Plastic product injection molding production line and production method thereof

Abstract

The present invention provides a plastic product injection molding production line and a production method thereof, the plastic product injection molding production line comprising: a CNC machine tool, a mold, a mechanical arm, a conveyor belt and a plurality of nuts located on the conveyor belt. The mold comprises a movable mold and a fixed mold, the CNC machine tool is used to drive the movable mold to approach or move away from the fixed mold; the conveyor belt moves toward an opening for driving the nuts to approach the CNC machine tool; the mechanical arm comprises a fixed seat, a feed guide rail, a lateral displacement guide rail, a longitudinal displacement guide rail and a mechanical claw, the fixed seat is arranged on the outer wall of the CNC machine tool, the feed guide rail is arranged on the fixed seat, and the feed guide rail extends toward the inner cavity of the CNC machine tool; a negative pressure suction nozzle is arranged on the mechanical claw, the negative pressure suction nozzle is used to pick up the nuts on the conveyor belt, and place the nuts in the fixed mold. In summary, the plastic product injection molding production line and the production method thereof can improve the structural strength of the screw column in the injection molded product, and avoid damage to the screw locking process and cause defects.

Description

Technical Field

[0001] The present invention relates to the field of plastic product processing, and in particular to a plastic product injection molding production line and a production method thereof. Background Art

[0002] Figure 1 This is a partial view of a lamp holder of a vehicle lamp. The lamp holder 20 and the lamp shade are both plastic products, obtained by injection molding. The lamp holder 20 and the lamp shade are locked by screws. The lamp holder 20 is provided with a screw column 21 that matches the lamp shade. During assembly, the screw is passed through the lamp shade, and the screw is threadedly connected to the screw column 21, thereby locking the lamp shade on the lamp holder 20.

[0003] However, since the lamp holder 20 is an injection molded product, its structural strength is low, and the screw column 21 formed by injection molding itself has low strength. The torque generated when tightening the screw can easily cause the internal thread on the screw column 21 to break and cause slippage. If the locking force is too large, it may even cause the screw column 21 to crack.

[0004] Therefore, how to avoid damage to the screw column when tightening the screw and improve the structural strength of the injection molded product is a problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a plastic product injection molding production line and a production method thereof, so as to improve the structural strength of the screw column in the injection molded product and avoid defects caused by damage during the screw locking process.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A plastic product injection molding production line, comprising: a CNC machine tool, a mold, a mechanical arm, a conveyor belt and a plurality of nuts on the conveyor belt;

[0008] The mold includes a movable mold and a fixed mold, and the CNC machine tool is used to drive the movable mold to approach or move away from the fixed mold;

[0009] The conveyor belt moves toward an opening for driving the nut close to the CNC machine tool;

[0010] The mechanical arm comprises a fixed seat, a feed guide rail, a transverse displacement guide rail, a longitudinal displacement guide rail and a mechanical claw, wherein the fixed seat is arranged on the outer wall of the CNC machine tool, the feed guide rail is arranged on the fixed seat, and the feed guide rail extends toward the inner cavity of the CNC machine tool, the transverse displacement guide rail is arranged on the feed guide rail, the longitudinal displacement guide rail is arranged on the transverse displacement guide rail, and the mechanical claw is rotatably arranged at the lower end of the longitudinal displacement guide rail;

[0011] The mechanical claw is provided with a negative pressure suction nozzle, and the negative pressure suction nozzle is used to pick up the nuts on the conveyor belt and place the nuts in the fixed mold.

[0012] In one of the embodiments, the inner side of the nut is filled with a paraffin layer, the center of the paraffin layer has a through hole, the fixed mold is provided with a forming hole, a demolding insert is provided in the forming hole, a limiting pin is provided at the end of the demolding insert, and the limiting pin is used to penetrate the paraffin layer.

[0013] In one embodiment, the diameter of the limiting pin is smaller than the diameter of the through hole.

[0014] In one embodiment, the diameter of the forming hole is larger than the diameter of the demolding insert.

[0015] In one of the embodiments, anti-slip grooves are provided on the outer wall of the nut.

[0016] In one of the embodiments, the negative pressure suction nozzle includes a telescopic rod and a suction head, and a blind hole is formed on the suction head, and the depth of the blind hole is less than the length of the nut.

[0017] In one of the embodiments, a gear rack transmission assembly is provided at the connection between the feed guide rail and the lateral displacement guide rail and at the connection between the lateral displacement guide rail and the longitudinal displacement guide rail.

