Injection molding process for automobile wire harness production

Abstract

The invention discloses an injection molding process for automobile wire harness production, and relates to the technical field of injection molding, and the injection molding process for automobile wire harness production comprises the following steps: step 1, raw material preparation; step 2, preparing an insert; thirdly, a mold is prepared; 4, injection molding is conducted; and 5, post-processing and detecting. Sixthly, machining is completed; through raw material preparation and pretreatment work, selected material batches can be cleaned, impurities adhered to the surfaces of the materials are removed, then the materials are dried, water in the materials is removed, the pretreatment efficiency of the materials is effectively improved, meanwhile, bubbles are prevented from occurring after injection molding of products, and product production is improved.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding, and in particular to an injection molding process for producing automobile wiring harnesses. Background Art

[0002] The injection molding process in automotive wiring harness production (commonly known as insert molding or overmolding) is a manufacturing technology that precisely injects molten plastic around pre-placed wires, terminals, connectors and other components. It plays a vital role in automotive wiring harness manufacturing and is mainly used for connector sealing, cable fixation and protection, stress relief and functional integration. The injection molding process in automotive wiring harnesses (insert molding / overmolding) is one of the core technologies for manufacturing high-performance and high-reliability wiring harness components. The key to its success lies in the design and manufacture of precision molds, precise positioning and fixation of inserts, appropriate selection of engineering plastics, and highly optimized control of injection molding process parameters.

[0003] The existing technology has the following problems:

[0004] The existing injection molding process for automotive wiring harness production produces automotive wiring harnesses through a process flow of design, material preparation, wiring harness production, injection molding, removal of injection molded parts, and quality inspection. However, the material batches are not cleaned and dried after the wiring harness is selected, resulting in a high moisture content in the material and the proneness to bubbles. At the same time, workers need to remove the wiring harness from the mold during demolding, making material removal difficult and affecting production efficiency. Summary of the Invention

[0005] The present invention provides an injection molding process for producing automobile wiring harnesses to solve the problems raised in the above background technology.

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

[0007] An injection molding process for producing an automotive wiring harness, comprising the following steps:

[0008] Step 1: Prepare raw materials;

[0009] Step 2: Insert preparation;

[0010] Step 3: Mold preparation;

[0011] Step 4: injection molding;

[0012] Step 5: Post-processing and testing;

[0013] Step 6: Processing completed.

[0014] A further improvement of the technical solution of the present invention is that the step 1 further includes the following steps:

[0015] A1: Materials are selected based on the requirements of the automotive industry and production needs. Specific materials include TPE / TPV, PA66, and PBT. The TPE / TPV composition ratio is as follows: base material ≥ 95%, additive flame retardant 8%-12%, antioxidant 0.3%-0.8%, and masterbatch 1%-2%. Furthermore, the material must meet the LV 312-1 flame retardant standard. The PA66 composition ratio is as follows: base material ≥ 93%, additive glass fiber 30%-35%, and PBT composition ratio is as follows: base material ≥ 90%, additive glass fiber 20%-30%, and flame retardant 12%-15%.

[0016] A2: Clean the selected materials in batches and then dry them to remove moisture. Drying: A / PBT: Dehumidifying dryer, 100-120℃ x 4-6 hours, dew point ≤ -40℃; TPE: 60-80℃ x 2-3 hours (anti-caking); Mixing: High-speed mixer (500-800rpm) for 5-8 minutes, color difference ΔE ≤ 0.8;

[0017] A3: Choose different types of masterbatches according to production requirements or customer needs to meet surface color requirements.

[0018] A further improvement of the technical solution of the present invention is that the step 2 further includes the following steps:

[0019] B1: Select wire harnesses and connector housings with pre-installed terminals based on the injection molding requirements. The connector housing positioning requires a positioning tolerance of ±0.05mm, secured by mold locating pins and vacuum adsorption. The wiring harness branch point positioning tolerance is ±0.1mm, secured by a custom fixture and pneumatic grippers.

[0020] B2: Pre-treat the inserts according to the injection molding requirements and production conditions, plasma cleaning (Ar / O2 mixed gas, power 300W×120 seconds) or alcohol wiping. PA / PBT inserts need to be preheated to 80-100℃ (to reduce thermal stress).

[0021] A further improvement of the technical solution of the present invention is that the step three further includes the following steps:

[0022] C1: Select the mold base that matches it according to production requirements;

[0023] C2: Check whether the mold base meets the functional standards according to injection molding and production requirements. The inspection work is divided into whether the gate, exhaust, cooling water channel, ejection mechanism, positioning mechanism and core pulling mechanism are set.

