The use of high thermal conductivity of copper alloy mold can make the manufacturing plant has a higher production efficiency, both to save money, but also improve product quality. Some car bumper and instrument panel manufacturers have adopted the mold of this material and achieved significant production efficiency.
Compared with the ordinary work / die steel, copper-based alloy materials because of the high cost, so in the mold production, many mold manufacturers have not yet found a better way to rational use of high thermal conductivity of copper alloy material, But in fact, the use of high thermal conductivity of copper alloy in saving time and improve efficiency and other aspects of the benefits are very significant.
The high thermal conductivity copper alloy discussed in this paper is a copper-based material which, by means of a combination of alloy and manufacturing techniques, is required to maintain a high thermal conductivity characteristic inherent in copper and to have a certain hardness In order to be able to make it suitable for a variety of processing conditions in a production environment.
The main advantages of copper alloy
The use of high thermal conductivity in the injection mold copper alloy mainly includes the following special advantages:
1, thermal diffusion performance
Plastic in the mold during the injection molding process, high thermal conductivity of copper alloy will absorb a lot of heat, of course, its initial absorption of heat is a key factor, and the latter part of the heat will mainly rely on the cooling system. In each plastic parts of the injection process, the initial heat absorption is the high thermal conductivity of copper alloy really play a role.
2, polishing performance
In the contact plastic packaging production process using high thermal conductivity copper alloy mold, its excellent polishing performance has been proven. In the use of highly polished high thermal conductivity copper alloy inserts, you can create high-quality transparent plastic packaging, so as to meet the packaging needs to be checked by the production. Practice has proved that this set of polishing time than the steel block required polishing time 4 times faster, the work cycle can be reduced by 57%.
In order to improve the wear resistance, the surface of the copper alloy with high thermal conductivity can be easily plated with a layer of non-electroless nickel coating, hard chromium coating, PVD coating (physical vapor deposition layer) or CVD coating (chemical vapor deposition Layer), so that the hardness of the coating surface to 60 ~ 90 HRC. The non-electroless nickel coating allows the coating to penetrate into each well at a uniform thickness, but it is not, as in the case of a galvanizing process, nor as a hard chrome plating process. In order to facilitate the removal of plastic parts, non-electroless nickel coating can be combined with PTFE or boron nitride materials. The surface of the mold part coated with PTFE or boron nitride non-electroless nickel coating is very smooth, as if it were coated with a soapy foam, so that the formed plastic parts were not adhered to the mold and the mold release was very easy.
Of course, the use of high thermal conductivity of copper alloy mold also has some limitations, such as the elimination of stress or annealing (the only way to maintain the hardness of the material properties) should avoid the mold for a long time above 900 ° F high temperature.
Application and benefit
Based on the above characteristics, in the following applications can be considered within the choice of high thermal conductivity of copper alloy:
□ injection mold, core and cavity, core pin and cooling plate;
□ composite plastic profile extrusion process used in the mold: here the application of high thermal conductivity of copper alloy can make the mold heat conduction speed, but also can improve the dimensional stability of parts;
□ production of liquid bottles with the blow mold;
□ injection nozzle: the use of high thermal conductivity of copper alloy, because of its heat conduction time is short, to maintain a uniform temperature can greatly simplify the entire temperature control system, thereby reducing energy costs.
In the injection mold production can be considered in the application of copper alloy mainly for the following reasons:
□ After the application of high thermal conductivity of copper alloy, the mold cooling rate greatly increased, the production cycle can be reduced by at least 20% (according to some users that the production cycle can even shorten 80%);
□ Due to the shortening of the production cycle, the number of parts produced during each working day is greatly increased and the productivity can be increased by at least 25%. According to some users of the headlamp manufacturing industry, their productivity is even increased by 500%
□ As the cooling rate increases, the mold temperature decreases rapidly, the forming time of the parts is shortened, so the number of "hot spots" in the mold and the degree of damage caused by it can be reduced, so that the quality of the parts is greatly improved and the deformation scrap rate is greatly reduced ;
□ Reduced scrap rate also shows that each part after each injection molding quality is more stable;
□ Because of the high thermal conductivity of copper alloy with super thermal conductivity characteristics (in general, its thermal conductivity than steel 5 to 10 times higher), the mold in the sensitive area of the heat can be quickly distributed out, so the mold and parts directly contact part The number of complex cooling channels can be reduced or directly omitted;
□ Due to the reduction in the number of cooling passages in the mold, the processing cost of the mold can be greatly reduced - the processing cost can be reduced by a factor of 4 compared to the tool steel mold with slower cooling speed.
In this paper, the table shows that the use of high thermal conductivity copper alloy to save time and costs brought about by the various benefits.
The above example illustrates the benefits of saving time and expense after using a high thermal conductivity copper alloy core.
In the process of producing bumper in the automobile industry, aluminum bronze inserts can be applied to steel molds, and some manufacturers even use a full set of high thermal conductivity copper alloy cores and cavities to produce their bumper.
The dashboards in the car can also be made with molds containing aluminum bronze inserts, which increase the thermal conductivity by about three times compared to the steel inserts used in the production.