mould steel corrosion reasons and solutions

-
Rusting of plastic molds is a normal phenomenon and  caused by special reasons.It is not always due to quality problems of steel products.


  • Melt Decomposition




mould steel corrosionSome plastic raw materials will release volatile gases after being heated, which are corrosive and corrode the mold steel.

Therefore, when the injection machine stops , wipe the mold clean with soft rag and close the mold.

If the mold downtime is for a long time, anti-rust  spray shall be used in the mold cavity.

Butter shall be used to plug the gate when the mold is closed.


  • Cooling Water




Cooling water is mostly used in the mold for cooling, so there is more moisture around and inside plastic mold.

If the mold is cooled below the dew point, moisture in the air will become water droplets on the surface of the mold, which will easily rust if it is not wiped off in time.

Even after the mold stops working for a short time, condensed water will be seen soon.

Therefore, when the molding is stopped, the cooling water should also be cut off and blow mold dry. 


  • Carbide Residue




Carbide residue is produced after the mold works for a long time, carbide is precipitated and decomposed in the molding material, which often causes the mold to corrode or rust.

If carbide residue is found, it should be removed immediately. The gas or residue produced by plastic materials decomposition is the most common corrosion source to plastic molds.

In order to prevent the mold from rusting, the most widely used method is to chrome-plate the mold cavity, but chrome-plating cannot fully solve the problem, because the decomposed gas also corrode the deep hole.

These are the places that cannot be plated.


  • How to solve?




Short-term: Wipe the surface of the mold cavity lightly with a rag. Fully dry the plastic material and reduce the temperature of the barrel to prevent the resin from decomposing.

Long-term: change to a new material that does not corrode the mold for decomposition. 

due to differences in plastic materials , such as PVC, POM, EVA, PC, foaming materials, etc. Some resin may decompose to release corrosive gas inside the mold, the plastic mold should be chrome plated. 

During the plastic mold short downtime, the mold cavity need to be  sprayed with anti-rust agent, and then the mold is closed. When the mold downtime is long , coat the outside of the mold and the movable parts with butter.

Comments

Post a Comment

Popular posts from this blog

Moulage Par Injection Et Fabricant De Moules En Chine

-
Image
Moulage Par Injection Et Fabricant De Moules En Chine-Topworks En tant que fabricant chinois de moules à injection et de moules en plastique sur mesure, Topworks est fier d'offrir à ses clients des moules et des pièces en plastique de la meilleure qualité, fabriqués à l'aide de technologies avancées. Avec plus d'une décennie d'expérience, Topworks entreprend chaque projet avec un haut niveau d'expertise et de dévouement. Nous mettons à votre disposition un personnel qualifié, compétent et dévoué qui se consacre à vos besoins en matière de moulage par injection de plastique. Topworks peut fabriquer un article complet tout au long de notre processus de fabrication, ou seulement des parties d'un système, régulièrement ou de manière ponctuelle, et offrir des services d'assemblage, d'estampage et d'emballage sur mesure lorsque cela est nécessaire et requis. OBTENIR UN DEVIS GRATUIT-30% INFÉRIEUR,15 JOURS MOINS Tous les employés de T
Read more

what is plastic mold?

-
Image
What Is Plastic Mold?   What is plastic mold? The tooling used for plastic injection molding is called plastic mold or plastic injection mold . Most plastic products are molded by plastic molds. Plastic molds are divided into two types: thermosetting and thermoplastic mold ,according to the molding plastic characteristics. Based on the molding process, the plastic mold is divided into plastic injection mold, blow mold, casting mold, pressing mold,and so on. The injection mold is made up of two main sections: the moving half and the fixed half. The moving half is mounted on the moving platen of the injection molding equipment, and the stationary half is mounted on the stationary platen. Over the injection molding, the moving and the stationary half are shut to develop an injection structure and a cavity structure. Once the mold is open, the moving half and the stationary half are split up to clear away the plastic item from the plastic mold. As a way to decrease the mold de
Read more

Injection product stress mark solution

-
Image
On plastic injection products, especially for raw materials such as ABS, PP and PC, you will often see shiny stress marks on the surface of products, such as injector pin stress marks, insert stress marks and stress marks of wall thickness difference . These apparent shiny, white markings are the result of internal stresses , which are nothing more than orientation and cooling shrinkage stresses. The irregular stress marks near the gate are caused by the typical orientation stress, and the difference of wall thickness is the result of orientation and contraction stress, those stress marks are made by ejector pins and sliders . Normally , with the increase of holding pressure and time, the first occurrence is the stress mark of wall thickness difference, the stress mark of ejector pin, then the stress mark of meat thickness difference, and finally the irregular stress mark near the gate (gray section will appear on the side), which of course also depends on the specific structure of the
Read more