Mercedes-BenzDate Published: 2008-07 Total No. of Pages: 12 Department: PWT/VWK Person in Charge: Stefan Schlayer Tel.: +49(0)7031 90-44275 Person in Charge: Thomas Zehnder Phone: +49-(0)711 17-39150 DBL 6218 Supply Specification Elastomer mounts, isolators and bushings Foreword DBL 6218 describes the supply specifications for elastomer mounts, isolators and bushings. The individual points and requirements shall be fulfilled in line with the Mercedes development process (MDS). The supplier is entitled to present alternative solutions. Such solutions shall allow the target to be reached with the same degree of fulfillment and shall be agreed with Daimler AG. Process ownership, product liability and warranty shall remain with the supplier. The supplier shall ensure that these requirements are known to any sub-suppliers and are complied with. Suppliers bear overall responsibility towards Daimler AG. In principle, this Standard does not claim to be complete. In the interest of continuous process optimization, the procedures and requirements shall always be adapted to the state of the art. The latest version of this document is available through the standards information systems of Daimler AG. Changes The following changes were made as against DBL 6218 edition 2002-11: Editorial revision Revision of Foreword Amendment and revision of Sections: 2.1.4; 2.1.9; 2.3.2; 2.3.9; 2.3.6 AK Requirement Specifications LH 10 "Index e“ updated to "Index f“ Product version 11 for elastomer-mounted absorbers added Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das, 2010-12-30) ............... 2010-12-30) ................. 2 Part 1: Development...................... process planning...................................................... Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das........07........ isolators and bushings... other applications Elastomer-mounted absorbers Abbreviated designation: For drawings in the block for material: e............ production .............................................. test methods. 3 Part 2 : General conditions........ Page 2 Contents 1 2 3 Application ...............................................DBL 6218 2008-07................................................g......... versions.. Composite material DBL 6218.......... 12 1 Application Application examples Annex to AKRequirement Specifications 10 Annex 01 Annex 02 Annex 03 Annex 04 Annex 05 Annex 06 Annex 07 Annex 08 Annex 09 Annex 10 Product version (PV) 01 02 03 04 05 06 07 08 09 10 11 Spring isolators/Shock mounts Tension/Compression control arm bushings Subframe bushings Control arm bushings Control arm bushings (rear axle) Track link bushings (rear axle) Differential mounts (rear axle) Drivetrain isolators (with comfort function) Drivetrain isolators (with guide/support function) Elastomer mounts................................... 5 Finite element design of the component with material data under the influence of temperature. stress. dispersion.2. fulfillment of component requirements on trial parts.2. Negative substance list for the selection of materials) 2. these shall be notified to Daimler AG 2.2 Definition of suitable quality characteristics for component description (characteristic curve. QM units shall verify planning and execution of capability certifications (Quality Gate C_B) Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das.5 Planning and determination of manufacturing locations.2 Planning and specification of vulcanization method.2.1.6 Selection of elastomer material.9 Early audit (e. geometry.3 Planning and specification of engineering of vulcanization molds (runner technology. VDA 6. temperature. temperature. Daimler AG Supplier.g.4 Planning and specification of pre-treatment process 2.1. Daimler AG Supplier.2.9 Definition of traceability requirements. determination of most highly stressed zone 2.4 Analysis of environment and definition of any corrosion requirements for components 2. process planning. press-in force). filling time study.2. media) 2.1 Part 1: Development.1. stress. determination of stress and strain spectrum (static-dynamic mechanical. damping. adhesion.7 Definition of appropriate quality characteristics and tolerances for the vulcanization process assurance (fracture pattern.2. machine concept (automation.2.2 Process development Responsible Supplier Supplier Supplier Supplier Supplier Supplier.1. exposure to substances. QM and PWT.1.DBL 6218 2008-07.8 Endurance test. Page 3 2 2.3 Definition of endurance test. 2010-12-30) .1. temperature. scorch Index taken into account 2.7 Consideration of environmental/legal requirements (ELV directive. Daimler AG DAIMLER AG 2.2.2.3 elements M1-3) by EP.8 Filling pattern simulation. the deviating methods shall be discussed with DAIMLER AG 2. reworking) 2. Daimler AG Supplier Supplier DAIMLER AG 2. definition of batch DAIMLER AG DAIMLER AG Supplier Supplier. no confluence of flow fronts in the most highly stressed zone. production Component development Responsible DAIMLER AG DAIMLER AG 2. evidence of the correlation of the test methods and results shall be provided. number of load changes (DBL 6218). In case of deviating test conditions. press-out force) 2.1 Planning and specification of mixing process. mixing plant 2. spatial and temporal volume distribution) 2. characteristic frequency. DBL approval 2.1. All quality characteristics shall be toleranced 2.1.1 Creation of component requirement specifications 2.1.6 Definition of appropriate characteristics and tolerances (derived from process FMEA) for process assurance of other raw materials and semi-finished products (metal part pretreatment) 2. pressure. 