JP2542487Y2 - Burning device for three-dimensional article printing machine - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention is intended to facilitate printing on electronic components such as semiconductor devices and other relatively small three-dimensional articles, and to increase the fixing strength of printing. The present invention relates to a burning device that performs preprocessing.

<Conventional technology> In a three-dimensional article printing machine (marking system) for printing a product name, a model number, etc. on the surface of a three-dimensional article such as an electronic component, the printing is performed by removing impurities such as oil film and dust on the surface of the article to be printed before printing. As a means for making the printing easier and increasing the fixing strength of the print, a method of washing with a volatile solvent or burning with a flame has been known. However, the amount of chemicals that cannot be stamped on mold materials such as electronic components has increased year by year, and it has become difficult to maintain the fixing strength of printing by washing with solvents, and wastewater after washing with solvents due to environmental pollution regulations. Due to the high cost of the treatment, the method of washing with a solvent has hardly been adopted in recent years.

On the other hand, when burning with a flame, burning hydrogen gas is known as a clean method that does not emit smoke. However, the burning gas is a mixed gas of hydrogen and oxygen in a ratio of 2: 1. It is dangerous to ignite and explode with fire when the lower explosive limit concentration reaches 4%. However, since there is no other easy method as described above, in recent years, by providing explosion prevention measures such as installing a gas alarm, it is necessary to increase the fixing strength of printing. As the means, a burning device is mainly used.

<Problems to be Solved by the Invention> Gas detectors or gas alarms are mainly mounted on ceilings and walls in factories and workplaces. However, the flow rate of gas used in the burning device for three-dimensional article printing machines is as low as 1 to 3 l / min per three-dimensional article printing machine, and leaked gas is scattered by the flow of air due to the movement of machines and human bodies. Therefore, it takes a considerable amount of time for the leaked gas to reach the lower explosion limit concentration of 4% and to be detected by gas detectors and gas alarms. Is often at risk of causing

Therefore, if the gas sensor is mounted directly above the nozzle in order to solve the above-described problem, the gas rises immediately above, so that an alarm is issued every time a small amount of gas leaks. The alarm is annoying to workers.
Therefore, there is a possibility that the switch of the alarm device is often turned off, which may cause a situation in which the alarm device does not operate in an emergency.

Accordingly, the present invention provides a three-dimensional article printing that can issue an alarm without giving an unnecessary alarm and promptly when a gas leak or stagnation reaches a concentration at which there is a possibility of ignition even in a small amount. An object of the present invention is to provide a machine burning device.

<Means for Solving the Problems> The present invention provides a burning apparatus for a three-dimensional article printing machine that burns a flame due to gas combustion on the surface of the three-dimensional article in a process before printing on a small three-dimensional article such as an electronic component. In the gas fuel supply system that guides the gas generated by the gas generator to the nozzle via a bubbler, a booster, a flow meter and a flashback prevention filter, and a gas concentration detected by a gas sensor having selectivity for detecting only a specific gas, A gas alarm device for issuing an alarm when a predetermined value is reached, and an opening is formed in a top surface of the safety cover, which is arranged so as to cover the periphery of the nozzle, except for a position directly above the nozzle. And the gas sensor is arranged opposite to the position above the opening.

Further, the gas sensor may be arranged in a vicinity of the inside of the safety cover except for a position directly above the nozzle without providing an opening in the safety cover.

<Operation> When a small amount of gas leaks from the nozzle without danger of explosion, the gas sensor is not located directly above the nozzle where the gas rises. There is no misdetection as density. If this gas leaks from the opening or if no opening is provided, it will be scattered by the flow of air, etc. and will not stay in the safety cover forever, so this kind of gas leakage will occur sporadically Even if the detection set concentration is not reached.

On the other hand, even if the amount of gas is small, even if the possibility of ignition is continuous and gas leaks out of the opening or stays in the safety cover, for example, after opening the gas cock, it takes time to ignite and the safety cover If the gas is filled and stays inside, an alarm is issued from the gas alarm device when the detection set concentration is reached. By closing the gas plug and stopping the ignition work, ventilating and stopping the alarm, and then performing the ignition work again,
Small explosions of gas can be prevented.

In addition, since the gas sensor has a selectivity of detecting only a specific gas, it can accurately detect only a gas that is always provided for burning without being affected by other combustible gases in any environment. An alarm can be issued.

