Pass Through Characteristics (PTC) refer to product features that emerge or become apparent during the manufacturing process but are not used, tested, or verified for functionality at a specific point in the production chain.
Thus, there is a very low chance of detecting these characteristics and a high probability of delivering non-compliant products to the OEM and end-user.
Potential Risks:
The primary risks include impacts on customer satisfaction or safe usage and handling, often resulting in shipment stoppages, market actions, warranty claims, and financial and legal penalties.
Finding information on handling PTCs
Where can we find information on how to appropriately manage these characteristics to ensure proper detection and subsequently reduce associated risks?
Pass Through Characteristics in relation to IATF standards
Requirements:
Responsibilities related to these characteristics can be found in section 8.4.2.1 “Type and Extent of Control – Supplement,” which states: “The organization shall have a documented process to identify outsourced processes and to select the types and extent of controls used to verify the conformity of externally provided products, processes and services to internal (organizational) Â and customer requirements”.
The process shall include the criteria and actions to escalate or reduce the type and extent of control and development activities based on supplier performance and risk assessment of products, material, or service risks.
Where characteristics or components “pass through” the organization’s quality management system  without validation or controls are in place at the point of manufacture [1].
This explanation clarifies the organization’s responsibility for Pass Through Characteristics.
Thus, the only guidance provided primarily concerns “what?” should be ensured from the customer’s and end user’s perspectives, without more detailed requirements in this area.
Requirements according to CQI-19
The CQI-19 Supplier Quality Management guide provides direct guidance on handling PTCs. The directive emphasizes the responsibility for identifying and defining PTCs correctly.
It is also essential to properly define these characteristics in the Control Plan. Additionally, we should take preventive actions to eliminate or reduce the occurrence of non-conformities related to these characteristics by:
- Control of these characteristics, such as error proofing or 100% inspection
- Use of clear work instructions
Pass Through Characteristics and CSR requirements
Customers or the Supplier Quality Manual often provide the most detailed information on handling PTCs through Customer Specific Requirements (CSRs) or additional requirements for suppliers.
These documents not only answer the question of “what?” should be ensured but also “how?” we should meet customer requirements in this regard.
Identification
A key requirement often found in CSRs during the APQP process is the need to properly define and agree upon all potential PTCs, including their impact on the end-user.
Consequently, PTCs should be appropriately communicated using customer-required forms and marked in complete process documentation – PFMEA, Control Plan, work instructions, and process plans, to ensure their proper identification.
Control
PTCs must have broadly understood control methods implemented, including incoming inspection, to protect the customer from receiving non-conforming products. Such requirements are often explicitly stated in various customer requirements.
Therefore, it is advisable to include PTCs early in the FMEA process to build appropriate controls into the manufacturing process, focusing on both detection and prevention controls.
Additionally, confirming their effectiveness is necessary to ensure that all products fully meet customer specifications.
The organization should maintain proper documentation along with necessary revisions. The purpose? To confirm that the FMEA process has been conducted and provide evidence if the customer requests it.
Typical examples of Pass Through Characteristics
Now that we have learned about PTCs, let’s look at some examples. They may appear in production, such as:
- Threaded holes in parts not used by the immediate customer but crucial for later assembly stages.
- Mounting pins used to join components at later production stages.
- Clamps or clips used to secure parts in the finished product.
- Connecting elements in an engine that must fit with other components in a car assembly plant (e.g., connections to the radiator or fuel lines).
- Products with characteristics related to fit, form, or function (Fit, Form, Function), not checked by the intermediate company but critical for the final product. Example: holes in the steering column to which the dashboard cross beam is attached.
Implementing PTC safeguards after a complaint
Expert Answer: It depends đ. If, after a complaint, there are no issues with receiving cost reimbursement from sub-suppliers, there may be no need for action. However, another scenario arises when the sub-supplier refuses to accept such costs.
Moreover, if we do not isolate problems with their subcomponents, we can conduct a cost analysis (complaint costs vs. investment costs) to decide whether to implement actions on our production line or quality control of incoming supplies.
This ensures that we will catch any similar issues at our location in the future.
Typical sources of problems with Pass Through Characteristics
Knowing a bit more about PTCs, it’s time to list the most common issues encountered during their implementation and management:
- Lack of identification. Failing to recognize or incorrectly identifying PTCs in the production process can lead to overlooked potential quality issues.
- Insufficient communication with Suppliers. Not clearly communicating requirements and specifications to suppliers can result in non-compliance with the customer’s expectations.
- Limited Quality Control. Reducing internal structures within companies, including limiting incoming inspections, may negatively impact the detection of defects related to PTCs.
- Inadequate supplier agreements. Insufficient agreements regarding PTC quality responsibility can lead to issues if defects arise.
- Inspection costs. High costs associated with PTC inspection may discourage companies from conducting thorough inspections, increasing the risk of overlooking defects.
- Complex supply chains. It’s no secret that longer and more complex supply chains increase the risk of PTC-related issues due to difficulties in control and communication.
- Lack of employee awareness. Insufficient understanding of the importance of PTCs among employees can lead to neglect in managing these characteristics.
- Inadequate Quality Planning. Failure to consider PTCs in quality documents. DFMEA, PFMEA, and Control Plans, can result in overlooked potential issues.
- Specification changes. Failing to account for or communicate PTC specification changes among suppliers can lead to non-compliance in the final product.
- Lack of monitoring. Insufficient tracking and analysis of PTC-related problems during production can prevent the early detection and resolution of recurring issues.
Conclusion
Regardless of the client’s requirements, criteria presented in the IATF 16949:2016 standard, or other automotive manuals, the organization must define and adopt its approach.
This approach should primarily be based on risk assessment throughout the manufacturing chain and consider the organization’s past experiencesâlessons learned. The main goal should always be to deliver only 100% compliant products to the customer.
Kinga Niedziela and Dariusz Kowalczyk
Bibliography:
1. IATF Automotive Quality Management System Standard â 1st edition, 1 October 2016Â
