Electrical equipment wire and cable manufacturers: cable insulation surface problems

Electrical equipment with wire and cable manufacturers: cable insulation surface problem solutions. We will explain the surface unevenness and bulge problems in the production process of silane crosslinked polyethylene insulated core, and analyze them, and put forward solutions and control measures.

Electrical equipment wire and cable manufacturers: the reasons are as follows

1. raw rubber phenomenon

In the production process, the cross-linked insulated core sometimes has the phenomenon of raw rubber, which becomes an insulating block or hard block. The main reason for this phenomenon is:

(1) The temperature of the neck or head is not enough, resulting in local cold glue inside.

(2) The temperature or shear force of the fuselage is insufficient, and the local plasticization is not good.

(3) When the filter gasket is not in place, it will affect the extrusion pressure of the cross-linked insulating material, and will also produce raw rubber, causing uneven lumps on the surface of the insulating core.

2. old glue phenomenon

The old glue phenomenon sometimes appears in the production process of the insulating core, which also becomes pre-crosslinking. It is caused by the high temperature of the cross-linked material extrusion timing head or the cross-linked material staying in the dead angle of the flow channel for a long time. The old glue is Amber, the longer the stay time, the darker the color and the darker the temperature. Generally speaking, the reasons for the old glue are as follows:

(1) If the extrusion speed is too fast and the screw speed is faster, the shear force of the cross-linked material in the screw barrel will be stronger, which will increase the local temperature of the fuselage and cause the phenomenon of old glue.

(2) The cross-linked insulating material stays in the cylinder for too long, and part of the insulating material is prematurely cross-linked, which makes the surface of the wire core uneven when it comes out of the mold.

(3) The displacement of the filter pad leads to uneven distribution of rubber pressure at the splitter plate, forming dead ends of the flow channel. In this case, old rubber may also be generated. At the same time, the filter screen may also lose part of its filtering function. After a long period of production, the old rubber accumulated on the screw head will be taken out during extrusion and mixed with the old rubber particles in the insulation layer, resulting in quality problems in the insulation core.

Stability of 3. materials

In ordinary two-step silane crosslinked polyethylene, silane is first grafted with polyethylene to produce crosslinkable polyethylene (referred to as material A). In order to speed up the crosslinking reaction, a masterbatch containing catalyst (referred to as material B) is made, and then material A and material B are evenly mixed in a certain proportion, and crosslinked in warm water after extrusion. The quality problem of insulating core caused by material stability is mainly caused by the following reasons:

(1) The components of the cross-linked polyethylene insulation material are not evenly mixed. Due to the cross-linking agent and a small amount of antioxidant contained in the material, if the antioxidant is unevenly stirred during the production process, the concentrated antioxidant will be heated and gasified after the thermal insulation material is extruded at high temperature by the extruder, and bulges will be formed in the thermal insulation layer.

(2) If the cross-linked polyethylene insulation material is stored improperly, even if no catalyst is added, the silane cross-linked polyethylene material will slowly cross-link at room temperature. This is because the material contains a small amount of water (about 5010-4%). If it is stored at high temperature and high humidity, the surface of the extruded insulation layer will not be smooth.

Electrical equipment with wire and cable manufacturers introduced here.