Heat treatment of carbon steel screws should be done well in these four points, and high-strength screws should be in order
Heat treatment of carbon steel screws should be done well in these four points, and high-strength screws should be in order
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Heat treatment of carbon steel screws should be done well in these four points, and high-strength screws should be in order
Advantage analysis of stainless steel faucet
At present, 99% of faucets at home and abroad are plated with copper. Stainless steel faucet is now popular, a new trend in the market. Stainless steel faucet has the advantage of inaccessible copper faucet. Due to the high processing difficulty, the price of stainless steel faucet is a little more expensive than copper faucet, but some classic styles have reached the same price as copper faucet, so stainless steel faucet is the star of faucet in the future.
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At present, 99% of faucets at home and abroad are plated with copper. Stainless steel faucet is now popular, a new trend in the market. Stainless steel faucet has the advantage of inaccessible copper faucet. Due to the high processing difficulty, the price of stainless steel faucet is a little more expensive than copper faucet, but some classic styles have reached the same price as copper faucet, so stainless steel faucet is the star of faucet in the future.
Selection of eccentric shaft counterweight
Because of the asymmetry of the eccentric shaft's shape, it will inevitably cause imbalance in the process of machining, so the first problem to be solved before the eccentric shaft is the counterweight. Selecting the right counterweight can make the workpiece drive smoothly in the processing, so as to meet the processing accuracy of the product.
There are three commonly used counterweight methods: one is to leave a chuck on the workpiece, and connect the special counterweight and the reserved chuck by keys and pins. The advantages of this connection method are high assembly precision, no relative movement between the workpiece and the counterweight, and the disadvantages are high manufacturing cost, and special site and special personnel are required to install during the installation process. The second is to directly carry out counterweight on the workpiece. The counterweight and the workpiece are fastened on the workpiece by clamping. The advantages are simple installation, low production cost, no need to process all kinds of auxiliary keyways and pin holes on the workpiece before installation. The disadvantage is that the counterweight and the workpiece are easy to move in the process of processing, which affects the processing accuracy of the product. The third is the weight of the chuck. This method is simple but not very accurate. Because the grinder has no chuck, this counterweight method can not be applied to the grinder.
According to the structural characteristics of eccentric shaft, a set of new tooling with large clamping force, natural indexing and simple counterweight adjustment is designed. Its design principle is: (1) the principle of Σ t = 0. By adjusting the left and right counterweights, the workpiece can rotate smoothly in the process of eccentric outer circle machining, and the machining difficulty caused by workpiece eccentricity can be solved. (2) The principle of improving the machining accuracy of workpieces. (3) The principle of increasing clamping force, reducing machining difficulty and improving machining efficiency. (4) The principle of reducing processing procedures.
The new tooling mainly consists of five parts: counterweight, three jaw self centering chuck, eccentric tailstock, indexing chuck and eccentric cushion block.
① The eccentric pad is fixed between the four jaw single acting chuck and the three jaw self centering chuck. Its function is to fix and adjust the eccentric position of the three claw self centering chuck relative to the spindle axis. Considering the need of counterweight, the eccentric cushion block is designed as an axisymmetric part, with a weight of about 24kg.
② The indexing chuck is fixed on the back of the centering chuck. After the workpiece is clamped, it is integrated with the centering chuck and the workpiece. Its function is: when the eccentric circle is reprocessed, the three claw self centering chuck can be positioned and the natural indexing can be realized through the three card slots.
Note: it can be seen from the assembly drawing that the maximum influence of the tolerance of eccentric pad and indexing chuck groove on the center deviation of three claw self centering chuck is 0.10 mm. Through the function calculation, the maximum deviation angle from the center of gravity of workpiece to the center of spindle is 0.115 ° ≈ 6 ′ 52 ″, and the influence on the 50 mm eccentricity is 0.00 01 mm. The influence of this maximum displacement relative to the 50 mm eccentricity on the processing quality of workpiece Equal to zero, fully meet the processing requirements.
③ The eccentric hole of the tailstock of the eccentric tailstock is used together with the outer circle of the eccentric shaft. The center hole is 50mm away from it, which is used together with the center of the tailstock. When in use, tighten the fastening bolt, eliminate the fit clearance of the shaft hole, and control the eccentricity within 0.05mm. Its function is: the tailstock precisely locates the axial position of the eccentric shaft and the eccentric circle, and at the same time adds a part of the counterweight to the tail.
④ The counterweight is 12mm × 60mm × 160mm steel plate. Through two M12 bolts, connected under the eccentric cushion block, the weight of the counterweight block is about 0.8kg, a total of 10 pieces. Its function is to balance the difference between the rotary moment generated by the eccentric shaft and the tooling during the processing.
