JINAN WELTOP MACHINERY EQUIPMENT CO.,LTD.

Test low pressure die casting machine in shanxi province datong city .The problem is pressuring curves fluctuation.   Yungang Grottoes is here. After finishing work I came here to have a look. It is 1500-year-old . in 2001 , unesco added it on the list of world heritage.

Centrifugal casting is a process that delivers castings of very high material soundness, and thus is the technology of choice for applications like jet engine compressor cases, petrochemical furnace tubes, many military products, and other high-reliability applications. In the centrifugal casting process, molten metal is poured into a spinning die. The die can be spinning either on a vertical or horizontal axis depending on the configuration of the desired part. Ring and cylinder type shapes are cast vertically; tubular shapes are made with the horizontal centrifugal process. Either process may be used to produce multiple parts from a single casting.  External structures and shaping can be cast in place to significantly reduce post-processing including machining or fabrication.   Because of the high g-forces applied to the molten metal in the spinning die, less dense material, including impurities, “floats” to the I.D. where it is subsequently removed by machining. Solidification

Symmetrical parts that can rotate on an axis Static casting material properties are inadequate Centerline shrink is an issue using other casting processes Limited I.D. features Large parts, up to 135,000 lbs./61,235 kg or more Net-shaping: Some tooling cost is often justifiable when significant finishing is required

Sand casting as a technology has been around for millennia, and is selected as a preferred method to produce shaped parts that weigh less than a pound, to very large parts. The process is versatile and cost effective, even for low volume runs because of tooling cost. Nearly any part configuration that can be made in another material can be reduced to a pattern and created as a sand casting.

Shaped or non-symmetrical parts Large parts Components with internal structures More liberal tolerances

Trunnion type centrifugal casting machines use a mold or flask that is supported and rotated by four trunnion wheels. These machines are used for producing castings that have lengths longer that their diameter.                          Common castings produced on trunnion type include bushings, bearings, cylinder liners, piston rings, pipe, and steel tubes and sleeves. Our automatic centrifugal casting machine all adopt trunnion type as main engine.

Sand casting, the most widely used casting process, utilizes expendable sand molds to form complex metal parts that can be made of nearly any alloy. Because the sand mold must be destroyed in order to remove the part, called the casting, sand casting typically has a low production rate.T he sand casting process involves the use of a furnace, metal, pattern, and sand mold. The metal is melted in the furnace and then ladled and poured into the cavity of the sand mold, which is formed by the pattern. The sand mold separates along a parting line and the solidified casting can be removed. The steps in this process are described in greater detail in the next section.

Centrifugal casting, sometimes called rotocasting, is a metal casting process that uses centrifugal force to form cylindrical parts. This differs from most metal casting processes, which use gravity or pressure to fill the mold. In centrifugal casting, a permanent mold made from steel, cast iron, or graphite is typically used. However, the use of expendable sand molds is also possible. The casting process is usually performed on a horizontal centrifugal casting machine (vertical machines are also available) and includes the following steps: Mold preparation  - The walls of a cylindrical mold are first coated with a refractory ceramic coating, which involves a few steps (application, rotation, drying, and baking). Once prepared and secured, the mold is rotated about its axis at high speeds (300-3000 RPM), typically around 1000 RPM. Pouring  - Molten metal is poured directly into the rotating mold, without the use of runners or a gating system. The centrifugal force drives the mater

Sand mould casting is a foundry technology that using the sand as the material of the mould to make the mould , and usually sand casting use gravity casting ,and sometimes if have special requirements also adopt low pressue casting , centrifugal casting ,ect. Sand casting have a wide flexibility ,produce of small size parts ,large size parts ,simple one.complex one ,singleton,mass can all adopt. Sand casting ,previously sand casting use the wooden mould ,now use the aluminum alloy mould or resin mould ,the cost of aluminum alloy mould and resin mold are high than wooden mold ,but in the basss produce ,the advantage of cost stand out . sand mold has a better refractoness than metal mould . so cooper alloy and ferrous metal which metting point is high usually use this type technology, but sand casting has the shortage ,because the mould can use only once .,after casting ,the mould is damaged .and need remake the new mould .the production efficiency is low , also the bulk property of sand

Low-pressure sand casting machine consists of two pieces: holding furnace and liquid surface pressure control system. The furnace cover of holding furnace is used for work table for sand box. The prepared sand box fixed on the cover of holding furnace directly and then pressure casting. Fluid surface forcing control system adopts the high performance proportional valve +precision pressure sensors，which can examine the pressure of holding furnace and control real-time and closed loop feedback by PID accommodation mode. The system has multi-linear pressure, leakage compensation for holding furnace and leakage compensation for liquid surface. The setting add-pressure craft’s curve can be tracked automatically. High precision control of pressure ensures the low press die casting process stable properties and good consistency. 

We can use computer or HMI with  upper location supervisory.With database technology, all the pressure process data save in database include each practically pouring process data. So we can query and analysis all the history process data to improve the process quality so much.