Hydraulic rubber hose assembly, quality control and inspection

Date:2016-8-22
In hydraulic rubber hose assembly manufacturing process, the factors that affect the quality of the final product are many, must be strictly controlled in the production process.
 
1, hydraulic rubber hose quality control and inspection
 
Production of hydraulic hose rubber hose assemblies used must be tested according to appropriate technical standards for compliance with the performance requirements and hose assembly. In the inspection focus on the following aspects.
 
(1) hose specifications, dimensions and actual deviation. Since the inner and outer layer of the outer diameter of the hose and the skeleton will fluctuate if the fluctuation range exceeds the allowed limit, it can not guarantee the quality of the balance of the amount withheld hose fittings, hose assembly is difficult to guarantee. Therefore, the hose assembly production of the selected hose, should strictly check the inner diameter, outer diameter of the skeleton layer meets the requirements of an outer diameter deviation requirement may be relaxed.
 
(2) the hose wall thickness deviation. Since the intermediate layer and the inner hose layer eccentric skeleton between the layers take the head affects the width of the wall thickness of the hose may lead to excessive deviation. If the wall thickness deviation exceeds the allowable range, it will affect subsequent sealing and anti-pull off strength, and even cause the hose assembly joint portion skew (tilted). Therefore, the deviation of the wall thickness of the hose should be strictly controlled, usually for more than 0.5mm thickness deviation of the hose should be carefully selected.
 
(3) the adhesion between layers hose. High-quality hose should have good integrity, that is between the structure layer should have a higher adhesion between the adhesive layer as a whole. So as to adapt to the connector assembly, withholding during the process requirements, to ensure the hose assembly performance requirements. Therefore necessary to control the adhesion between the layers of the hose is not less than the technical standards, and should try to choose the production of high adhesion hose for hose assembly.
 
(4) the appearance of quality hose. Hose appearance quality can not be ignored, it not only affects the appearance of the quality of the hose assembly, also affects quality. As the outer layer bubbles, pores or damage to the equipment, make skeleton layer exposed, causing corrosion of the skeleton layer hose reduce the compressive strength of a direct impact on the life of the hose assembly, or even an accident in use. Therefore, the hose should check the appearance of quality, performance hose assembly affect the appearance of defects should be removed.
 
2, the quality control of the terminal metal member
 
Joint core tube, jackets and quality of the connection portion of the seal, before the joint assembly must be strictly tested. Inspection of the project in addition to size, with tolerance and precision should be consistent with the provisions of the joint drawing, you must also check the hoses and interchangeability matches joints, should also focus on the core tube surface finish inspection, sharp edges rounded edges and corners of the degree . If found fitting metal parts have sharp corners or burrs must be carefully trimmed in order to use, otherwise it will seriously affect the hose assembly performance and life.
 
Since the process was the joint metal steel itself has potential drawbacks, the naked eye is not easy to find, and withhold joints in the assembly process or during hydraulic fracture test will occur radial or axial gap. So, should the same batch of the terminal metal member-by-member rigorous testing to eliminate potential hazards.
 
3, strictly control the quality of the operation of the process
 
Manufacturing process of hydraulic rubber hose assembly, since many manual operations, to ensure the quality of the hose assembly must be strictly quality control operations, the impact of human factors to a minimum.
 
Measuring and cutting (1) the length of the hose. Measuring the length of the hose should be accurate, but must pay full attention to the hose itself bending phenomenon. In the range of hose assembly length requirement should rather long not to short. As a result of the internal pressure hose
There shortened by the following trends. If the length is too short, although you can barely fitting on the installation, but in the use of hoses and fittings will be affected by tensile stress and reduce the service life.
 
(2) Quality control of rubber mill. Wear rubber jacket long enough to affect the assembly is not in place, will reduce the hose fitting sealed in length, affect assembly sealing performance; wear rubber length is too large, skeleton layer exposed after the connector assembly withhold, vulnerable to corrosion and damage.
 
(3) strictly control the accuracy of the hose wall thickness measurement. Hose wall thickness is an important basis for withholding determine joint size, and therefore the measurement must be accurate, careful to minimize measurement errors and calculation errors.
 
(4) to strengthen joint assembly quality inspection and control. To ensure proper assembling position in the assembly process prone to problems, leaving the outer package is not in place the core tube is inserted deep enough, or in the assembly of the core tube so that the hose exits from the housing, resulting in reduced seal segments, Joints sealing performance. Therefore, we must pay attention to coat the assembly position.
 
4, withholding process of quality control and inspection
 
Withhold hose assembly is a key step in the manufacturing process. Strengthening withhold process quality control and quality assurance checks on the quality of the hose assembly is very important.
 
(1) Select the correct withholding mold. When choosing a mold, it should not be satisfied as long as the diameter to achieve the required withholding, also taking into account the size of the mold withholding gap.
 
(2) withholding to determine the size. According to the structure, properties and structure of the joint hose compression ratio determined later and should be verified by testing, especially for the first piece of the first test. According to the hose wall thickness measured, according to the selected compression ratio to calculate the diameter of the jacket after withholding were withholding, then the hydraulic test, pull test joints, sealing performance test hose and anti-pull-off strength of the joint.
 
(3) strictly control the withholding appearance. Note that coordination, control joints withholding position size, to prevent crushing the joint position and are not allowed to withhold. Try to avoid duplication withhold.
 
5, hydraulic rubber hose assembly quality inspection
 
Hydraulic rubber hose assembly finished product testing is necessary. Almost every form of joint sealing a comprehensive test hose specifications, length, joint angle and direction of the curved joint, withheld appearance quality and cleanliness within the hose and other surfaces. For the test pressure, burst pressure, anti-pull off strength test and impulse items of life, to conduct sampling method according to standards.

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