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Context 1
... Fig. 17a, the life values of the second-group circu- lar, cast polyamide-guided die springs were shown. In these springs, 2.5 × 10 6 cycles were achieved while the average number of repetitions for the tests was Fig. 15 Safety factor for 38% compression ...
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... Fig. 17a, the life values of the second-group circu- lar, cast polyamide-guided die springs were shown. In these springs, 2.5 × 10 6 cycles were achieved while the average number of repetitions for the tests was Fig. 15 Safety factor for 38% compression ...
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... tests were repeated for the springs guided with cast polyamide as well. In the analyses, cast polyamide ma- terial was modelled as linear elastic. Hence, in FEA, the max. stress was calculated as 6.9 MPa and the max. strain as 5.4 × 10 À4 (Fig. 16a). This strain value is lower than 3% of strain limit; therefore, the polyamide material ex- hibits linear-elastic behaviour (Fig. 16b). There is no loading condition in our experiments that exceeds strain limit; therefore, nonlinearity was not considered in the ...
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... tests were repeated for the springs guided with cast polyamide as well. In the analyses, cast polyamide ma- terial was modelled as linear elastic. Hence, in FEA, the max. stress was calculated as 6.9 MPa and the max. strain as 5.4 × 10 À4 (Fig. 16a). This strain value is lower than 3% of strain limit; therefore, the polyamide material ex- hibits linear-elastic behaviour (Fig. 16b). There is no loading condition in our experiments that exceeds strain limit; therefore, nonlinearity was not considered in the ...
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... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
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... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
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... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
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... (b) 2.043 × 10 6 . The safety factor for 2.043 × 10 6 load repeti- tions was minimum 1.254, as reported in Fig. 17b. When the compression ratio of the spring is lowered below 38%, the life and safety factor values obtained would be ...
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... to the fatigue tests conducted, none of the circular die springs are of the capability equivalent to the rectangular die springs. However, the desired life value was obtained for the springs with the cast polyamide guide. To find a solution to the question such as whether the increase in fatigue life was due to the guide type or the guide material, the springs were guided with brass guide of the same size, and a new test was conducted. No change in the fatigue life of brass-guided spring related to guide was observed. As a result of the tests conducted, it was observed that guide does not extend the fatigue life of the springs. However, guide with cast polyamide material with a high damping capability extended the fatigue life of circular die springs by 1.5 times of the rectangular die spring. Additionally, cast polyamide guides increase fatigue life of circular die springs by 5.68 times com- pared with circular springs without guides. Polyamides have very good mechanical properties, are particularly tough and have excellent sliding, high mechanical damping characteristics, good fatigue strength and wear characteristics. 16 Oral 17 showed that the usage of cast polyamide pulleys instead of steel pulleys increases the life of wire ropes by 5.8 times. Oral indicates that the increase in the life of wire ropes stems from the damping capability of cast polyamide. The damping capability of cast polyamide is used in many industrial applications. 17 In order to evaluate the damping capa- bilities, dynamic analyses for single loading of springs guided by cast polyamide, brass and steel materials were conducted using Ansys LS-DYNA (Ansys, Inc., Cecil Township, PA ,USA) (Fig. 18a). Analysed results were given in Fig. 18b-d. In finite element analyses, three types of material were considered: cast polyamide, brass and steel. The deformation of the spring for all material types was the same. In these analyses, calculated reaction force for each material was investigated while the deforma- tions in the springs were equivalent. As the result of dynamic analyses, the reaction force at the lower face was calculated as 13.8, 82.8 and 96.7 N for cast polyam- ide, brass and steel guides, respectively. These FEA results revealed that cast polyamide has a damping ...