[0024] A further improvement of the technical solution of the present invention is that the step 4 further includes the following steps:

[0025] D1: Install the insert in the mold according to the production standards, and then close the mold;

[0026] D2: The injection molding machine injects the material dissolved in liquid into the mold cavity so that the material wraps the insert and maintains a certain pressure after injection. The typical values ​​of TPE / TPV materials in the plasticizing stage: the barrel temperature should be 160-180-190-195℃, the screw speed is 60-80rpm, the injection stage: the injection pressure is 60-90MPa, the injection speed is 40-60mm / s, the VP switching position is 95% of the cavity filling volume (mm), the holding pressure stage: the holding pressure is 50%-70% of the injection pressure, the holding time is 3-8s, the cooling stage: the mold temperature The typical values ​​for PA66 / PBT are: barrel temperature should be 240-260-270-275℃, screw speed 40-60rpm, injection stage: injection pressure 80-120MPa, injection speed 30-50mm / s, VP switching position 98% cavity filling volume mm, holding stage: holding pressure 60%-80% of injection pressure, holding time 5-15s, cooling stage: mold temperature 70-90℃, cooling time 10-15s / mm;

[0027] D3: After a period of cooling until the material injection is completed, the mold is opened and the product is ejected from the mold through the ejection mechanism. Finally, the burrs at the intersections and other parts of the mold are removed. When TPE / TPV materials are ejected, the ejection speed should be in the range of 10-20 mm / s, and the ejection speed of PA66 / PBT materials should be in the range of 5-15 mm / s.

[0028] A further improvement of the technical solution of the present invention is that the step five further includes the following steps:

[0029] E1: Post-process the product according to production standards, stress relief annealing (for PA / PBT), temperature: 100-120℃ (20℃ lower than the material HDT), time: wall thickness ≤ 3mm → 30 minutes; extend by 15 minutes for each additional 1mm;

[0030] E2: Check the appearance, size and functionality of the product according to the production standards. Functional inspection includes air tightness test, adhesion test, dimensional accuracy test and voltage resistance test. The air tightness test method is air pressure test 0.3MPa×30s. The acceptance standard is leakage ≤0.5mL / min (IP67). The frequency requires 100% full inspection. The adhesion test method is wire pull test. The acceptance standard is ≥80N ( Conductor), frequency is 2 times per shift, dimensional accuracy test method is CMM measurement, acceptance standard key dimension CPK≥1.33, frequency first piece +2h / time, voltage resistance test method is 1500VAC×60s, acceptance standard: no breakdown, frequency is batch sampling.

[0031] Due to the adoption of the above technical solution, the present invention has the following technical advancements compared to the prior art:

[0032] 1. The present invention provides an injection molding process for the production of automotive wiring harnesses. Through raw material preparation and pretreatment, the selected material batches can be cleaned to remove impurities adhering to the material surface, and then the material is dried to remove moisture from the material, thereby effectively improving the pretreatment efficiency of the material, while preventing bubbles from appearing after the product is injected, thereby improving the production quality of the product.

[0033] 2. The present invention provides an injection molding process for the production of automotive wiring harnesses. Through the mutual cooperation between the mold and the ejection mechanism, the mold is opened after the injection molding is completed, and then the ejection mechanism ejects the injection-molded product from the mold. The staff can directly remove the product without the need to laboriously remove the product from the mold, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0035] The present invention is described in further detail below in conjunction with the embodiments:

[0036] Example 1

[0037] like Figure 1 As shown, the present invention provides an injection molding process for producing automobile wiring harnesses, and the injection molding process for producing automobile wiring harnesses includes the following steps:

[0038] Step 1: Prepare raw materials;

[0039] Step 2: Insert preparation;

[0040] Step 3: Mold preparation;

[0041] Step 4: injection molding;

[0042] Step 5: Post-processing and testing;

[0043] Step 6: Processing completed.

[0044] Step 1 also includes the following steps:

[0045] A1: Materials are selected based on the requirements of the automotive industry and production needs. Specific materials include TPE / TPV, PA66, and PBT. The TPE / TPV composition ratio is as follows: base material ≥ 95%, additive flame retardant 8%-12%, antioxidant 0.3%-0.8%, and masterbatch 1%-2%. Furthermore, the material must meet the LV 312-1 flame retardant standard. The PA66 composition ratio is as follows: base material ≥ 93%, additive glass fiber 30%-35%, and PBT composition ratio is as follows: base material ≥ 90%, additive glass fiber 20%-30%, and flame retardant 12%-15%.

[0046] A2: Clean the selected materials in batches and then dry them to remove moisture. Drying: A / PBT: Dehumidifying dryer, 100-120℃ x 4-6 hours, dew point ≤ -40℃; TPE: 60-80℃ x 2-3 hours (anti-caking); Mixing: High-speed mixer (500-800rpm) for 5-8 minutes, color difference ΔE ≤ 0.8;

[0047] A3: Choose different types of masterbatches according to production requirements or customer needs to meet surface color requirements.