[0018] In one of the embodiments, a drag chain is provided at the connection between the feed guide rail and the lateral displacement guide rail and at the connection between the lateral displacement guide rail and the longitudinal displacement guide rail.

[0019] In one of the embodiments, a control panel is disposed on the fixing base.

[0020] A production method, based on the above-mentioned plastic product injection molding production line, comprises the following steps:

[0021] Step 1: Fill the nut with paraffin wax to form a paraffin wax layer in the inner cavity of the nut, and transfer the nut with the paraffin wax layer to a conveyor belt, which conveys the nut to the location of the CNC machine tool;

[0022] Step 2: The CNC machine tool separates the movable mold from the fixed mold;

[0023] Step 3: The robotic arm starts, the robotic claw descends, and the negative pressure nozzle picks up the nut;

[0024] Step 4: After the mechanical claw rises and returns to its original position, flip the mechanical claw 90°;

[0025] Step 5: The feed guide rail is started to drive the mechanical claw into the inner cavity of the CNC machine tool, so that the negative pressure suction nozzle faces the forming hole;

[0026] Step 6: Drive the mechanical claw close to the fixed mold, insert the limit pin into the paraffin layer until the nut abuts against the end of the demoulding insert;

[0027] Step 7: driving the mechanical claw to leave the inner cavity of the CNC machine tool, and the CNC machine tool closes the movable mold and the fixed mold, injecting the injection liquid into the mold cavity, and the injection liquid and the nut are integrally formed to obtain the target injection molded product;

[0028] Step 8: Drive the movable mold and the fixed mold to separate again, and take out the target injection molded product.

[0029] In summary, the plastic product injection molding production line and the production method thereof can improve the structural strength of the screw column in the injection molded product and avoid defects caused by damage during the screw locking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a structural schematic diagram of the location of the screw column of the existing lamp holder;

[0032] Figure 2 This is a structural diagram of a plastic product injection molding production line;

[0033] Figure 3 It is a schematic diagram of the structure of the robotic arm;

[0034] Figure 4 This is the coordination state diagram of the robot arm and the conveyor belt;

[0035] Figure 5 is a schematic diagram of the structure of a nut;

[0036] Figure 6 is a schematic cross-sectional view of a nut;

[0037] Figure 7 This is a diagram of the coordination between the fixed mold and the negative pressure nozzle;

[0038] Figure 8 for Figure 7 Magnified view at A.

[0039] Attached figures: 10, plastic product injection molding production line; 100, CNC machine tool; 210, movable mold; 220, fixed mold; 221, molding hole; 230, demoulding insert; 231, limit pin; 300, mechanical arm; 310, fixed seat; 311, control panel; 320, feed guide rail; 330, lateral displacement guide rail; 340, longitudinal displacement guide rail; 350, mechanical claw; 360, negative pressure suction nozzle; 361, telescopic rod; 362, suction head; 31, blind hole; 370, rack and pinion transmission assembly; 380, drag chain; 400, conveyor belt; 500, nut; 510, paraffin layer; 511, through hole; 520, anti-slip pattern. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0041] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0043] See also Figure 2 The present invention provides a plastic product injection molding production line 10, which includes: a CNC machine tool 100, a mold, a robot arm 300, a conveyor belt 400 and a plurality of nuts 500 located on the conveyor belt 400.

[0044] The mold includes a movable mold 210 and a fixed mold 220, and the CNC machine tool 100 is used to drive the movable mold 210 to approach or move away from the fixed mold 220;

[0045] The conveyor belt 400 moves toward the opening for driving the nut 500 close to the CNC machine tool 100;

[0046] See also Figure 3The robot arm 300 includes a fixed seat 310, a feed guide rail 320, a lateral displacement guide rail 330, a longitudinal displacement guide rail 340 and a mechanical claw 350. The fixed seat 310 is arranged on the outer wall of the CNC machine tool 100, the feed guide rail 320 is arranged on the fixed seat 310, and the feed guide rail 320 extends toward the inner cavity of the CNC machine tool 100, the lateral displacement guide rail 330 is arranged on the feed guide rail 320, the longitudinal displacement guide rail 340 is arranged on the lateral displacement guide rail 330, and the mechanical claw 350 is rotatably arranged at the lower end of the longitudinal displacement guide rail 340;

[0047] See also Figure 3 and Figure 4 A negative pressure suction nozzle 360 ​​is provided on the mechanical claw 350 , and the negative pressure suction nozzle 360 ​​is used to pick up the nut 500 on the conveyor belt 400 and place the nut 500 in the fixed mold 220 .