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... to the fatigue tests conducted, none of the circular die springs are of the capability equivalent to the rectangular die springs. However, the desired life value was obtained for the springs with the cast polyamide guide. To find a solution to the question such as whether the increase in fatigue life was due to the guide type or the guide material, the springs were guided with brass guide of the same size, and a new test was conducted. No change in the fatigue life of brass-guided spring related to guide was observed. As a result of the tests conducted, it was observed that guide does not extend the fatigue life of the springs. However, guide with cast polyamide material with a high damping capability extended the fatigue life of circular die springs by 1.5 times of the rectangular die spring. Additionally, cast polyamide guides increase fatigue life of circular die springs by 5.68 times com- pared with circular springs without guides. Polyamides have very good mechanical properties, are particularly tough and have excellent sliding, high mechanical damping characteristics, good fatigue strength and wear characteristics. 16 Oral 17 showed that the usage of cast polyamide pulleys instead of steel pulleys increases the life of wire ropes by 5.8 times. Oral indicates that the increase in the life of wire ropes stems from the damping capability of cast polyamide. The damping capability of cast polyamide is used in many industrial applications. 17 In order to evaluate the damping capa- bilities, dynamic analyses for single loading of springs guided by cast polyamide, brass and steel materials were conducted using Ansys LS-DYNA (Ansys, Inc., Cecil Township, PA ,USA) (Fig. 18a). Analysed results were given in Fig. 18b-d. In finite element analyses, three types of material were considered: cast polyamide, brass and steel. The deformation of the spring for all material types was the same. In these analyses, calculated reaction force for each material was investigated while the deforma- tions in the springs were equivalent. As the result of dynamic analyses, the reaction force at the lower face was calculated as 13.8, 82.8 and 96.7 N for cast polyam- ide, brass and steel guides, respectively. These FEA results revealed that cast polyamide has a damping ...
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... a result of the fatigue tests implemented, it has been observed that the breakages for rectangular and circular die springs occurred in the interior sections of the springs. As shown in Fig. 12, it was revealed in FEM analysis that most of the stress occurs on the inte- rior sections of the springs. In the graphic, the stress values obtained at 16 separate points from the outer edge of the spring wire to the inner edge are shown. In the figure, the seventh point is the centre point of the spring wire, and as such, the stress reported at this point is the ...
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... elasticity modulus of cast polyamide is 50 times lower compared with the steel. Thus, the effect of elas- ticity modulus on the deformations and the reaction forces was apparent in FEA. Thus, lower reaction force of cast polyamide can be interpreted as it has higher damping capability. Damping capability of polyamide was realised in the literature. 16,17 C O N C L U S I O N Fatigue tests were conducted to evaluate whether the circular die springs can be used in place of rectangular Fig. 18 Finite element analysis (FEA) analyses results for guide ...
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... the fatigue test, springs are put into the test device without pretensioning; therefore, the stress ratio R is zero as shown in Fig. 11. This (which is called unidirec- tional (R ≠ 0) testing) is applying that the contact is not preloaded in our fatigue ...
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... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
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... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
Context 18
... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
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... Fig. 13, the stress values are shown for rectangular die springs and circular ones that could be equivalent to rectangular die springs. Maximum shear stress value for rectangular die spring is 1295 N/mm 2 , whereas it is 1363.1 and 1110.4 N/mm 2 for the first and second groups of circular die springs, respectively. Maximum shear stress values obtained are lower than the tensile strength value of each ...
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... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
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... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
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... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
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... operations, springs work between two fixed posi- tions. At these positions, the operating stress can be mea- sured. Performance of a spring can be defined according to the relationship between the loads applied and the shortening of the spring. These values are used to fore- cast the fatigue life. In Fig. 1, block form of a spring with 76 mm length, 15.7 mm external diameter and 2.8 mm wire diameter is shown. As the spring approaches to its blocking position, contact between the large rings does not happen at the same time because of the small gradient differences between the coils. It occurs in the form that follows each other from one ring to the other. The con- tact established leads to an impact, surface deformation and increase in ...
Context 24
... Fig. 17a, the life values of the second-group circu- lar, cast polyamide-guided die springs were shown. In these springs, 2.5 × 10 6 cycles were achieved while the average number of repetitions for the tests was Fig. 15 Safety factor for 38% compression ...
Context 25
... Fig. 17a, the life values of the second-group circu- lar, cast polyamide-guided die springs were shown. In these springs, 2.5 × 10 6 cycles were achieved while the average number of repetitions for the tests was Fig. 15 Safety factor for 38% compression ...
Context 26
... tests were repeated for the springs guided with cast polyamide as well. In the analyses, cast polyamide ma- terial was modelled as linear elastic. Hence, in FEA, the max. stress was calculated as 6.9 MPa and the max. strain as 5.4 × 10 À4 (Fig. 16a). This strain value is lower than 3% of strain limit; therefore, the polyamide material ex- hibits linear-elastic behaviour (Fig. 16b). There is no loading condition in our experiments that exceeds strain limit; therefore, nonlinearity was not considered in the ...
