Develop the Design and Production of the Connection Harness

The final plan for designing the connection harness is determined:
Concept: Before mass production of connected wire harnesses, process engineers need to verify the process method after dividing the work stations (that is, the process method used during SOP). Adjustments and re-verifications are made during the verification process, and the finalized process method is the final plan.
Time to determine the plan: In the later stages of the PPAP stage, before the official ramp-up, process engineers need to finalize the final plan.
Determine the purpose of the program
1. In order to ensure the smooth progress of the process during the official launch. Problems discovered during the verification process can be solved as early as possible and will not be left during mass production.
2. There will be no major problems or bottleneck stations in the early stages of mass production.
3. It enables the team to complete mass production within the specified time, smoothly enter the SOP stage, and seamlessly connect with the customer’s SOP stage.
4. Ensure that the quality of the wire harness produced in the mass production stage is intact.

Criteria for determining the final design of the connection harness
A. Each station runs smoothly according to the process method. The so-called smoothness means that the process method operates smoothly, and people and people and machines cooperate with each other tacitly, without conflicts or waiting. The specific standards are as follows:

Correct assembly sequence
For the assembly of the wire harness assembly, the manual steps are complicated. When formulating the process method, special attention should be paid to the assembly sequence. Although the assembly sequence has been initially verified when accepting the operation card, when the final plan is determined, the content and sequence of the assembly still need to be studied and analyzed, because these work contents need to be completed within the cycle time. At this stage, more attention is paid to the details of the operator’s operations on the workstation, such as whether the material taken is in accordance with the operating sequence, whether there are conflicts in the operations of multiple people on the workstation, etc.
B. The time for each station to complete the wire harness assembly is within the cycle. We require that the effective (value-added) operation time of each workstation not only needs to be within the cycle time, but also needs to be infinitely close to the cycle time, so as to ensure that the operator’s efficiency is maximized. Maximizing efficiency means maximizing the effective (value-added) operation time of personnel within the specified time. The concept involves effective, value-added operation time, which is specifically understood as follows:
For the operations in the wire harness production process, it is divided into the following four types:
1. Value-added actions: effective operations, operations necessary for wire harness production, such as inserting terminals, wrapping tape, and installing positioning parts. These are necessary actions when assembling components. Without these operations, the wiring harness cannot be assembled.
2. Actions that do not add value: That is, invalid operations, unnecessary operations for wire harness production. Such as straightening out the wires to prevent them from being disordered; holding the terminals in the wrong direction when inserting terminals; needing to rotate the wires to adjust the direction of the terminals, picking up dropped materials, etc. These actions are additional actions generated during assembly and will affect the assembly time. These actions are actions that IE needs to discover and eliminate.
3. Waiting: that is, waiting within the specified time. There are two types of waiting: one is when the employee has completed all the work at this station, but the takt time has not yet reached and there is nothing to do, indicating that the workload at this station is not enough. The other is that employees need the line passed from the previous work station to complete the operation of this work station. However, at the specified time, the previous work station did not pass the incoming line, indicating that there was a bottleneck at the previous work station and the work could not be completed within the specified time and transferred to the next work station. These waits are also what IE needs to eliminate.

Walk back and forth:
When employees operate, they need to move from point A to point B before they can enter the operation; however, there is no operation during the overshoot from A to B, only walking. The most common situation is that one employee operates two workstations, and the employee needs to go from A to B. These times of moving around are also undesirable. Therefore, when laying out the workstation, try to put the content that the same employee needs to operate on one workstation, or place the workstation parts as close as possible to avoid moving back and forth.
We hope to fully schedule employees’ value-added operations within a limited cycle time and verify that it is feasible during the finalization of the solution.
C. The connection between workstations is clear and smooth. Specifically reflected in the following aspects:
1. When wire harnesses are transferred between workstations, the tools used for transfer are reasonably designed to make it easier for employees to place the wire harnesses. The wire harness is placed on the transfer tool in a clear manner without damaging the wire harness, and the quantity placed is clearly defined.
2. The transfer process is simple and easy for employees to operate. At the same time, it is easy to pick up the wiring harness at the next workstation.
3. The information is transmitted completely without loss. After getting the wire harness at this station, clearly guide the model or ID of the wire harness in hand. In testing the wiring harness, you need to use the wiring harness ID to retrieve the corresponding wiring harness program. Therefore, during the delivery process, the carrier that displays the harness ID, such as the harness order or label, must be consistent with the harness itself, and the identity cannot be lost during delivery.

