How to design and make foaming molds 10

1. Design and production of foaming mold: Foaming products should be reasonably designed. The requirements for the mold are that the heating should be uniform and the cooling should be uniform.

The stomata are selected in a large space. During the production, the foaming resin is directly filled into the mold, so that it is heated and melted to form a gas-liquid saturated solution, and a large number of tiny bubble nuclei are formed through nucleation, and the bubble nuclei grow to make foam plastic parts. There are three commonly used foaming methods:

Physical foaming method, chemical foaming method and mechanical foaming method.

2. Mold (mú jù), a variety of molds and tools used in industrial production to obtain the required products by injection molding, blow molding, extrusion, die-casting or forging molding, smelting, stamping and other methods. In a nutshell, a mold is a tool used to shape an item, which is made up of various parts, and different molds are made up of different parts. It mainly realizes the processing of the shape of the item through the change of the physical state of the molded material.

Known"The mother of industry"The title.

First of all, the foaming product itself should be reasonably designed. Don't make too much difference in thickness and too much of a center of gravity, and have support for weak points. The requirements for the mold are that the heating should be uniform and the cooling should be uniform.

The holes are small and dozen, and the mold should be carried at a sufficient slope in order to take out the product smoothly. The choice of stomata is also very important, so choose a place with a large space.

What mold do you mean?

Injection molds, extrusion molds, blow molds.

Different molds have different designs.

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Dear, I am glad to answer for you: polyethylene foaming mold algorithm A: polyethylene foaming mold algorithm:

Polyethylene touches auspicious specific gravity, HDPE: LDPE=1:1, and its specific gravity is:

The specific gravity of the foaming degree should be calculated according to the foaming degree p, that is, the amount of the combined dielectric constant. General combination = (2 +1-2p( -1) * 2 +1 + p( -1)) dielectric constant of dielectric material (PE takes the same wire diameter with foaming degree, and the equivalent dielectric constant of different foaming degrees is also different, the larger P, the smaller the combination, and the lighter the weight.

(1) Steamer foaming For the production of small, thin-walled and complex plastic parts, steamer foaming molding is mostly used. The mold filled with expandable polystyrene raw material is put into the steamer and heated by steam, and the steam pressure and heating time depend on the size and thickness of the plastic part. Generally, the steam pressure is controlled at MPa, and the heating time is 2 3 min, and it can be more than 10 min as needed.

The pre-foamed particles in the mold are softened and expanded by heat and fused together with each other, and the mold is taken out from the steamer, and the foam plastic parts can be obtained after cooling and demolding.

2) Foam Molding Machine Foaming Foam molding machine is a widely used polystyrene foam molding equipment in China, which can be divided into two types: packaging molding machine and sheet forming machine. Foam parts with large thickness or large and medium-sized foam parts are often directly foamed by foam molding machine. There is a 4mm diameter ventilation hole for ventilation on the mold, the heating steam that is first introduced before molding, after the mold is preheated for min, the air outlet is opened, the pre-foamed particles are injected into the mold cavity by air delivery method, the air outlet is closed, and the steam of MPA is introduced into the steam chamber, so that the temperature rises to about 1100C, and the pre-foamed particles in the cavity are expanded and bonded as a whole, the steam valve is closed and kept for 1 2min, and then the cooling water is passed, and finally the mold is demolded.

Styrofoam molding mold.

The structure of the foam molding mold is relatively simple. For small, thin-walled and complex styrofoam parts or small-batch production of styrofoam parts, manual operation molds of steamer foaming are often used; For large, thick-walled or mass-produced styrofoam parts, a styrofoam molding machine with a steam chamber is often used to directly pass the steam foaming mold.

Manually operate the mold.

There is no steam chamber for manual operation of the mold itself, but the whole mold is placed in a steamer and heated by steam, and then moved out of the box for cooling after molding. Manual steamer foaming mold for packaging lid, one piece at a time. When clamping, the mold sleeve 1 and the lower template 3 are positioned in a circle.

In order to be convenient to open the mold, be provided with a pry 8 around the mold. Upper template 2, lower template 3 and mold sleeve 1 are all provided with the ventilation hole of diameter 1, and hole spacing is 15-20mm. The whole set of molds is locked by hinge bolt 6 and wing nut 5, and the hinge bolt swing should be flexible and should have sufficient strength.

