The application of copper alloys in mould making industry

Let’s first take a look at the position of copper alloys in mould making industry.

Before 1987, the application of copper alloys as mould surface materials was very limited, so does that as mould material. At that time, most think that coppy alloys as mould material, the hardeness, strength and flexibility can’t meet the demands.

A research paper published in 1988 pointed out that all injection mould manufacturers and blow mould manufacturers who want to succeed in mould industry must put out the question that what we should do in order to work with speed and efficiency to meet customers’ demands. Starting from this point of view, the paper discussed why and how to use copper alloys in mould industry and what the effects were in adopting coppy alloys to reduce delivery time and improve component quality.

We look back to the past 19 years and posted the following questions.

Q: Until now, how many mould workers and manufacturers are still in this field?

A: It is estimated that about 50% mould workers and manufacturers are still using this technology. Some workers and manufacturers have retreated from this field. Part of them lost their business, part are still insisted in the area.

Q: does the reserved workers and manufacturers applied coppy alloy in mould making?

A: In most application area, coppy alloy is less used. And under most conditions, the using coppy alloy, to certain extend, is not the right material, it is not suitable in the unique area. To use the wrong coppy alloy and make wrong decision, maybe is caused by misleading information, e.g., the misunderstanding about special properties and product information, or price and source. All these can resulted in inappropriate use and reduced life, or a total failure.

Q:  Do all products applied in mould industry are good products? Does this technology effected or influenced by misleading information, or suppliers, or some other unpredicted elements?

A: For a long time, views on the application of coppy alloy were wrong. Coppy alloy was wrongly used becaused of suppliers misleading information and misunderstanding. A certain kind of products or its brand may change for some unnoticed reasons, which have deep effect on mould component’s life and performance. E.g., coppy alloys which are of similar hardeness with iron, the heat conductivity is better. Another example is that coppy alloy which hardeness is near to 40RC, its extensibility is poor, and the extention rate is less than 3%. Poor extensibility and low extention rate will always lead to breakage of mould components.

table I  hardeness, extention rate and heat conductivity

CDA #       hardeness      extention rate         heat conductivity

C17510       20 r/c           5%~15%                    145

C17200       30 r/c             3%~8%                    75

C17200       40 r/c              1%~3%                    60

C18000       20 r/c              9%~13%                  150

Null          28~30 r/c            7%                    80~90

C72700       30 r/c               4%                   35~40

C72900        34 r/c            min 3%-5%                22

C95400        89 r/b              12%~14%                36

C95900        30 r/c              1.5%                   25

Null          29~32 r/c             1%                    25

The application of coppy alloy

In the past 20 years, all around use of coppy alloy in mould industry has not been recommended, the application range is not clear, but the application area is becoming larger and larger. Compared to the development of machinery, processing equipments and resin, the application area of coppy alloy was limited by market. Under certain circumstances, people knows little of the products.

An inquiry to mould workers and manufacturers showed that most people thought that coppy alloy was little used, and was of little help. They thought the application of coppy alloy could not really reduce mould processing period, and didn’t improve products quality and performance. In addition, they were afraid that maintainence cost and primary cost would go up.

However, mould manufacturers experience showed that the application of coppy alloy did reduce mould processing period, and could improve mould component quality and reduce maintainence cost. Workers and manufacturers who have little experience on the products, and who can only adopt condition at that very time will increase products quantity. Generally speaking, because of processing technic, copper alloy mould parts can reduce cost.

Beryllium-copper alloy and copper-nickel alloy

Alloy chemical composition is devided into two series. Alloys made from these two kinds of chemicals have the property of high hardeness and good heat conductivity, are the best choice for mould surface material. The two series are berllium-copper alloy and copper-nickel alloy. There are also microelement in the alloy, and each alloy has its unique usage.

Because of competition and some problems in berllium-copper alloy, and because suppliers may not provide copper alloy with berllium. Sometimes, alloys are named as follows according to the proportion of berllium.

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