Maintenance Of Fiberglass Pultrusion Mold


Maintenance Of Fiberglass Pultrusion Mold:

FRP pultrusion mold must be smooth to buckle down on the mold frame, avoid higgledy-piggledy chaos stacked, resulting in deformation of FRP mold. In case of deformation, the pressure can be pressed under the sun and can be restored to the original state. Like the long lines of the small bending phenomenon, the production of the natural correction over, do not have to pressure, but the use of the mold, after cleaning must be the flat buckle. The time is long, the mold surface roughness phenomenon may brush a 191# resin material, but must thin after the dry grinding and polishing can the entire old as new. In the process of production and application of FRP pull die, the failure of different situations often occurs, and wastes a lot of manpower and material resources, which affect the production schedule. The following are mainly about the basic failure of the mold and the reasons for the failure and the preventive measures.

1 FRP pultrusion mold failure

The basic form of failure in the service of cold and hot dies can be divided into plastic deformation, wear, fatigue, fracture.

(1) plastic deformation.

Plastic deformation is the deformation of the load greater than the yield strength. If the die cavity appeared to collapse, hole expansion, edge collapse and depression appear upsetting punch, longitudinal bending, etc.. Especially hot for FRP pultrusion die, the contact surface and high-temperature materials, cavity surface temperature often exceeds the hot work die steel tempering temperature, groove wall due to softening and collapsed or stack.

(2) wear failure

Wear failure refers to the edge gate passivation, edges and corners circle, surface subsidence, surface groove marks, spalling mucosa (in the friction in the die working table and stick some metal blank).

(3) fatigue failure

Fatigue failure characteristics: some parts of the die after a certain service and the initiation of the tiny crack, and gradually to the depth of the expansion, the expansion to a certain size, seriously weakened die of bearing capacity and cause a fracture. Fatigue crack initiation was born in should force large parts, especially the stress concentration position (size transition, gap and marks, wear crack, etc.), fatigue fracture TB door is divided into two parts, a part for the development of fatigue crack formation of fatigue rupture section, showing a conchoidal. Fatigue source is located in the shell vertex. The other part is the abrupt rupture, the rough section of the uneven roughness is presented.

The root cause of the fatigue damage of the die is the special ring load, and all the factors that can promote the surface tension stress can accelerate the initiation of the fatigue crack.

(4) fracture failure. Fracture failure common forms: chipping, splitting crack, break off and cracking and so on, different fiberglass pultrusion die fracture of a different driving force. There are two kinds of fracture processes in the FRP pultrusion  die: one time fracture and fatigue fracture. The one time fracture is the mold sometimes when the ram suddenly breaks, the crack initiation once, after namely, the instability, the extension. The main reason is that severe overload or die material is severely brittle (e.g., overheat, tempering, severe stress sets ten and severe metallurgical defects.

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