by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
button in toolbar for more information.
Metal Casting Technologies : September 2008
It is interesting that none of the lost foam foundries in China are partially or wholly owned by foreign investors although a lot of foundries owned by foreign investors have already been well established in China. The present status of lost foam technology Equipment Equipment currently in operation in lost foam foundries in China are at various levels, from the simple, manually operated, to the top-quality, automatically operated, with sophisticated features. This just reflects the current status of the lost foam industry and the whole foundry industry in China. Equipment innovation is a critical part of lost foam technology development. Fully automatic batch type pre-expanders were developed in China in 2005 for foam bead pre-expansion. Steam is used for bead pre-expansion. Novel design provides even heating on foam beads. It can be used for EPS, EPMMA and co-polymers. Productivity of the pre-expander is 20 to 30 kg/h. Density of pre-expanded beads can be controlled to ± 1% accuracy. One lost foam foundry in China developed its own fully automatic foam bead pre-expander, using an electric heating system replacing the complicated steaming system. Pre-expansion of beads is 40 to 60 times as the original volume. Most of the foam molding machines for pattern blowing in service are designed and manufactured in China. More and more lost foam foundries have adopted fully automatic models with hydraulic operation systems becoming more affordable. Some foundries are still using the semi-automatic or manually operated foam molding machines with screw driven systems. Vertical operation mode (horizontal parting line) is the most popular, especially for small foundries. Vertical parting molding machines are operated in a few large lost foam foundries for mass production; one example is the casting shown in Figure 2. For sand filling and compaction, the compaction table probably is the most critical piece of equipment. Several domestic suppliers in China have been involved in developing compaction tables specifically for the lost foam process. The challenge is to compact the sand particles tightly enough inside the cavities of foam patterns without causing too much deformation. One patented technology is the so-called “compaction table with circular motion”.7 It is claimed that three dimensional vibration is achieved by using circular motion along the X- and Y-axis vertically and that along the Protect your moulds permanently with COMP MetCast The innovative release coating for greater productivity Nanocomp MetCast is the world’s first permanent nano-ceramic release coating – perfectly suited for open-mould casting in metal production. The working principal: applied in a thin layer to the mould, it allows long-term production with excellent process stability. Nanocomp MetCast is insensitive to temperature shock, molten metal and cooling water. Even in continuous production, a MetCast coating holds up for several weeks, after which it merely needs to be reapplied on specific areas. Your benefits: ? Effective separating effect and excellent demoulding properties ? Minimal consumption thanks to its extremely long service life and very thin layer application ? Greater productivity and optimal use of casting plant capacity When you choose permanent Nanocomp MetCast coating, you choose unbeatable efficiency for the production process and pass a milestone on the road to achieving an environmentally compatible “white” casthouse. ItN Nanovation AG Untertürkheimer Straße 25 66117 Saarbrücken, Germany ? Improved quality due to consistent process stability ? Convincing savings of time and expenses when compared to single-use products ? Lasting relief for employees, equipment and the environment Tel.: +49 (0) 681 / 50 01 – 561 Fax: +49 (0) 681 / 50 01 – 499 email@example.com www.itn-nanovation.com METAL Casting Technologies September 2008 69 Nanotechnology for ingot casting