[0048] Step 2 also includes the following steps:

[0049] B1: Select wire harnesses and connector housings with pre-installed terminals based on the injection molding requirements. The connector housing positioning requires a positioning tolerance of ±0.05mm, secured by mold locating pins and vacuum adsorption. The wiring harness branch point positioning tolerance is ±0.1mm, secured by a custom fixture and pneumatic grippers.

[0050] B2: Pre-treat the inserts according to the injection molding requirements and production conditions, plasma cleaning (Ar / O2 mixed gas, power 300W×120 seconds) or alcohol wiping. PA / PBT inserts need to be preheated to 80-100℃ (to reduce thermal stress).

[0051] Step three also includes the following steps:

[0052] C1: Select the mold base that matches it according to production requirements;

[0053] C2: Check whether the mold base meets the functional standards according to injection molding and production requirements. The inspection work is divided into whether the gate, exhaust, cooling water channel, ejection mechanism, positioning mechanism and core pulling mechanism are set.

[0054] Step 4 also includes the following steps:

[0055] D1: Install the insert in the mold according to the production standards, and then close the mold;

[0056] D2: The injection molding machine injects the material dissolved in liquid into the mold cavity so that the material wraps the insert and maintains a certain pressure after injection. The typical values ​​of TPE / TPV materials in the plasticizing stage: the barrel temperature should be 160-180-190-195℃, the screw speed is 60-80rpm, the injection stage: the injection pressure is 60-90MPa, the injection speed is 40-60mm / s, the VP switching position is 95% of the cavity filling volume (mm), the holding pressure stage: the holding pressure is 50%-70% of the injection pressure, the holding time is 3-8s, the cooling stage: the mold temperature The typical values ​​for PA66 / PBT are: barrel temperature should be 240-260-270-275℃, screw speed 40-60rpm, injection stage: injection pressure 80-120MPa, injection speed 30-50mm / s, VP switching position 98% cavity filling volume mm, holding stage: holding pressure 60%-80% of injection pressure, holding time 5-15s, cooling stage: mold temperature 70-90℃, cooling time 10-15s / mm;

[0057] D3: After a period of cooling until the material injection is completed, the mold is opened and the product is ejected from the mold through the ejection mechanism. Finally, the burrs at the intersections and other parts of the mold are removed. When TPE / TPV materials are ejected, the ejection speed should be in the range of 10-20 mm / s, and the ejection speed of PA66 / PBT materials should be in the range of 5-15 mm / s.

[0058] Step 5 also includes the following steps:

[0059] E1: Post-process the product according to production standards, stress relief annealing (for PA / PBT), temperature: 100-120℃ (20℃ lower than the material HDT), time: wall thickness ≤ 3mm → 30 minutes; extend by 15 minutes for each additional 1mm;

[0060] E2: Check the appearance, size and functionality of the product according to the production standards. Functional inspection includes air tightness test, adhesion test, dimensional accuracy test and voltage resistance test. The air tightness test method is air pressure test 0.3MPa×30s. The acceptance standard is leakage ≤0.5mL / min (IP67). The frequency requires 100% full inspection. The adhesion test method is wire pull test. The acceptance standard is ≥80N ( Conductor), frequency is 2 times per shift, dimensional accuracy test method is CMM measurement, acceptance standard key dimension CPK≥1.33, frequency first piece +2h / time, voltage resistance test method is 1500VAC×60s, acceptance standard: no breakdown, frequency is batch sampling.

[0061] In this embodiment, through raw material preparation and pretreatment, the selected material batches can be cleaned, impurities adhering to the surface of the material can be removed, and then the material can be dried to remove moisture from the material, thereby effectively improving the pretreatment efficiency of the material, while preventing bubbles from appearing after product injection molding, improving product production, and opening the mold after injection molding. The ejection mechanism then ejects the injected product from the mold, allowing staff to directly remove the product without the need to laboriously remove the product from the mold, thereby improving work efficiency.

[0062] While the present invention has been generally described above, modifications and improvements are readily apparent to those skilled in the art. Therefore, modifications and improvements that do not depart from the spirit of the present invention are intended to be within the scope of the present invention.

Claims

1. An injection molding process for producing automotive wiring harnesses, characterized in that: The injection molding process for producing an automotive wiring harness comprises the following steps: Step 1: Prepare raw materials; Step 2: Insert preparation; Step 3: Mold preparation; Step 4: Injection molding; Step 5: Post-processing and testing; Step 6: Processing completed.

