Issue 2009-06 Class. No.:
02245
Des cr cri pt ptors:
RPS, referenc e poi nt nt s ys ystem
Drawing specifications
Reference point systems (RPS) must be designed in such a way as to enable a component or subassembly to be installed at its destination on a dimensionally stable basis. This system is used as the basis for dimensional acceptance and sampling of components, both internally and with suppliers, and as a basis for the manufacturing process. A component-orien component-oriented ted reference reference system that does does not not satisfy the specifications specifications in this this standard standard must must not be referred to as an RPS.
VW 01055: 1996-12
The following changes have been made as compared to VW 01055: 1996-12: –
Preface added
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Section 2.1 "Component-orie "Component-oriented nted reference system system supplemented", supplemented", Figure 1 added added
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Section 2.2 "Standard "Standard values/characteristics values/characteristics of RPS mountings" supplemented, supplemented, Table Table 1 and Ta‐ ble 2 revised
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Section 3 "3-2-1 "3-2-1 rule" supplemented, supplemented, Figure 3 designations designations revised
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Section 4.1 "RPS "RPS designation" designation" supplemented supplemented and revised, Table Table 3 and Figure Figure 4 added, subse‐ subse‐ quent Figures renumbered
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Section 4.3 "Procedure "Procedure for sub-assemblies sub-assemblies containing containing components components without drawing" drawing" supple‐ supple‐ mented
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Section 5.1 "General" "General" supplemented supplemented and revised revised
Page 1 of 18 Technical responsibility
PKP-P/G
Walter Schlicker
Standards Department
Tel.: +49-5361-9-196708
EKTC/4 Norbert Wisla
EKTC
Tel.: +49-5361-9-48869
Manfred Terlinden
VWNORM-2008-12f-patch1
S I L O N : E L L E U Q
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–
Section 5.2 "Component-oriented reference systems parallel to the coordinate system grid" Fig‐ ure 6 – descriptions and Table revised
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Section 5.3 "Rotated component-oriented reference systems" Figure 7 and Figure 8 – descrip‐ tions and Table revised
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Section 6 "Design requirements" added, subsequents Sections renumbered
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Section 7.1 "General" supplemented
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Section 7.2 "Specification of reference points" last sentence removed
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Section 8 "Referenced standards" added
Page
1 2 2.1 2.2 3 4 4.1 4.2 4.3 5 5.1 5.2 5.3 6 7 7.1 7.2 7.3 8
Scope ................................... .................................... ................................... ................... 2 Theoretical principles ................................................................... .................................. 2 Component-oriented reference system .................................................................. ........ 3 Standard values/characteristics of RPS mountings ....................................................... 4 The 3-2-1 rule ..................................................... .................................... ....................... 6 Designation and drawing representation ................................. .................................... .. 7 RPS designation ................................ ................................... .................................... ..... 7 Drawing representation ................................... ................................... ............................ 9 Procedure for sub-assemblies containing components without drawing ....................... 9 Dimensioning and tolerancing ................................................................... ................... 10 General information ................................. ................................... ................................. 10 Component-oriented reference systems parallel to the coordinate system grid .......... 11 Rotated component-oriented reference systems .............................................. ........... 11 Design requirements ................................ .................................... ................................ 14 Consistency ................................ .................................... ................................... .......... 15 General information ................................. ................................... ................................. 15 Specification of reference points ............................................. .................................... . 15 Specification of functional areas ....................................... .................................... ....... 15 Referenced documents .................................. .................................... .......................... 18
This standard applies to the dimensioning, manufacture, and inspection of individual parts or subassemblies in all product development phases: –
For uniform positioning consistently throughout the manufacturing and inspection areas
–
For assuring equal dimensional references
–
As the basis for tolerance sequence research for process assurance
–
To enable joining without additional auxiliary means
Use of the reference point system ensures that the spatial position of the component is explicitly defined. The position of the RPS element is specified using point coordinates. However, each RPS element is linked with one or more geometry types (surface, ring surface, round hole etc.). Each of the RPS
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elements is given an explicit function within the reference point system, which is apparent from the RPS designation. The RPS elements, or their geometry types, are used to fix the components during the individual process steps of vehicle development. Fixing means that the RPS elements of the component come to rest at the mountings of the joining or measuring equipment. This is normally done by clamping. The method of fixing must be described in Performance Specifications and Test Specifications on a component-dependent, production-de‐ pendent, and test method-dependent basis and must be coordinated with respect to t he manufac‐ turing and measurement equipment. The type and number of RPS elements must be selected to achieve explicit, but not overdetermined, fixing of the necessary degrees of freedom. For components that are not rigid with respect to bending, additional secondary RPS elements must be provided. These secondary RPS elements result theo‐ retically in overdetermination of the component. However, they are necessary to correct unstable areas and deformable component zones in the joining and measuring equipment in such a way as to minimize non-process-relevant deformations. The deformation must be measured and a tolerance for process compatibility must be specified. The RPS elements must be selected with respect to function according to general design guidelines and at the greatest possible distance from one another. RPS elements must be arranged at a position in the coordinate system; that is, they must be orthog‐ onal to the spatial axes. This can also be achieved through embossments parallel to the coordinate system grid.
