The processing technology
Rubber tracks are mainly produced by wire cord with joint type and without joint type.
Wire cord joint type process using extruder or calendering mechanism to prepare wire cord, plate vulcanization machine vulcanization belt body, and then lap ring shape joint vulcanization.
The advantages of this production process are high automation, high production efficiency and low labor intensity.
The disadvantage is that the thickness of the track joint lap position deviation is large, steel cord and belt rubber in the joint position easy to produce relative slip.
Steel wire cord without joint technology adopts single wire winding method to produce steel wire cord, and then adopts plate vulcanizing machine to vulcanize in sections.
The advantages of this kind of production technology are small elongation of rubber crawler, good pitch stability of crawler, good coordination between core gold and mechanical gear, high overall tensile strength of crawler;
The disadvantage is that there are many technological factors affecting the quality of the track, the degree of vulcanization at the vulcanization joint is not easy to control, the production efficiency is low, the labor intensity is large.
Mixing, extrusion and calendering processes in the production of rubber tracks are basically the same as those in the production of conventional rubber products. This paper only briefly introduces the problems needing attention in the surface treatment of core gold, steel wire coating, preforming and vulcanization processes.
Surface treatment of core gold by sandblasting rust removal, cleaning, drying and dipping adhesive (self-moving or manual) to make the core gold and rubber after curing more firmly.
Core gold sandblasting treatment to specification, before sandblasting carefully check the core gold, avoid the use of quality defects of the core gold.
After sandblasting according to the specified quality and time, check whether the surface of the core gold is clean. The core gold with air holes, slag inclusion, shrinkage holes and missing corners must be picked out. The core gold with unclean surface and other attachments should be sandblasted again.
When contacting the core gold after sandblasting, a clean hand cover should be worn to prevent the surface of the core gold from being contaminated.
After sandblasting, the core gold should be dipped and coated with adhesive within 60 min, and sandblasting for 10 min after 60 min.
The core gold should be stored in a dry and clean environment and used up within 1 week, otherwise it must be sandblasted again.
2 steel wire covering glue
(1) when the extruder USES the extrusion mechanism to prepare steel wire cord, the tension of the covering rubber should be even, the width and thickness of the covering rubber should meet the construction standards, and the steel wire should be arranged neatly without bending or overlapping.
In the process of extrusion operation, steel wire cord should be supplemented according to the construction standard if the steel cord is broken or missing.
Find steel cord rust or rubber abnormal, and should be replaced.
The steel cord shall be stored in a sealed box with desiccant, and the suspension time on the spindle rack shall not exceed 72 h. No sprinkling is allowed in the spindle room.
Cover rubber wire cord storage temperature should be below 40, the storage time should not exceed 15 days, if the storage more than 15 days, should be first brush gasoline, and then coated with a layer of glue.
(2) when the winding machine is used to produce steel cord with the winding machine, the glue concentration shall be strictly controlled, and the steel cord plate belt shall not be allowed to appear the phenomenon of lack of glue, yellowing, steel wire bending and overlapping.
When winding steel wire is not allowed to appear the phenomenon of uneven density, loose.
After the completion of wire cord winding, if there is a local yellowing phenomenon, should be timely coated with glue paste, glue paste should be painted evenly, do not allow the appearance of glue paste accumulation.
The wire curtain after winding and brushing the glue paste should be turned back on the plate, to dry the rear can be taken off, the two sides of the film can not overlap.
After the wire curtain cloth is taken off, it should be stored on the rack, not allowed to fall to the ground, twist, winding, etc., to ensure the smooth wire curtain cloth.
Preforming the core metal pitch template shall be filled with extruded plastic material in accordance with the requirements, and the core metal shall be inlaid with the specified quantity and specifications. The process of making the standard quality molding parts shall be preforming.
Extrusion materials, steel cord and core gold, etc. need to reach the prescribed parking time before pre-forming, and the parts are not allowed to be placed on the ground.
During preforming, the specified amount of core gold shall be symmetrical and equidistance placed in the template hole, and the core gold shall be covered with thin film and tamped with special tools in order to fix the core gold.
Soft film is used to cover the gold tooth tip of the core to prevent damage to the surface of the mold.
(1) wire cord with joint type process first for long mold molding vulcanization, according to the wheel side rubber, tooth rubber, core gold, intermediate rubber and wire cord, quality adjustment rubber, decorative pattern side rubber order will be loaded into the semi-finished parts of the mold in turn.
Check whether the core gold is inserted into the hole, whether it is perpendicular to the center of the mold, and whether the steel cord is placed in the set position.
The quality adjustment glue should be placed on both sides of the steel cord, which should be filled evenly.
All kinds of glue materials into the mold should be butt joint, not allowed to lap, to avoid causing the pitch to lengthen, in the joint should be brushed with glue, and then connected with thin film.
After vulcanization, the surface of the patterned side adhesive should be free of bubbles and other quality defects, and pay attention not to damage both ends of the belt body.
After curing the long die, vulcanize the ring joint. Remove the rubber edges at both ends of the unvulcanized or semi-vulcanized part of the belt body, cut off 5-6mm in the direction of the length, cut out the bevel, brush the glue paste at both ends, and add the connecting glue butt.
After the necessary dressing, the joint is vulcanized again after the recirculation caused by the vulcanization demoulding of the long mold or the cavity formed by the positioning of the core gold.
(2) wire cord link-less process adopts wire cord link-less process, during the curing, it should be noted to control the curing degree of the vulcanization junction, to prevent excessive sulfur or undersulfur at the vulcanization junction.