2. The injection molding process for producing automotive wiring harnesses according to claim 1, characterized in that: The step 1 further comprises the following steps: A1: Materials are selected based on the requirements of the automotive industry and production needs. Specific materials include TPE / TPV, PA66, and PBT. The TPE / TPV composition ratio is as follows: base material ≥ 95%, additive flame retardant 8%-12%, antioxidant 0.3%-0.8%, and masterbatch 1%-2%. Furthermore, the material must meet the LV 312-1 flame retardant standard. The PA66 composition ratio is as follows: base material ≥ 93%, additive glass fiber 30%-35%, and PBT composition ratio is as follows: base material ≥ 90%, additive glass fiber 20%-30%, and flame retardant 12%-15%. A2: Clean the selected materials in batches and then dry them to remove moisture. Drying: A / PBT: Dehumidifying dryer, 100-120℃ x 4-6 hours, dew point ≤ -40℃; TPE: 60-80℃ x 2-3 hours (anti-caking); Mixing: High-speed mixer (500-800rpm) for 5-8 minutes, color difference ΔE ≤ 0.8; A3: Choose different types of masterbatches according to production requirements or customer needs to meet surface color requirements.

3. The injection molding process for producing automotive wiring harnesses according to claim 2, characterized in that: The step 2 further comprises the following steps: B1: Select wire harnesses and connector housings with pre-installed terminals based on the injection molding requirements. The connector housing positioning requires a positioning tolerance of ±0.05mm, secured by mold locating pins and vacuum adsorption. The wiring harness branch point positioning tolerance is ±0.1mm, secured by a custom fixture and pneumatic grippers. B2: Pre-treat the inserts according to the injection molding requirements and production conditions, plasma cleaning (Ar / O2 mixed gas, power 300W×120 seconds) or alcohol wiping. PA / PBT inserts need to be preheated to 80-100℃ (to reduce thermal stress).

4. The injection molding process for producing automotive wiring harnesses according to claim 3, characterized in that: The step three further comprises the following steps: C1: Select the mold base that matches it according to production requirements; C2: Check whether the mold base meets the functional standards according to injection molding and production requirements. The inspection work is divided into whether the gate, exhaust, cooling water channel, ejection mechanism, positioning mechanism and core pulling mechanism are set.

5. The injection molding process for producing automotive wiring harnesses according to claim 4, characterized in that: The step 4 further comprises the following steps: D1: Install the insert in the mold according to the production standards, and then close the mold; D2: The injection molding machine injects the material dissolved in liquid into the mold cavity so that the material wraps the insert and maintains a certain pressure after injection. The typical values ​​of TPE / TPV materials in the plasticizing stage: the barrel temperature should be 160-180-190-195℃, the screw speed is 60-80rpm, the injection stage: the injection pressure is 60-90MPa, the injection speed is 40-60mm / s, the VP switching position is 95% of the cavity filling volume (mm), the holding pressure stage: the holding pressure is 50%-70% of the injection pressure, the holding time is 3-8s, the cooling stage: the mold temperature The typical values ​​for PA66 / PBT are: barrel temperature should be 240-260-270-275℃, screw speed 40-60rpm, injection stage: injection pressure 80-120MPa, injection speed 30-50mm / s, VP switching position 98% cavity filling volume mm, holding stage: holding pressure 60%-80% of injection pressure, holding time 5-15s, cooling stage: mold temperature 70-90℃, cooling time 10-15s / mm; D3: After a period of cooling until the material injection is completed, the mold is opened and the product is ejected from the mold through the ejection mechanism. Finally, the burrs at the intersections and other parts of the mold are removed. When TPE / TPV materials are ejected, the ejection speed should be in the range of 10-20 mm / s, and the ejection speed of PA66 / PBT materials should be in the range of 5-15 mm / s.

6. The injection molding process for producing automotive wiring harnesses according to claim 5, characterized in that: The step five further comprises the following steps: E1: Post-process the product according to production standards, stress relief annealing (for PA / PBT), temperature: 100-120℃ (20℃ lower than the material HDT), time: wall thickness ≤ 3mm → 30 minutes; extend by 15 minutes for each additional 1mm; E2: Check the appearance, size and functionality of the product according to the production standards. Functional inspection includes air tightness test, adhesion test, dimensional accuracy test and voltage resistance test. The air tightness test method is air pressure test 0.3MPa×30s. The acceptance standard is leakage ≤0.5mL / min (IP67). The frequency requires 100% full inspection. The adhesion test method is wire pull test. The acceptance standard is ≥80N ( Conductor), frequency is 2 times per shift, dimensional accuracy test method is CMM measurement, acceptance standard key dimension CPK≥1.33, frequency first piece +2h / time, voltage resistance test method is 1500VAC×60s, acceptance standard: no breakdown, frequency is batch sampling.

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