[0048] The operation process of the plastic product injection molding production line 10 is as follows:

[0049] After the CNC machine tool 100 is started, the movable mold 210 is separated from the fixed mold 220, leaving enough space between the fixed mold 220 and the movable mold 210;

[0050] The robot arm 300 is started, and the longitudinal displacement guide rail 340 drives the mechanical claw 350 to descend, so that the negative pressure suction nozzle 360 ​​contacts the nut 500 on the conveyor belt 400, and after the negative pressure suction nozzle 360 ​​adsorbs the nut 500, the mechanical claw 350 is driven to rise;

[0051] The lateral displacement guide rail 330 enters the inner cavity of the CNC machine tool 100 along the extension direction of the feed guide rail 320 until the negative pressure suction nozzle 360 ​​faces the fixed mold 220 and places the nut 500 into the cavity;

[0052] The mechanical arm 300 resets the mechanical claw 350 , and the CNC machine tool 100 drives the movable mold 210 and the fixed mold 220 to close the mold again, and injects the injection liquid into the mold cavity. After the injection liquid is cooled, the lamp holder 20 can be obtained.

[0053] It can be seen that before injecting the injection liquid, the mechanical arm 300 is used to embed the nut 500 in the mold cavity, so that the nut 500 is embedded in the screw column 21. When the screw is locked, the nut 500 bears the torque from the screw, which can avoid the problem of slipping. At this time, the screw column 21 and the nut 500 are integrally formed, which can prevent the screw column 21 from cracking during the screw locking process. That is, the plastic product injection molding production line 10 can improve the structural strength of the screw column in the injection molded product and avoid damage during the screw locking process to cause defects.

[0054] It can be seen from the above-mentioned injection molding process that in the present application, in order to improve the structural strength of the screw column 21 position of the injection molded product, before injecting the injection molding liquid into the mold cavity, the nut 500 is built into the fixed mold 220 using the robot arm 300, so that the nut 500 and the injection molded product are integrally formed. When locking the screw, the nut 500 bears the torque from the screw, which can avoid the problem of slipping. The force applied during the screw tightening process will not directly act on the screw column 21, which can effectively avoid defects caused by the screw column 21 cracking due to torque.

[0055] It should be noted that, since the inner wall of the nut 500 is provided with internal threads, in order to facilitate the removal and avoid damaging the internal threads of the nut 500, the parts of the mechanical claw 350 and the fixed mold 220 that contact the nut 500 need to avoid the internal threads. Because of this, the nut 500 and the fixed mold 220 are not directly connected. When the injection molding liquid is injected into the mold, the position of the nut 500 is easily offset under the impact of the injection molding liquid, and the high density of the injection molding liquid makes it easy for the nut 500 to float. Before the injection molding liquid cools and solidifies, if the nut 500 is separated from the fixed mold 220, the injection molding liquid will penetrate into the inner cavity of the nut 500, blocking its internal threads, and then causing the nut 500 to be unable to be connected with the screw thread.

[0056] To solve the above problems, the present application also makes the following improvements to the fixed die 220 and the nut 500:

[0057] See also Figure 4 , Figure 5 and Figure 6 The inner side of the nut 500 is filled with a paraffin layer 510 , and the center of the paraffin layer 510 has a through hole 511 . A forming hole 221 is opened on the fixed mold 220 , and a demolding insert 230 is arranged in the forming hole 221 . A limiting pin 231 is arranged at the end of the demolding insert 230 , and the limiting pin 231 is used to penetrate the paraffin layer 510 .

[0058] The diameter of the limiting pin 231 is smaller than the diameter of the through hole 511. That is, there is an interference fit between the limiting pin 231 and the through hole 511, and the paraffin wax is soft in texture. When the limiting pin 231 penetrates the through hole 511, it will squeeze the paraffin wax layer 510. After the nut 500 is placed in the molding hole 221, the paraffin wax layer 510 fills the gap between the limiting pin 231 and the inner cavity of the nut 500 to fix the nut 500, so that the nut 500 can resist the impact force from the injection liquid during the injection molding process.

[0059] The diameter of the forming hole 221 is larger than the diameter of the demoulding insert 230. The injection liquid is cooled in the forming hole 221 to form the screw column 21.

[0060] See also Figure 4 and Figure 7Preferably, the negative pressure suction nozzle 360 ​​includes a telescopic rod 361 and an adsorption head 362, and the adsorption head 362 is provided with a blind hole 31, and the depth of the blind hole 31 is less than the length of the nut 500. The nut 500 is taken and placed by vacuum adsorption.

