JP3869217B2 - Post-processing method of synthetic resin molded product and apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a post-processing method for a synthetic resin, in particular, a thermoplastic synthetic resin molded product, and more particularly to a method and an apparatus for performing fusion sealing and welding by heating a part of the molded product to complete the product as a product. .
[0002]
[Prior art]
For example, when the body of a carburetor that supplies fuel to a gasoline engine is made of synthetic resin, many of the fuel passages provided in the interior and the air passages for introducing air into the interior of the carburetor are simultaneously formed by the rod member provided in the mold. A hole is formed, thus opening in the fuselage surface. In order to make this hole function as a fuel or air passage, it is necessary to seal the opening end to the fuselage surface with a metal ball plug or ultrasonically weld a synthetic resin plug. It is sealed by means of.
[0003]
When the hole has a small diameter, generally 1 mm or less and it is difficult to use the plug, an annular protrusion is provided around the opening end of the hole, and this is sealed by melting it with hot air and flowing it into the opening end. Some are done.
[0004]
On the other hand, the technique of joining two molded products by superimposing them together and welding them with hot air, high frequency, ultrasonic vibration, etc. is well known. Hot air welding generally uses hot jet guns to apply hot gas to the welding site. It is done by spraying.
[0005]
[Problems to be solved by the invention]
The method of sealing the opening end of the hole with a plug requires not only a procedure for preparing a very small separate part and fitting it into the hole, which causes the product to be expensive to manufacture, In particular, a metal ball plug has a problem that creep is generated in order to press-fit a hard dissimilar material, and it is difficult to obtain high reliability with respect to pressure resistance and airtightness due to a difference in thermal expansion coefficient.
[0006]
Therefore, it is conceivable to melt and seal with hot air instead of the plug. However, since the synthetic resin required for sealing is very small for the holes of about 1 mm or less, the hot air is simply blown in a very short time without causing any adverse thermal effects on the surroundings. The annular protrusion can be melted and sealed, but for large diameter holes, the annular protrusion used for sealing has a large volume, so it is considerably longer than before to melt and reach sealing. It takes time, and even if the temperature and flow rate of the hot air are adjusted, it is inevitable that the surroundings will be adversely affected such as thermal deformation, physical property changes and melting.
[0007]
In addition, when hot-air welding of two molded products, it is necessary to melt a large amount of the synthetic resin in the overlapping portion for those requiring high joint strength. Inevitable to give.
[0008]
In the present invention, when a part of a synthetic resin molded product is heated and melted with hot air for sealing or welding, especially when the amount of the synthetic resin to be melted is large, it is unavoidable to have a thermal adverse effect on the surroundings. In order to solve the above-mentioned problem that sealing and welding become incomplete when hot air blowing is stopped before adversely affecting the heat, the sealing and welding of the surface of the molded product are performed. The objective is to accurately heat and melt only the necessary parts so that a reliable sealing and welding point can be made without adversely affecting the surroundings.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems of the conventional technique in which a part of the surface of a molded product is heated and melted to perform post-processing, the present invention provides a surface of the molded product where a molten synthetic resin is required for post-processing. And arranging a shielding member with a through hole in front of the nozzle for blowing heated air; and facing the nozzle across the through hole of the generation part, the pressure is 0.01 to 0.5 atm, and the flow rate is 1 Heating air having a low pressure and a small flow rate of × 10 to 2 × 10 ⁵ (cc / min) is blown from the nozzle, and a part thereof is blown through the through-hole to be melted. Heated air other than the above was blocked by a shielding member so as not to be sprayed on the surface of the molded product other than the generated part.
[0010]
More specifically, the generated portion is a protrusion provided around the opening end of the hole formed in the molded product and opened on the surface, and the protrusion is melted by the heated air passing through the through hole and flows into the hole. It consists of a protrusion and a groove provided along the overlapping edge of two molded products with sealed holes or overlapped product parts, and the protrusion is melted and opened by heated air that has passed through the through-hole. It flows in first and joins two molded products by welding.
[0011]
Furthermore, in order to solve the above-mentioned problems, the present invention provides an air flow generating means, a control means for adjusting the air flow generated by the generating means to a required pressure and flow rate, and the adjusted air flow by melting synthetic resin. The heating means for heating to a temperature higher than the temperature, the blowing means for squeezing and blowing the heated air, and the shielding means for passing a part of the blown heated air and blocking the rest, passed through the shielding means. A measure was taken such that heated air was blown onto the molten synthetic resin production part of the molded product.