7 Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das.1 process model B. initial sample Statement of each cavity from one shot. At least 50 consecutive shots shall be measured for each representative cavity. Preliminary process capability and long-term capability: in analogy with VDA 4.9) and before concept design of the production mold.3 Documentation of incidents permitted provided that Point 2. Determination of capability evidence in analogy with VDA 4.3. Short-term: to be presented at the time of Quality-Gate B / Quality-Gate 2.8 DAIMLER AG shall be notified in time before planned process relocations so that all approvals and sampling are completed before production starts 2. Batches and cavity influences shall be taken into account. production facilities and process. Determination of effects of process parameter changes on quality characteristics (ranges for action limits. 2.5 Filling study on production mold 2.. limit values) 2.2 Capability studies: capability studies shall be performed with regard to product. Process capability evidence shall be coordinated at the early audit (Section 2.7 Assembly of stops under flow 2. otherwise documentation of all product-relevant parameters (vulcanization time. maximum water content in hydraulic systems for supplies to DAIMLER AG.3. 2. Measurement of temperature distribution in mold.1.3.3. qualification of personnel Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier 2. provision of inspection.2).DBL 6218 2008-07.).4 Establishment of capability evidence Responsible Supplier Capability shall be determined on the component based on the defined characteristics and tolerances (Section 2.3.3. Statement and specification of representative cavities (at least 2).3 Production process planning Responsible 2. Page 4 2. test and measuring equipment for the determination of the quality characteristics.9 Creation of test plans.6 Specification and assurance of a toleranced..3. 2010-12-30) .3.2.2 is fulfilled.3. temperature. production test 2.1 Transfer of quality characteristics to intended production process 2. . pressure. Page 5 2. It consists of hexahedron or square tetrahedron elements and is a 3D model. Metal parts are rigid or are simulated by rigid fixing. 2010-12-30) . 2.5. Example: Computer model for the load case transverse force in stop direction (1/8) With regard to the mesh resolution.2 Example Example: Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das.5 Guideline for stress analysis This guideline specifies minimum requirements for the computational design of chassis mounts. 2. Square tetrahedron models require a higher-resolution mesh than hexa models.1 Computer model The computer model represents an elastic model of the elastomer body. a feasible compromise is required between model quality and model size. isolators and bushings using the FE method.5.DBL 6218 2008-07. but are easier to generate using automatic mesh generators. Symmetries may be used (depending on the load case). 2 Boundary conditions Window sheet (not modeled) surface nodes fixed in the 3 translational directions Stop plug (not modeled) Core (rigid element) Central node of the core for applying loads (shift or twist) Non-linearities caused by major deformations and contact changes as well as incompressible material behavior shall be taken into account in the computation.5. Page 6 2.DBL 6218 2008-07. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das. 2010-12-30) . in each case by a given shift / twist of the central node Where high loads are concerned. Computation up to half the maximum shift / twist amplitude is therefore specified as minimum requirement.3. the computational method must be still further developed significantly with regard to the numerical stability and suitable damage parameters.3. 2. half of maximum amplitude Transverse shift Longitudinal shift in direction of mount/isolator axis Cardanic twist around both lateral axes Torsion around longitudinal axis Superimposition of 3 most important load directions.5.2 Working loads (quasi-static). Page 7 2. 