Hydraulic rubber hose assembly quality control and inspection
In the production process of hydraulic rubber hose assembly, there are many factors affecting the quality of the final product, which must be strictly controlled in the whole process of production.
1. Quality control and inspection of hydraulic rubber hose
The rubber hose used in the production of hydraulic rubber hose assembly must be inspected according to the corresponding technical standards to confirm whether it meets the performance indicators and use requirements of the rubber hose assembly. Pay attention to the following aspects in the inspection.
(1) The size and actual deviation of the rubber hose. Because the inner and outer diameter of the hose and the outer diameter of the skeleton layer will fluctuate, if the fluctuation range exceeds the allowable limit, it can not ensure the balance of the buckle of the hose joint, and the quality of the hose assembly is difficult to ensure. Therefore, for the hose assembly production of the selected hose, should strictly check whether the inner diameter, skeleton layer diameter meets the requirements, the diameter deviation, the requirements can be relaxed.
(2) deviation of the wall thickness of the rubber tube. Due to the influence of the eccentricity of the rubber layer inside the hose and the width of the middle rubber layer between the skeleton layers, the deviation of the wall thickness of the rubber tube may be too large. If the wall thickness deviation exceeds the allowable range, it will affect the subsequent sealing and pulling strength, and even cause the hose assembly joint part to skew (tilt head). Therefore, the deviation of the wall thickness of the rubber tube should be strictly controlled. Generally, the rubber tube with the wall thickness deviation of more than 0.5mm should be carefully selected.
(3) adhesion between the layers of the hose. High quality hose should have good integrity, that is, there should be high adhesion between the structural layers, and the adhesive layers should be bonded into a whole. In this way, it can meet the technical requirements in the process of joint assembly and clamping, and ensure the performance requirements of the hose assembly. Therefore, we must control the adhesion between the layers of the hose can not be lower than the provisions of the technical standard, and we should try to choose the high adhesion of the hose for the production of the hose assembly.
(4) Appearance quality of rubber hose. The appearance quality of the hose can not be ignored. It not only affects the appearance quality of the hose assembly, but also affects the quality of use. If there are bubbles, pores or mechanical damage in the outer rubber layer, the skeleton layer will be exposed, causing corrosion of the skeleton layer, reducing the compressive strength of the hose, directly affecting the service life of the hose assembly, and even accidents will occur in use. Therefore, attention should be paid to the appearance quality of the hose, and the appearance defects affecting the performance of the hose assembly should be removed.
2. Quality control of joint metal parts
The quality of the joint core tube, the jacket and the connecting seal must be strictly inspected before the joint is assembled. In addition to the size, tolerance and machining accuracy of the inspection project should meet the requirements of the joint drawings, it is necessary to check the interchangeability of the joint and whether the rubber hose used matches, and it is also important to check the surface finish of the core tube and the smoothness of the sharp edges and corners. If the joint metal parts are found to have sharp corners or burrs, they must be carefully trimmed before use, otherwise they will seriously affect the performance and life of the hose assembly.
Due to the potential defects of the steel used for processing, the joint metal parts are not easy to be found by the naked eye. Radial fracture or axial crack will occur during the assembly and compression of the joint or in the hydraulic test. Therefore, the joint metal parts of the same batch should be strictly inspected one by one to eliminate potential hidden dangers.
3. Strictly control the operation quality in the process
In the manufacturing process of the hydraulic rubber hose assembly, due to the manual operation, in order to ensure the quality of the hose assembly, the operation quality must be strictly controlled to minimize the influence of human factors.
(1) Measurement and cutting of hose length. The measurement of the length of the hose should be accurate, but full attention must be paid to the bending of the hose itself. The length of the hose assembly should be longer than shorter. Because of the internal pressure of the hose
There is a tendency to shorten under use. If the length is too short, although it can be barely installed on the joint, but in use, the hose and the joint will be affected by tensile stress and reduce the service life.
(2) Control the quality of grinding glue. Insufficient grinding length will affect the coat assembly is not in place, will reduce the length of the rubber hose in the joint sealing section, affect the sealing performance of the assembly; The length of rubber grinding is too large, the joint assembly will make the skeleton layer exposed, easy to be damaged by corrosion.
(3) Strictly control the measurement accuracy of the wall thickness of the rubber tube. The wall thickness of the rubber tube is an important basis for determining the joint clamping size, so the measurement must be accurate and careful to minimize the measurement error and calculation error.
(4) Strengthen the inspection and control of joint assembly quality. To ensure the correct assembly position, the easy problem in the assembly process is that the outer set is not in place and the core tube insertion depth is not enough, or the rubber tube is removed from the jacket when assembling the core tube, resulting in the reduction of the sealing section and affecting the sealing performance of the joint. Therefore, it is necessary to pay attention to the location of the coat assembly.
4. Quality control and inspection in the process of withholding
Crimping is a key process in the manufacturing process of rubber hose assembly. It is very important to strengthen the quality control and quality inspection in the process of clamping to ensure the quality of the hose assembly.
(1) Correct selection of clamping mold. When choosing the mold, it should not only be satisfied to reach the required diameter of withholding, but also take into account the size of the gap between the mold after withholding.
(2) Determination of compression size. According to the structure, performance and joint structure of the rubber hose to determine the compression rate, should be verified by the test, especially the first part of the test. According to the measured wall thickness of the rubber tube, the diameter of the jacket after compression is calculated according to the selected compression rate, and then the hydraulic test, the joint pulling test, to check the sealing performance of the rubber tube and the joint pulling strength.
(3) Strictly control the appearance quality of clamping. Pay attention to coordination and coordination, control the joint clamping positioning size, prevent the joint from being crushed and inaccurate clamping position. Try to avoid repeated withholding.
5. Quality inspection of hydraulic rubber hose assembly
It is very necessary to inspect the finished product of hydraulic rubber hose assembly. The specifications of the hose, the length, the connection sealing form of the joint, the Angle and direction of the curved joint, the appearance quality of the buckle and the cleaning degree of the inner surface of the hose are almost all to be comprehensively inspected. For test pressure, burst pressure, pull-out strength and pulse life test, random inspection shall be carried out according to the method specified in the standard.
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