A plastic insert molding process for electronic components

Abstract

The application relates to the technical field of plastic insert forming process, and discloses an electronic component plastic insert forming process, which comprises the steps of insert pretreatment, mold preparation, precise positioning, injection molding, cooling and shaping, demolding and taking and post-treatment. Through optimization of insert surface design, development of a high-precision positioning system and innovation of injection process parameters, precise forming of a micro metal insert in a plastic base body is realized. The process can make the positioning precision of products reach + / -0.01 mm, the torque performance be improved by more than 30%, and the yield rate reach 99.5%, and is particularly suitable for forming small screw inserts of electronic equipment such as mobile phones and notebook computers.

Description

Technical Field

[0001] This invention relates to the field of plastic product molding technology, specifically to a molding process for plastic inserts for electronic components. Background Technology

[0002] With the trend towards lighter and smaller electronic devices, embedding threaded metal inserts into plastic parts has become a common structural design. Traditional insert molding processes present the following technical challenges:

[0003] Insufficient positioning accuracy of the insert causes the thread axis to shift, affecting subsequent assembly;

[0004] Plastic shrinkage causes inserts to loosen, resulting in a decrease in torque and tensile strength.

[0005] Thin-walled areas are prone to defects such as shrinkage marks and stress cracking.

[0006] Low production efficiency makes it difficult to guarantee the yield rate.

[0007] Existing technologies such as CN108582648A disclose a plastic insert injection molding process, but they do not solve the molding problem of small inserts (M1-M2.5) in precision electronic components. Electronic devices have an increasing demand for micro inserts, but existing processes are difficult to meet their high precision requirements. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] To address the shortcomings of existing technologies, this invention provides a molding process for plastic inserts of electronic components, which has advantages such as high precision and high reliability, and solves problems such as poor insert positioning accuracy and low torque tensile strength.

[0010] (II) Technical Solution

[0011] To achieve the objectives of high tensile strength and good positioning accuracy of the insert, the present invention provides the following technical solution:

[0012] A molding process for plastic inserts for electronic components includes the following steps:

[0013] S1. Insert pretreatment: Select suitable metal inserts and perform surface cleaning and activation treatment;

[0014] S2. Mold Preparation: Design and manufacture a special mold, which includes an upper mold, a lower mold, and an insert positioning system;

[0015] S3. Insert positioning: The pre-treated insert is precisely placed into the mold cavity using a positioning system;

[0016] S4. Injection molding: Molten plastic material is injected into the mold cavity to cover the insert and form an integral structure;

[0017] S5. Cooling and Shaping: Maintain mold pressure to ensure the product cools and sets fully;

[0018] S6. Demolding and Part Removal: Open the mold and remove the molded product;

[0019] S7. Post-processing: Repairing and quality inspection of the product.

[0020] Preferably, the metal insert in step S1 is made of brass JIS 3604, stainless steel SUS303, or aluminum alloy.

[0021] Preferably, the surface activation treatment in step S1 includes electroless nickel plating, zinc-nickel alloy plating, or passivation treatment.

[0022] Preferably, the insert positioning system in step S1 adopts a tapered positioning structure, and the positioning accuracy reaches ±0.01mm.

[0023] Preferably, the plastic material in step S4 is PPS, ABS, PP, PC, or PA engineering plastic.

[0024] Preferably, in step S4, a multi-stage injection molding process is used, with an injection pressure of 80-120 MPa and a mold temperature of 80-150℃.

[0025] Preferably, the cooling time in step S5 is the plastic wall thickness (mm) × (8-12) seconds.

[0026] Preferably, it also includes a secondary processing step performed after step S7, including thread repair, dimensional finishing or surface treatment.

