TR201807004A2 - Method for reducing the weight of plastic parts - Google Patents

Abstract

The invention is a plastic injection method for lightening the surfaces of plastic parts used in vehicles without deterioration. before injection of the material consisting of thermoplastic raw material and foaming agent, filling the gas into the mold cavity to produce a reverse pressure greater than the injection pressure of the material, initiating the material injection, simultaneously releasing the gas in the mold cavity at the same time as the material injection, the injection of the material in a controlled manner stops. The amount includes the steps of opening back.

Description

DESCRIPTION METHOD FOR REDUCING THE WEIGHT OF PLASTIC PARTS Technical Area Plastic parts produced by the plastic injection method used in the automotive industry; chemical By using foaming agents, the counter gas pressure and mold recovery, which control the plastic flow in the mold by integrating with the opening technology, the surfaces of the plastic parts are preserved without deteriorating the density and It is related to the method of reducing the weight.

State of the Art Plastic components make up 12-15% of the weight of today's modern vehicles. a vehicle in different sizes and dimensions such as headlights, fenders, body cladding plastics, engine components, clips. There are over 2000 plastic parts in different sizes. In the automotive industry, fuel Vehicle lightening plays an important role in reducing consumption and greenhouse gas emissions.

A method currently used in plastic injection is the counter gas pressure method. Pattern After it is closed, Nz or 002 gas is filled into the cavity inside and plastic is filled in the mold. Prior to injection, a back pressure higher than the injection pressure is created. Plastic When the injection is started, the N2 or CO2 gas in the mold is discharged from the injection nozzle. by meeting the incoming plastic material, spreading the material evenly into the mold makes it fill.

Chemical foaming method is the addition of a certain amount of foaming agent into the plastic raw material. It is a method of obtaining plastic parts with a lower density and weight.

When chemical foaming is used in existing moulds, the cavity in the mold is fixed. When the plastic material stops flowing, foaming and air gap formation can be achieved at the desired level. is not possible.

Another problem is mold flow marks on the surface of the plastic part when chemical foaming is used. and silver sprinkling spots.

In order for the foaming process to take place more, various molds used in the present are used. modifications have been made. One of these; After the injection process of the molten plastic, retracting the moving group in the moving die or making room for a second component It is a core pulling method that takes place by opening it.

Another modification is; After the injection process of the molten plastic, the moving mold is It is the foaming process by opening the amount back or making room for a second component.

As stated in file US897422352, the chemical foaming process can be done by core extraction or Its use with mold opening method produces more foaming than its use in existing molds. it provides. However, mold flow marks and silver sprinkling spots on the surface of the plastic part formation cannot be prevented.

As a result, the existence of the above problems and the inadequacy of the existing solutions are in the relevant technical field. made it necessary to make an improvement.

Purpose of the Invention The invention is an invention that satisfies the above-mentioned requirements, eliminates all disadvantages and has additional It is about the plastic injection method that brings some advantages.

The primary purpose of the invention is; reducing fuel consumption and greenhouse gas emissions in vehicles for the lightening of vehicles. For this reason, chemical foaming of plastic parts in vehicles method is expected to be mitigated.

Another purpose of the invention; some re-opening of the mold after injection of molten plastic This is to ensure that the chemical foaming process takes place at the highest possible level.

Many decorative plastic parts as well as non-decorative plastic parts in vehicles are available. During the molding of decorative plastic parts, it is the most important that their surfaces are not deteriorated. is one of the essential requirements.

Another purpose of the invention is; plastic injection during plastic injection with chemical foaming method. Control of the deteriorated surface of the parts by molten plastic using counter gas pressure technology. It is to ensure that it flows in a way.

Opposite gas pressure technology, homogeneous air gaps and smooth plastic part during foaming provides the surface. It is also plastic because it provides the controlled flow of molten plastic. There is no need for ironing during injection. Removing the ironing process, the cycle It reduces the time of injection and ensures that the injection process is completed in a shorter time.

To realize all the advantages mentioned above and which will be understood from the detailed description below The invention is a plastic injection method; 0 chemical foaming technology, o opposite gas pressure technology, It has been achieved by integrating die and die back opening technology.

Brief Description of Figures Figure 1 System view before injection Figure 2 System view during injection Figure 3 Re-opening of the mold after injection Figure 4 Foaming of the product with the product gap formed after the mold is opened back Reference Numbers Thermoplastic raw material foaming agent Immobile mold Moving pattern Current product range gas supply unit gas discharge duct new product range Detailed Description of the Invention In this detailed description, the subject of the invention is the preferred production method of plastic parts and only for a better understanding of the subject and without any limiting effect. is explained.

The invention uses chemicals to lighten plastic parts used in vehicles without deteriorating their surfaces. It is a method in which foaming, counter gas pressure and mold back-opening technologies are integrated.

Foaming agent suitable for the process temperature of the thermoplastic raw material (1) to be used first (2) is determined. In the ratio determined in accordance with the thermoplastic raw material (1) and the raw material (1) The foaming agent (2) is filled into the loading hopper.

As seen in Figure 1, 1.5 mm of the mold whose design was developed in accordance with the foaming process Ng or CO2 gas through the gas supply unit (6) into the existing product space (5), which is filled in the existing product space (5), before the material injection, the material A back pressure greater than the injection pressure is created.

Injection of material into the existing product cavity (5) filled with N2 or 002 gas in figure 2 is started. The gas in the mold meets the material coming from the injection nozzle. By ensuring that the material is spread evenly in the mold, the foaming reaction it also prevents it from starting. During injection, N2 or COZ gas is discharged in a controlled manner. In Figure 3, after the injection process is completed, the movable mold (3) remains stationary. (4) It opens back 2 mm and creates a new product space (8) for the foaming of the material.

In Figure 4, since the parts of the material in contact with the mold start to cool, the material is more foaming occurs in the hot interior. Thus, the surface quality is lightened without deterioration. plastic part is obtained.

Claims (4)

REQUESTS 1. The invention is a plastic injection method for lightening the surfaces of plastic parts without deterioration, and its feature is; . Before the injection of the material consisting of thermoplastic raw material (1) and foaming agent (2), gas is filled into the product cavity (5) in the mold to create a reverse pressure greater than the injection pressure of the material, the injection of that material is started, the injection of the material in the existing product cavity (( 5) evacuation of gas in a controlled manner, . it includes the steps of opening the movable mold (4) back a little after the injection of the material has stopped. 2. A method according to claim 1, its feature is; The reason is that the foaming agent (2) has an exothermic structure. 3. It is a method according to claim 1 and its feature is; is that the gas filled in the product cavity (5) in the mold is nitrogen gas. 4. A method according to claim 1, its feature is; the material contains 98% by weight of thermoplastic raw material (1) and 2% by weight of foaming agent (2). It is a method according to claim 1 and its feature is; the gas is fed from the gas supply unit (6). It is a method according to claim 1, its feature is; gas discharge channel (7) is used to discharge the gas. It is a method according to claim 1 and its feature is; The current product gap (5) is 1.5 mm. It is a method according to claim 1 and its feature is; the new product gap (8) is 3.5 mm.