DD148024A1 - METHOD AND APPARATUS FOR PRODUCING FREE OF CHARGE WORKSTUECKE - Google Patents

Abstract

The invention relates to a method and a system for producing burr-free workpieces. Under the influence of a brief heat shock, a chemical process takes place in a pressure-tight chamber, during which burrs, sharp corners and edges are burnt off. The method is mainly used in connection with cutting machining processes in mechanical engineering. The object of the invention is a rational and cost-effective operation of the method. The inventive method works on the basis of a oxidizable gas with non-constant combustion properties. This gas or gas mixture is mixed with air or with a gas with higher heating power in a veraenderlicher manner and regulated by means of the required firing technical values. For this purpose, a system according to the invention is described.

Description

Hans Uwe Kastner

Title of the invention

Method and plant for producing burr-free workpieces

An Wendu the Fiction invention The invention relates ngsgebiet, to a method for producing burr-free workpieces in which a workpiece is subjected to a brief heat shock and burrs, sharp corners and edges

1.0 be burned.

The process is mainly following machining machining processes on workpieces from all commonly used in mechanical engineering materials such. Steel, cast iron and alloys, non-ferrous metals and plastics applied.

Chara k teristi k the ^ known technical solutions A method for producing burr-free workpieces on a thermal-chemical basis has become known in principle with the US-PS 3,475,229.

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This method is used to remove superfluous projections of thin cross-section, such as sharp edges and burrs of workpieces and articles of manufacture of a much larger diameter,

The workpiece to be treated is first stored in a pressure-tight sealed chamber. In this chamber, a compressed gas mixture is introduced and ignited electrically. This creates a heat shock whose temperature is sufficient to remove the superfluous projections without affecting the workpiece

 The short-term prevailing temperature and pressure values are determined by the nature of the material of the workpiece.

As a gas mixture according to the aforementioned US Patent 3,475,229-hydrogen, natural gas and lower alkanes, alkenes and alkynes having 1 to 4 carbon atoms in conjunction with an oxidizing agent such as _o pure or diluted with air oxygen, air, halogens, etc. to application

   A corresponding system for carrying out this method consists roughly of a gas metering system consisting of two metering cylinders for measuring the required volume of volume of the two gases, the mixing block and a stable and closable pressure chamber.

In the practical application of this method are preferred as oxidizable gas hydrogen, methane or natural gas and oxygen as the oxidant.

All these oxidizable gases or »gas mixtures

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have in common that they have different but at any time 'constant firing properties.

However, there are some problems with procurement and deployment. Hydrogen, methane and natural gas are relatively expensive to buy · In addition, hydrogen and methane can be provided only in a bottled state, which requires a considerable effort for transport and storage.

The use of natural gas fails wherever no connection to a gas pipeline is possible *

' Z JeI _{1 of} the invention

It is the object of the invention to develop a method for producing burr-free workpieces, which is rational and inexpensive in their operation.

Presentation of the. Wes.ens the, object of the invention is to develop a suitable oxydierfähiges gas or gas mixture ₀ of a method for producing burr-free workpieces. . ^ ·

According to the invention this object is achieved in that or ₀ gas mixture is used as oxydierfähiges gas, a gas mixture with non-constant burning properties, which is mixed in variable .Weise with air or a gas having a higher heating power and controlled at the required burning technical values.

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The invention relates primarily to the use of town gas »However, all other z. B. used in industry mixed gases are used. To carry out the method according to the invention, a plant is proposed according to the invention, which has a mixing and control range for processing of the oxidizable gas mixture to a gas mixture with konstagnten firing properties, a compressor and a gas pressure reservoir. The controlled system includes two measuring points in which the volume ratio is checked and, if necessary, the volume volume of the air is regulated via a mixture regulator and an adjusting device. Eine'weitere measuring point is used to measure the firing cone length and acts via a regulator, the mixture controller and the adjusting device also on the regulation of the volume amount of air. At a further measuring point, the heating power is measured and corrected by means of a controller and an adjusting device by a pressure change in the power.

The key advantage of this invention is the fact that such systems, which are mainly used in mechanical engineering for deburring machined workpieces, can be operated with a cheap gas mixture, which is everywhere available as in the case of town gas ο The higher cost of the plant is relatively low.

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Exporting ice piel

Pig. 1: Schematic representation of the system according to the invention

The method for producing burr-free workpieces operates on the basis of a chemical process under heat. For this purpose, the workpiece 1 to be treated is surrounded within a stable and closable pressure chamber 2 by a gas mixture consisting of a oxidizable gas and an oxidizing agent.