[0027] (III) Beneficial Effects

[0028] Compared with the prior art, the present invention provides a molding process for plastic inserts of electronic components, which has the following beneficial effects:

[0029] This electronic component plastic insert molding process achieves an insert positioning accuracy of ±0.01mm, meeting the requirements for micro threaded inserts, improving torque performance by more than 30%, increasing tensile strength by 25%, achieving a product yield of over 99.5%, and shortening the molding cycle by 20%. Attached Figure Description

[0030] Figure 1 This is a process flow diagram of the present invention;

[0031] Figure 2 This is a schematic diagram of a typical insert structure of the present invention;

[0032] Figure 3 This is a schematic diagram of the multi-segment injection pressure curve during injection molding of the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: M1.6 Insert Molding for Mobile Phone Casing

[0035] Materials preparation:

[0036] 1. Insert: Mini-Tek series MT-M1.6x3.0-OD2.5B, made of brass C3604, with zinc-nickel alloy plating.

[0037] 2. Plastic: 30% glass fiber reinforced PA6

[0038] Process steps:

[0039] 1. Insert pretreatment:

[0040] Ultrasonic cleaning removes oil stains

[0041] • Chemically plated zinc-nickel alloy (thickness 3-5μm)

[0042] Dry at 120℃ for 30 minutes

[0043] 2. Mold preparation:

[0044] The mold core is made of SKD61 steel with a hardness of HRC52-54.

[0045] • Locating pin diameter 2.50±0.003mm

[0046] • Mold temperature controller maintains mold temperature at 100±2℃

[0047] 3. Insert positioning:

[0048] • Use robotic arms for automatic material feeding

[0049] • The taper positioning system ensures coaxiality ≤ 0.01mm

[0050] Vacuum adsorption fixing insert

[0051] 4. Injection molding:

[0052] • Barrel temperature: 260 / 270 / 280 / 265℃

[0053] Injection pressure: Three-stage (100 / 85 / 70MPa)

[0054] • Holding pressure: 50MPa, time: 3 seconds. • Cooling and shaping:

[0055] Cooldown time: 25 seconds

[0056] • Adopts conformal cooling water channel design

[0057] 6. Demolding and part removal:

[0058] • Ejection speed 10mm / s

[0059] ·Automatic part picking by robotic arms

[0060] 7. Post-processing:

[0061] Laser deburring

[0062] • Coordinate measuring machine for key dimensions

[0063] Torque test (pass standard ≥ 0.3 N·m)

[0064] Test results:

[0065] • Insert coaxiality: 0.008mm

[0066] Torque performance: 0.38 N·m

[0067] • Tensile strength: 210N

[0068] • No surface defects such as shrinkage marks or bubbles

[0069] Example 2: M3 Insert Molding for Notebook Computers

[0070] Materials preparation:

[0071] • Insert: ST-M3x5.7-OD4.4SS, made of SUS303 stainless steel.

[0072] • Plastics: Flame-retardant PC / ABS alloy

[0073] Process improvement points:

[0074] 1. Plasma activation treatment is performed on the surface of the insert.

[0075] 2. Use hot runner molds to reduce material loss.

[0076] 3. Real-time monitoring by in-mold pressure sensor

[0077] 4. Pulse pressure control is used during the pressure holding stage.

[0078] Effect verification:

[0079] • Production cycle time reduced from 45 seconds to 36 seconds

[0080] • Material utilization rate increased by 15%

[0081] • Product weight consistency ±0.02g

[0082] Example 3: Molding of M6 Automotive Sensor Insert

[0083] Special process:

[0084] 1. Preheat inserts to 150°C to reduce thermal stress.

[0085] 2. Gas-assisted molding is used to eliminate shrinkage marks in thick-walled structures.

[0086] 3. Online X-ray inspection of internal defects

[0087] Reliability testing:

[0088] • Passed 1000 thermal cycling tests (-40℃~125℃)

[0089] No corrosion after 500 hours of salt spray testing.

[0090] Vibration testing conforms to ISO 16750 standard.

[0091] Technological Innovation Points

[0092] 1. Precision positioning technology:

[0093] A "secondary positioning" system based on tapered fit was developed.

