SU1458066A1 - Method of producing sand moulds - Google Patents

Abstract

The invention relates to foundry, namely the manufacture of one-off sand molds using air impulse. The aim of the invention is to reduce energy consumption for compaction, increase the speed of the molding machines. The method involves compacting the sand, which is loosely poured into the mold tooling, by applying a high-pressure air pulse to the mix surface. The new method is to match the time of air supply with the time of pressure increase above the surface of the mixture, namely, the time of air supply is equal to the time of reaching the maximum pressure above the surface of the mixture and is 0.003-0.03 seconds. 1 il. $ (L

Description

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The invention relates to foundry, namely the manufacture of one-off sand molds using an air impulse.

The aim of the invention is to reduce energy consumption for compaction.

The drawing shows the device DP implementation of the method.

The device contains model plate 1, model 2, plate 3, filling frame 4, receiver 5, plate 6 with receiver receiver by-pass devices, gate valve 7 by-pass device, pneumatic cylinders 8 and 9, compressed air supply nozzle 10 into the receiver.

The method is described as follows.

On the model plate 1 with the model 2 is put technological capacity

(Flask 3 with a filling frame 4) into which the molding mixture 11 is poured. Then the process tank is hermetically pressed against the receiver 5. The gate valve 7, which closes the plate with crevices and is driven by the pneumatic cylinders 8 and 9, takes the left position. The pistons of the pneumatic cylinders 8 and 9 are also retracted to the left, and the slots of the plate 6 are closed. In receiver 5, air is pumped through pipe 10. By means of pneumatic cylinders 8 and 9, valve 7 is moved to the right position. When the valve-7 moves, the slits of the plate 6 are first opened, as a result of which air is supplied to the process tank with the mixture, and then it is closed again, and the air supply is stopped. In the manufacture of the following form

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Pan 7 moves in a similar manner - from right to left.

The molding mixture is freely poured into the molds and the impulse, air is supplied to the surface of the mixture, and the air supply time is equal to the time that the maximum pressure is reached above the surface of the mixture and is 0.003-0.03 seconds.

the stage of acceleration, the stage of deceleration, will come out of the mixture and loosen it. Experimental studies of air compaction of wet sand-clay molding compounds have shown that, for a good compaction of the molds, the pressure build-up time should be no more than 0.03 s. In general, the smaller the build-up time on the surface of the mixture, the better is the compaction of the mold. However, dp forms with a volume of more than 0.02 m are difficult to achieve a pressure build-up over time.

The positive effect of the invention is realized by

account of the time of filing

spirit with a time of acceleration of the mixture. Favorably less than 0.002 s due to the complexity of fast conditions for the acceleration of formulating valves of high-wound mixture towards the model plate and the model exist up to

starting capacity. Thus, the optimal time for the air to be supplied to the surface of the mixture is 0.003 pores, while in the mixture column there is

starting capacity. Thus, the optimal time for air to reach the surface of the mixture is 0.00325

the difference in pressure of the interstitial air is 20–0.03 s (during this time the air is not of time. This difference arises at the moment of escape into the atmosphere through the slots. air is supplied to the surface of the molding mixture and is maintained until the pressure above the surface reaches the maximum. After that, the process of equalizing the pressure of the interstitial air to the height of the mixture column begins. At this moment the air supply is stopped in order to reduce the air flow from the receiver.

between the flask and receiver, the flask and the model plate). In experiments with a receiver volume of 0.2 m and an effective gap area of 2 cm, the characteristic time of pressure relief for the receiver was 0.2-0.3 s.

The method allows to reduce the time lost for each new filling of the receiver. For receiver volume

0.5 m and a working pressure of 5 atm. Filling time is reduced by 10-12 seconds.

the acceleration stage, the deceleration stage, will come out of the mixture and loosen it. Experimental studies of the air compaction of wet sand-clay molding compounds have shown that, for a good compaction of the molds, the pressure build-up time should be no more than 0.03 s. In general, the less the build-up time above the mixture surface, the better the shape compaction is obtained. However, dp forms with a volume of more than 0.02 m are difficult to achieve pressure build-up over time.

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less than 0,002 due to the complexity of high-speed valves

starting capacity. Thus, the optimal time for air to reach the surface of the mixture is 0.003

0.03 s (during this time the air does not have time to escape into the atmosphere through the slots.

between the flask and receiver, the flask and the model plate). In experiments with a receiver volume of 0.2 m and an effective slit area of 2 cm, the characteristic time of pressure relief for the receiver was 0.2-0.3 s.

The method allows to reduce the time lost for each new filling of the receiver. For receiver volume

0.5 m and a working pressure of 5 atm. The filling time is reduced by 10-12 seconds.

If the pressure in the receiver is 5 atm, then after the mixture acceleration stage has ended, it decreases to about 4.5 atm (for real machines that have a receiver volume 4-6 times larger than the flask volume). If the air flow continues, the air will flow out of the receiver into the flask, and from the gaps between the flask and the modular plate - into the atmosphere. As a result, the entire air supply in the receiver is consumed. In addition, excess air trapped in the mixture after completion

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the invention

The method of making sandy molds, which includes filling the molding sand into the casting equipment and applying a pulse, air to the surface of the mixture,

40 characterized in that, in order to reduce the energy consumption for compaction, the time for supplying air is equal to the time for reaching maximum duration of the mixture above the surface of the mixture and is 0.003-0.03 s.

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Claims (1)

Claim. A method of manufacturing sand molds, including filling the molding sand into foundry equipment and supplying an air pulse to the surface of the mixture, characterized in that, in order to reduce energy consumption for compaction, the air supply time is equal to the time to reach maximum pressure above the surface of the mixture and is 0.003-0, 03 sec