Context 27
... tests were repeated for the springs guided with cast polyamide as well. In the analyses, cast polyamide ma- terial was modelled as linear elastic. Hence, in FEA, the max. stress was calculated as 6.9 MPa and the max. strain as 5.4 × 10 À4 (Fig. 16a). This strain value is lower than 3% of strain limit; therefore, the polyamide material ex- hibits linear-elastic behaviour (Fig. 16b). There is no loading condition in our experiments that exceeds strain limit; therefore, nonlinearity was not considered in the ...
Context 28
... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
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... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
Context 30
... were fixed from their bottom face. Because no buckling was observed because of the pin running through the spring, the interior face is defined as sliding (a) (b) Fig. 9 (a) S-N data input screen shot and (b) S-N curve for rectangular die springs. Fig. 10 Loading and boundary conditions. support, and the F force is applied from the top face as can be seen from Fig. 10. On the top, a space was left to render the shape change relative to the possible compression ratio (38 or 50%) applied. Springs were compressed by 38 and 50% each time, and the boundary condition is therefore the fixed displacement. (a) (b) Fig. 12 Variation of stress in the spring ...
Context 31
... (b) 2.043 × 10 6 . The safety factor for 2.043 × 10 6 load repeti- tions was minimum 1.254, as reported in Fig. 17b. When the compression ratio of the spring is lowered below 38%, the life and safety factor values obtained would be ...
Context 34
... to the fatigue tests conducted, none of the circular die springs are of the capability equivalent to the rectangular die springs. However, the desired life value was obtained for the springs with the cast polyamide guide. To find a solution to the question such as whether the increase in fatigue life was due to the guide type or the guide material, the springs were guided with brass guide of the same size, and a new test was conducted. No change in the fatigue life of brass-guided spring related to guide was observed. As a result of the tests conducted, it was observed that guide does not extend the fatigue life of the springs. However, guide with cast polyamide material with a high damping capability extended the fatigue life of circular die springs by 1.5 times of the rectangular die spring. Additionally, cast polyamide guides increase fatigue life of circular die springs by 5.68 times com- pared with circular springs without guides. Polyamides have very good mechanical properties, are particularly tough and have excellent sliding, high mechanical damping characteristics, good fatigue strength and wear characteristics. 16 Oral 17 showed that the usage of cast polyamide pulleys instead of steel pulleys increases the life of wire ropes by 5.8 times. Oral indicates that the increase in the life of wire ropes stems from the damping capability of cast polyamide. The damping capability of cast polyamide is used in many industrial applications. 17 In order to evaluate the damping capa- bilities, dynamic analyses for single loading of springs guided by cast polyamide, brass and steel materials were conducted using Ansys LS-DYNA (Ansys, Inc., Cecil Township, PA ,USA) (Fig. 18a). Analysed results were given in Fig. 18b-d. In finite element analyses, three types of material were considered: cast polyamide, brass and steel. The deformation of the spring for all material types was the same. In these analyses, calculated reaction force for each material was investigated while the deforma- tions in the springs were equivalent. As the result of dynamic analyses, the reaction force at the lower face was calculated as 13.8, 82.8 and 96.7 N for cast polyam- ide, brass and steel guides, respectively. These FEA results revealed that cast polyamide has a damping ...
Context 35
... to the fatigue tests conducted, none of the circular die springs are of the capability equivalent to the rectangular die springs. However, the desired life value was obtained for the springs with the cast polyamide guide. To find a solution to the question such as whether the increase in fatigue life was due to the guide type or the guide material, the springs were guided with brass guide of the same size, and a new test was conducted. No change in the fatigue life of brass-guided spring related to guide was observed. As a result of the tests conducted, it was observed that guide does not extend the fatigue life of the springs. However, guide with cast polyamide material with a high damping capability extended the fatigue life of circular die springs by 1.5 times of the rectangular die spring. Additionally, cast polyamide guides increase fatigue life of circular die springs by 5.68 times com- pared with circular springs without guides. Polyamides have very good mechanical properties, are particularly tough and have excellent sliding, high mechanical damping characteristics, good fatigue strength and wear characteristics. 16 Oral 17 showed that the usage of cast polyamide pulleys instead of steel pulleys increases the life of wire ropes by 5.8 times. Oral indicates that the increase in the life of wire ropes stems from the damping capability of cast polyamide. The damping capability of cast polyamide is used in many industrial applications. 17 In order to evaluate the damping capa- bilities, dynamic analyses for single loading of springs guided by cast polyamide, brass and steel materials were conducted using Ansys LS-DYNA (Ansys, Inc., Cecil Township, PA ,USA) (Fig. 18a). Analysed results were given in Fig. 18b-d. In finite element analyses, three types of material were considered: cast polyamide, brass and steel. The deformation of the spring for all material types was the same. In these analyses, calculated reaction force for each material was investigated while the deforma- tions in the springs were equivalent. As the result of dynamic analyses, the reaction force at the lower face was calculated as 13.8, 82.8 and 96.7 N for cast polyam- ide, brass and steel guides, respectively. These FEA results revealed that cast polyamide has a damping ...
