using process names, as shown at the bottom of Figure 2.2. There may be just one or a dozen processes at each node in the selection matrix representing the possible candidates for final s electi on. As seen in Figure 1.11, there are many cost drivers in manufacturing process selection, not least component size, geometry, tolerances, surface finish, capital equipment and labor costs. The justification for basing the matrix on material and production quantity is that it combines technological and economic issues of prime importance. Many manufacturing processes are only viable for low-volume production due to the time and labor involved. On the other hand, some processes require expensive equipment and are, therefore, unsuitable for low production volumes. By considering production quantities in the early stages, the process that will prove to be the most economical later in the development process can be identified and selected. The boundaries of economic production, however, can be vague when so many factors are relevant, therefore the matrix concentrates rather more on the use of materials. By limiting itself in this way, the matrix cannot be regarded as comprehensive and should not be taken as such. It represents the main common industrial practice, but there will always be exceptions at this level of detail. It is not intended to represent a process selection methodology in itself. It is essentially a first-level filter. The matrix is aimed at focusing attention on those PRIMAs that are most appro- priate based on the important consideration of material and prod uction quantity. It is the PRIMAs that do the task of guiding final manufacturing process selection. Note that conventional and Non-Traditional Machining (NTM) processes are often con- sidered as secondary rather than primary manufacturing processes, although they can be applicable to both situations. The user should be aware of this when using the PRIMA selection matrix. Also, the conventional machining processes are grouped under just two headings in the matrix, manual and automatic machining. Reference should be made to the individual processes for more detail. 2.3.2 Assembly system selection Assemblies involve two or more combined components of varying degrees of build complexity and spatial configuration. The assembly technologies used range from simple manual opera- tions through to dedicated and fully mechanized systems. The final system or combination of systems selected has the task of reproducing the product at the volume dictated by the 24 Selecting candidate processes //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 25 – [19–34/16] 13.5.2003 7:43PM customer, in a cost-effective way for the producer, being technically appropriate for the components manipulated and composed, and ultimately satisfying the functional require- ments dictated by the specification. The assembly phase represents a significant proportion of the total production cost of a product and can outweigh manufacturing costs in some industries (2.3). Through the identi- fication of the most effective manufacturing and assembly technologies early in the development process, downstream activity, inefficiency and costs can be reduced. Significantly, assembly is a major source of late engineering change, rework and production variability in product development (2.4). The cost of recovering from these problems during assembly is high and is estimated to be in the range of 5–10 per cent of the final cost (2.5). In part, this is due to the fact that assembly is governed by much less controllable and less tangible issues than manu- facturing, such as assembly actions and fixture design (2.6). In practice, assembly selection is a very difficult task. It does not mean, however, that we cannot make a sound decision about the most appropriate assembly technology to use for a given set of conditions or requirements. A number of researchers have proposed strategies for assembly system selection. The reader interested in this topic can find more information in References (2.7–2.9). Prior to the selection of an assembly technology, a number of activities should be under- taken and factors considered, some of which also help drive the final quality of the assembly: . Business level – Identification and availability of assembly technologies/expertise in-house, integration