[0012]
By preventing the heated air from being sprayed on the surface of the molded product other than the melted synthetic resin generating portion by the shielding member, there is no fear of causing thermal adverse effects such as thermal deformation, physical property change, and melting due to direct spraying to the surroundings. In addition, it can be heated intensively by blowing low-pressure, low-flow-rate heated air only on the molten synthetic resin production part, and it has little thermal adverse effect on its surroundings. Good welding without causing destruction of the layer of molten synthetic resin that is trying to block the opening end of the metal, and in the case of welding, filling the molten synthetic resin into the groove without causing it to flow out. Therefore, the purpose of making a reliable sealing and welding point can be achieved.
[0013]
In the latter means, at least one of the intervals between the molten synthetic resin production part of the molded product, the blowing means, and the shielding member is made variable so that the heated air is appropriately adjusted according to the size of the production part. It is suitable for spraying. In addition, if the sonic nozzle is used as the control means, the air can be adjusted to a stable small flow rate with a simple structure, and if the nozzle is provided at the tip of the heating means using the blowing means, the configuration can be simplified. Can do.
[0014]
In addition, the heated air blown to the molten synthetic resin production part is blown at a low pressure, a low flow rate, and therefore at a low speed and at a high temperature as much as possible without decomposing the synthetic resin, so that the required melting can be achieved in a short time. Finishing is preferred to obtain a good processed part. Therefore, the heated air blown out from the nozzle is at a temperature about 10 to 350 (° C.), preferably about 100 to 300 (° C.) higher than the melting temperature of the synthetic resin, and the pressure is 0.01 to 0.5 atm. The flow rate is preferably about 1 × 10 to 2 × 10 ⁵ (cc / min).
[0015]
Furthermore, in the actual post-processing operation, the maximum diameter of the protrusion provided around the opening end to seal the hole or the maximum total of the protrusion and groove provided on the overlapping edge of the two molded products to be welded Preventing the through-hole of the shielding member from being larger than the width, and sufficiently reducing the distance between the nozzle tip and the through-hole and the distance between the top of the projection and the through-hole, respectively, makes it possible to efficiently melt the heated air with less waste. It is preferable when spraying on the synthetic resin production part.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a case where an opening end portion of a hole 22 formed in a molded article 21 of a thermoplastic synthetic resin and opened on the surface is sealed. An annular projection 23 surrounding the open end of the hole 22 is formed when the molded product 21 is molded. The protrusion 23 has a volume that forms a wall capable of closing the hole 22 with a thickness having a required strength.
[0017]
The air flow generating means A is a fan 1, and its discharge line 2 has a sonic nozzle 3 as a control means B on the way and is connected to a heater 4 as a heating means C. The heater 4 includes a cylindrical body 5 and a heating element 6 formed by spirally winding a nichrome wire that generates electric resistance heat. The body 5 is an end opposite to the connection end of the discharge pipe 2. The nozzle 7 which is the blowing means D protrudes from the part. In addition, a flat shield member 8 serving as a shield means E is disposed in front of the nozzle 7, and the shield member 8 has a through hole 9. Note that the heating means C is not limited to electrical resistance heat, and any means for heating air by an appropriate electrical method such as electromagnetic induction heating can be applied.
[0018]
The through hole 8 has a diameter equal to or smaller than the maximum diameter of the protrusion 23 of the molded product 21. Further, the distance between the tip of the nozzle 7 and the through hole 9 is sufficiently small, and the amount of air that is blocked by the shielding member 8 through the through hole 9 before the heated air blown from the nozzle 7 is greatly expanded. We try to use it efficiently as much as possible. In addition, the distance between the through hole 9 and the top end of the protrusion 23 is sufficiently small, and the air that has passed through the through hole 9 spreads greatly and is directly blown to the outer region of the protrusion 23, so that the molded product 21 is thermally expanded. The inconvenience of being adversely affected is avoided. Specifically, although it depends on the dimensional relationship between the tip diameter of the nozzle 7 and the through-hole 9, it is a standard guideline that the interval is 0.5 to 10 (mm). Further, although depending on the dimensional relationship between the through-hole 9 and the maximum diameter of the protrusion 23, when the through-hole 9 is an intermediate diameter between the diameter of the hole 22 and the maximum diameter of the protrusion 23, the distance between them is 0.1. A standard guideline is ˜5 (mm).