2.5 Outlook The reliability of the mount/isolator design should be further increased significantly in future by means of durability computations using in-phase superimposition of the operational forces and accumulation of the material damage. In order to achieve this objective. Pre-optimisation with rotationally symmetric computational models and the application of numerical optimization methods make useful contributions towards the reduction of the modeling and computation input.3 2.5. convergence problems often occur due to extreme mesh distortions leading to an abortion of the computation / long computation periods. however.5. The frequency of load cycles in the different directions shall be taken into account when evaluating the computational results. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das. 2010-12-30) .5.DBL 6218 2008-07.4 Evaluation Spring characteristic for all working load directions Tensile stress distribution (σ1) on the surface of the rubber body Tendency towards wrinkling in pressure area The objective is the development of a mount/isolator contour with sufficient durability and minimum bulk volume by a (tensile) stress distribution which is as uniform as possible and by avoiding wrinkling on the pressure side.1 Load cases Pre-loads (static) Shrinkage due to cooling during production (Δ T) Calibration (radial shift of nodes with contact to sleeve) Assembly (with slotted sleeve) KO position (shift of central node in core) 2.5. 6. The procedure in the event of deviations shall be clearly defined.6.2 2. Daimler AG shall be informed without delay.1.6. Rejected goods shall be collected in marked containers and evaluated.2.2. Contamination resulting from wood chips and packaging material (or conceivably pallets) shall be prevented.1.10 For back-up samples and material returned from production.2. release status.6.6. batch.6. A test instrument for qualitative identity checking (e.g. During incoming inspection. Contingency strategies shall be established for each raw material used. In the event of non-availability of raw materials. An individual test plan shall be created for each raw material.1.3. if possible) with the product designation.6.9 2. Page 8 2. including in particular an overview of the use-by dates. Storage conditions (temperature.1. During material development. care shall be taken that the availability of the raw materials is ensured throughout the intended delivery period.5 2.7 2.11 Mixtures shall be wrapped so that they are protected against contamination. Individual containers (including those already opened) shall be marked clearly (in color.6.1.1.6 2. and the manufacturing and use-by dates.2 Incoming goods area.3. 2.1. material flow During delivery and while storing care shall be taken to ensure that the goods are protected against water (suitable containers.3 2. The warehouse management system shall offer a simple facility for carrying out evaluations of the current inventory.1. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das. 2. The part and material status shall be clearly recognizable.: IR.4 2.2 2. Transportation of parts or raw and finished materials with no risk of confusion shall be ensured.6.1 2.6 Production 2. In addition to the specifications on drawings. No goods may be stored outdoors. own tests shall be performed at least on a random basis (assessment of the supplier's test report is not sufficient).1 2. 2. warehouse.3 2.6. canopy in unloading area).1.1. shelf life. time) shall be specified for each raw material and adhered to. Use-by dates shall be indicated and systematically monitored (including the containers in the mixing room).2 Weighing During the filling of the containers in the mixing room care shall be taken to ensure that raw materials cannot be confused.6.6.1.1 Feed stock / Elastomer / Purchased parts The processability of any new materials presented shall be assured. TGA analysis) shall be available for incoming inspection of raw materials and mixture monitoring. separate material specifications shall be available including all relevant functional characteristics (see DBL 5555). When dates are exceeded. 2010-12-30) .6.DBL 6218 2008-07. purchased part and semi-finished product.8 2.6.6.1 2. the retention period and alternate usage shall be clearly defined.6. The individual components shall be weighed in at the weighing stations (identity and weight) using a computer-based system. The individual batches (including bulk goods) shall not be put into storage until the incoming inspection has been passed.6.3 2.6. An approval system shall exist and shall be applied consistently.6. the raw materials shall be barred. 2. 4.4 2. temperature in mixing chamber. Screen packs shall be protected against confusion. Malfunctions shall be evaluated. the product quality shall be verified by the supplier following restarting. dwell time. documented and relevant action taken. The use of energy as regulation and control variable shall be targeted.DBL 6218 2008-07.5 2.3. injection speed. Page 9 2.6.g. speed.6.4 2. no mixture dropping on the floor). cooling time. 2. these parameters shall be monitored and documented (e.3. Screen residues shall be analyzed with regard to their provenance. speed. The mixing temperature shall be directly monitored.5. During the mixing process. tolerances and frequencies shall be specified. and important parameters shall be defined with tolerances (e. roll mill) which could have an impact on a quality characteristic.6. dynamic pressure.6 Roll mill / Stock blender Homogenization and cooling shall be adapted to the individual mixture and performed in a defined way (roll temperature.9 Analysis of mixture For each mixture.6. Related cooling systems shall be monitored. stamping pressure. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das. 2.5.g. any prevulcanization) shall be determined. a test plan with inspection characteristics.6. mixer. Malfunctions shall be evaluated.3 Loading of mixer The addition of the bulk components plasticizer and carbon black shall be ensured with regard to identity and weight. Contamination of the mixture shall be excluded (e. gap.6.6.6.6. The system shall be protected against contamination.g. including in the event of overweighing. The use of mixtures shall also be described by means of envelope curves in rheovulcameters. number of passes.8 Strainer (if used) The strainer process shall be adapted to the elastomer mixture.6.3 2. 2010-12-30) .2 2.1 2. cooling). documented and relevant actions initiated. All significant parameters for the mixing process shall be specified and toleranced.6. number of changes on the stock blender).6. Following maintenance of production facilities (e.6. Ancillary systems such as cooling and grease pumps shall be monitored and checked. the mixing constituents shall be stored appropriately. These shall be monitored and maintained (e.g.4. 2. 2. Any impact on the vulcanization properties (reduction of shelf life. mesh size of screen. Any carry-over of chemicals shall be excluded. temperature). Mixer loading shall be specified with regard to time.4 The tolerance (< 1 % to be targeted) shall be adapted to the weighed-in portion. In order to avoid temperature fluctuations when loading the mixer.1 2. 2. energy input).6.g.4.2 Mixing process Only the mixing process specified for the product shall be used.6.3 2.5.5. components and component temperature and shall be executed within the tolerances. 2. All important parameters shall be specified and toleranced. temperature.7 Batch-off system Release agents and application quantities shall be specified. 3 An approval sequence.6.g.2 A reasonable durability shall be specified for the blasted and pre-treated parts.2 Changes in the pre-treatment process necessitate a new parts approval process. documented and relevant actions initiated.3 In the event of transportation of accelerated mixtures or other reactive input materials.12 Coating of metal parts 2.12. holding time in drier.6.6. process windows shall be defined. safeguards shall be in place to confirm that the primer has been applied.10 Storage of mixture / Shelf life 2. observed and documented (e. 2.12.12.1 Product-related work instructions including processes. if applicable. abrasive and blasting time.6. 2. documented and relevant actions initiated.12. refrigerated means of transport shall be used. The process for reuse.11.6. cycle time and temperature shall be toleranced and continuously monitored.5 If the limit value is exceeded. different sensitivities of the polymers. The timely replacement of the abrasive shall be ensured.10.11.4 Reference samples shall be available for visual inspection. 2.6. 2. They shall be monitored. In case of 2-component systems. the effects of the transportation shall be examined (the maximum permissible temperature spectra shall be determined and monitored).6. Page 10 2.5 Suitable measuring equipment for layer thickness measurements shall be available (accuracy < layer thickness). 2. if applicable.13.6. 2.6. 2. Permissible dwell times in the extruder shall be known depending on the temperature and mixture and assured by means of rheo-vulcameter curves. Malfunctions shall be evaluated.6. the system shall signal a malfunction. process parameters and vulcanizate properties shall be known.6.11 Input material/metal parts 2. pressure.13. accelerated and non-accelerated mixtures.1 The vulcanization process shall be adapted to the product.6. 2. shall be clearly defined.6.10. 2. Malfunctions shall be evaluated. shall be Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das.6.2 The process shall be described unambiguously in the production plan.6. For the maximum storage period. The process data shall be archived and used for the creation of capability evidence. 2.12. a specific test plan and an adequate shelf life shall be defined for binders. 2.13.1 The storage conditions shall be specified. If necessary.3 The process technology interrelationships between the mixing properties. The blasting results to be achieved shall be monitored by means of suitable tests (surface roughness. 2.DBL 6218 2008-07. 2.13 Vulcanization 2.6. documented and relevant actions initiated.3 The part status shall be visible at any time. 2. 2.13. film break). viscosity). injection pressure.13. shall be available for the blasting of metal parts.4 Where vacuum molds are used. As a result of systematic examinations.6.6.1 All important parameters for the coating and drying process shall be specified and provided with tolerances. Malfunctions shall be indicated.2 The process for reuse of expired mixtures and residual materials. 