into business practices/strategy, geographical location and future competitive issues, such as investment in equipment. . Product level – Anticipated lead times, product life, investment return time-scale, product families/variants and product volumes required. . Supplier level – Com ponent quality (process capability, gross defects) and timely supply of bought-in an d in-house manufactured parts. The final point is of particular importance. A substantial proportion of a finished product, typically, two-thirds, consists of components or s ub-assemblies produced by suppliers (2.10). The original equipment manufacturer is fast becoming purely an assembler of these bought-in parts, and therefore it is important to realize the key role suppliers have in developing products that are also ‘assembly friendly’. Consideration must be given to the tolerances and process variability associated with component parts from a very early stage, especially when using automated assembly technologies, because production variability is detrimental to an assembly process. From the above, a number of drivers for assembly technology selection can be highlighted: . Availability of labor . Operating costs . Production quantity . Capital cost of assembly equipment . Production rate required . Number of components in the assembly . Number of product variants . Handling characteristics (safety, environmental hazards, supply logistics) . Complexity of components and assembly operations . Size and weight of components to be assembled. PRIMA selection strategies 25 //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 26 – [19–34/16] 13.5.2003 7:43PM Figure 2.3 maps several of the important selection drivers with assembly technology. It is a general guide for the selection of the most appropriate assembly system based on: . Number of product variants (flexibi lity), and . Production rate, or . Production quantity per annum,or . Capital cost of the assembly equipment (although this is more of an outcome than a requirement). Three basic assembly systems can be identified and are classified in Figure 1.14 and with their respective PRIMA number below: . Manual (with or without mechanized assistance) [6.1] . Flexible (programmable, robots) [6.2] . Dedicated (special purpose) [6.3]. Upon candidate selection, further reference is made to the individual PRIMAs for each assembly system type in order to fully understand the technical and economic implications of the final decision and explore system variants available. This is pa rticularly advantageous when Figure 2.3 shows that a set of requirements is on the boundary of two assembly system types. Fig. 2.3 Assembly system selection chart. 26 Selecting candidate processes //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 27 – [19–34/16] 13.5.2003 7:43PM 2.3.3 Joining process selection There is extensive evidence to suggest that many industrial products are designed with far too many parts. DFA case studies indicate that in many designs large proportions of excess components are only used for fastening (2.11). These non-value added components increase part-count and production costs without contributing to the product’s functionality. In many cases, inco rrect joining processes are used due to a lack of knowledge of such factors as availability, cost and functional performance of alternatives. As with primary and secondary manufacturing processes, selecting the most suitable joining process greatly influences the manufacturability of a design, but the selection of the joining technology to be used can also greatly influence the assemblability of a design. The method chosen can also have a significant influence on the product architecture and assembly sequence and it is well known that complicated joining processes lead to incorrect, incomplete an d faulty assemblies (2.12). Selecting the most appropriate joining technique requires consideration of many factors relating to joint design, material properties and service conditions. During the selection procedure the designer is required to scrutinize large quantities of data relating to many different technologies. Several selection methods exist for the selection of the process variants within individual joining technologies. However, selecting the most appropriate technology itself remains a design-orientated task that