Method for plasma treatment of injection molded part

Abstract

The invention relates to the technical field of automobile plastic part processing, in particular to a method for plasma treatment of an injection molded part, which comprises the following steps: producing the automobile injection molded part through injection molding, constructing a mathematical model about surface tension, and determining plasma processing equipment; and processing the automobile injection molding part at a set plasma processing speed by using plasma processing equipment, monitoring the distance between the plasma and the automobile injection molding part in real time, calculating the target distance between the plasma and the automobile injection molding part according to the target surface tension and the constructed mathematical model, and adaptively adjusting to the target distance. Plasma is used for bombarding the surface of the automobile injection-molded part, deburring of the automobile injection-molded part is achieved, meanwhile, oxygen-containing and nitrogen-containing functional groups are introduced into the surface of the automobile injection-molded part through the plasma, the surface polarity is increased, the coating adhesive force is improved, the target surface tension can be obtained through self-adaptive adjustment by means of the pre-constructed mathematical model, and therefore the surface tension of the automobile injection-molded part is improved. And the automation degree of the plasma processing process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of automobile plastic parts processing, and more specifically, to a method for plasma processing injection molded parts. Background Art

[0002] Among automotive parts made of plastic, external parts need to be pre-treated to remove burrs before being painted to add aesthetic elements to the functionality. However, the adhesion between injection molded parts and paint is insufficient, and primer is usually required to improve the adhesion between the injection molded parts and the paint, resulting in many operation steps and a long time consumption.

[0003] Plasma is the fourth state of matter. When gas molecules absorb a certain amount of energy, they exist in the form of charged particles (anions or cations, free radicals, electrons) and neutral particles (atoms). Since this plasma exists in a high-energy and highly reactive state, it has the property of reacting rapidly with other materials. By utilizing the properties of this plasma, the properties of the solid surface can be chemically changed.

[0004] The prior art discloses a method for painting a plastic wheel cover by flame plasma surface treatment, which performs flame plasma surface treatment by using the mixing ratio of air / LPG or air / LNG introduced into an external plastic injection molded product, the distance between the plasma source and the external plastic injection molded product, the plasma treatment speed, and the mixing amount of the gas as variables. In this scheme, conventional pretreatment and primer processes can be omitted by using flame plasma surface treatment, however, in this scheme, the variable values ​​cannot be adaptively adjusted, and the degree of automation is low. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiency of low automation degree of plasma treatment of injection molded parts in the prior art, and to provide a method for plasma treatment of injection molded parts. While utilizing plasma treatment to improve the coating adhesion of the surface of automobile injection molded parts, the plasma processing equipment can be adaptively adjusted to improve the automation degree of the plasma processing process.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for plasma treating an injection molded part is provided, comprising the following steps:

[0008] S1: According to the process requirements, select the resin raw materials for automobile injection molding processing, and produce automobile injection molding parts by injection molding;

[0009] S2: Construct a mathematical model of the surface tension Y with respect to the distance D between the plasma and the automotive injection molded part and the plasma processing speed V for the plasma processing equipment, and determine the plasma processing equipment;

[0010] S3: using plasma processing equipment to process automobile injection molded parts at a set plasma processing speed V, monitoring the distance D between the plasma and the automobile injection molded parts in real time during the processing, and calculating the target distance between the plasma and the automobile injection molded parts according to the target surface tension and the constructed mathematical model;

[0011] S4: Adaptively adjusting a plasma gun head for emitting plasma in a plasma processing device according to the calculated target distance, so that a distance D between the plasma and the surface of the automobile injection molded part is the target distance.

[0012] The method for plasma treatment of injection molded parts of the present invention utilizes plasma emitted by plasma processing equipment to bombard the surface of automobile injection molded parts to achieve deburring of automobile injection molded parts. At the same time, the plasma introduces oxygen-containing and nitrogen-containing functional groups into the surface of automobile injection molded parts to increase surface polarity and improve coating adhesion. Moreover, through a pre-constructed mathematical model, adaptive adjustment can be made during the processing to obtain the target surface tension, thereby improving the degree of automation of the plasma processing process.