2010-12-30) .10.6. evaluated. Any subsequent use shall be documented. the following parameters shall be taken into account: temperature in warehouse.11. All important parameters such as vulcanization time. the vacuum shall be continuously monitored.6. 6.13 Parts produced during machine set-up shall be scrapped.8 Process parameters shall be defined specific to each mixture. the relevant process parameters shall be documented.9 After use of a release agent.15.6. 2.6. Any subsequent use shall be documented. care shall be taken to ensure that any pre-crosslinked mass cannot enter the downstream process (ejection of elastomer mass from the cylinder and runner system). the properties of the vulcanizate shall be determined on a batch-by-batch basis (see Section 2. shall be appropriate for its purpose. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das.14.7).15 Determination of part properties (final inspection) 2. care shall be taken to ensure that no air inclusions are formed and that no contamination can enter the system. for visual surface examination (visual inspection).6.1 The maximum water contents shall be defined and toleranced.13.15.7 For the case of system standstill periods. Any preheating.6. 2. e.6. 2.6.14.4 The lighting of test stations.6.6.2. 2. 2. binding tests and durability tests shall be performed at scheduled intervals. the holding time in the mold and the contamination shall be considered.6.3 In-process function tests such as static and dynamic characteristics.13. 2. if possible).5 Reference samples and currently occurring product defects shall be placed at the test stations. 2.13.13.DBL 6218 2008-07. a minimum flash-off time and maximum dwell time in the mold shall be defined.13. 2. Page 11 clearly defined and assured by means of internal release analyses. Following a change of mixture. material identity checks shall also be performed.14 Hydraulic systems 2. 2.6 For mechanical tests on parts.6.13.13.15. Besides the dimensional and functional final inspection. 2.6.15. 2010-12-30) .6.10 The mold history shall be documented with reference to event and shot numbers. 2.6.15. Temperature control facilities are indispensable. 2. 2.6.g. 2. any carry-over of waste rubber shall be prevented.1 Using appropriate measuring methods.6.12 Remaining mold separating skins are not permissible within hydraulic systems.7 The fracture pattern. 2. location and force shall be determined when checking adhesion and vulcanization.6.15. 2.6.6.13.2 Adequate test capacity for the determination of the functional characteristics shall be available.6 The handling of coated inserts shall be specified.15. at least within the context of requalifications.11 Flash shall be removed completely (in one piece. The fluid shall be continuously cleaned.2 During filling. 2. BMW. Porsche and VW) valid within Daimler AG for the marque Mercedes-Benz. The technical requirements specified in existing Daimler AG Supply Specifications have overriding validity. general requirements This Supply Specification renders the Requirement Specifications of the Working Group Elastomer Mounts (AK LH 10) of the Strategy Group Durability/Test Methods (strategy group of the automotive manufacturers Audi. Porsche and VW. the "Purchase Conditions for Production Materials and Spare Parts for Motor Vehicles" and "MB Special Terms" are deemed constituent parts of the agreement. If required.2 General properties of the materials. These Supply Specifications shall additionally be listed on the drawing (e. Copyright Daimler AG 2008 Uncontrolled copy when printed (Product Development: Abhijit Das. Daimler AG. MB-Special Terms. for elastomers: DBL 5557. versions. test methods 3. In addition. 3. stipulations deviating from these test guidelines shall be agreed in individual cases. Daimler AG. Page 12 3 Part 2 : General conditions.1 Field of application.DBL 6218 2008-07. DBL 8585.g. raw materials and supply condition The general conditions in accordance with DBL 5555 and DBL 8585 shall be observed. 3. DBL 5558 or for corrosion protection). Porsche and VW.4 Tests AK Requirement Specifications LH 10 "Index f" of the Strategy Group Durability/Test Methods of the automotive manufacturers Audi. 2010-12-30) . In case of components where the above mentioned product versions cannot be assigned unambiguously or whose stress types are not completely covered by the test guidelines. 3. Daimler AG. BMW. Porsche and VW. BMW. Daimler AG. AK Requirement Specifications LH 10 "Index f" of the Strategy Group Durability/Test Methods of the automotive manufacturers Audi. 3.3 Technical data AK Requirement Specifications LH 10 "Index f" of the Strategy Group Durability/Test Methods of the automotive manufacturers Audi. BMW. the relevant applicable test guideline shall be specifically agreed in each individual case between supplier and buyer.5 Other applicable standards Special Purchase Conditions. DBL 5555.