often does not get the attention it deserves. It can be concluded that a selection methodology that incorporates joining processes and tech- nologies that can be applied at an early stage in the design process is a useful tool to support designing and particularly DFA. Considering joining processes prior to the development of detailed geometry enables components to be tailored to the selected process rather than limiting the number of suitable processes. Addressing such issues during the early stages of product development actively encourages designers to employ good DFA practice an d reduces the need for costly redesign work. As mentioned above, a number of other selection methods exist for different joining technologies, and the reader interested in further information is referred to: . Adhesive bonding (2.13)(2.14) . Welding, soldering and brazing (1.6 )(1.7)(2.15) . All joining technologies (1.10)(2.16). Currently, available selection techniques tend to focus on particular joining technologies or do not offer the designer a wide range of suitable joining processes or in enough detail to support the selection process. The aim of the joining process selection methodology pre- sented here is to provide a means of identifying feasible methods of joining regardless of their fundamental technology. The methodology is not intended to selec t a specific joining method, for example, torch brazing or tubular rivet, but to highlight candidate processes that are capable of joining under the given conditions. The final selection can be made after considering process specific data and detailed data against design requirements from the PRIMAs. Joining process classification Due to the large number of different joining processes and variants, only the most commonly used and well-established processes in industry are included. Investigations PRIMA selection strategies 27 //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 28 – [19–34/16] 13.5.2003 7:43PM highlighted 73 major joining techniques, as shown in Figure 1.15. In order to classify them, a common factor is used, based on technology and process. Technology class refers to the collective group that a process belongs to, for example, welding or adhesive bonding. The process class refers to the specific joining technique, for example, Metal Inert-gas Welding (MIG) or anaerobi c adhesive. Each process is derived from a particular fundamental technology providing a means for classification. From this, the joining processes have been divided into five main categories: welding, brazing, soldering, mechanical fastening and adhesive bonding. Technical classes can be separated into sub-categori es based on distinct differences in underlying technology. Although the basic premise of all welding processes is the same, specific techniques differ considerably due to the particular processes involved in generating heat and/or enabling the fusion process. This can be used as a means of classifying sub- sets. Both brazing and soldering have a number of different processes, hence they have been split into two sub-sets. Mechanical fasteners can be divided in two ways, by group technologies and degree of permanence. The latter has been chosen as it relates to the functionality of the fastener in service and therefore product requirements. Due to the large number of specific adhesives, which in many cases are exclusive to the producer, adhesive bonding has been viewed from a generic level, therefore, only the adhesive group can be selected. Joining process selection criteria 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. A review of important joining requirements has identified a number of possible selection criteria, as shown in Figure 2.4 and discussed below. . 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 //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 29 – [19–34/16] 13.5.2003 7:43PM product’s operating environment such as corrosion resistance. The material type is relevant to all joining technologies because they need to be compatible. Jo int 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 differ- ent joining technologies. Therefore, consideration of operating temperature is more appro- priate during final selection. . Spatial – Geometric characteristics of the joint are accounted for by the spatial require- ments. 