Everyone knows the difference between plastic injection moulding and pressure die casting. Although both use moulds to form the final product the moulds are distinctly different, the injection is different, and, more importantly, the materials and temperatures used are not even comparable.
That is why, even if in both technologies hydraulic cylinders are used to move parts of the mould, the characteristics required are quite different. To cope with the differences encountered, Vega Hydraulic Cylinders have developed a special range of products and tailored them for use in the pressure die casting industry, the affordable models V215 and V450.
The V215 model is designed for situations where a long stroke is required. Amongst it’s features it offers magnetic switches and cushioning. The V450 is a small compact cylinder for short strokes, especially useful where space constraints exist.
Let’s have a look at the individual challenges pertinent to a die casting environment and then see how Vega Hydraulic Cylinders cope with each scenario.
The Vega V215CR tier rod cylinder
Hydraulic fluid: In Europe, the standard fluid used in pressure die casting is water-glycol, a mixture of water, thickener and a glycol (ethylene, diethylene or polypropylene), in percentages that may vary. Being water based, this fluid can be aggressive for some components. In the Far East, on the contrary, there are companies that use normal hydraulic oil and the issues are not so evident. Vega’s response for these cylinders is to use special seals that are 100% compatible with water glycol, unlike Viton/FKM. Of course, they work very well with hydraulic oil too, says Vega.
Forces: Pressure die casting forces are higher than plastic injection moulding. Cylinders with small diameters just won’t cut it! Vega’s response is that they have created cylinders with bores that span from 50mm to 200mm (in the case of the V215 models). This provides more than enough strength for most applications.
The Vega V450CM mono-block cylinder
Temperature: Temperatures involved in die casting are much higher than with plastic injection moulding. Therefore effective cooling is essential for the cylinder rods. Vega’s HNBR (hydrogenated nitrile butadiene rubber) seals have good temperature resistance, and the HT version for sensors is the same. In addition, insulating plates can be provided for a temperature drop of around 30°C. For the V450 model only, it is possible to use water cooling for the rod. This provides an opportunity to reduce temperature by about 50°C.
Environment: Cylinders on die casting moulds are subject to really heavy-duty service. They get dirty very fast and all components, especially sensors, must be extremely sturdy, as well as waterproof. Built-in male rod ends are recommended because of their resistance to wear. All Vega cylinders undergo manganese phosphating, thus improving resistance to corrosion. Sensors are large, heavy-duty sensors from top-tier brands, and they are water resistant. Options are mechanical or inductive on both the V215 and the V450, while the magnetic type is confined to the V215 alone. Built-in male rod ends are available on both cylinders.
Old cylinders are often reused on other moulds making reliability in any condition and time span, a real must. Vega have developed an affordable solution covering any condition and life span. The V215 and V450 models are the most widely used and the sturdiest cylinders available. Over the years Vega Cylinders have built a reputation for reliability and affordability well known to all Vega users. In addition, should it be required, spares are readily available locally.
Vega has been selling cylinders for pressure die casting for many years. The latest changes – material for seals and improved sensors – do not drastically mutate the product, they merely improve what was already good to start with. Vega have a lot of experience in this field – enough to be very sure of the results. The biggest change, the water-cooled rod, has already been tested in the field, with excellent results.
For further details contact Mould & Die Solutions on TEL: 010 410 5350 or 021 555 2701 or visit www-m-d-s.co.za