[0019]
Then, the nozzle 7, the through hole 9, and the hole 22 are placed on the same central axis, the fan 1 is operated, the discharge air is adjusted to a predetermined pressure and flow rate by the sonic nozzle 3, and sent to the heater 4. When heated to a predetermined temperature and squeezed and blown off by the nozzle 7 at the tip, the heated air flows while gradually spreading, its central portion passes through the through-hole 9 and its outer peripheral portion collides with the shielding member 8 and is deflected outward. . The heated air that has passed through the through-hole 9 flows while spreading, collides with the protrusions 23, and is heated. Contour of the air flow for heating the protrusion 23 is shown by a two-dot chain line L _A.
[0020]
The central portion of the heated air flows into the hole 22 and heats the protrusion 23 from the inside. In addition, by adjusting the heating air so that it collides with the top end surface of the projection 23 and does not substantially collide with the outer peripheral surface, the heating air heats the projection 23 intensively and collides with the projection 23. Since it escapes outward, it is not sprayed directly on the surface of the surrounding molded product 21.
[0021]
The air adjusted to a low pressure and a small flow rate by the sonic nozzle 3 is heated to a temperature considerably higher than the melting temperature of the synthetic resin by the heater 4 and blown out from the nozzle 7, whereby the protrusion 23 is heated and melted in a short time. The generated synthetic resin flows into the opening end of the hole 22 and forms a wall that closes the hole. At that time, the low pressure and small flow rate of heated air does not have a flow velocity that breaks through and breaks the molten synthetic resin layer, which is a wall formed by viscosity and surface tension. Does not impede completion. When almost all of the protrusions 23 are melted, the opening end of the hole 22 is closed with a wall 24 having a predetermined thickness and is completely sealed.
[0022]
FIG. 2 shows a case in which the edges of two molded products 31 and 33 of thermoplastic synthetic resin are overlapped and joined by welding, and a strip-like protrusion extending along the edge is formed on the surface of one molded product 31. 32 is made when the molded product 31 is molded. Further, the other molded product 33 is formed with a ledge shaped groove 34 extending along the edge and opened to the surface when the molded product 33 is molded. The protrusion 32 and the groove 34 have substantially the same volume.
[0023]
The air flow generating means A is an air compressor 11 and a pressure accumulator 12, and a discharge line 13 extending from the pressure accumulator 12 is a heating means C having a manual flow rate adjusting valve 14 which is a control means B on the way. Connected to the heater 4. This heater 4 is the same as that of the embodiment shown in FIG. 1, and has a nozzle 7 as a blowing means D protruding from the tip of a cylindrical main body 5 in which a heating element 6 is built. Yes. Moreover, it is the same as that of embodiment shown in FIG. 1 that the shielding member 8 which is the flat form which is the shielding means E, and has the through-hole 9 is arrange | positioned ahead of the nozzle 7. FIG.
[0024]
The through hole 8 has a diameter equal to or smaller than the maximum total width of the protrusion 32 and the groove 34, and the distance between the tip of the nozzle 7 and the through hole 9 and the distance between the through hole 9 and the protrusion 32 are as follows. The intervals are sufficiently small, so that the heated air blown from the nozzle 7 can be used efficiently and the surroundings of the welded portions of the molded products 31 and 33 are not adversely affected by heat. ing.
[0025]
The superposed surfaces of the nozzle 7, the through-hole 9 and the molded products 31 and 33 are placed on the same central axis, and the air sent from the pressure accumulator 12 is adjusted to a predetermined pressure and flow rate by the flow rate control valve 14 and heated. When it is fed into the vessel 4 and heated to a predetermined temperature and blown out from the nozzle 7 at the tip, the heated air flows while gradually spreading, its central portion passes through the through-hole 9 and its outer peripheral portion collides with the shielding member 8. Is deflected outward. The heated air that has passed through the through-hole 9 flows while spreading, collides with the protrusion 32 and the groove 34, and heats them. The contour of the air flow is indicated by two-dot chain line L _B.
[0026]
The heated air that collides with the protrusion 32 escapes outward, and the heated air that collides with the groove 34 escapes outward and upward along the inclined surface, so that it is not directly blown onto the surfaces of the surrounding molded products 31 and 33. . Then, the heating air is set to a temperature considerably higher than the melting temperature of the synthetic resin as in the above embodiment, so that the protrusion 32 and the groove 34 are melted in a short time, and the melt synthesis in which the protrusion 32 is generated. The resin flows into the groove 34 and is integrated with the melted portion so as to gradually fill the groove 34. Further, since the heated air has a low pressure and a small flow rate, it does not have a flow rate for extruding the molten synthetic resin flowing into the groove 34 to the surface of the molded product 33, does not hinder the growth and completion of the welded meat, and flows in the molten Maintain the molten state of the synthetic resin. When almost all of the protrusions 32 are melted, the groove 34 is filled with a molten synthetic resin, which becomes a welded meat 35 and the two molded products 31 and 33 are welded.