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 develop- ment 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. . Economic – 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 Fig. 2.4 Classification of joint requirements. PRIMA selection strategies 29 //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 30 – [19–34/16] 13.5.2003 7:43PM 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. In order for the selection methodology to be effective in the early stages of design appraisal, the chosen parameters must apply to all joining processes. Also, it is essential that the parameters relate to knowledge that is readily available and appropriate to the level of selection. Having reviewed the requirement against the joining processes, four selection parameters have been chosen for initial stages of the methodology: . Material type – Accounts for the compatibility of the parent material with the joining process. A large proportion of the materials used in engineering manufacture have been included in the selection methodology, from ferrous alloys to precious metals. In situa- tions involving multiple material types the selection methodology must be ap plied for each. . Material thickness – Divided into three ranges: thin 3 mm, medium from 3 mm to 19 mm and thick !19 mm. When selecting the material type and thickness, the designer considers many other factors that can be attributed to the joint requirements, such as corrosion resistance, operating temperature and strength. Consequently, the requirements should be known and can be comp ared to joining process design data for making the final choice at a later stage. . Degree of permanence – This is a significant factor in determining appropriate joining processes, as it relates to the in-service behavior of the joint and considers the need for a joint to be dismantled. This selection criterion is divided into three types: 1 Permanent joint – Can only be separated by causing irreparable damage to the base material, functional element or characteristic of the components joined, for example, surface integrity. A permanent joint is intended for a situation where it is unlikely that a joint will be dismantled under any servicing situation. 2 Semi-permanent joint – Can be dismantled on a limited number of occasions, but may result in loss or damage to the fastening system and/or base material. Separation may require an additional process, for example, re-heating a soldered joint or plastic deforma- tion. A semi-permanent joint can be used when disassembly is not performed as part of regular servicing, but for some other need. 3 Non-permanent joint – Can be separated without special measures or damage to the fastening system and/or base material. A non-permanent joint is suited to situa- tions where regular dismantling is required, for example, at scheduled maintenance intervals. 30 Selecting candidate processes //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 31 – [19–34/16] 13.5.2003 7:43PM . Quantity – Production quantity per annum, and consequently the number of joints to be produced, accounts for the economic feasibility of the joining process. The quantities speci- fied for selection purposes are the same as for the manufacturing process selection strategy. Joining process selection matrix 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. The key to the joining processes used in the matrix is shown in Figure 2.5 together with the relevant PRIMA number, where information can be found regarding that individual process or joining technology. Due to size constr aints, the joining process selection matrix is divided into two parts; Figures 2.6(a) and (b) toget her show the complete matrix. The matrix representation of the selection technique provides an intuitive way of navigating a large quantity of data. This makes the selection process simple and quick to use. Supporting the selection matrix with design advice through the use of the PRIMAs completes the Fig. 2.5 Key to joining process PRIMA selection matrix. PRIMA selection strategies 31 //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 32 – [19–34/16] 13.5.2003 7:43PM IRONS THIN £3mm STEEL (carbon) STEEL (tool, alloy) STAINLESS STEEL COPPER & ALLOYS ALUMINIUM & ALLOYS MAGNESIUM & ALLOYS ZINC & ALLOYS TIN & ALLOYS [W6][W13] [W15][B1] [W6][W13] [W15][B1] [F19][F20] [F23] [F19][F20] [F23] [W3][W6] [W8][W9] [W11][W13] [W14][W15] [B1] [W3][W6] [W9] [W11] [W13][W14] [W15] [B1] [W6][W7] [W9][W10] [W13][W15] [F20] [W2][W3] [W6][W8] [W9][W11] [W13][W14] [W15][B1] [W2][W3] [W9][W11] [W13][W14] [W15][B1] [W3][W7] [W9][W10] [W13][W15] [F20] [F19][F20] [F19][F20] [W2][W3] [W6][W8] [W9][W11] [W13][W14] [W15][B1] [W2][W3] [W9][W11] [W13][W14] [W15][W17] [B1] [W9][W10] [W13][W15] [W17] [F20] [F19][F20] [F19][F20] [W1] [W1] [S1][S8] [W1][W2] [W3][W9] [W13][W14] [B1] [W1][W2] [W3][W9] [W13][B1] [W3][W7] [W9] [W13] [F19][F23] [F19][F23] [W1][W2] [W3][W6] [W8][W9] [W11][W13] [W14][B1] [W1][W2] [W3][W6][W9] [W11][W13] [W14][B1] [W3][W9] 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[W11][W14] [W18][W19] [W20][B2][B3] [B4][B5][B7] [B8][F7][F9] [W4][W11] [W14][W19] [B2][B3][B8] [B8] [S2][S3][S4] [S5][S7][S9] [W8][W14] [W18][W20] [B2][B3] [B4][B8] [W4][W14] [W18][W20] [B3][B8] [S2][S3][S4] [S5][S7][S9] [B3][B8] [B3][B8] [W18][W20] [W21] [B3] [B8][F7][F9] [W4][W18] [W20] [W21] [B3][B8] [W4][W21] [B3][B8] [W18][W20] [W21][B3] [B8] [W4][W18] [W20][W21] [B3] [B8] [W4][W21] [B3] [B8] [F11] [W18][W20] [W21][B3] [B8][F7][F9] [W4][W18] [W20][W21] [B3] [B8] [W4][W21] [B3][B8] [F11][S3] [S3][S9] [W18][W20] [W21] [B3] [B8][F7][F9] [W4][W18] [W20][W21] [B3][B8] [W21][B3] [B8] [W4][W18] [W20][W21] [B3][B8][F7] [F9] [W4][W21] [B3][B8] [W18][W20] [B3][B8] [W18][W20] [W21][B3] [B8] [W21] [S3][S9] VERY LOW 1 TO 100 LOW 100 TO 1,000 LOW TO MEDIUM 1,000 TO 10,000 MEDIUM TO HIGH 10,000 TO 100,000 HIGH 100,000+ ALL QUANTITIES [F1][A1] [A2][A4] [A5][A8] [A10] [F1] [F12][F13] [F12][F13] [F15][F16] [F18][F21] [F15][F18] [F21] [W5][W12] [A1][A2][A4] [A5][A8][A10] [F1][F5][F6] [F8][F10] [W12][A1] [A2][A4] [A5][A10][F1] [F1] [A9][F14] [F12][F13] [F12][F13] [F15][F17] [F21] [F15][F17] [F18][F21] [F15][F17] [F21] [W5][W12] [F1][A1][A2] [A4][A5][A8] [A10] [F1][A1][A2] [A4][A5][A10] [F1] [F13][A9] [F12][F13] [F12][F13] [F15][F17] [F21] [F15][F17] [F21] [F15][F17] [F21] [W5][W12] [F1][F5][F6] [F8][F10] [A4] [A10] [W12][F1] [A4] [A10] [F1] [F13][A9] [F14] [F12][F13] [F12][F13] [F15][F17] [F21] [F15][F17] [F18[F21] [F15][F17] [F18[F21] [W12][F2] [F10][F14] [A4] [W12][F2] [F2] [F13][A9] [F14] [F13] [F16][F21] [F16][F21] [F21] [W12][F1] [F5][F6][F8] [F10][A1] [A2][A4] [A5][A10] [W12][F1] [F10][A4] [A10] [F1] [A9][F13] [F14] [F12][F13] [F12][F13] [F16][F21] [F16][F18] [F21] [F18][F21] [W5][W12] [F1][F2][F5] [F6] [F8][F10] [A2][A4][A5] [A7][A10] [W5][W12] [F1][F2][A2] [A4][A5][A7] [A10] [F1][F2] [F13] [A9] [F14] [F12][F13] [F12][F13] [F15][F16] [F17][F21] F[15][F16] [F17][F18] [F21] [F15][F17] [F18][F21] [W12][F1] [F2][A1][A4] [A5] [W12][F1] [F2][A4] [A5] [F1][F2] [F13][A9] [F16][F21] [F16][F18] [F21] [F18][F21] [W12][F2] [F10][F14] [W12][F2] [F2] [F15][F16] [F21] [F15][F16] [F18][F21] [F15][F18] [F21] [S2][S3][S4] [S5][S7] [S9] [S2][S6] [S8] [S1][S8] [S1][S8] [W1][W2] [W3][W8] [W9][W11] [W13][W14] [B1][B6] [W21][B8] [W1] [W1] [S1][S8] [W1] [W1] [S1][S6][S8] [W1][W2] [W3][W9] [W11][W13] [W14] [B1][B6] [W3][W8] [W9][W11] [W13][W14] [W15][B1] [B6] [W4][W11][W13] [W14][W16] [W17][W18] [W19][W20] [B2][B3][B4][B8] [S3] [S9] [S1] [S1] [S6] [S3] [S3] [S1] [S1] [S3] [S9] [F12][F13] [F12][F13] [F14] [W19] [W19] [F11] [F11] [F11] [F11] MATERIAL & THICKNESS QUANTITY & PERMANENCE MED. 3 to 19mm THICK ³19mm NP SP P NP SP P NP SP P NP SP P NP SP P NP SP P MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm [F19][F20] [F19][F20] [F19][F20] Note - The joining process PRIMA selection matrix cannot be considered as comprehensive and should not be taken as such. It represents the main common industrial practice, but there will always be exceptions at this level of detail. Also, the order in which the PRIMAs are listed in the nodes of the matrix has no significance in terms of preference. Dissimilar metals also accounts for joining metals with coatings. Fig. 2.6 (a) Joining process PRIMA selection matrix ^ part A. 32 Selecting candidate processes //SYS21///INTEGRAS/B&H/PRS/FINALS_07-05-03/0750654376-CH002.3D – 33 – [19–34/16] 13.5.2003 7:43PM LEAD & ALLOYS NICKEL & ALLOYS TITANIUM & ALLOYS THERMOPLASTICS THERMOSETS FR COMPOSITES CERAMICS REFRACTORY METALS PREC- IOUS METALS DISSIMILAR MATERIALS [W1] [W1] [S1][S8] [F23] [F23] [W2][W3] [W6][W8] [W9][W11] [W13][W14] [W15] [W2][W3] [W9][W11] [W13][W14] [W15] [W9][W10] [W13][W15] [S1][S8] [F20] [F20] [F20] [W2][W3] [W9][W13] [W14] [W2][W3] [W9][W13] [W14] [W3][W9] [W13] [W22] [W22] [W22] [S1] [F22] [F22] [W2][W3] [W8][W9] [W13][W14] [B1] [W2][W3] [W9][W13] [W3] [W1][W2] [S1][S8] [W2][W3] [W8][W9] [W11][B1] [W2][W3] [W9][W11] [B1] [W3][W9] [F20] [F19][F20] [F22] [F19][F20] [F22] [W1][W14] [W1][W14] [S1][S8] [F23] [F23] [W2][W3] [W8][W9] [W11][W13] [W14][W15] [B6] [W2][W3] [W9][W11] [W13][W14] [W15][W16] [W9][W13] [W15] [S1][S8] [F20] [F20] [F20] [W2][W3] [W9][W13] [W14] [W2][W3] [W9][W13] [W14] [W3][W9] [W13] [W22] [W22] [W22] [W2][W3] [W8][W9] [W13][W14] [B1] [W2][W3] [W9][W13] [W4] [W1][W2] [S1][S8] [W2][W3] [W9][W8] [W11][B1] [W2][W3] [W9][W11] [B1] [W3][W9] [S1][S8] [F20] [F19][F20] [F22] [F19][F20] [F22] [W1][W14] [S2][S6][S8] [S2][S3][S4] [S5][S7] [S9] [W2][W13] [W14][W19] [B4] [W2][W13] [W14][W19] [W13] [S2][S3][S6] [F22] [F22] [W2][W8] [W14][B2] [B4] [W2] [W2] [W1] [S2][S8] [W2][W8] [W11][W19] [B2] [W2][W11] [B2] [S2][S3][S6] [S8][F11] [F11] [F22] [F22] [W8][W11] [W14][W18] [W20][B3] [B4][B5][B7] [B8][F9] [W4][W11] [W14][W16] [W18][W20] [B3][B8] [W4][B3][B8] [S2][S3][S4] [S5] [S7][S9] [W8][W14] [W18][W19] [W20][B3] [B4][B7][B8] [W4][W14] [W18][W19] [W20][B3] [B8] [B3][B8] [S7] [F7] [F11] [F11] [F7] [F11] [S2][S3][S4] [S5][S7] [W18][B2] [B4][B5] [B7][B8] [W4][W18] [S2][S3][S4] [S5] [W8][W11] [W19][W20] [B2][B3][B8] [F7][F9] [W4][W11] [W20][B2] [B3][B8] [W4][B3][B8] [S2][S3][S4] [S5][S7][F11] [F11] [S3][S9] [W18][W20] [W21][B3] [B8][F9] [W4][W18] [W20][W21] [B3] [B8] [W4][W21] [B3][B8] [S3][S9] [W18][W20] [W21][B3] [B8] [W4][W18] [W20][W21] [B3][B8] [W21][B3] [B8] [F7] [F11] [F11] [F7] [F11] [W18][W21] [B8] [W4][W18] [W21] [W20][W21] [B3][B8][F7] [F9] [W4][W20] [W21][B3] [B8] [W4][B3][B8] [F11] [F11] VERY LOW 1 TO 100 LOW 100 TO 1,000 LOW TO MEDIUM 1,000 TO 10,000 MEDIUM TO HIGH 10,000 TO 100,000 HIGH 100,000+ ALL QUANTITIES [F2][F10] [A1][A4] [F2][F10][A4] [F2] [F16][F21] [F16][F21] [F21] [W5][W12] [F1][A4][A8] [W12][F1] [A4] [F1] [F13] [F12][F13] [F12][F13] [F15][F16] [F17][F21] [F15][F16] [F17][F18] [F21] [F15][F17] [F18][F21] [W12][A11] [A11] [A9] [F15][F17] [F21] [F15][F17] [F18][F21] [F15][F17] [F18][F21] [W5][F2][F3] [F1][F4] [F6] [F10] [A2] [A4][A8] [A10] [F2][F3] [F1][F10] [A2][A4][A8] [A10] [F1][F2] F3][A4] [A10] [A9] [F17][F21] [F23] [F17][F18] [F21] [F23] [F17][F18] [F21] [F23] [F2][F3][F4] [F10][A2][A4] [A7][A8] [F2][F3][A2] [A4][A7][A8] [F2][F3][A7] [F16][F17] [F21][F23] [F15][F16] [F17][F18] [F21] [F23] [F15][F17] [F18][F21] [F23] [F2][F4][A2] [A4][A7] [A8][A10] [A2][A4][A7] [A8][A10] [A4] [F16][F17] [F21][F23] [F16][F17] [F21][F23] [F21][F23] [F2][A2][A4] [A5][A7][A8] [A10] [F10][A2][A4] [A5][A7][A8] [A10] [F10][A2][A4] [A5][A7][A8] [A10] [F13] [F12][F13] [F13] [F15][F17] [F21] [F15][F17] [F18][F21] [F15][F17] [F18][F21] [F1] [F1] [F1] [F13] [F12][F13] [F12][F13] [F18][F21] [F18][F21] [W5][F1] [F8][A4] [F16][F17] [F18][F21] [W5][W12] [F1][F2][F5] [F6][F10] [W12][F1] [F2][F10] [F1] [F13][F14] [F12][F13] [F12][F13] [F15][F16] [F17][F18] [F21][F23] [F15][F16] [F17][F18] [F21][F23] [F15][F17] [F18][F21] [F23] [W2][W8] [W9][W11] [W13][W14] [B4][B6] [W2][W11] [W13][W14] [W16] [W13] [S2][S6][S8] [S1] [F22] [F22] [S1][S8] [W1][W14] [F21] [W14][W14] [W4] [W4] [W21] [F11] [F11] [F11] [F11] [F11] [F11] [F11] [F11] [F11] [F11] [A9] [F12] [F12] [F11] [F11] [F11] [F11] [F12] [F12] MATERIAL & THICKNESS QUANTITY & PERMANENCE NP SP P NP SP P NP SP P NP SP P NP SP P NP SP P THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm MED. 3 to 19mm THICK ³19mm THIN £3mm Note - The joining process PRIMA selection matrix cannot be considered as comprehensive and should not be taken as such. It represents the main common industrial practice, but there will always be exceptions at this level of detail. Also, the order in which the PRIMAs are listed in the nodes of the matrix has no significance in terms of preference. Dissimilar metals also accounts for joining metals with coatings. Fig. 2.6 (b) Joining process PRIMA selection matrix ^ part B. PRIMA selection strategies 33 . an early stage in the design process is a useful tool to support designing and particularly DFA. Considering joining processes prior to the development of detailed. of many factors relating to joint design, material properties and service conditions. During the selection procedure the designer is required to scrutinize