One of the main ideas on which the reference point system is based is the component-oriented co‐ ordinate system according toVW 01052. A vehicle is dimensioned by means of a global coordinate system (mathematical vehicle coordinate system), whose origin is defined in the center at the location of the front axle of a vehicle (see VW 01059-1, mandatory reference for the vehicle coordinate system is VW 01052), see Figure 1.
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Starting from the axes of this coordinate system, grid lines are extended parallel to the axes, spaced 100 mm apart and penetrating the vehicle theoretically. These grid lines are used to locate all points on the vehicle, i.e., they help to define the position of each component in a vehicle. These grid lines are also used as an aid for dimensioning. A component-oriented reference system is the basis for the reference point system. The origin of the component reference system is defined by the intersection of three reference planes. The reference planes are formed by means of the RPS main mountings defined on the component. For an assembly with multiple parts, these are toleranced with respect to each other. After joining, the sub-assembly is described by a common, component-related reference system. This is formed in one of the following ways: –
By adopting one of the existing reference systems
–
By forming a new reference system based on the existing reference points
–
By introducing new reference points suitable for the respective function, provided that it is not possible to reuse the existing RPS points of individual parts and/or sub-assemblies in a reason‐ able manner
The new reference system is defined with orientation to the function of the sub-assembly.
The mounting holes with high accuracy requirements that are used multiple times, must be built with the appropriate stability. As a rule, the standard values as specified in Table 1 and Table 2 must be used. For holes in RPS surfaces, attention must be paid that the size of the contact surfaces is sufficient and process reliable. The directions of RPS holes must always be arranged parallel to the coordinate system grid. Likewise, the RPS surfaces around holes must be embossed parallel to the coordinate system grid. The specified dimensions must be projected onto the component parallel to the axes.
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Designation
Nominal dimension
Tol. (mm)
Graphical representation
(mm) e g l n , b i s a t e g n l u o g o h u l M p
Round hole
see VW 01077
10 15 Square
+1 20 25 6 x 20 10 x 20
Rectangu‐ lar
s e c a f r u S
+1
15 x 20
∅ 15 ∅ 20
Circle
+1
∅ 25 Radius inner circle: Hole radius or radius runout for plunged holes + 1 mm Ring sur‐ faces
Radius outer circle: Ra‐
+1
dius inner circle + 5 mm. For design see al‐ so Production Equip‐ ment standard 39 D690.
For further standard values, see VW 01077 and PHS 387 "RPS Standard Template Catalog"
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Designation
e l b a g g u l p , s e l o h g n i t n u o M
Nominal dimension W xL
Tol.
Graphical representation
Long hole
see VW 01078 Long hole in angular posi‐ tion
For further standard values, see VW 01078 and PHS 387 "RPS Standard Template Catalog"
RPS points lie in the center of holes (including long holes). For outer skin parts (e.g., for door outer panels, hood outer panels, etc.) that receive RPS surface points, these must be designed 2 mm from the radius runout line (see Table 1, square or rectangle, graphical representation on right).
