The grinding of the piston rod of the truck crane telescopic cylinder (long rod) is easy to waste, and according to our experience, the following anti-waste measures are taken.
1. Carefully measure the amount of grinding at each point of the workpiece
Whether it is possible to grind according to the data such as bending, yaw, misalignment and depth of the tool mark.
(1) For the part where the grinding amount does not exceed 0.50 mm, the operator can carefully measure the values ​​of yaw, distortion, misalignment, and knife marks. For workpieces with a grinding volume below 0.20 mm, it is necessary to ask the relevant personnel to agree and then grind.
(2) If the yaw or bending amount exceeds one third of the grinding amount, it should be straightened and then ground.
(3) The diameter data on both sides of the misalignment part and the yaw data on both sides can be used to subtract the yaw value of the maximum yaw part from the grinding value at the minimum diameter, and the difference is the actual grinding amount. For example, the minimum diameter of the misalignment is 0.40 mm, the maximum deflection of the yaw is 0.30 mm, and the actual wear is equal to 0.40 - 0.30 = 0.10 mm. Less, it is very likely that burns will occur during grinding, resulting in waste.
(4) In the deep part of the knife mark, it is best to use a file to pry out the local symmetry point (the most severe and most deviated part) out of the two symmetrical planes before grinding, and measure according to the smashed part. If the measured diameter minus the diameter of the tool mark is less than 0.20 mm, it should be re-grinded after the request.
2. Properly handle burns during grinding
(1) Before grinding, according to the above requirements, after grinding, if the spark is extremely large and there is partial burn during rough grinding, and the burned part cannot be eliminated after two reciprocating grindings, the workpiece deflection value must be performed. Measurement. If the yaw value and the grinding amount are both lower than the above limit values, alignment should be performed. When it cannot be eliminated by straightening, it must be scrapped.
(2) Pay attention to the change of spark during fine grinding. Once the burn occurs, the workpiece becomes waste. Particularly mild burns, if the measured yaw value is less than one-third of the grinding amount, grinding can continue; more than one-third should be scrapped.
The cause of the burn is also related to the type of the grinding wheel and the material of the workpiece. The precautionary measures are to repair the grinding wheel in time and adjust the amount of cutting (when coarse grinding or fine grinding, if the cutting amount is too small, it will produce slight burns), add enough coolant, adjust the workpiece and the grinding wheel speed.
3. Watch the spark carefully
Once the spark is too large during grinding, the knife must be retracted immediately. The spark should not be interrupted after all rough grinding. If the yaw value of the broken part exceeds one quarter of the grinding amount, straighten it. Each time the grinding wheel approaches the workpiece, the spark is gradually increased. It should be checked whether the temperature of the tip is too high. If the tip temperature is consistent with the workpiece, the tip of the tail should be tight. If the spark becomes large when passing through the bracket, it indicates that the top of the bracket is unreasonable, causing the temperature to rise there. There should be no intermittent view of sparks during fine grinding. If the fire is severe, the yaw and the amount of grinding should be measured. When the yaw exceeds one quarter of the grinding amount, it cannot be ground.
4. Strictly control processing quality and accuracy
When the diameter values ​​of the points are inconsistent, the bracket and tailstock should be adjusted in time.
(1) After coarse grinding and semi-finishing, the cylindricity of the workpiece should not be exceeded. If there is a misfire in the elliptical degree, the yaw value should be measured. If the value exceeds 30 μm, it must be straightened and re-tested; after several infeeds, the total amount of the infeed exceeds 50 μm. When the spark will no longer be broken, the ellipticity should be zero; if the ellipticity is still exceeding the tolerance, the grinding wheel should be trimmed and then tried. If the ellipticity is still not eliminated, check whether the tip hole is damaged or not. Injury (the surface of the workpiece is now multi-edge).