[0013] Preferably, in step S2, the mathematical model constructed is:

[0014] Y=k1D 2 +k2D+k3V -0.143 -146

[0015] Wherein, Y represents the surface tension of automobile injection molded parts; D represents the distance between plasma and automobile injection molded parts; V represents the processing speed of plasma; k1, k2, and k3 are all constants, and the value range of k1 is -0.425 to -0.490, the value range of k2 is 18.00 to 18.50, and the value range of k3 is 11.00 to 12.00.

[0016] Preferably, in step S1, the resin raw material is modified polypropylene.

[0017] Preferably, in step S1, the thickness of the automobile injection molded part is 2.0 mm to 3.4 mm.

[0018] Preferably, in step S3, the parameters of the plasma processing equipment include: the plasma flame width is 5mm-15mm, the plasma flame height is 30mm-40mm, the plasma power is 100W-1000W, the input gas pressure is not less than 0.6MPa, the input voltage is 220V, and the frequency of the input voltage is 50Hz.

[0019] Preferably, in step S3, the distance between the plasma and the automobile injection molded part allowed by the plasma processing equipment is 10 mm to 24 mm.

[0020] Preferably, in step S3, the plasma processing speed allowed by the plasma processing equipment is 275 mm / s to 625 mm / s.

[0021] Preferably, in step S3, the plasma power is 900W.

[0022] Preferably, the value of k1 is -0.475, the value of k2 is 18.27, and the value of k3 is 11.87.

[0023] Preferably, in step S2, the process of constructing the mathematical model is:

[0024] S201: Start the plasma processing equipment to grab the injection molded parts for testing, and determine the basic process parameters of the plasma processing equipment according to the burr treatment effect of the injection molded parts and the coating adhesion test quality requirements to be achieved;

[0025] S202: using a control variable method, activating a plasma processing device for testing, performing plasma treatment on a test injection molded part, setting different distances D between the plasma and the test injection molded part and different plasma treatment speeds V during the test, using a laser displacement sensor for data collection, and measuring the surface tension Y of the test injection molded part after each parameter adjustment test;

[0026] S203: According to the parameters adjusted each time and the measured surface tension, the relationship between the surface tension Y and the distance D between the plasma and the test injection molded part and the plasma processing speed V is measured.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] Plasma is used to bombard the surface of automotive injection molded parts to achieve deburring of automotive injection molded parts. At the same time, plasma will introduce oxygen- and nitrogen-containing functional groups to the surface of automotive injection molded parts, increase surface polarity, and improve coating adhesion. Through the pre-constructed mathematical model, the plasma processing equipment can be adaptively adjusted during the processing to obtain the target surface tension, thereby improving the degree of automation of the plasma processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flow chart of a method for plasma treatment of injection molded parts in an embodiment of the present invention;

[0030] Figure 2 is a fitting curve diagram of the surface tension and the distance between the plasma and the automobile injection molded part in the first embodiment of the present invention;

[0031] Figure 3 This is a fitting curve diagram of surface tension and plasma processing speed in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with specific implementation modes.

[0033] Embodiment 1

[0034] This embodiment is the first embodiment of the method for plasma treatment of injection molded parts. Figure 1 As shown, the following steps are included:

[0035] S1: According to the process requirements, select the resin raw materials for automobile injection molding processing, and produce automobile injection molding parts by injection molding;

[0036] S2: Construct a mathematical model of the surface tension Y with respect to the distance D between the plasma and the automotive injection molded part and the plasma processing speed V for the plasma processing equipment, and determine the plasma processing equipment;

[0037] S3: using plasma processing equipment to process automobile injection molded parts at a set plasma processing speed V, monitoring the distance D between the plasma and the automobile injection molded parts in real time during the processing, and calculating the target distance between the plasma and the automobile injection molded parts according to the target surface tension and the constructed mathematical model;

[0038] S4: Adaptively adjusting a plasma gun head for emitting plasma in a plasma processing device according to the calculated target distance, so that a distance D between the plasma and the surface of the automobile injection molded part is the target distance.