[0027]
When the welding is finished at one place, the molded products 31 and 33 are moved, or the heater 4 and the shielding member 8 are moved and the adjacent places are welded sequentially to complete the entire welding. The groove 34 may be V-shaped or U-shaped, and each of the two molded products 31, 33 may be provided with a protrusion 32 along the groove 34. In this case, each protrusion 32 is made smaller. Further, it can be melted and welded in a short time.
[0028]
In the two embodiments shown in FIGS. 1 and 2, the melted synthetic resin producing portions of the molded products 21, 31, 33, particularly the top ends of the projections 23, 32, the tip of the nozzle 7, and the shielding member 8, It is possible to carry out post-processing of a specific molded product having the same dimensions with the interval fixed. However, the position of at least one of the nozzle 7, the shielding member 8, and the molded products 21, 31, and 33 can be made variable so that the distance between the top ends of the projections 23 and 33 and the tip of the nozzle 7 and the top ends of the projections 23 and 33 are shielded. When at least one of the intervals with the member 8 and, therefore, the interval between the tip of the nozzle 7 and the shielding member 8 is made variable, the heated air is appropriately applied to those having different sizes of the melted synthetic resin generating portion. Further, even if the spread of the heated air blown out from the nozzle 7 varies depending on the pressure and flow rate, it is possible to make it possible to respond appropriately.
[0029]
【The invention's effect】
As described above, according to the present invention, heated air is blown only to a specific portion of a synthetic resin molded product to melt without fear of adversely affecting the surroundings, and the required post-processing is performed accurately to ensure reliability. A certain sealing and welding point can be made.
[Brief description of the drawings]
FIG. 1 is a layout diagram showing an embodiment of the present invention. FIG. 2 is a layout diagram showing a different embodiment of the present invention.
[Explanation of symbols]
3 Sonic nozzle, 7 nozzle, 8 shielding member, 9 through hole, 21, 31, 33 molded product, 22 holes, 23, 32 protrusion, 34 groove, A generating means, B control means, C heating means, D blowing means , E shielding means,

Claims (7)

A method in which a part of the surface of the molded product is heated and melted to be post-processed,
Providing a production part of a melted synthetic resin required for post-processing on the surface of the molded product, and disposing a shielding member with a through hole in front of a nozzle for blowing heated air;
Then, the generated part is opposed to the nozzle across the through hole, and the pressure is 0.01 to 0.5 atm, and the flow rate is 1 × 10 to 2 × 10 ⁵ (cc / min) at low pressure and small flow rate. A heated air is blown out from the nozzle and a part of the heated air is blown to the generation part by passing through the through hole, and the other heating air is blocked by the shielding member and is not the generation part. Do not spray on the surface of the molded product,
A post-processing method for a synthetic resin molded product.   The generation part is a protrusion provided around the opening end of the hole formed in the molded product and opened on the surface, and the protrusion is melted by the heated air passing through the through hole and flows into the hole to be sealed. The post-processing method of the synthetic resin molded product described in Claim 1.   It consists of a protrusion and a groove provided along the overlapping edge of the two molded products on which the generation part overlaps, and the protrusion is melted by the heated air passing through the through hole and flows into the groove. The post-processing method of the synthetic resin molded product according to claim 1, wherein the two molded products are joined by welding.   Air flow generating means, control means for adjusting the air flow generated by the generating means to a required pressure and flow rate, heating means for heating the adjusted air flow to a temperature higher than the synthetic resin melting temperature, A blowing means for narrowing the blown air and a shielding means for passing a part of the blown heated air and blocking the remainder, and the heated air that has passed through the shielding means is used as a molten synthetic resin production part of the molded product A post-processing apparatus for a synthetic resin molded product, characterized by being sprayed.   5. The post-processing apparatus for a synthetic resin molded product according to claim 4, wherein at least one of the intervals between the molten synthetic resin generation portion, the blowing means, and the shielding means is variable.   The post-processing apparatus for a synthetic resin molded product according to claim 4, wherein the control means is a sonic nozzle.   The synthetic resin molded product post-processing apparatus according to claim 4 or 5, wherein the blowing means is a nozzle provided at a tip of the heating means.

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