Standard STD 105-0007 Volvo Group

Issue date September 2015 Issue 3 Page 1 (11)

The English language version is the original and the reference in case of dispute.

Special characteristics Definition and application

Orientation This issue differs from issue 2 in that section 1 has been updated with a clarification regarding former practices of STD 105-0001.

This standard is a merge of:

• STD 105-0001 Critical characteristics of design products – Identification and grading • STD 186-0002 Application of critical characteristics on assembly requirements – Screw joints • STD 186-0003 Critical and significant characteristics on assembly requirements – excluding

screw joints

Definitions and wordings are aligned with ISO/TS 16949:2009.

The standard also includes a definition of “special characteristic” and contains minimum requirements on manufacturing processes and quality assurance of suppliers and products.

There is no equivalent international standard.

This standard can be supplemented with other standards or instructions that describe in a more detailed way how characteristics marked with a special-characteristics class ([CC] (Critical Characteristics) or [SC] (Significant Characteristics)) shall be treated within a specific Volvo Group company.

Contents 1 Scope and field of application ......................................................................................................... 2 2 Classes of “special characteristic” ................................................................................................. 2 3 Basic principles ................................................................................................................................. 2 4 Special characteristics – Classification and requirements .......................................................... 3 5 Symbols and indication .................................................................................................................... 4 6 Responsibilities ................................................................................................................................. 5 7 Principal process logic for definition of Special Characteristics ................................................ 6 8 Reference to other relevant standards and documents ................................................................ 7 9 Reference to this standard ............................................................................................................... 7 10 Example .............................................................................................................................................. 8

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1 Scope and field of application This standard describes and defines the Volvo Group method for applying special characteristics in design-engineering documentation and in production:

• Identification and application of special characteristics in order to control product risks related to characteristics. These characteristics require variation control to ensure optimal form, fit, function, performance or service life.

• Definition of manufacturing-process control requirements to manage process variation.

The use of a special-characteristics class shall not apply to embedded software development.

If the symbols from STD 105-0001 ([1], [2] or [3]) are still present in a drawing or other Volvo Group document, these indications are valid and the characteristics shall fulfil the requirements stipulated in STD 105-0001 and other Volvo Group documents. Symbols from STD 105-0007 and STD 105-0001 shall not be used together in the same document.

2 Classes of “special characteristic” The term “special characteristic” is defined in ISO/TS 16949 as a “Product characteristic or manufacturing process parameter which can affect safety or compliance with regulations, fit, function, performance or subsequent processing of product”.

Within the Volvo Group, the following special-characteristics classes are used:

Critical Characteristics [CC] refer to special characteristics which can affect safety;

Significant Characteristics [SC] refer to special characteristics which can affect compliance with regulations (for emission regulations use STD 105-0004), form, fit, function and performance, or subsequent manufacturing-process steps.

3 Basic principles The objective and challenge for the development, design-engineering and manufacturing processes are:

• Product risk related to the product design’s sensitivity to process variation should be minimized.

• Special characteristics shall be applied only after all design/process alternatives have been exhausted.

The necessary associated special quality-assurance actions shall have been identified and implemented. Thereby, the need to assign special characteristics will be limited.

Design-engineering documentation is always expected to be met and delivered.

Application of special characteristics is a method for communicating which of the requirements that need further quality-assurance measures to control process variations.

The basis for identifying special characteristics must be the product-risk management.

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The identification of special characteristics must be:

• a result of a cross-functional dialogue between Product development and the internal or external manufacturer of the part or systems.

• based on performed and documented product-risk analysis and estimation, preferably by the use of D-/P-FMEA (Design/Process – Failure mode and effect analysis) applied in accordance with STD 105-0005. Equivalent methods that are verified to meet EN ISO 12100 are also acceptable.

The flowchart in section 10 explains the logic for defining special characteristics in connection with FMEA.

Identified special characteristics shall be objectively measurable values with tolerance indication and/or parameter information, defined in the design-engineering documentation, e.g., PVR (part version report), drawings and Technical Requirements.

4 Special characteristics – Classification and requirements Special characteristics shall be analysed using D-/P-FMEA1 and classified in accordance with table 1.

Table 1

Special characteristics Critical Characteristic [CC]

Significant Characteristic [SC]

Applies to product characteristic or process parameter where non- compliance leads to the following effect: Risk of accident and injuries with

or without warning

Unplanned stop in operations with or without warning and/or Non-compliance with legal or governmental requirements that lead to the above-mentioned consequences (for non-compliance with emission regulation see STD 105-0004)

Failure rate target Zero = “less than 1 PPM” N/A

Minimum requirement on process capability as per STD 105-0002

Demonstrated process capability Cpk ≥ 1,67 AND Checking frequency adequate to demonstrate

• On-going process control

• Compliance with capability requirement

or, if not possible, 100 % control with documentation requirements

Demonstrated process capability Cpk ≥ 1,33 AND Checking frequency adequate to demonstrate

• On-going process control

• Compliance with capability requirement

or, if not possible, tailored sampling control with documentation requirement

Minimum quality-assurance requirements

• Design-FMEA and Process-FMEA mandatory. • All special characteristics must be monitored in the control plan. • Function testing of tightening machines or tools shall be included in

verification systems in accordance with STD 820-0001.

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Minimum documentation requirements for manufacturing

• Verified results shall be documented in such a way that they can easily be linked to the individual manufactured product (e.g. manufacturing number/chassis number/batch identity dates).

• Manufacturing-process records and documentation have a minimum retention period of ten (10) years after product phase-out or end of production. These requirements do not supersede any regulatory requirements.