[0061] Based on the above improvements, a method for producing a plastic product is provided, comprising the following steps:

[0062] Step 1: Fill the nut 500 with paraffin wax to form a paraffin wax layer 510 in the inner cavity of the nut 500, and transfer the nut 500 with the paraffin wax layer 510 to the conveyor belt 400, and the conveyor belt 400 transports the nut 500 to the location of the CNC machine tool 100;

[0063] Step 2: The CNC machine tool 100 separates the movable mold 210 from the fixed mold 220 to expose the forming hole 221 in preparation for the placement of the nut 500;

[0064] Step 3: The robot arm 300 starts, the robot claw 350 descends, and the negative pressure nozzle 360 ​​picks up the nut 500;

[0065] Step 4: After the mechanical claw 350 rises and returns to its original position, the mechanical claw 350 is turned over 90°;

[0066] Step 5: The feeding guide rail 320 is started, driving the mechanical claw 350 to enter the inner cavity of the CNC machine tool 100, so that the negative pressure suction nozzle 360 ​​faces the forming hole 221;

[0067] Step 6: Drive the mechanical claw 350 close to the fixed mold 220 and put the nut 500 into the molding hole 221. During this process, the limiting pin 231 is inserted into the paraffin layer 510 until the nut 500 abuts against the end of the demoulding insert 230 and the nut 500 is placed in place. Figure 8 As shown;

[0068] Step 7: driving the mechanical claw 350 to leave the inner cavity of the CNC machine tool 100, and the CNC machine tool 100 closes the movable mold 210 and the fixed mold 220, injecting the injection liquid into the mold cavity, and the injection liquid and the nut 500 are integrally formed to obtain the target injection molded product;

[0069] Step 8: The movable mold 210 is driven to separate from the fixed mold 220 again, and the target injection molded product is taken out.

[0070] It should be noted that in the process of placing the nut 500 into the molding hole 221, the limiting pin 231 will be inserted into the paraffin layer 510, and the paraffin layer 510 will wrap the limiting pin 231 and fill the gap between the limiting pin 231 and the nut 500, so that the nut 500 can be "temporarily" fixed in the molding hole 221, avoiding the position of the nut 500 from being changed due to the impact of the injection liquid during the injection molding process.

[0071] It should be emphasized that the melting point of paraffin is between 50°C and 60°C, while the temperature of the injection molding liquid is above 100°C. When the injection molding liquid just enters the molding hole 221, the paraffin layer 510 has not yet melted, that is, the paraffin layer 510 is temporarily solid at this time, and the paraffin layer 510 fills the gap between the limit pin 231 and the nut 500, so that the nut 500 lacks movable space, thereby ensuring that the position of the nut 500 does not shift during the injection process. On the other hand, since the paraffin layer 510 fills the gap between the limit pin 231 and the nut 500, the injection molding liquid cannot penetrate, thereby ensuring that the internal thread in the nut 500 is intact.

[0072] It needs to be emphasized again that after the injection molding liquid fills the mold cavity, the temperature of the entire mold rises. When the mold temperature rises to the melting point of paraffin, the paraffin layer 510 begins to melt, and the paraffin changes from solid to liquid until the paraffin layer 510 disappears. The connection between the limit pin 231 and the nut 500 is released, that is, the nut 500 is no longer connected to the limit pin 231. In the process of removing the target injection molded product, the limit pin 231 will not generate resistance to pull the nut 500, which facilitates the demolding of the injection molded product and avoids the nut 500 from falling off the screw column 21 due to the pulling force during the demolding process, thereby ensuring the injection molding quality.

[0073] When taking out the injection molded product, it is necessary to separate the movable mold 210 from the fixed mold 220 again. After taking out the injection molded product, the molding hole 221 is exposed. At this time, high-pressure gas can be sprayed toward the location of the molding hole 221 to blow away the liquid paraffin remaining in it, keeping the inside of the molding hole 221 clean.

[0074] Furthermore, during the injection molding process, a paraffin layer 510 is filled in the nut 500. After the paraffin layer 510 is melted by the injection molding liquid, a small amount of paraffin will remain on the internal thread. The paraffin can be used as a lubricant to facilitate the subsequent screw locking. It is beneficial for the outer teeth on the screw to enter the internal thread more smoothly, which is beneficial to reduce the impact force on the screw column 21 during the screw locking process, thereby reducing the probability of the screw column 21 cracking due to torsional force.

