Copper alloy mold with high thermal conductivity is adopted
The use of copper alloy molds with high thermal conductivity can make the manufacturing workshop have higher production efficiency, which can not only save money, but also improve product quality. Some manufacturers of automobile bumpers and instrument panels have adopted molds of this material and achieved significant production benefits.
Compared with ordinary work/mold steel, due to the higher cost of copper-based alloy materials, many mold manufacturers have not yet found a better way to reasonably use copper alloy materials with high thermal conductivity, but in fact, the benefits of using copper alloys with high thermal conductivity in saving time and improving efficiency are very significant.
The high thermal conductivity copper alloy discussed in this article is a copper-based material, through a combination of alloy and manufacturing technology, not only to maintain the inherent high thermal conductivity characteristics of copper, but also to make it have a certain hardness, so that it can be suitable for various processing conditions in the production environment.
The main advantages of copper alloys
The use of copper alloys with high thermal conductivity in injection molds mainly includes the following special advantages:
1. Thermal diffusion performance
In the injection molding process of plastic in the mold, the copper alloy with high thermal conductivity will absorb a lot of heat, of course, the heat absorbed at the beginning is a key factor, and the later heat dissipation will mainly rely on the cooling system. In the injection molding process of every plastic part, the initial heat absorption is where the high thermal conductivity copper alloy really comes into play.
2. Polishing performance
The use of high thermal conductivity copper alloy mold in the production process of contact plastic packaging has been confirmed by practice with excellent polishing performance. By using highly polished copper alloy inserts with high thermal conductivity, high-quality transparent plastic packaging can be manufactured to meet the production needs of inspection through packaging. This insert has been shown to have a polishing time up to four times faster than that required for steel inserts, while reducing cycle times by 57%.
In order to improve wear resistance, the surface of copper alloy with high thermal conductivity can be easily coated with a layer of non-electroplated nickel coating, hard chrome coating, PVD coating (physical vapor deposition layer) or CVD coating (chemical vapor deposition layer), so that the hardness of the coating surface reaches 60~90 HRC. Non-electroplated nickel coating can make the coating penetrate into each hole with a uniform thickness, but its essence is not like the galvanizing process, nor is it like the hard chrome plating process. To make it easier to release plastic parts, non-electroplated nickel coatings can be combined with polytetrafluoroethylene (PTFE) or boron nitride materials. Mold parts coated with PTFE or boron nitride non-electroless nickel coating have a very smooth surface as if coated with soap foam, so that the formed plastic parts do not stick to the mold, and demolding is very easy.
Of course, there are some limitations to using copper alloys with high thermal conductivity, such as stress relief or annealing (which can maintain the hardness characteristics of the material) to avoid exposing the mold to temperatures above 900°F for extended periods of time.
Application and benefits
Based on the above characteristics, copper alloys with high thermal conductivity can be considered in the following application ranges:
□ injection molds, cores and cavities, core latches and cooling plates;
□ molds used in the extrusion process of composite plastic profiles: the application of copper alloys with high thermal conductivity here can increase the heat conduction speed of the mold, and also improve the dimensional stability of the parts;
□ Blow molding mold for the production of liquid packaging bottles;
□ Injection nozzles: When using copper alloys with high thermal conductivity, maintaining a uniform temperature greatly simplifies the entire temperature control system due to its short thermal conduction time, thereby reducing energy consumption costs.
There are several main reasons why copper alloys can be considered in injection mold production:
□ After the application of copper alloys with high thermal conductivity, the cooling rate of the mold is greatly improved, and the production cycle can be shortened by at least 20% (according to some users, the production cycle can even be shortened by 80%);
□ Due to the shorter production cycle, the number of parts produced per working shift is greatly increased, and productivity can be increased by at least 25%, according to some users of the automotive headlight manufacturing industry, their productivity can even increase by 500%;□ Due to the increase in cooling rate, the temperature of the mold decreases quickly, and the forming time of the part 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 part is greatly improved, and the deformation scrap rate is greatly reduced;
□ The reduction of scrap rate also indicates that the quality of each part after each injection molding is more stable;
□ Because the copper alloy with high thermal conductivity has super thermal conductivity characteristics (in general, its thermal conductivity is 5~10 times higher than steel), the heat in the sensitive area of the mold can be quickly dissipated, so the number of complex cooling channels in the direct contact part of the mold and the part can be reduced or directly omitted;□ Due to the reduction in the number of cooling channels in the mold, the processing cost of the mold can
be greatly reduced - compared to the tool steel mold with a slower cooling rate, the processing cost can be reduced by 4 times.
The figures and tables in this article show the various benefits of using copper alloys with high thermal conductivity in terms of time and cost savings.
The above examples illustrate the time and cost savings benefits of using a high thermal conductivity copper alloy core.
In the automotive industry, bumper inserts can be applied to steel molds, and some manufacturers even use a full range of high thermal conductivity copper alloy cores and cavities to produce their bumpers.
Instrument panels in automobiles can also be produced with molds containing aluminum bronze inserts, which have about 3 times higher thermal conductivity than steel inserts used in production.