[0039] The above-mentioned method of plasma treatment of injection molded parts utilizes the plasma emitted by plasma processing equipment to bombard the surface of automobile injection molded parts to achieve deburring of automobile injection molded parts. At the same time, the plasma will introduce oxygen- and nitrogen-containing functional groups into the surface of automobile injection molded parts, increase surface polarity, and improve coating adhesion. In addition, through the pre-constructed mathematical model, adaptive adjustments can be made during the processing to obtain the target surface tension, thereby improving the degree of automation of the plasma processing process.

[0040] In step S2, the mathematical model constructed is:

[0041] Y=k1D 2 +k2D+k3V -0.143 -146

[0042] In the formula, Y represents the surface tension of the automobile injection molded part; D represents the distance between the plasma and the automobile injection molded part; V represents the plasma processing speed; k1, k2, and k3 are all constants, and the value range of k1 is -0.425 to -0.490, the value range of k2 is 18.00 to 18.50, and the value range of k3 is 11.00 to 12.00. It should be noted that if different types and brands of resin raw materials are selected for plasma treatment, the constants k1, k2, and k3 can change accordingly within the corresponding numerical range.

[0043] In step S1, the resin raw material is modified polypropylene, the modified polypropylene material nose is 1.03-1.05, the melt index MI is 40g / min-48g / min, and the modified polypropylene has good dimensional and chemical stability, meeting the mechanical properties, impact resistance, and mechanical properties requirements required by the product.

[0044] In step S1, the thickness of the automobile injection molded part is 2.0 mm to 3.4 mm.

[0045] In step S2, the parameters of the plasma processing equipment include: the plasma flame width is 5mm-15mm, the plasma flame height is 30mm-40mm, the plasma power is 100W-1000W, the input gas pressure is not less than 0.6MPa, the input voltage is 220V, and the frequency of the input voltage is 50Hz.

[0046] The distance between plasma and automobile injection molded parts allowed by plasma processing equipment is 10mm~24mm, the plasma processing speed allowed by plasma processing equipment is 275mm / s~625mm / s, and the plasma power is 900W, which not only ensures the resin burr processing, but also avoids the fire quality of automobile injection molded parts affected by excessive temperature.

[0047] In this embodiment, the process of constructing the mathematical model is:

[0048] S201: Start the plasma processing equipment to grab the test injection molded parts, and determine the basic process parameters of the plasma processing equipment according to the burr treatment effect of the test injection molded parts and the required coating adhesion test quality requirements; among which, the vacuum pressure is selected to be 2.0MPa and the plasma power is 900W;

[0049] S202: Using the control variable method, starting the plasma processing equipment for testing, performing plasma treatment on the test injection molded part, setting different distances D between the plasma and the test injection molded part and different plasma treatment speeds V during the test, using a laser displacement sensor for data collection, and measuring the surface tension Y of the test injection molded part after each parameter adjustment test; specifically:

[0050] When the plasma processing speed V is kept constant, the distance D between the plasma and the test injection molded part is changed from 10mm to 24mm, with each 1mm as a data point. After each parameter adjustment, the appearance quality of the test injection molded part must be confirmed and the surface tension must be measured. The appearance quality test includes the appearance test of whether there are burrs remaining and over-fire conditions. The Dyne pen is used to test the treated position, and the relationship between the surface tension Y and the distance D between the plasma and the test injection molded part is recorded. After a set of curves are measured, the plasma processing speed V is adjusted to another constant value, and the next set of curves is measured. Similarly, when the distance D between the plasma and the test injection molded part is constant, the plasma processing speed V is changed from 275mm / s to 625mm / s, with a step length of 25mm / s, and the relationship between the surface tension Y and the plasma processing speed V is measured. The test injection molded part with a thickness of 2.2mm is tested, and the test results are shown in Table 1:

[0051] Table 1 Changes in surface tension of injection molded parts after testing

[0052]

[0053] According to the test data in Table 1, a fitting curve diagram of the YDV relationship is drawn, such as Figure 2 , Figure 3 shown.