Every rigid body has six degrees of freedom in three-dimension space – three translational motions parallel to the axes of a reference system and three rotational motions around the axes; see Figure 2.
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In order to support a non-axially symmetric body in an explicitly defined manner, it must be fixed in all six possible motion directions. The 3-2-1 rule provides such an explicit fixing. It defines the following main mounting distribution, for example: 3 mountings
In Z-direction (largest possible surface)
2 mountings
In Y-direction (largest possible length to prevent rotation)
1 mounting
In X-direction (function-related specification in order to prevent translational displacement)
The implementation of this rule is illustrated using the graphical representation in Figure 3.
The three mountings in the Z-direction limit three degrees of freedom: the translation in the Z-direction and the rotation around the X-axis and Y-axis. The pin in the round hole prevents a motion parallel to the axes in the X-direction and Y-direction, and the pin in the long hole prevents a rotation around the Z-axis; see Figure 3. This rule applies accordingly to every other rigid component even if its design is far more complex. In a system of rigid bodies whose elements are connected together using joints or guides, it is nec‐ essary to fix more than 6 degrees of freedom through additional main mountings. For components without inherent stability, additional secondary RPS elements must be defined for support of the component based on RPS considerations. RPS 1 must be the point that fixes the most degrees of freedom.
All RPS points must be included in the part drawing as specified in Figure 5 and Figure 6. The designation of the main reference points, system of rigid bodies, secondary reference points, and fixation directions is based on Table 3. See Figure 4 for designation examples.
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1 to 6
→
H=
hole / pin
1 to 6
→
F=
surface / point
1 to 6
→
T=
theoretical point, formed out of two sec‐ ondary reference points
51 to 99
→
H/F/T
from 101
→
h=
hole / pin
from 101
→
f=
surface / point
21 to 50
→
f/h =
from 101
→
x, y, z
for component-oriented reference systems parallel to the coordinate system grid
from 101
→
a, b, c
for component-oriented reference systems in rotated condition
hole/pin/surface/point
secondary reference points forming a "T" (symmetry)
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The numbering for each individual part and each sub-assembly starts with the main reference points. This RPS designation system is used for explicit function assignment and identification of RPS ele‐ ments for a component or sub-assembly. For a consistent inter-process RPS designation, this designation system is not sufficient on its own. For cross-component functions (application in systems), an identification system building on this basic system description must be used to enable measurement and evaluation in systems. Thus, for ex‐ ample, assignment of a component number offers the possibility of explicit differentiation in systems.
The drawing representation is created according to the valid drawing guidelines. The RPS surfaces must be marked with cross-hatching. If a part does not yet have a drawing, the RPS Dimensions Sheet FE 5151) must be used. As soon as the part drawing exists, the specifications in the RPS Dimensions Sheet must be trans‐ ferred directly to the drawing, or in text macro NO-F232), and must be maintained there.
The RPS points for components without a drawing (w/o drawing) must be labeled by a specified item or part number. RPS tables for parts w/o drawing must be represented for all components in the subassembly drawing. A drawing is available for part 1, but parts 2 and 3 are w/o drawing; see Figure 5.
1)
Stored in KVS (design data administration system) under FEO 000 515
2)
Stored in KVS under NOF 000 023
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Dimensions and tolerances can be entered directly in the drawing or via the RPS table; see Figure 6. The dimensioning of components is generally with respect to the origin of the reference system. The shape dimensions and functional dimensions with tolerances must always reference the origin of the reference system. Example: Within a group of holes, the holes are dimensioned with respect to one another. The position of the hole group is dimensioned with respect to the reference planes. The main location points lie relative to the vehicle coordinate system/reference system in the fixing direction without tolerances. In the secondary direction(s), the tolerances must be specified in con‐ formance with functional requirements by the Design Engineering Department or in the Simultaneous Engineering Team (SET) – see z/c-tolerance in Figure 6 to Figure 8 for 101 fz or 101 fc, respectively. The origin/reference point is apparent in the drawing or table. If two or three fixing directions are fixed in one point, the RPS element must be separated into a hole and surface. For the surface RPS point, the surface in the tolerance zone is set to zero. In the line in which the hole has the zero setting, the tolerance zone for the surface must be indicated with a horizontal dash; see Table in Figure 6. The tolerance values specified in the Tables in Figure 6, Figure 7, and Figure 8 were selected only by way of example. These tolerance values must be specified in conformance with requirements.
