The molding machine first appeared in the mid-19th century. The early molding machine was a simple manual compaction and mold ejection mechanism. Later, compressed air was used as the power to vibrate and compact the molding sand. In 1890, the shock molding machine appeared, which improved the molding efficiency and sand mold accuracy. Molding machines can be divided into compaction type, vibration type, shock type, injection type molding machine and sand blasting machine according to their different methods of compacting molding sand.
use

1. Shock-pressure molding machine: By compacting the shaken sand mold, a sand mold with tight upper and lower parts can be obtained. Commonly used is the micro-seismic compaction molding machine, which uses the drop of the workbench to collide with the floating vibrating iron, micro-vibration to compact the molding sand, and then compact it. Microseismic vibrations replace the low frequency (60 to 120 times/min) and large amplitude vibrations of the shock molding machine with vibrations of higher frequency (500 to 1000 times/min) and small amplitude (5 to 25 mm). The sand molds produced by this molding machine are of good quality and have low basic requirements.
2. Shock-type molding machine: This type of molding machine can be divided into two types: shock-type and micro-shock molding machines. The sand box and pattern are fixed on the workbench of the molding machine. When the workbench falls, the collision with the impact surface of the anvil and the inertia of the sand grains are used to tighten the sand mold. This type of molding machine has serious noise and the compactness of the upper part of the sand mold is very low. It has been replaced by micro-seismic compaction molding machines.
3. The press head of the high-pressure molding machine is divided into several structural forms such as flat press head, forming press head and multi-contact press head. Among them, high-voltage multi-contact molding machines are the most widely used. The pressure head of the high-pressure multi-contact molding machine is divided into many small squares-contacts that can move up and down, and a large pressing force can be obtained through the hydraulic cylinder. During compaction, each contact exerts corresponding pressure according to the height of the mold below it (that is, the thickness of the compressed sand layer), so that the sand mold obtains high and uniform compactness and hardness. This type of molding machine is equipped with a micro-shock shock mechanism, which can adapt to complex shapes. High-voltage multi-contact molding machines mostly adopt a four-column structure, with single-station and double-station types. In order to adapt to the production of small and medium-sized batches of castings, this type of molding machine is often equipped with a template quick-changing device. When changing the template, the molding machine does not need to be shut down. Using high-pressure multi-contact molding, sand casting can cast castings with thin walls, precise dimensions and smooth surfaces.
structure

The molding machine consists of a fuselage, a mold ejection mechanism, a shock compaction mechanism, a rotating arm pressure head part, and a pneumatic piping system.
1. The fuselage is a solid hollow frame workpiece. The upper part supports the pressing head of the rotating arm. During compaction, the rotating arm hooks the fuselage so that the compaction force is borne by the fuselage. The fuselage and the shock mechanism are connected together with bolts. The rotating arm For the pressure head part, the pressure head is fixed on a rotatable rocker arm. The pressure head has a screw elevator that can be adjusted to the distance between the pressure head and the sand box according to the height of the sand box.
2. The rotating arm controls the reciprocating movement of the cylinder piston through a hand-operated valve to realize the movement of the forward arm and the rotating arm.
3. The ejection structure consists of two ejection cylinders, connecting rods, balance shafts, ejection tables, ejection rods, etc. When the ejection cylinder is started, it drives the connecting rods, balance shafts, and ejection tables to make the four ejector rods push simultaneously. Eject the mold from the sand box.
4. Shock compaction structure. It adopts spring micro-shock pneumatic compaction structure, and the compaction shock increases the vibration. When the mold is lifted, the clamping cylinder locks the vibration cylinder, and when the mold is dropped, the clamping cylinder is loosened.
5. Pneumatic pipeline system: The input compressed air passes through the air filter to remove water and impurities in the compressed air, and then lubricating oil is injected through the lubricator to supply various pneumatic components and mechanisms. The machine movement is realized by the hand valve console. .
6. Air supply and lubrication. The machine uses air as energy source and oil as lubrication to achieve its work. The intake pressure and oil volume are adjusted by the pressure reducing valve and the oil regulating valve respectively. When the air source passes through the oil mist device, the oil is sucked into the pipeline according to the siphon principle, and the mist enters each pipeline system for lubrication.
Compaction molding machine
Use air or hydraulic pressure to apply pressure to the molding sand in the flask through a pressure head or pattern to compact the molding sand. The pressure is generally 0.25 to 0.4 MPa. This kind of molding machine makes the sand mold far away from the pressure surface poor in compactness. In the early 1950s, high-pressure molding machines appeared, and the pressure on the sand mold plane was above 0.7 MPa. The pressure heads of high-pressure molding machines are divided into several structural forms, such as flat pressure heads, forming pressure heads and multi-contact pressure heads. Among them, high-voltage multi-contact molding machines are the most widely used. The pressure head of the high-pressure multi-contact molding machine is divided into many small squares-contacts that can move up and down. A large pressing force can be obtained through the hydraulic cylinder. During compaction, each contact exerts corresponding pressure according to the height of the mold below it (that is, the thickness of the compressed sand layer), so that the sand mold obtains high and uniform compactness and hardness. This type of molding machine is equipped with a micro-shock shock mechanism, which can adapt to complex shapes. High-voltage multi-contact molding machines mostly adopt a four-column structure, with single-station and double-station types. In order to adapt to the production of small and medium-sized batches of castings, this type of molding machine is often equipped with a template quick-changing device. When changing the template, the molding machine does not need to be shut down. Using high-pressure multi-contact molding, sand casting can cast castings with thin walls, precise dimensions and smooth surfaces.
Shock molding machine
This type of molding machine can be divided into two types: shock-type and micro-shock molding machines. The sand box and pattern are fixed on the workbench of the molding machine. When the workbench falls, the collision with the impact surface of the anvil and the inertia of the sand grains are used to tighten the sand mold. This type of molding machine has serious noise and the compactness of the upper part of the sand mold is very low. It has been replaced by micro-seismic compaction molding machines.
Shock molding machine
By compacting the shaken sand mold, a sand mold with tight upper and lower parts can be obtained. Commonly used is the micro-seismic compaction molding machine (see picture), which uses the drop of the workbench to collide with the floating vibrating iron, micro-vibration to compact the molding sand, and then compact it. Microshocks replace the low-frequency (60-120 times/min) and large-amplitude vibrations of the shock molding machine with vibrations of higher frequency (500 to 1000 times/min) and small amplitude (5 to 25 mm). The sand molds produced by this molding machine are of good quality and have lower basic requirements.