[0054] S203: According to the parameters adjusted each time and the measured surface tension, the relationship between the surface tension Y and the distance D between the plasma and the test injection molded part and the plasma processing speed V is measured:

[0055] Y=-0.475D 2 +18.27D+11.87V -0.143 -146.

[0056] Embodiment 2

[0057] This embodiment is the second embodiment of the method for plasma processing injection molded parts, which prepares injection molded parts with a thickness of 2.2 mm to ensure that their surfaces are smooth and free of defects; the injection molded parts are placed on plasma processing equipment, and the target surface tension is adjusted to 57 dynes / cm to ensure that the injection molded parts are stable during processing; the plasma processing speed is set to 500 mm / s so that the plasma processing equipment performs uniform processing along the surface of the injection molded parts, and the flame width is adjusted to 10 mm to ensure that the flame covers the surface of the injection molded parts during processing; the plasma height is adjusted to 35 mm to maintain an appropriate distance between the plasma and the surface of the injection molded parts; the plasma processing equipment is turned on, the plasma power is set to 900 W, the injection molded parts are processed, and the plasma pressure is adjusted to 0.6 MPa to optimize the processing effect. The processing process shows that the distance between the adjusted plasma and the injection molded parts is 18 mm. After inspection, the burrs of the injection molded parts are removed, the surface tension is improved, and the expected effect is achieved.

[0058] Embodiment 3

[0059] This embodiment is the third embodiment of the method for plasma processing injection molded parts. This embodiment is similar to the second embodiment, except that an injection molded part with a thickness of 3.4 mm is prepared to ensure that its surface is smooth and defect-free; the injection molded part is placed on the plasma processing equipment, and the target surface tension is adjusted to 59 dynes / cm to ensure that the injection molded part is stable during the processing; the plasma processing speed is set to 625 mm / s so that the plasma processing equipment performs uniform processing along the surface of the injection molded part, and the flame width is adjusted to 15 mm to ensure that the flame covers the surface of the injection molded part during the processing; the plasma height is adjusted to 40 mm to keep an appropriate distance between the plasma and the surface of the injection molded part; the plasma processing equipment is turned on, the plasma power is set to 1000 W, the injection molded part is processed, and the plasma pressure is adjusted to 2.0 MPa to optimize the processing effect. The processing process shows that the distance between the adjusted plasma and the injection molded part is 20 mm. After inspection, the burrs of the injection molded part are removed, the surface tension is improved, and the expected effect is achieved.

[0060] Embodiment 4

[0061] This embodiment is the fourth embodiment of the method for plasma processing injection molded parts. This embodiment is similar to the second embodiment, except that an injection molded part with a thickness of 2.0 mm is prepared to ensure that its surface is smooth and defect-free; the injection molded part is placed on the plasma processing equipment, and the target surface tension is adjusted to 43 dynes / cm to ensure that the injection molded part is stable during the processing; the plasma processing speed is set to 275 mm / s so that the plasma processing equipment performs uniform processing along the surface of the injection molded part, and the flame width is adjusted to 5 mm to ensure that the flame covers the surface of the injection molded part during the processing; the plasma height is adjusted to 30 mm to keep an appropriate distance between the plasma and the surface of the injection molded part; the plasma processing equipment is turned on, the plasma power is set to 1000 W, the injection molded part is processed, and the plasma pressure is adjusted to 0.6 MPa to optimize the processing effect. The processing process shows that the distance between the adjusted plasma and the injection molded part is 14 mm. After inspection, the burrs of the injection molded part are removed, the surface tension is improved, and the expected effect is achieved.

[0062] Embodiment 5

[0063] This embodiment is the fifth embodiment of the method for plasma processing injection molded parts. This embodiment is similar to the second embodiment, except that an injection molded part with a thickness of 2.8 mm is prepared to ensure that its surface is smooth and defect-free; the injection molded part is placed on the plasma processing equipment, and the target surface tension is adjusted to 52 dynes / cm to ensure that the injection molded part is stable during the processing; the plasma processing speed is set to 500 mm / s so that the plasma processing equipment performs uniform processing along the surface of the injection molded part, and the flame width is adjusted to 9 mm to ensure that the flame covers the surface of the injection molded part during the processing; the plasma height is adjusted to 35 mm to maintain an appropriate distance between the plasma and the surface of the injection molded part; the plasma processing equipment is turned on, the plasma power is set to 1000 W, the injection molded part is processed, and the plasma pressure is adjusted to 0.65 MPa to optimize the processing effect. The processing process shows that the distance between the adjusted plasma and the injection molded part is 15 mm. After inspection, the burrs of the injection molded part are removed, the surface tension is improved, and the expected effect is achieved.