<Embodiment> Fig. 1 shows a configuration of a gas fuel supply system of a burning device for a three-dimensional article printing machine according to an embodiment of the present invention. The hydrogen / oxygen mixed gas generator 1 is configured as an ion exchange membrane type. Pure water is electrolyzed by an electrochemical cell in which an anode and a cathode made of a platinum group metal are integrally joined on both sides of an ion exchange membrane to generate hydrogen and oxygen. From this outlet, high-temperature (about 50 ° C) Generates saturated gas of high humidity (about 98% humidity) mixed with hydrogen and oxygen.

The gas generated from the gas generator 1 is sent to a bubbler 3 via a first backflow water recovery tank 2, where the water is removed by bubbling with purified water (pure water) inside. It becomes a gas with about 90% humidity. Further, it is sent to the booster 5 through the second backflow water recovery tank 4,
The gas passes through the aqueous methanol solution in the booster 5 and is cooled to become a gas having a humidity of 75 to 79%. Although this gas is somewhat cooled and dehumidified by the bubbler 3 and the booster 5, its temperature is slightly lower than that at the time of output of the gas generator 1. Therefore, when the gas in the piping tube is fed through a piping tube made of a special rubber tube or a silicon tube, the gas in the piping tube is further cooled at an outside air temperature and condenses on the inner wall of the tube. It temporarily stays in the lower part of the piping tube and is gradually fed by the gas pumped through the tube.

Moisture absorber 6 arranged after booster 5
A gas inlet 6b is provided on the lower edge side surface of the main body container 6a, and a gas outlet 6c is provided on the upper edge side surface, and a partition rod 6d is erected at a position slightly above the gas inlet 6b inside the main body container 6a. ing. Then, a moisture absorbent 6e in the form of a pack which is sealed in a water-permeable storage bag 6f made of a porous material is inserted into the container body 6a and placed on the partitioning rod 6d, and the body by the cap 6g. The container 6a is sealed in the main container 6a by a cover. The moisture absorbing agent 6e has a function of converting from a powder body to a solid state by absorbing moisture, and transferring to fine particles (snow-like form) by further absorbing moisture. That is, this moisture absorbent 6e is made of sodium polyacrylate (CH ₂ CHCOONa).
Is a special water-absorbing polymer whose main component is water, which instantaneously absorbs water and swells when it comes into contact with water, expands to a fine powder volume, and has a function of retaining water absorbed by extremely little dissolution in water.

Therefore, when the gas passes through the moisture absorber 6, the dehumidifying agent 6e obtains a dehumidifying effect of 10 to 30% to be in a state close to the indoor humidity.
Removes 100% of water.

The gas which has been dehumidified and in a good state is supplied to the flow meter 7.
After passing through the flashback prevention filter 8, the fuel is burned and ejected from the nozzle 10 at the tip of the nozzle holder 9, and oil and grease and dust on the surface of the three-dimensional article of the printing target disappear. This nozzle 10
The gas sent to the heater is dehumidified to about the indoor humidity by the moisture absorber 6, so that the flame temperature hardly changes and the fixing strength of printing is increased to maintain the required value, thereby preventing the occurrence of defective printing. it can. Further, since all the dew condensation water droplets are absorbed by the moisture absorber 6, no discoloration or rust occurs on the article conveying path.

A hydrogen gas alarm 11 as the gist of the present invention is disposed near the nozzle 10, and FIG. 2 shows an arrangement state of the hydrogen gas alarm 11, and FIG. The same components as those in FIG. 1 are denoted by the same reference numerals. The hydrogen gas alarm 11 is provided between the moisture absorber 6 and the flow meter 7, and a hydrogen gas sensor 11 a connected to the hydrogen gas alarm 11 by a cord wire is provided so as to cover the upper part of the nozzle 10. An opening 12a which is led out of the installed safety cover 12 and is formed in a corner of the top surface of the safety cover 12
It is arranged and mounted above. This hydrogen gas sensor 11a is a hydrogen gas detection dedicated sensor with high selectivity that detects only hydrogen gas by the potentiostatic electrolysis method, and is applicable to all other combustible gases such as LPG, city gas, hydrogen gas and gasoline. It is completely different from the catalytic combustion type or the hot-wire type semiconductor type which reacts, and always reliably detects only hydrogen gas regardless of other flammable gas in any environment.

Further, when the gas concentration detected by the gas sensor 11a reaches the detection set concentration of 1/100 of the lower explosive limit concentration, the gas alarm 11 emits a buzzer sound for urging the ventilation required for the speaker 11a.
It is set so as to emit from b and to blink the warning light emitting diode 11c.

Therefore, when a small amount of gas leaking from the nozzle 10 without danger of explosion occurs sporadically, the gas sensor 10a is arranged outside the safety cover 12 and the gas rising into the safety cover 12 just above the nozzle 10 Is not directly detected, and this leaked gas intermittently leaks from the opening 12a at the upper corner of the safety cover 12 with the flow of air. Even if the leaked gas concentration does not reach the detection set concentration of the gas alarm 11,
No alarm is output erroneously.