, After electrical ignition of the gas mixture, the following chemical reaction takes place:

Components of the oxidizable gas and parts of the oxygen combine. This heat is released in a temperature range of about 3000 ⁰ C with appropriate compression, which acts on all surfaces in the pressure chamber. The low mass surfaces, such as burrs, are overheated and, with the remaining parts of oxygen, form a particular metal oxide

Due to the short-term heat exposure occurred on the workpiece 1 no changes as a oxydierfähiges gas can only be a gas or gas mixture ₀ with constant burning properties are used. Town gas, for example, does not have such properties. Depending on the gas production process, city gas consists of lower and higher molecular hydrocarbons, hydrogen and inert gases with different and varying proportions.

For the treatment of the city gas to a gas

mixed with constant firing properties, city gas is mixed with air or a gas with a higher heat output in a specific volume ratio and regulated to the required firing values by means of regulating and adjusting devices. A plant according to the invention for carrying out the method according to the invention is described in the Pig. 1 symbolically represented the system consists of the mixing and control area, a compressor 3 »a gas pressure reservoir 4 and a dosing. and feed system 5 and the stable and closable pressure chamber 2.

At the entrance of the mixing and control area, two supply lines 7, 8 (city gas and air) open at a mixing point 9 into a common line 10. Before the mixing point 9, a measuring point 11 j 12 is arranged, which has a mixture regulator 13 and an adjusting device 14 with a located in the air line 7 location 15 are in operative connection. Downstream of the mixing point 9 is a measuring point 16, which also has a Brennrichgelmeßeinrichtung 17, a controller 18, the mixture controller 13 and the adjusting device 14 with the location 15 compound «, The conclusion of the mixing and control area forms a measuring point 19, the over a Heizleistungsmeßeinrichtung 20, a controller 21 and a control device 22 acts on a control point 23

 The puncture of the system is as follows:

The oxidizable gas or gas mixture is fed via a measuring point 12 to the mixing and control

area, fed. Air or gas with higher heat output is fed via the measuring point 11.

Deviation from the nominal VoIumenanteile be corrected by the mixture controller 13 via the adjusting device 14 at the location 15. From the measuring point 16, the city gas mixed with air a Brennkegelmeßeinrichtung 17 is supplied ο deviations from the Sollbrennkegellänge be compensated by the controller 18, the mixture controller 13 and the adjusting device 14 by changing the volume of the air at the location 15. The change in the thermal output of the gas mixture occurring as a result of the control of the firing cone height is compensated by means of a downstream heating power control.

For this purpose, the previously treated gas mixture is supplied from the measuring point 19 of a Heizleistungsmeßeinrichtung 20. By the downstream controller 21, the adjusting device 22 deviations from the desired heat output by increasing the pressure in the line 10 are corrected at the location.

Subsequently, the gas or gas mixture prepared for defined combustion properties is compressed in a compressor 3 to the required nominal pressure and stored in a gas pressure vessel 4. From there, the treated, oxidizable gas or gas mixture in a line 24 and pure oxygen in a line 25 to the dosing and feed system 5 and the mixing system 6 of the pressure-tightly sealed chamber 2 of the deburring device 26 is supplied. In the pressure chamber 2, in which the workpiece 1 is located, the

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Gas mixture electrically ignited dem material to be deburred workpiece according to the metering and feed system different mixing ratios of oxidizable gas mixture and oxygen and different pressures in the chamber realized.

Are known mixing ratios of 7: 6 and 1: 1 and pressures of 5-35 bar _o

Claims (1)

-3- 21 P ea ent olfr 1 · Method for producing burr-free workpieces, wherein an oxidizable gas or _o gas mixture is mixed with a suitable oxidizing agent in a specific ratio, compressed and ignited in a stable and closable pressure chamber, characterized i ze GEK hen et n that a gas mixture with non-constant burning properties is used as oxydierfähiges gas or "gas mixture in variable. Mixed with air or a gas with higher heat output and regulated by facilities to the required firing values. 2ο installation for carrying out the method according to point 1 consisting of a metering and feed system for the oxidizable gas or gas mixture and the oxidizing agent and a stable and closable pressure chamber, d adur chg ek e η η ζ e J ₁ ch η et that in a mixing and control range measuring points (11} 12) are arranged for the purpose of regulating the volume amount of air in operative connection with a metering valve (13) and a On the other hand at a measuring point (16) is provided a means (17) for measuring the focal length of the cone, for the purpose of regulating the volume of air in operative connection with a regulator (18), the mixture regulator (13) and the adjusting device (14) Furthermore, there is a device (20) for measuring the heating power at a mosquito site (19)
Pressure change in the line (10) in
.Wirkverbindung with a Governor (21) and an adjusting device (22) are and the
Mixing and control range after a compressor (3) and a gas-pressure reservoir (4) is assigned «. For this / page. Drawing.