Moment calculation the moment produced by the cushion block is:
T1=F?L=G1?L=24×90=2160(㎏?mm)=21.6N?m
Where G1 - mass of eccentric pad
L --- the distance from the center of gravity of the cushion block to the center of the four jaw single acting chuck the total torque generated by the indexing chuck, the three jaw self centering chuck and the workpiece after rough turning is:
T2=F?L=G2?L=90×50=4500(kg?mm)=45N?m
Where: G2 = P? V = (60 × 285 × 130 × 7.85) / 100000 = 17.5 (n)
Where G2 is the total mass of indexi
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Because of the asymmetry of the eccentric shaft's shape, it will inevitably cause imbalance in the process of machining, so the first problem to be solved before the eccentric shaft is the counterweight. Selecting the right counterweight can make the workpiece drive smoothly in the processing, so as to meet the processing accuracy of the product.
There are three commonly used counterweight methods: one is to leave a chuck on the workpiece, and connect the special counterweight and the reserved chuck by keys and pins. The advantages of this connection method are high assembly precision, no relative movement between the workpiece and the counterweight, and the disadvantages are high manufacturing cost, and special site and special personnel are required to install during the installation process. The second is to directly carry out counterweight on the workpiece. The counterweight and the workpiece are fastened on the workpiece by clamping. The advantages are simple installation, low production cost, no need to process all kinds of auxiliary keyways and pin holes on the workpiece before installation. The disadvantage is that the counterweight and the workpiece are easy to move in the process of processing, which affects the processing accuracy of the product. The third is the weight of the chuck. This method is simple but not very accurate. Because the grinder has no chuck, this counterweight method can not be applied to the grinder.
According to the structural characteristics of eccentric shaft, a set of new tooling with large clamping force, natural indexing and simple counterweight adjustment is designed. Its design principle is: (1) the principle of Σ t = 0. By adjusting the left and right counterweights, the workpiece can rotate smoothly in the process of eccentric outer circle machining, and the machining difficulty caused by workpiece eccentricity can be solved. (2) The principle of improving the machining accuracy of workpieces. (3) The principle of increasing clamping force, reducing machining difficulty and improving machining efficiency. (4) The principle of reducing processing procedures.
The new tooling mainly consists of five parts: counterweight, three jaw self centering chuck, eccentric tailstock, indexing chuck and eccentric cushion block.
① The eccentric pad is fixed between the four jaw single acting chuck and the three jaw self centering chuck. Its function is to fix and adjust the eccentric position of the three claw self centering chuck relative to the spindle axis. Considering the need of counterweight, the eccentric cushion block is designed as an axisymmetric part, with a weight of about 24kg.
② The indexing chuck is fixed on the back of the centering chuck. After the workpiece is clamped, it is integrated with the centering chuck and the workpiece. Its function is: when the eccentric circle is reprocessed, the three claw self centering chuck can be positioned and the natural indexing can be realized through the three card slots.
Note: it can be seen from the assembly drawing that the maximum influence of the tolerance of eccentric pad and indexing chuck groove on the center deviation of three claw self centering chuck is 0.10 mm. Through the function calculation, the maximum deviation angle from the center of gravity of workpiece to the center of spindle is 0.115 ° ≈ 6 ′ 52 ″, and the influence on the 50 mm eccentricity is 0.00 01 mm. The influence of this maximum displacement relative to the 50 mm eccentricity on the processing quality of workpiece Equal to zero, fully meet the processing requirements.
③ The eccentric hole of the tailstock of the eccentric tailstock is used together with the outer circle of the eccentric shaft. The center hole is 50mm away from it, which is used together with the center of the tailstock. When in use, tighten the fastening bolt, eliminate the fit clearance of the shaft hole, and control the eccentricity within 0.05mm. Its function is: the tailstock precisely locates the axial position of the eccentric shaft and the eccentric circle, and at the same time adds a part of the counterweight to the tail.
④ The counterweight is 12mm × 60mm × 160mm steel plate. Through two M12 bolts, connected under the eccentric cushion block, the weight of the counterweight block is about 0.8kg, a total of 10 pieces. Its function is to balance the difference between the rotary moment generated by the eccentric shaft and the tooling during the processing.
Moment calculation the moment produced by the cushion block is:
T1=F?L=G1?L=24×90=2160(㎏?mm)=21.6N?m
Where G1 - mass of eccentric pad
L --- the distance from the center of gravity of the cushion block to the center of the four jaw single acting chuck the total torque generated by the indexing chuck, the three jaw self centering chuck and the workpiece after rough turning is:
T2=F?L=G2?L=90×50=4500(kg?mm)=45N?m
Where: G2 = P? V = (60 × 285 × 130 × 7.85) / 100000 = 17.5 (n)
Where G2 is the total mass of indexi