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The origin of the reference system is specified by means of a translation and without tolerance in the global vehicle coordinate system grid; see Figure 6.
For rotated reference systems, the theoretical angles of rotation must be specified in the RPS Di‐ mensions Sheet FE 5151) and/or in the drawing table macro text NO-F232). If there is more than one angle of rotation, the angle specification and, thus, the sequence of the rotations must be taken from the drawing. The text "see drawing" must appear in the table in place of the angle of rotation entry. The position of the reference point is determined by its X, Y, and Z coordinates in the global vehicle coordinate system. 1)
Stored in KVS (design data administration system) under FEO 000 515
2)
Stored in KVS under NOF 000 023
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The angles of rotation around the X, Y, and Z axes are entered using mathematically positive or negative values. Positive angles are specified in the counterclockwise direction, while negative angles are specified in the clockwise direction. The horizontal axis is assigned to the zero angle in the coordinate system. The nominal dimensions and tolerances are specified in a, b, and c values in the RPS table. The fixation directions of the RPS points are specified in a, b, c values in t he table and/or drawing, e.g., RPS 1 Hab, see Figure 7 and Figure 8.
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At a minimum, the information for the RPS elements shown in the RPS table must be created and documented in a system in conjunction with the part model (TM – German abbreviation). The design of RPS elements (holes) must be elaborated in the part model, including specification of the hole directions.
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The RPS elements must always be designed on the side described by CAD.
The purpose of the RPS is to achieve a process that is reliable/capable and exactly reproducible and does not rely on adjustments by workers. A consistent use of reference points must be ensured in all manufacturing, assembly, inspection, and installation processes. For separate functional areas, such as the side panel fuel filler door, a functional reference relative to RPS planes is permissible. These are strictly local functional alignments. These can also be overdetermined. Prior to specification of RPS points, the mandatory functions of the individual part and the relevant sub-assemblies must be specified along with their required functional tolerances. Reference points established at the start of a process must be retained as long as possible. To avoid changes of arranged reference points, these will be specified as early as possible during the design and development process in consultation with all areas involved in the manufacturing process. Reference points must be positioned in areas of a component that are stable, will not be changed during further development and/or manufacturing processes, and will remain accessible for mea‐ surement purposes. Reference points on components that move relative to the body during driving operation can only be measured in the as-designed position according to the 3-2-1 rule. The RPS points on components that are used more than once in vehicles and, thus, reference the global coordinate system grid multiple times may be represented in the technical drawing without a global coordinate reference.
When reference points are introduced, attention must be paid to ensure parallelism with the coordi‐ nate system grid (holes and surfaces). In the case of rotated systems, parallelism with the reference planes must be ensured. The RPS points must be manufactured in the tool sequence in which the maximum dimensional stability is achieved. To the extent possible, reference points must be designed according to a standardized geometry (hole, surface), which must be defined in detail. If holes cannot be introduced into a component, surfaces must be chosen for specifying reference points.
Use of the RPS on a complex subarea of the vehicle, such as the dashboard, requires a set-up that is adopted into the development and design system and integrates all parts, individual parts, and subassemblies. A functional area includes all visible and concealed components that, together with their function points, have a direct effect on their adjacent surroundings.
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The specification of reference planes is dependent on the component's geometric position in space relative to its surroundings. The reference planes are the same for a given functional area, that is: components or component groups and their surroundings have the same starting basis; see Figure 9.
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The following documents cited in this standard are necessary for application. In this Section terminological inconsistencies may occur as the original titles are used. Standards with the titles given in German are either only available in German or may be procured in other languages from the institution issuing the standard. VW 01052
Technical Drawings; Representations
VW 01059-1
Requirements for CAD/CAM Data; Representation of Technical Charac‐ teristics
VW 01077
Operating Process: Cutting; Round Holes
VW 01078
Cutting; Long Holes
PHS 387
RPS Standard Template Catalog