[0094] A servo motor-driven fine-tuning mechanism achieves a positioning accuracy of 0.005mm, while an embedded sensor provides real-time position feedback.

[0095] 2. Interface integration enhancement technology:

[0096] Optimize the knurling design of inserts (such as diamond knurling and reverse spiral knurling) and develop specialized surface treatment processes to improve the bonding strength between plastics and metals.

[0097] Controlling the crystallization morphology of plastic on the insert surface

[0098] 3. Process control technology:

[0099] Establish a mathematical model of injection molding parameters and product performance.

[0100] Develop an adaptive control system to adjust process parameters in real time.

[0101] Optimize production parameters using machine learning algorithms

[0102] The comparative experiment selected three mainstream processes on the market and compared them with the present invention:

[0103]

[0104] Experimental data show that the present invention is significantly superior to the prior art in all key indicators.

[0105] Technical Effects: The electronic component plastic insert molding process of the present invention has the following outstanding advantages:

[0106] 1. High precision:

[0107] Achieving precision molding of micro inserts (M1-M3)

[0108] Positional tolerance is controlled within ±0.01mm.

[0109] Thread coaxiality reaches 0.005mm

[0110] 2. High strength:

[0111] Torque performance improved by 30-50%

[0112] The tensile strength reaches 150% of the standard requirement.

[0113] 3. High efficiency: Passes rigorous environmental reliability testing.

[0114] High degree of automation reduces manual intervention and shortens the molding cycle by more than 20%.

[0115] 4. Low cost: Enables continuous 24-hour production

[0116] Material utilization rate reached 98%.

[0117] Mold life exceeds 500,000 cycles

[0118] Overall costs reduced by 15-20%

[0119] Industrial Applications: This technology has been successfully applied in the following fields:

[0120] 1. Consumer electronics:

[0121] Smartphone casing threaded insert

[0122] Laptop stand connector

[0123] Smartwatch charging port 2. Automotive electronics:

[0124] Sensor housing

[0125] Car display bracket

[0126] ECU connector

[0127] 3. Medical equipment:

[0128] Portable detector casing

[0129] Surgical instrument handles

[0130] Medical connectors

[0131] Practical application cases show that products manufactured using this process have significant improvements in assembly efficiency, connection reliability, and service life.

[0132] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A molding process for plastic inserts of electronic components, characterized in that, Includes the following steps: S1. Insert pretreatment: Select suitable metal inserts and perform surface cleaning and activation treatment; S2. Mold Preparation: Design and manufacture a special mold, which includes an upper mold, a lower mold, and an insert positioning system; S3. Insert positioning: The pre-treated insert is precisely placed into the mold cavity using a positioning system; S4. Injection molding: Molten plastic material is injected into the mold cavity to cover the insert and form an integral structure; S5. Cooling and Shaping: Maintain mold pressure to ensure the product cools and sets fully; S6. Demolding and Part Removal: Open the mold and remove the molded product; S7. Post-processing: Repairing and quality inspection of the product.

2. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, The metal insert mentioned in step S1 is made of brass JIS 3604, stainless steel SUS303 or aluminum alloy.

3. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, The surface activation treatment in step S1 includes electroless nickel plating, zinc-nickel alloy plating, or passivation treatment.

4. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, The insert positioning system described in step S1 adopts a tapered positioning structure, and the positioning accuracy reaches ±0.01mm.

5. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, The plastic material mentioned in step S4 is PPS, ABS, PP, PC or PA engineering plastic.

6. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, In step S4, a multi-stage injection process is used during injection molding, with an injection pressure of 80-120MPa and a mold temperature of 80-150℃.

7. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, The cooling time in step S5 is the plastic wall thickness (mm) × (8-12) seconds.

8. The molding process for plastic inserts of electronic components according to claim 1, characterized in that, It also includes secondary processing steps performed after step S7, including thread repair, dimensional finishing, or surface treatment.

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