[0064] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for plasma treatment of injection molded parts, characterized in that: The following steps are involved: S1: According to the process requirements, select the resin raw materials for automobile injection molding processing, and produce automobile injection molding parts by injection molding; S2: Construct a mathematical model of the surface tension Y with respect to the distance D between the plasma and the automotive injection molded part and the plasma processing speed V for the plasma processing equipment, and determine the plasma processing equipment; S3: using plasma processing equipment to process automobile injection molded parts at a set plasma processing speed V, monitoring the distance D between the plasma and the automobile injection molded parts in real time during the processing, and calculating the target distance between the plasma and the automobile injection molded parts according to the target surface tension and the constructed mathematical model; S4: Adaptively adjusting a plasma gun head for emitting plasma in a plasma processing device according to the calculated target distance, so that a distance D between the plasma and the surface of the automobile injection molded part is the target distance.

2. The method for plasma treatment of injection molded parts according to claim 1, characterized in that: In step S2, the mathematical model constructed is: Y=k1D 2 +k2D+k3V -0.143 -146 Wherein, Y represents the surface tension of automobile injection molded parts; D represents the distance between plasma and automobile injection molded parts; V represents the plasma processing speed; k1, k2, and k3 are all constants, and the value range of k1 is -0.425 to -0.490, the value range of k2 is 18.00 to 18.50, and the value range of k3 is 11.00 to 12.

00.

3. The method for plasma treatment of injection molded parts according to claim 2, characterized in that: In step S1, the resin raw material is modified polypropylene.

4. The method for plasma treatment of injection molded parts according to claim 3, characterized in that: In step S1, the thickness of the automobile injection molded part is 2.0 mm to 3.4 mm.

5. The method for plasma treatment of injection molded parts according to claim 4, characterized in that: In step S3, the parameters of the plasma processing equipment include: plasma flame width of 5mm-15mm, plasma flame height of 30mm-40mm, plasma power of 100W-1000W, input gas pressure of not less than 0.6MPa, input voltage of 220V, and input voltage frequency of 50Hz.

6. The method for plasma treatment of injection molded parts according to claim 5, characterized in that: In step S3, the distance D between the plasma and the automobile injection molded part allowed by the plasma processing equipment is 10 mm to 24 mm.

7. The method for plasma treatment of injection molded parts according to claim 6, characterized in that: In step S3, the plasma processing speed V allowed by the plasma processing equipment is 275 mm / s to 625 mm / s.

8. The method for plasma treatment of injection molded parts according to claim 7, characterized in that: In step S3, the plasma power is 900W.

9. The method for plasma treatment of injection molded parts according to claim 8, characterized in that: The value of k1 is -0.475, the value of k2 is 18.27, and the value of k3 is 11.

87.

10. The method for plasma treating an injection molded part according to any one of claims 1 to 9, characterized in that: In step S2, the process of constructing the mathematical model is: S201: Start the plasma processing equipment to grab the injection molded parts for testing, and determine the basic process parameters of the plasma processing equipment according to the burr treatment effect of the injection molded parts and the coating adhesion test quality requirements to be achieved; S202: using a control variable method, activating a plasma processing device for testing, performing plasma treatment on a test injection molded part, setting different distances D between the plasma and the test injection molded part and different plasma treatment speeds V during the test, using a laser displacement sensor for data collection, and measuring the surface tension Y of the test injection molded part after each parameter adjustment test; S203: According to the parameters adjusted each time and the measured surface tension, the relationship between the surface tension Y and the distance D between the plasma and the test injection molded part and the plasma processing speed V is measured.

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