(2) The reason for the multi-edge surface after grinding and the trimming measures are as follows: if the grinding wheel has been blunt, it should be trimmed; if the grinding wheel has obvious vibration, it should be adjusted; the head frame and motor frame vibration isolation facilities are damaged and must be repaired. If the vibration of the workpiece itself is too large, the speed should be appropriately reduced; when the tip is too tight or too loose, it must be adjusted.
(3) If a large spiral surface appears during rough grinding, the reason is that the grinding wheel is not well-trimmed, and the grinding wheel must be uniform when it is finely ground. There must be no obvious single-angle spark phenomenon. The surface of the workpiece is prone to be large after the grinding wheel is blunt. Spiral.
(4) When finishing grinding, the workpiece tends to be pulled, scratched, and the coolant is not clean. To prevent this from happening, the newly refined grinding wheel should be brushed with a wire brush (note safety).
(5) When the phenomenon of workpiece occurrence during finish grinding is taper, drum shape, saddle shape, diameter at both ends is larger or smaller, the bracket, tailstock, grinding wheel overrun and the number of workpieces and the stop of the grinding wheel at both ends of the workpiece should be adjusted. time.
5. Strictly control the temperature of the two top parts
It can be judged whether the tip tightness is reasonable according to the change of the temperature of the two tips; generally, the temperature of the tip is slightly higher than the temperature of the workpiece.
(1) The reasons why the temperature of both tips are too high: one is too tight, and the other is that the tip is not concentric with the center hole of the workpiece. If the top is too tight, first loosen the tip and add butter to the two center holes before adjusting the tightness of the tip.
(2) If the temperature of a certain tip is too high, the tip is not concentric with the center hole of the workpiece.
(3) When the temperature of the two tips is consistent with the temperature of the workpiece, there will be no multi-edge phenomenon on both ends of the workpiece, and the spark is relatively uniform, and the grinding can be continued at this time. If there is a multi-edge phenomenon at both ends of the workpiece, the tip should be tightened first. If the workpiece is not burned, it can be completely ground. When the spark at both ends of the workpiece is uneven, it is necessary to tighten the tip of the tail.
1. Carefully measure the amount of grinding at each point of the workpiece
Whether it is possible to grind according to the data such as bending, yaw, misalignment and depth of the tool mark.
(1) For the part where the grinding amount does not exceed 0.50 mm, the operator can carefully measure the values ​​of yaw, distortion, misalignment, and knife marks. For workpieces with a grinding volume below 0.20 mm, it is necessary to ask the relevant personnel to agree and then grind.
(2) If the yaw or bending amount exceeds one third of the grinding amount, it should be straightened and then ground.
(3) The diameter data on both sides of the misalignment part and the yaw data on both sides can be used to subtract the yaw value of the maximum yaw part from the grinding value at the minimum diameter, and the difference is the actual grinding amount. For example, the minimum diameter of the misalignment is 0.40 mm, the maximum deflection of the yaw is 0.30 mm, and the actual wear is equal to 0.40 - 0.30 = 0.10 mm. Less, it is very likely that burns will occur during grinding, resulting in waste.
(4) In the deep part of the knife mark, it is best to use a file to pry out the local symmetry point (the most severe and most deviated part) out of the two symmetrical planes before grinding, and measure according to the smashed part. If the measured diameter minus the diameter of the tool mark is less than 0.20 mm, it should be re-grinded after the request.
2. Properly handle burns during grinding
(1) Before grinding, according to the above requirements, after grinding, if the spark is extremely large and there is partial burn during rough grinding, and the burned part cannot be eliminated after two reciprocating grindings, the workpiece deflection value must be performed. Measurement. If the yaw value and the grinding amount are both lower than the above limit values, alignment should be performed. When it cannot be eliminated by straightening, it must be scrapped.
(2) Pay attention to the change of spark during fine grinding. Once the burn occurs, the workpiece becomes waste. Particularly mild burns, if the measured yaw value is less than one-third of the grinding amount, grinding can continue; more than one-third should be scrapped.