Minimum documentation requirements for engineering

• Product-controlling documents shall be stored in accordance with the respective product-development processes or minimum ten (10) years after product phase-out or end of production. These requirements do not supersede any regulatory requirements.

1 Equivalent methods that are verified to meet EN ISO 12100 are also acceptable.

5 Symbols and indication Each identified special characteristic shall be accompanied by its class that follows the following rules of indication:

• a letter combination, either [CC] or [SC] • placed after the critical requirement concerned.

Besides indication on drawings, special-characteristics classes can be indicated in other design-engineering documents (e.g. Technical Requirement) and, in that case, in a way that clearly indicates which requirement the indication applies to.

Table 2

Example Interpretation

Special-characteristics class [SC] applies to weld class C.

Static torsional strength 200 Nm min [CC]

Special-characteristics class [CC] applies to the requirement on static torsional strength.

Spheroidal graphite iron VISG500/7 +AC/HT, STD 310-0002 With the following exceptions: Yield strength: Min 350 MPa [CC] Tensile strength: Min 550 MPa [CC] Elongation: Min 6 % [CC]

Example of a material designation where a special- characteristics class [CC] applies to the requirements on yield strength, tensile strength and elongation.

In this example, the special characteristic is identified in the Technical Requirement being part of the PVR.

+0,2 ∅30 0 [SC]

Special-characteristics class [SC] applies to the lower tolerance limit.

+0,2 [SC] ∅30 0 [SC]

Special-characteristics class [SC] applies to the lower and upper tolerance limit.

[SC]

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100 Nm ± 10 Nm [SC] Special-characteristics class [SC] applies to 100 Nm ±10 Nm.

0,2 [SC] Special-characteristics class [SC] applies to the straightness requirement.

Special-characteristics class [SC] applies to the surface texture requirement.

Special-characteristics class [SC] applies to ∅66 h6.

Special-characteristics class [SC] applies to the surface- texture requirement.

Special-characteristics class [SC] applies to ∅66 h6 and to the surface-texture requirement.

6 Responsibilities From D-FMEA, the potential special characteristics are identified and applied in B-release design-engineering documentation.

For special-characteristics [CC] or [SC], the manufacturing unit, the suppliers and the subcontractors shall be responsible for quality-assurance activities in accordance with table 1. Decision and confirmation of special characteristics shall be made by design engineering and production engineering, based on the evaluation of performed risk reduction in D-FMEA and P-FMEA and later applied in C-release design-engineering documentation.

Product-development engineering is responsible for the final decision and documentation of special characteristics in design-engineering documentation.

The product-development engineer is responsible for indicating special-characteristics information in all the intended areas of the PDM (product data management) system.

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7 Principal process logic for definition of Special Characteristics

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8 Reference to other relevant standards and documents STD 105-0002 Capability – Basic concepts and methods

STD 105-0005 Failure Mode and Effect Analysis, FMEA

STD 100-0009 Terminology for product development and production

9 Reference to this standard Reference to this standard on drawings or other design-engineering documentation shall be made through a reference standard or directly with the following note:

SPECIAL CHARACTERISTICS STD 105-0007

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HUB

10 Example How to connect a D-FMEA with the application of special characteristics The purpose of this example is to visualize how Product Risk Management (D-FMEAs) and the identified risks are connected to special characteristics and managed through the application of risk-reduction actions. The example has been adjusted for educational purposes.

1. Identify the System-of-Interest and its context, interfaces and functions. Example: Performing D-FMEA of a Hauler Axle identifies that the hub can have safety-related failure modes.

2. The Product Risk is managed through the application of a D-FMEA. Example: Extract of D-FMEA for hub.

a. There are risks identified for Volvo CE’s hardening process at plant SE-75 that require Quality Assurance. The customer consequence is severe (S = 10, RPN = 600, which by VCE-internal rules is not tolerable), thus triggering Risk-Reduction Actions and “Potential” need for special characteristics.

b. A criticality for supplied forging material quality (specified in TR (Technical Requirements)) and a need for Quality Assurance of the supplier and the supplier process through application of APQP (Advanced Product Quality Planning) are identified. The customer consequence is severe (S = 10, RPN = 480, which by VCE-internal rules is not tolerable), thus triggering Risk-Reduction Actions and “Potential” need for special characteristics.

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3. The Technical documents are updated as a first step, released in B-status to Operations (SE-75) and Purchasing & Supply Management to feed APQP. The D-FMEA (as depicted in the image above) is communicated together with the Drawing to Operations and Purchasing & Supply Management.

Example – Drawing of hub with areas to be hardened

4. Operations in SE-75 perform a P-FMEA for the Hub unit and hardening process, see image below. The P-FMEA identifies a number of required quality-assurance actions, such as Quality Assurance of supplier and supplier processes and implementation of a SPC in the “Hub hardening line” at SE-75 Operations.

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5. Purchasing and Supply Management initiate an APQP. Based on the D-FMEA, with the objective to Quality Assure Supplier and Supplier processes. As results are achieved, objective evidence of achieved results and Quality Assurance work is communicated to the D- and P-FMEA for documentation and updating of rating.

6. The D-FMEA is updated with respect to performed Quality-Assurance actions and the achieved results communicated from the P-FMEA and APQP. As can be seen, the Severity S = 10 remains but RPN has been reduced. This means that with the Quality-Assurance processes and products in Operations and at the supplier, the required product quality can be achieved. However, the [CC] will need to remain on the drawing and the drawing is C-released! See updated D-FMEA below.

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7. The Operations Statistical Process Control (SPC) triggered by Special Characteristics [CC]. The Operations process requires the development and Quality Assurance of a Statistical Process Control (SPC) and documentation thereof, including the requirements triggered by Special Characteristics of the type [CC]. An example can be seen below.