QUALITY CONTROL FOR HYDRAULIC HOSES

(ONE) IN LABORATORY, BEFORE PRODUCTION

1) After finishing rubber sheet, in our laboratory, we test the hardness, according to our requirement in Shore A 82-85, rubber tensile must be above 12 MPA, which is for inner tube of hydraulic hoses. Outside rubber will be 80 Shore A and 8 MPA in tensile.

2) After we buy Steel Wire in middle parts, in our laboratory, we test the tensile, according to our requirement in 2750-2950N.The tensile must be in our required tolerance, to assure the working pressure and burst pressure.

3) In our laboratory, we make vulcanization inner tube rubber and outer rubber with steel wire. To check how much adhensive pulling power between them, to assure adhension in rubber hoses. Also, we will imitate vulcanization of production to assure rubber vulcanization is under our control in 5 minutes , 10 minutes, half hour and one hour above.

(TWO) IN WORKSHOP, DURING PRODUCTION

1) To prepare PP or steel mandril in previous day, and dry the mandrill to assure it separate well from inner rubber, but not hurt inner tube.

The PP mandril OD is higher requirement hen SAE and EN standards to control exact proper diameters of hydraulic hoses.

2) We adjust steel joint machines every week. We test the steel wire length difference according the tolerance of XN(7N,8N,9N,10N,11N,12N) standard to assure same length before braiding machine.

3 In Germany technology braiding machines, we adjust spider tension 0.5kg higher then standard of 8KGS, to assure braiding cover more compact and in good shape , higher than standard. The finishing of hydraulic hoses are in very good shape.

4) We use advanced cold feeder extruder, controlled by PLC computer. Cold feeder extruder has more power to extrude rubber inner tube in good shape.

5) After finishing extruding inner tube,we require to make it recovery previous shape in normal temperature, at least 8 hours, we begin to put in colding machine in -30C for braiding machine.

6) In braiding and spiral machine, we require pitch and steel wire distance in our standard. To assure the steel wire angle in control.

(THREE) ATFER PRODUCTION, BEFORE SHIPPMENT.

1) After finishing hoses, we test proof pressure in 1.8 times of working pressure on EACH HOSE for one minute checking any possible leak or defective point of rubber hoses , before shipping to our customers.

2) The burst pressure of hydraulic hoses must reach 4 times of working pressure.

3) The impulse testing must be above 200000 circles for braided hydraulic hoses, and 400000 circles for spiraled hydraulic hoses.