[0075] See also Figure 6 In one embodiment, an anti-slip pattern 520 is provided on the outer wall of the nut 500 . During injection molding, the anti-slip pattern 520 is embedded in the screw column 21 to prevent the nut 500 and the screw column 21 from rotating relative to each other.

[0076] See also Figure 3 In one embodiment, a gear rack transmission assembly 370 and a drag chain 380 are provided at the connection between the feed guide rail 320 and the lateral displacement guide rail 330 and at the connection between the lateral displacement guide rail 330 and the longitudinal displacement guide rail 340 .

[0077] See also Figure 3In one embodiment, a control panel 311 is disposed on the fixing base 310 , and the movement parameters of the robot arm 300 can be adjusted through the control panel 311 .

[0078] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A plastic product injection molding production line, characterized in that: include: CNC machine tools, molds, robotic arms, conveyor belts, and several nuts on the conveyor belts; The mold includes a movable mold and a fixed mold, and the CNC machine tool is used to drive the movable mold to approach or move away from the fixed mold; The conveyor belt moves toward an opening for driving the nut close to the CNC machine tool; The mechanical arm comprises a fixed seat, a feed guide rail, a transverse displacement guide rail, a longitudinal displacement guide rail and a mechanical claw, wherein the fixed seat is arranged on the outer wall of the CNC machine tool, the feed guide rail is arranged on the fixed seat, and the feed guide rail extends toward the inner cavity of the CNC machine tool, the transverse displacement guide rail is arranged on the feed guide rail, the longitudinal displacement guide rail is arranged on the transverse displacement guide rail, and the mechanical claw is rotatably arranged at the lower end of the longitudinal displacement guide rail; The mechanical claw is provided with a negative pressure suction nozzle, and the negative pressure suction nozzle is used to pick up the nut on the conveyor belt and place the nut in the fixed mold; The inner side of the nut is filled with a paraffin layer, the center of the paraffin layer has a through hole, the fixed mold is provided with a forming hole, a demoulding insert is provided in the forming hole, a limiting pin is provided at the end of the demoulding insert, and the limiting pin is used to penetrate the paraffin layer.

2. The plastic product injection molding production line according to claim 1, characterized in that: The diameter of the limiting pin is smaller than the diameter of the through hole.

3. The plastic product injection molding production line according to claim 1, characterized in that: The diameter of the forming hole is larger than the diameter of the demoulding insert.

4. The plastic product injection molding production line according to claim 1, characterized in that: Anti-slip grooves are arranged on the outer wall of the nut.

5. The plastic product injection molding production line according to claim 1, characterized in that: The negative pressure suction nozzle comprises a telescopic rod and a suction head, wherein a blind hole is provided on the suction head, and a depth of the blind hole is less than a length of the nut.

6. The plastic product injection molding production line according to claim 1, characterized in that: A gear rack transmission assembly is provided at the connection between the feed guide rail and the lateral displacement guide rail, and at the connection between the lateral displacement guide rail and the longitudinal displacement guide rail.

7. The plastic product injection molding production line according to claim 1, characterized in that: A drag chain is provided at the connection between the feed guide rail and the lateral displacement guide rail and at the connection between the lateral displacement guide rail and the longitudinal displacement guide rail.

8. The plastic product injection molding production line according to claim 1, characterized in that: A control panel is arranged on the fixing seat.

9. A production method, characterized in that: The plastic product injection molding production line according to any one of claims 1 to 8 comprises the following steps: Step 1: Fill the nut with paraffin to form a paraffin layer in the inner cavity of the nut, and transfer the nut with the paraffin layer to a conveyor belt, which conveys the nut to the location of the CNC machine tool; Step 2: The CNC machine tool separates the movable mold from the fixed mold; Step 3: The robotic arm starts, the robotic claw descends, and the negative pressure nozzle picks up the nut; Step 4: After the mechanical claw rises and returns to its original position, turn the mechanical claw 90°; Step 5: The feed guide rail is started to drive the mechanical claw into the inner cavity of the CNC machine tool, so that the negative pressure suction nozzle faces the forming hole; Step 6: Drive the mechanical claw close to the fixed mold, insert the limit pin into the paraffin layer until the nut abuts against the end of the demoulding insert; Step 7: driving the mechanical claw to leave the inner cavity of the CNC machine tool, and the CNC machine tool closes the movable mold and the fixed mold, injecting the injection liquid into the mold cavity, and the injection liquid and the nut are integrally formed to obtain the target injection molded product; Step 8: Drive the movable mold and the fixed mold to separate again, and take out the target injection molded product.

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