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How companies can save while selecting the die caster
The most important element selecting the materials for the production and processes is trying to minimize costs of the product and its production. Producing, finishing, delivering and assembling costs depend on a wide range of factors. In this post we are going to understand in which areas companies can obtain costs savings.
There are different areas where designers can save:
- Surface finishing
- Packaging for delivery
The cost of zinc alloy material in a raw way depends on the weight of the casting and obviously on the price of the alloy per ton. Normally is possible to lose metal about 5% during the casting process. To avoid waste of material given by overflows and runners is necessary a good design and a good process. This reduction shorten melting loss costs and less melting energy means less CO2 production.
Regarding the cost of material it is impossible for casting buyers to predict it. Normally this kind of alloys are sold linked to the price of zinc given by the London Metal Exchange at the moment of buying. For this reason costs of all the raw materials change and it’s impossible to predict them. In fact the only solution possible is to make comparisons based on average prices of the past months and on future trends. For the die caster the cost of raw material is an important part of the process costs. For this reason die caster needs to control at regular intervals during the production the price to avoid rising costs in production.
The price of tools affects the good success of the casting process. Of course the price of tools depends on the degree of their complexity and precision that depends on the design of the casting that is required. A right product design allows to have a less complex so less expansive mould that helps to save in economic terms. Another problem regarding die tools that affects cost reduction is that die tools are vulnerable to deterioration and failure. During die casting process the heat that goes from the molten metal to the die causes a phenomenon called die wash that is die steel erosion. Loss of sharp definition, deterioration of the surface quality and thickening of some sections are the most clear visual effects of the die degeneration. To minimize costs, related to such wearing of the tool, is important to do extraordinary maintenance like cores refurbishing or substitution.
Compared to other alloys zinc can provide a better die life and lower maintenance costs, the typical die life might be around 1 million shots, much more than aluminium (200,000) and magnesium (400,000) ones. Furthermore moulds in zinc die casting allow a large amount of shots, however to guarantee the productivity is advisable a backup mould to allow correct maintenance activities of the mould that ensures a smooth production process.
Zinc alloys productivity is higher than the one of aluminium and magnesium. The most common used zinc alloys can be produced by hot chamber process that is faster compared to cold chamber process, commonly used for Aluminum HPDC .To achieve higher speeds of die casting process is useful to improve the process parameters such as temperature, injection speed, filling time and cooling time. The key element of keeping costs down is an uninterrupted production of castings. In terms of die casting production there are different way of producing components for die casting machines: automatic or semi-automatic way. If the machine operates semi-automatic the operator removes the complete shot from the die, if instead it is an automatic production the die cast can be removed by a robot. Moreover automatic production is normally used to produce a large volume of manufacture. The high automation level allows important savings, is possible to have second operations close to die casting machines and integrated with it through robots.
Trimming is the process of removing the die castings from runners and overflows. Zinc die casting process often allows to avoid trimming operation with thin gate areas and less overflows.
The casting can be produced without flash and the runners can often be removed with a barreling operation. Breaking the runners saves the cost of a press and a trimming tool; furthermore the barreling operation is more cost saving than press trimming.
To remove at the same time the runners and the flash it is possible to use a press trim tool that will cost around a 10% of the cost of the die. It is a metal shearing operation.
This kind of tools are manually operated in low quantity production, with high volume production the trimming tool works in line with the die-casting machine. It is important that the casting designer ensures that the features are not vulnerable to damages otherwise the casting will be rejected.
In this case this press trimming operation has the same cost as other die casting alloys.
Machining on zinc casting is required to produce features that cannot be cast such as inner threading or complex features on parts at low quantity demand. In terms of saving in a large production it is possible and convenient to make moving die elements while in a lower quantity production a mold with complex moving elements will affect the costs.
Zinc die casting alloys can ensure a better quality in a saving way. In terms of machines in fact the one used in zinc die casting are faster and can avoid loss of time and money. Compared to other materials zinc has the advantage of accuracy in terms of datum surfaces provided for clamping.
Surface finishing can affect costs in a large or small proportion depending on the aims above described.
The most expansive finishes are the one that demand a large amount of manual work; if these costs are really high it is important to focus on maximizing the castings suitability. Therefore is important that the die caster and the finisher work as a team to reach clients’ expectation and create a perfect and functional product.
Assembling costs are affected by the amount of work that is required and the tooling and equipment that are needed to complete the process. Zinc die casting alloys allow designers to apply cost effective procedures such as automatic assembly.
Packaging for delivery
If the component has been given a high finish needs to be transported in a way to prevent each components any problem; otherwise if the product has a normal finish it can be delivered without any separation in cardboard boxes.
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