In addition, for example, when it takes time to ignite after opening the gas stopper, even if the amount of continuously emitted gas is small, it fills a relatively small volume of the safety cover 12 and leaks from the opening 12a. The gas may reach the detection set concentration of the gas alarm 11. This is detected by the gas alarm 11 through the gas sensor 11a, and a buzzer sound is emitted from the speaker 11b of the gas detector 11, and the light emitting diode 11c for alarm display blinks. As a result, even if the gas plug is closed, the ignition work is temporarily stopped, ventilation is performed, and the alarm is stopped due to the decrease in the gas concentration of the leaked gas. it can. Such a small explosion due to the ignition of the gas retained in the safety cover 12 does not substantially cause damage, but is accompanied by a loud sound, and is extremely surprising to the operator.

In addition, gas leakage may occur while not being noticed due to a defect or malfunction of the exhaust blower or stopper, but since the gas sensor 11a is located very close to the fire, even a small amount of explosion occurs. Can be detected and an alarm can be issued as soon as the concentration reaches a level where there is a possibility that the density may become low.

Further, since the gas sensor 11a has a selectivity of detecting only hydrogen gas, even if it is arranged outside the safety cover 12, it always reliably detects only hydrogen gas without being affected by other combustible gases. And can give an accurate alarm.

Incidentally, without drilling the opening 12a in the safety cover 12,
Even if the gas sensor 11a is arranged at the inner corner in the safety cover 12 as shown by the dashed line in FIG. 2, the same effect as in the above embodiment can be obtained. That is, when a small amount of gas leakage without a danger of explosion from the nozzle 10 occurs sporadically, the gas sensor 11a does not directly detect the gas rising directly above the nozzle 10, and this leaked gas is Since it is scattered by air flow and does not stay in the safety cover 12 for a long time, even if such a gas leak occurs sporadically, the gas concentration inside the safety cover 12 will not exceed the detection set concentration of the gas alarm 11. It does not reach and does not output an alarm erroneously.

In addition, if it takes time to ignite after opening the gas stopper, even if the amount of gas is small, it stays and fills in the safety cover 12 and reaches the detection set concentration of the gas alarm 11, so it is possible to detect this. it can. Further, since the gas sensor 11a is arranged at a position closest to the fire in the safety cover 12,
Even when the concentration is small enough to cause an explosion, it can be quickly detected and an alarm can be issued.

<Effects of the Invention> As described above, according to the burning device for a three-dimensional article printing machine of the present invention, a small amount of gas leaking without a possibility of explosion does not erroneously output an alarm, and even if the amount is small, an explosion occurs. When the gas concentration reaches the potential of the above, it is possible to reliably detect this and issue an alarm. Therefore, even if there is no damage, it is possible to reliably prevent a small explosion that surprises the worker due to the loud sound. In addition, since the gas sensor detects only the gas used for burning, it is possible to reliably detect a leaked gas and issue an accurate alarm without being affected by other combustible gases.

[Brief description of the drawings]

 FIG. 1 is a structural view of an embodiment of the present invention, and FIG. 2 is a cut-away side view of a main part thereof. 1 ... gas generator 3 ... bubbler 5 ... booster 7 ... flow meter 8 ... flashback prevention filter 10 ... nozzle 11 ... gas alarm 11a ... gas sensor 12 ... safety cover

Claims (2)

(57) [Scope of request for utility model registration] In a burning apparatus for a three-dimensional article printing machine for burning a flame by gas combustion on a surface of the three-dimensional article in a pre-process of printing on a small three-dimensional article such as an electronic component, a gas generated by a gas generator is provided. And a gas fuel supply system that guides the nozzle through a bubbler, a booster, a flow meter, and a flashback prevention filter, and an alarm when a gas concentration detected by a gas sensor having selectivity to detect only a specific gas reaches a predetermined value. A gas alarm device that emits gas, and a safety cover arranged to cover the upper periphery of the nozzle, an opening is formed in a vicinity of the upper surface of the safety cover except immediately above the nozzle, and the gas sensor is A burning device for a three-dimensional article printing machine, wherein the burning device is arranged opposite to a position above the opening. 2. The safety cover according to claim 1, wherein an opening is not provided in the safety cover, and the location of the gas sensor is changed to a position above the opening, except for a position directly above the nozzle inside the safety cover. A burning device for a three-dimensional article printing machine, which is installed in a vicinity.