why bubbles in injection molding

-
In the process of injection molding, the bubble inside is a serious defect.

Air bubbles in injection molded transparent parts will affect the appearance quality of products. At the same time, it will also reduce the strength of injection molded products.

The bubbles are mainly produced in the process of injection molding:

  • The raw materials are not dried enough or air mixed in the raw materials.

  • In the injection molding process, the injection speed is too fast, the residual material inside barrel is too much, and the back pressure is too low.

  • Poor mold venting and low mold temperature.


How to solve:



  • Raw materials should be fully dried.

  • Reduce the screw temperature and the temperature of the feeding port.

  • Increase the back pressure  and reduce the ejection position of screw (more residual material).

  • Reduce injection speed and increase mold temperature.

  • Increase the injection pressure and time and improve the venting of the mold.

  • Retain bubbles on the nozzle material or main runner by changing the injection position for cold runner mold.


CASE STUDY:

injection molding bubbles 

The curve part of this product is easy to get bubbles, and the solution steps :

  1. raw materials should be fully dried. （120℃、4h）

  2. Properly reduce the screw temperature and the temperature of the nozzle to prevent premature melting and decomposition of PC materials, and air cannot be eliminated.

  3. Because the gate is small, it is difficult to squeeze bubbles out of the cavity by increasing the holding pressure and time.

  4. This product is designed with a cold runner , so the best solution is to keep bubbles on the nozzle material. (Increase the injection position of the first stage, reduce the injection speed of the first stage and appropriately increase the back pressure  )


bubble in runner

 

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

How to Present Your Product Idea to a Design Firm

-
Image
How to Present Your Product Idea to a Design Firm   You have a product idea you want to take to market. Now what? Aspiring entrepreneur, tinker, engineer…Your mind runs 1,000 miles per hour thinking of the many different ways you can improve your environment. Just recently you have come up with a product idea that you know can benefit many different people. It’s worth a shot to try to develop it and take it to market — but how do you even start? If your idea is a physical product, this article is for you. We’ll walk you through exactly how to present your product idea to a design company — an activity that will serve as the beginning of the design phase of your project. We’ll cover everything you need to know in order to compile a presentation-style document that explains your idea to a design firm. It can be a standard presentation with slides or any document of your choice that includes relevant content.  You’re welcome to dive right into the sample presentation we made available on
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