Context 36
... a result of the fatigue tests implemented, it has been observed that the breakages for rectangular and circular die springs occurred in the interior sections of the springs. As shown in Fig. 12, it was revealed in FEM analysis that most of the stress occurs on the inte- rior sections of the springs. In the graphic, the stress values obtained at 16 separate points from the outer edge of the spring wire to the inner edge are shown. In the figure, the seventh point is the centre point of the spring wire, and as such, the stress reported at this point is the ...
Context 37
... elasticity modulus of cast polyamide is 50 times lower compared with the steel. Thus, the effect of elas- ticity modulus on the deformations and the reaction forces was apparent in FEA. Thus, lower reaction force of cast polyamide can be interpreted as it has higher damping capability. Damping capability of polyamide was realised in the literature. 16,17 C O N C L U S I O N Fatigue tests were conducted to evaluate whether the circular die springs can be used in place of rectangular Fig. 18 Finite element analysis (FEA) analyses results for guide ...
Context 38
... the fatigue test, springs are put into the test device without pretensioning; therefore, the stress ratio R is zero as shown in Fig. 11. This (which is called unidirec- tional (R ≠ 0) testing) is applying that the contact is not preloaded in our fatigue ...
Context 39
... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
Context 40
... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
Context 41
... Fig. 14, load repetitions until spring life expires for rectangular die springs and equivalent circular ones are shown. The results obtained in this analysis are linked to the fatigue life-stress diagram acquired as a result of fatigue tests. In Fig. 14a, it is shown that the rectangular die spring can stand a load repetition of at least 1.2 × 10 6 , and in Fig. 15a, it is shown that 1 million repetitions could be realised with a safety of ...
Context 42
... Fig. 13, the stress values are shown for rectangular die springs and circular ones that could be equivalent to rectangular die springs. Maximum shear stress value for rectangular die spring is 1295 N/mm 2 , whereas it is 1363.1 and 1110.4 N/mm 2 for the first and second groups of circular die springs, respectively. Maximum shear stress values obtained are lower than the tensile strength value of each ...
Context 43
... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
Context 44
... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
Context 45
... the fatigue life-stress values entered in Fig. 14b, it can be seen that the spring would operate with a safety of 1.092 up to 237 200 load repetitions. According to Fig. 14c, it can be said that the second group of cir- cular die springs could break after 347 600 load repeti- tions at a 38% compression ratio. As can be seen from Fig. 15c, the safety factor has been determined to be 1.284 > ...
Context 46
... operations, springs work between two fixed posi- tions. At these positions, the operating stress can be mea- sured. Performance of a spring can be defined according to the relationship between the loads applied and the shortening of the spring. These values are used to fore- cast the fatigue life. In Fig. 1, block form of a spring with 76 mm length, 15.7 mm external diameter and 2.8 mm wire diameter is shown. As the spring approaches to its blocking position, contact between the large rings does not happen at the same time because of the small gradient differences between the coils. It occurs in the form that follows each other from one ring to the other. The con- tact established leads to an impact, surface deformation and increase in ...
Citations
... Selecting cutting tools or cutting data101112. Several potential research areas were identified with respect to expert systems in manufacturing131415. Kojiyama et al. [16] have discussed in their articles a framework for machining operation planning systems, in which machining know-how extracted and organized from electronic tool catalogs and machining instance databases available in the Internet environment plays a principal role. ...
In the modern manufacturing of sophisticated parts with 3D sculptured surfaces, die and mold making operations are the most widely used machining processes to remove unwanted material. To manufacture a die or a mold, many different cutting tools are involved, from deep hole drills to the smallest ball nose end mills. Since the specification of each tool is very different from each other, each mold or die is specific with their complicated shapes and many machining rules exist to consider, a great deal of expertise is needed in planning the machining operations. An expert system (DieEX) developed for this purpose is described in the present work. The geometry and the material of the workpiece, tool material, tool condition and operation type are considered as input values and various recommendations about the tool type, tool specifications, work holding method, type of milling operation, direction of feed and offset values are provided.
