2021-05-08
Automotive Wiring Harness Is Also Known As The "Blood Vessel" Of A Car, Which Is Usually Called The Central Nervous System Of A Car. The Design Of Automotive Wiring Harness Plays A Very Important Role In The Whole Vehicle. It Is Of Great Significance To Study The Quality Control Points In The Manufacturing Process Of Automobile Wiring Harness For Improving The Qualification Rate And Reliability Of The Whole Vehicle. There Are Four Steps In The Main Process Of Automobile Wire Harness Production: Offline Crimping Pre Assembly Final Assembly. The Production Process For Different Production Processes, Formulate The Corresponding Standardized Operation Specification, So That The Quality Of The Harness Products Can Be Effectively Guaranteed.
Off Line Technology
Off Line (Known As Stripping Head) Refers To Stripping The Insulation Skin On The Wire According To The Requirements Of The Operation Instruction, And The Length Should Meet The Requirements. Good Stripping Requires That The Wire Type, Diameter, Color, Length, Stripping Length And Appearance Meet The Requirements. Precautions During Stripping: ① The Stripping Length Meets The Requirements; ② The Section Of Insulating Skin Is Uniform; ③ The Wire Core Is Not Cut Or Injured, And The Wire Core Is Not Scattered Or Twisted; ④ There Is No Loose Wire In The Core; ⑤ The Wire Core Is Not Oxidized And Blackened. If The Wire Core Is Oxidized And Blackened, It Is Easy To Cause Virtual Connection. After Stripping, The Wires Shall Be Bundled Into Bundles According To A Certain Number, And Each Stripping Head Shall Be Provided With A Protective Cover, So As To Prevent The Wire Core From Branching Or Scattering. It Shall Be Placed On The Wire Rack, And The Handling Process Shall Be Reduced As Far As Possible. In The Production Process, Some Companies Do Not Take Necessary Protective Measures After Stripping, Or Improper Protective Measures Are Easy To Cause The Core Scattered, Forked, Twisted Or Broken. As A Result, It Is Difficult To Operate And The Quality Of Crimping Is Poor.
The Crimping
Crimping Process Of Terminal Is The Most Important Part In The Whole Process Of Wire Harness Production. The Wire Type, Specification, Color, Terminal Specification And Crimping Dimension On The Process Card Must Be Carefully Checked For Crimping. It Is Particularly Important To Check The Quality Of This Link. The Quality Of Terminal Crimping Is Mainly Guaranteed By Crimping Die On Crimping Equipment And Equipment. In Terminal Crimping, The Wire Stripping Head Shall Be Positioned Instead Of Visual Assurance By Operators. After The Crimping Is Completed, To Ensure The Mechanical And Electrical Performance Of The Terminal, Pull Off Force Test Must Be Conducted To Check The Crimping Inspection Of Crimping Terminal Of Crimping Quality Terminal ① Appearance Inspection: The First Piece Inspection Must Be Conducted For Terminal Crimping, And 3-5 Pieces Of First Piece Shall Be Taken For Judgment. Whether The Visual Terminal Crimping Appearance Is Good; Whether There Is Leakage Of Wire Wire; Whether The Wire Is Broken Or The Insulation Layer Is Pierced Or Cut. Whether The Insulation Layer And Wire Are Closely Connected With The Terminal, Whether They Are In The Specified Area ② Pull Force Test: The Pull-Out Force Test Mainly Tests The Tightness Of The Combination Of The Terminal And The Harness. Through The Pull Off Force Test, Confirm Whether The Maximum Pulling Force Meets The Requirements. Normal Batch Production Can Only Be Carried Out After The Pull Force Test Meets The Requirements. The First Piece Must Be Kept To Ensure Subsequent Traceability. In The Process Of Terminal Crimping, Many Enterprises Pursue Speed, And Think That The Faster The Operator Crimp Terminal, The Better, To Measure The Performance Of Employees. This Is Not Desirable. Korean Enterprises Have Made Clear That Crimping Terminals Cannot Exceed A Certain Speed, Because Only In Such A Speed And State, The Quality And Qualification Rate Of Crimping Terminals Are The Best.