The cause of the burn is also related to the type of the grinding wheel and the material of the workpiece. The precautionary measures are to repair the grinding wheel in time and adjust the amount of cutting (when coarse grinding or fine grinding, if the cutting amount is too small, it will produce slight burns), add enough coolant, adjust the workpiece and the grinding wheel speed.
3. Watch the spark carefully
Once the spark is too large during grinding, the knife must be retracted immediately. The spark should not be interrupted after all rough grinding. If the yaw value of the broken part exceeds one quarter of the grinding amount, straighten it. Each time the grinding wheel approaches the workpiece, the spark is gradually increased. It should be checked whether the temperature of the tip is too high. If the tip temperature is consistent with the workpiece, the tip of the tail should be tight. If the spark becomes large when passing through the bracket, it indicates that the top of the bracket is unreasonable, causing the temperature to rise there. There should be no intermittent view of sparks during fine grinding. If the fire is severe, the yaw and the amount of grinding should be measured. When the yaw exceeds one quarter of the grinding amount, it cannot be ground.
4. Strictly control processing quality and accuracy
When the diameter values ​​of the points are inconsistent, the bracket and tailstock should be adjusted in time.
(1) After coarse grinding and semi-finishing, the cylindricity of the workpiece should not be exceeded. If there is a misfire in the elliptical degree, the yaw value should be measured. If the value exceeds 30 μm, it must be straightened and re-tested; after several infeeds, the total amount of the infeed exceeds 50 μm. When the spark will no longer be broken, the ellipticity should be zero; if the ellipticity is still exceeding the tolerance, the grinding wheel should be trimmed and then tried. If the ellipticity is still not eliminated, check whether the tip hole is damaged or not. Injury (the surface of the workpiece is now multi-edge).
(2) The reason for the multi-edge surface after grinding and the trimming measures are as follows: if the grinding wheel has been blunt, it should be trimmed; if the grinding wheel has obvious vibration, it should be adjusted; the head frame and motor frame vibration isolation facilities are damaged and must be repaired. If the vibration of the workpiece itself is too large, the speed should be appropriately reduced; when the tip is too tight or too loose, it must be adjusted.
(3) If a large spiral surface appears during rough grinding, the reason is that the grinding wheel is not well-trimmed, and the grinding wheel must be uniform when it is finely ground. There must be no obvious single-angle spark phenomenon. The surface of the workpiece is prone to be large after the grinding wheel is blunt. Spiral.
(4) When finishing grinding, the workpiece tends to be pulled, scratched, and the coolant is not clean. To prevent this from happening, the newly refined grinding wheel should be brushed with a wire brush (note safety).
(5) When the phenomenon of workpiece occurrence during finish grinding is taper, drum shape, saddle shape, diameter at both ends is larger or smaller, the bracket, tailstock, grinding wheel overrun and the number of workpieces and the stop of the grinding wheel at both ends of the workpiece should be adjusted. time.
5. Strictly control the temperature of the two top parts
It can be judged whether the tip tightness is reasonable according to the change of the temperature of the two tips; generally, the temperature of the tip is slightly higher than the temperature of the workpiece.
(1) The reasons why the temperature of both tips are too high: one is too tight, and the other is that the tip is not concentric with the center hole of the workpiece. If the top is too tight, first loosen the tip and add butter to the two center holes before adjusting the tightness of the tip.
(2) If the temperature of a certain tip is too high, the tip is not concentric with the center hole of the workpiece.
(3) When the temperature of the two tips is consistent with the temperature of the workpiece, there will be no multi-edge phenomenon on both ends of the workpiece, and the spark is relatively uniform, and the grinding can be continued at this time. If there is a multi-edge phenomenon at both ends of the workpiece, the tip should be tightened first. If the workpiece is not burned, it can be completely ground. When the spark at both ends of the workpiece is uneven, it is necessary to tighten the tip of the tail.
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