Several testing standards for connecting wiring harnesses

Several steps to make a connection harness

Connection Harness Design Process

Connection harness production process
A. Preparatory work: Some preliminary preparations are required before the final plan is determined. These tasks need to be prepared in advance before the verification of process methods can be implemented. The specific details are as follows:
1. The tooling and equipment status is up to date and has been released. Because wiring harness engineering changes are frequent, engineering changes are inevitable even during the ramp-up phase. Therefore, the on-site tooling and equipment need to ensure that the engineering changes have been implemented correctly and have been accepted by the quality department and can be used for production.
2. The layout of the on-site production area is complete and there are no defects. The tool rack is placed in the correct position, the tooling and equipment are intact and fault-free, and the tools used are placed in the correct position.
3. The process method has been initially verified by IE, and the engineering status is the latest.
4. The status of parameters required for various productions is up to date and has been verified and released.
5. Wires and other raw materials should be carried in the correct way (conductors, material boxes, etc.) and placed in the correct position on the tooling rack.
6. The connection system is complete: the connection tools used are reasonably designed, the information transmission is continuous and complete, and the information carriers (wire harness orders, information cards, labels) used at the starting end of the information are all ready.
7. The network connection is good: test result recording and communication, wire harness tracking system, etc. are running normally, label printing is normal and the information displayed on the label is correct.
8. Operators are in place. Operators are required to be experience production employees. It requires employees with rich production experience, or employees with experience in the production of this wire harness, who are familiar with the assembly process of this wire harness and are skilled in operation. When multiple employees operate at the same work station, the number of employees on this work station needs to be matched and verified at the same time. Otherwise, it cannot be verified whether there is a conflict between workstations.
According to the process card, the operation content of each workstation is divided into several action units and placed in the action list. When dividing, you need to pay attention to the appropriate size of the action division. Generally, IE is measured manually on site with a stopwatch, and there are errors in the measurement itself. If the division is too fine, the errors present in the measurement will be amplified, resulting in inaccurate work hours for this action. If the division is too rough, the actual working hours of this action after some actions are moved to other stations cannot be obtained when balancing the work station. According to experience, this division method is generally followed:
1: Take the wires from the material rack, insert the terminals, and lay the wires (these three actions generally form an action unit for measurement).
2: Take the plastic parts from the material rack and place them in the fixed fixture.
3: The circuit in the same work station and the same plastic part is divided into several action units for testing. An action unit contains more than 2 loops.
4: Take the tape from the material rack, tear off the tape, and wrap the branch. Generally, there is one action unit per branch.
5: Take the positioning piece from the material rack, install the positioning piece, and cut off the tail.

Measurement of man-hours for producing connection harnesses:
After the preparatory work is completed, IE needs to study each workstation and measure its operating hours. The specific implementation methods are as follows:
Actual working hours:
After dividing the action units, fill in the working hours measurement table, and then measure the working hours according to the actions. 10 valid data need to be recorded. Judgment of valid data
in principle:
When the operation time of the unit is ≤30 seconds, the range of 10 sets of data should be: 90% * Average (10 sets of data) ~ 110% * Average (10 sets of data).
When the operation time of the unit is >30 seconds, the range of 10 sets of data should be: 95%*Average (10 sets of data) ~ 105%*Average (10 sets of data).
Time spent walking around and waiting needs to be measured as well. In addition to recording actual operating hours, it is also necessary to observe the details of employees while operating. When measuring work hours, you need to distinguish between value-added and non-value-added actions. If it is found that there are non-value-added actions in the operation, the measured working hours need to be specially marked, and the test will be retested after improvement.

Balancing station for producing connection harnesses:
The working hours of each workstation are added and extracted to form a workstation balance wall. Analyze and adjust the work station balance wall:
a. Eliminate bottleneck stations: Move work that exceeds the cycle time to a station that is not full. As shown in the picture below, part of the work in station 3 has been moved to station 2.
b. Eliminate walking time: observe the actual operation and put the parts that need to be moved together as much as possible
c. Eliminate waiting time: move overflow work from other stations to this station
d. Discover non-value-added work, optimize work stations, increase value-added work content, and improve efficiency

-After balancing the workstation
After obtaining the new work content of the work station, it is necessary to re-measure the working hours of the work station to verify whether the balanced solution is feasible. If there is still an imbalance after verification, the above operation needs to be repeated again.
C. Update process: After the work station is balanced, the content that needs to be updated is as follows: Determine the specific update items according to the actual situation.
1. Update the process operation card and resubmit it to quality release.
2. Update the workstation balance wall
3. Update the content of the tooling board, especially the content of the kit board and assembly line assembly board; quality release is still required after the update.
4. Update the content of equipment operation, parameter adjustment, etc., and submit it to quality release after updating.
5. Update the tool rack to include tools for connecting the system. Due to the adjustment of the workload, the corresponding materials used will also be adjusted. The corresponding tooling racks will take increasing and decreasing positions to place the materials, and the labels of the materials will be updated at the same time.
6. Update information flow, wire harness orders/labels and other information to be corrected based on the latest workstation information
7. Update the work layout on site, implement the latest design plan, and release quality again.
8. Train on-site operators according to the latest production process plan to familiarize them with the methods.