“Graphite has been increasingly difficult to procure as a result of a world shortage. Prices have been rising and with a lower purity and accordingly a lower quality offered. This has led us to design and commission a new graphite milling plant at our facility in Alrode, Gauteng,” said owner and founder Axel Bastian.
“Graphite is a key raw material for Fochem International’s products. Therefore we had to take steps to ensure that we are in control of this key area of our manufacturing process. We are now able to process raw pieces of graphite into nano particle sizes. This will make our company independent from the worldwide resource market for fine graphite powders,” continued Bastian.
“Fine graphite powders are used as a base for products such as lubricating oils and greases, dry lubricant films, packing and seals, rubber and plastics, extrusion lubricants, release agents, drawing compounds, forging, wire drawing, TV tubes, brake linings, clutch facings, batteries, conductive coatings, colour pigments and powder metallurgy,” said Bastian.
“Our comprehensive portfolio ranges from release agents, lubricants and coatings to customised products. The industries we service include die-casting, forging, extrusion, mining, aluminium refineries, conductive cable coatings and seamless tube manufacturers,” said Bastian.
“Graphite is a key functional material in many of our products, especially in plunger lubricants. It can be supplied in a variety of carriers, in the form of wax beads, oils, greases and water based products. The carrier serves not only as a lubricant itself, but also helps to distribute the additives over the surface of the shot sleeve. Once applied the additives cover the plunger through the capillary action,” explained Director Alexander Saam.
“In high-pressure die-casting the molten metal is injected into the die cavity through a cylindrical sleeve by a plunger that forces the molten metal through a narrow orifice at high speed and pressure. Proper lubrication of the plunger is essential to provide smooth filling of the cavity, reduce energy consumption during the shot and extend the life of the plunger tip and sleeve. Plunger lubricants are used to minimise the wear to the plunger tip, thus increasing its lifetime and reducing the downtime for replacement,” continued Saam.
“Porosity is one of the biggest problems in die-casting. The die-casting process is very often used to make lightweight components out of light metals, with the objective to replace steel or iron components. Yet the intrinsic strength of these lighter metals is less than that of steel and iron, therefore anything that can adversely affect the strength of the component is undesirable. The presence of small pores within the cross section of the casting can have a big impact on the tensile strength. Gas porosity is a consequence of the very high velocities at which the metal is injected into the mould. However, it can also be aggravated by the presence of water on the die and the decomposition of any organic compounds within the die and the shot sleeve.”
“Another common concern in the shot-end of the die-casting machine is the formation of smoke and flames when molten metal is injected into the shot sleeve. The heat of the melt can cause the organics in the lubricant to catch fire and, as this is a low oxygen environment, the incomplete combustion results in the formation of smoke.”
New bead plant
“We started manufacturing wax based beads in 2001. The reason we chose the wax route, as against oil based beads, is that it is more environmentally friendly and the beads can be dosed precisely and consistently in an automated manner. The beads act as a protective against erosion of the sleeve and once the wax has burnt off a solid lubricant remains, thus lubricating the entire plunger.”
“Solid plunger lubes are applied by an automated device through the pour hole into the shot sleeve. The beads are so constituted that they melt and consequently assist in the distribution of additives over the surface of the tip and shot sleeve. In order to achieve this, it is necessary that the temperature of the plunger is 20°C higher than the congealing point of the wax.”
“Our plant in Alrode has now been virtually rebuilt from scratch and production, which is now at 10 tons per day, commenced in May this year. There are a number of reasons we have made this major investment in plant and equipment but one of the main reasons is that we needed to increase our production capacity to meet demand both locally and internationally, as we now export to 17 different countries. Moreover, through an improved and innovative manufacturing process, we have revolutionised the lubricating quality of our beads.”
“With the introduction a new 35 metre high processing tower and a new thermo-oil system has ensured a reliable and more efficient manufacturing process. The new thermo-oil system not only melts the wax in the mixing tanks, but also heats the jacketing of the wax transporting pipes so that the wax is kept at a constant temperature. Screening, sieving and storage are now more efficient and the consistent quality of our products is guaranteed.”
“The plant produces six different sizes of beads, that range from dust to 0.2mm to 3.0mm. Beads are offered in both graphite and white pigment colouring. Our graphite beads are a striking success and a valuable asset to our product portfolio. The newest development, ‘white beads’, offers excellent lubricating properties as well, due to a solid content of 20%.”
“However, the presence of dark or discolored areas on the surface of the castings can invariably be traced to the application of plunger lubricants and has nothing to do with the graphite product. Even an over dosage of white beads or clear oils can cause discoloured areas on the biscuit and the casting. In most cases either too much lubricant or the wrong kind of lubricant has been applied. This could be due to a lack of care or variation between operators. Using too much plunger lubricant is usually a sign that the plunger life is being stretched or there is some misalignment.”
“We have now developed an automated dispensing unit that, used in conjunction with our beads, will apply the correct amount of lubricant for the specific application. This eliminates any dark or discoloured areas as the amount of beads per shot can be precisely dosed. We can assure you that you will not have to deal with any problems relating to blockages of the dosing tubes, fluctuating dosing amounts and discoloured areas. The entire operation of our “Bead Dispenser 3D” is reliable, precise and the work environment remains clean.”
Other products – oils and pastes
“We offer a range of other plunger lubricants in the form of oils and pastes, graphite-based as well as graphite-free. These products are applied by means of spray or a drip application. The selection of the most suitable lubricant depends on the manufacturing and application process.”
Fochem International was founded in South Africa in the early 1970’s as one of the first manufacturers of colloidal graphite. In the early 1990’s Tribo-Chemie GmbH was founded in Germany for the purpose of being closer to the company’s customers in Europe. The company is ISO 9001:2008 certified and exhibits at GIFA and related exhibitions worldwide. They distribute their products through agents based in India, Brazil, USA, Taiwan, Malaysia, Japan and others.
For further details contact Fochem International on TEL: 011 903 9720 or
The new thermo-oil system
The new screening, sieving and bagging area
Bagged product ready for shipment
The company is ISO 9001:2008 certified and takes particular care in the quality department
The new 35 metre high processing tower