Pre Assembly Process
Insert The Wire Of Crimped Terminal Into The Connector Hole According To The Sequence And Method Specified In The Process. Or Insert The Waterproof Bolt Into The Connector Hole. Key Points: Before Subpackage, Carefully Check The Type Of Sheath And Wire Specified On The Process Card, And Check The Quality Of Sheath, Wire And Terminal Crimping. If The Material Or Semi-Finished Product Is Unqualified, Subpackage Is Not Allowed. The Terminal Must Be Inserted In Place And Flat, That Is, The Top Of The Terminal Is On The Same Plane Without Skew And Deformation. If The Assembly Is Not In Place, The Wire Will Fall Out Of The Plug Box In The Subsequent Process. Therefore, During The Assembly Process, Pull Back To Confirm Whether The Terminal Is Completely Inserted Into The Plug-In Box. The Quality Standard Is As Follows: ① The Hole Position Of The Terminal Must Meet The Hole Position Requirements Of The Sub Assembly Drawing - The Hole Position Arrangement Is Seen From The Terminal Insertion Direction; ② The Plug-In Terminal Must Be Implemented According To The Three Steps Of "Push", "Listen" And "Pull", So As To Ensure That The Terminal Is In Place And Will Not Exit. In Particular, It Is Necessary To Pull Back After Inserting The Terminal. If The Terminal Does Not Withdraw After Pulling Back, It Means That The Terminal Is Inserted In Place. ③ The Appearance Of The Terminal After Inserting Must Be Neat And In Place, Without Deflection. ④ The Wire Led Out After The Sheath Must Be Smooth, Without Obvious Length Difference, Which May Cause Single Stress
Assembly Process
The General Assembly Process Is To Assemble The Clip According To The Process Requirements, Bind And Wind The Sheathed Wire On The Assembly Plate To Form A Special Wire Harness. Matters Needing Attention In General Assembly: ① Assembly Error Of Hole Position (Also Known As Wrong Wiring), Which Is The Most Serious Error In Assembly And Affects The Safety Of Use (Key Points And Quality Requirements In Each Process Of Harness Production). ② Attention Should Be Paid To Wrong And Missing Assembly In Harness Assembly Process. If Wrong And Missing Assembly Can Not Be Found In Time, It Will Cause A Large Number Of Repair Work And Secondary Injury Of Harness. There Are Few Clips In The Wiring Harness, Which Makes It Impossible To Assemble When Loading. The Wrong Position Of The Harness Clip, Resulting In Unable To Load. ③ The Harness Is Not Wound Or Tightly Wound, Resulting In Loose Wires And Missing Wires. In The Assembly Process Of The Whole Vehicle Harness, The Harness Is Scratched, And The Single Wire Is Too Large, Which Eventually Leads To The Damage Of The Harness. ④ If The Harness Has A Bifurcation, The Direction Of The Harness Must Be Smoothed, And Then It Is Bound Or Wound. Otherwise, In The Process Of Loading, It Is Easy To Cause The Wiring Harness To Be Twisted, Or The Size Is Not Enough, The Force On The Buckle Or Fixed Point Is Too Large, Resulting In The Damage Of The Fixed Point, The Final Abnormal Noise, Or The Abrasion Of The Wiring Harness. ⑤ The Tail Of The Retained Part Should Be 5 ~ 15mm After Cutting The Binding Belt, And There Should Be No Sharp Corners; ⑥ After The Wiring Harness Is Assembled, It Shall Be Hung On The Wire Rack. The Wire Rack Shall Be Made Reasonably. The Wire Harness Shall Not Be Dragged On The Ground, Causing The Sheath Or Terminal To Be Scratched Or Trampled, Causing Damage.
Final Inspection
After The Wiring Harness Is Assembled, It Is Necessary To Carry Out Power On Inspection And Appearance Dimension Inspection. First Of All, Power On Inspection Is To Plug And Connect The Sheaths And Connectors Of The Wiring Harness With The Detection Equipment. After The Connection Is In Place, The Equipment Will Automatically Enter Each Line For Judgment. There Are Pre Input Detection Procedures For Each Type Of Wiring Harness In The Equipment. After All The Wires Are Qualified, The Equipment Will Display 0k. If There Is A Fault In A Certain Branch Line, The Equipment Display Will Display In Different Colors, And The Inspectors Will Check And Repair According To The Equipment Prompts, And Then Carry Out The Test Again. Until All Qualified. Do Not Pull The Harness Savagely To Avoid Damage. The Unqualified Products Shall Be Marked With Red Tape And Put In The Special Unqualified Product Box Or The Designated Trailer To The Designated Repairman For Repair. Power On Inspection Must Be 100% Inspection. Secondly, The Appearance And Size Inspection. The Appearance Dimension Inspection Is Placed After The Power On Inspection, Mainly Because The Terminal Connector On The Power On Inspection Equipment Of Some Enterprises Is Damaged, Which May Cause The Pin On The Harness To Be Damaged, Skewed, Fallen Off And Broken. Appearance Inspection Shall Start From The End Of The Line, And Shall Be Conducted One By One Along One Direction To Avoid Omission. Check Whether The Pins In Each Sheath Are Skewed Or Uneven, Whether The Coarse And Close Winding Of The Thread Are Qualified, Whether The Waterproof Bolt Falls Off, Whether It Is Assembled In Place, And Whether The Buckle Is Loose. Once Found Unqualified, It Is Necessary To Label The Unqualified Place, Write The Unqualified Mode, And Place It In The Unqualified Product Area For Rework. Finally, The Dimension Inspection Is Mainly To Place The Harness On The Inspection Tool, Position The Harness, Check Whether The Position Of Each Clip Is Within The Specified Range, Whether The Harness Length Meets The Requirements, And Whether The Length Of Each Branch Meets The Requirements. After The Inspection Is Qualified, The Qualified Label Shall Be Pasted And The Packing And Warehousing Shall Be Carried Out
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