Foam packaging needs to make a foaming mold according to the required shape, and fill the mold with foaming agent to make it foam and form. Foaming materials are divided into two types: chemical foaming materials and physical foaming materials.

The mold of foaming molding is the plastic foaming mold. Foaming mould English: foaming mould

The foaming resin is directly filled into the mold, so that it is heated and melted to form a gas-liquid saturated solution, and through nucleation, a large number of tiny bubble nuclei are formed, and the bubble nuclei grow to make foam plastic parts.

The die head has a streamlined runner surface, and the two-half mold body design makes it easy to disassemble and clean the die. Manually fine-tune the elastic lip or movable lip design to suit the different thickness requirements of the extruded sheet. The vertical or inclined 45° choke bar is designed to accommodate the uniform distribution of melt flows of different viscosities.

The mold body is made of high-quality mold steel or imported alloy steel to prolong the life of the mold.

The surface of the runner is all hard chrome plated, with an average thickness of 25 m to 50 m, and is mirror-polished.

The die fasteners are made of high-strength bolts.

The heating element is made of high-quality, durable stainless steel heating rod and heating ring. PVC mold.

The following steps need to be followed to open the mold of foamed products:

1.Design the mold: according to the shape, size and requirements of the required products, draw the drawing paper of the mold. Reasonable design is carried out taking into account factors such as fluidity, shrinkage, cooling time and other factors of the material.

2.Make the mold: make the actual mold according to the design drawings. Usually CNC machine tools, EDM, wire cutting and other high-precision machines are used to make molds to ensure the accuracy and quality of molds.

3.Mold trial adjustment: The mold is installed on the injection molding machine, the mold trial production is carried out, and the mold is adjusted according to the actual situation to achieve the best molding effect.

4.Mass production: When the mold trial adjustment is completed, you can start mass production, and complete the production task step by step according to the production plan.

In the process of mold development, it is necessary to pay attention to the quality selection of the mold, the structural design of the mold, the surface treatment of the mold, etc., so as to ensure the quality and life of the mold.

To put it simply, it is to use physical methods to foam plastic. There are generally three ways to do this:

1) First, the inert gas is dissolved in the plastic melt or paste under pressure, and then the gas is released under reduced pressure to form pores and foam in the plastic;

2) foaming by evaporating a low-boiling liquid dissolved in a polymer melt;

3) Add hollow balls to the plastic to form foam for foaming.

The cost of the physical foaming agent used in the physical foaming method is relatively low, especially the cost of carbon dioxide and nitrogen is low, and it is flame retardant, so its application value is high. In addition, there is no residue after foaming of the physical foaming agent, which has little effect on the performance of the foaming mold. However, it requires special injection molding machines and auxiliary equipment, which is technically difficult. Chemical foaming method.

The chemical foaming method is to use the gas generated by the chemical method to foam the plastic: the chemical foaming agent added to the plastic is heated to separate the gas and release the foam; In addition, it is possible to foam using gases released by chemical reactions between various plastic parts.

The injection molding process of chemical blowing agent foaming mold is basically the same as that of general injection molding. The heating, mixing, plasticizing, and most of the foaming and expansion of the plastic are done in the injection molding machine.

In short, no matter which plastic raw material is selected or which foaming method is adopted, the foaming process generally has to go through the stages of bubble core formation, bubble core expansion, and bubble body solidification.

Structural foaming molding.

Structural foaming is a chemical foaming method that is a revolution in injection molding technology. It retains many advantages of the traditional injection molding process, and avoids the problems of insufficient product strength, long production cycle, and low molding rate encountered in the traditional injection molding process.

In addition, the use of structural foaming technology can also be used to form large and complex products, using low-cost molds, and operating multiple cavities at the same time, thereby reducing the production cost of the product. Structural foamed products are a kind of conjoined foam materials with dense surfaces, and their strength and stiffness per unit weight are 3 4 times that of similar unfoamed materials.

The principle of physical hair plate mold generally uses this sufficient volume, and then carries out thermal expansion and cold contraction of the volume to complete the operation of the generalization function.