Gripping | ECAD WIKI

Component Description

Mon, 12 Sep 2022 00:00:00 +0000

Before reading these implementation guidelines, it is highly recommended to read the “Description of Parts” section in the VEC Online Model Description.

This section explains the concepts for the representation of part master data and component specifications in the VEC. For a general explanation of the terms, see the parent section Product Definition. If you search information about specific component types e.g. wires, connectors etc. see Component Types

Aspects of a Component Description

Due to the various supported use cases, the VEC’s concept for component specifications is designed modular. The figure above contains the most relevant elements

Note: The picture is for illustration purpose only and is taken from a current VEC version at the time of writing. The classes, attributes etc. might have changed in the mean time.

The unique identification of a component is its PartVersion. It is serves as an identifier and contains only additional PDM information like Approval,Creation or ChangeDescription. The actual description of the properties of a component is done via PartOrUsageRelatedSpecifications, whereby each specification covers only a certain aspect of the component. A holistic description of a component is a combination of multiple specifications, but no more than one of a specific specification type at a time. Those specifications can be divided into two groups:

General Component Data: Specifications in this group describe general properties of components that are applicable to all or at least a large group of components. For example:
- GeneralTechnicalPartSpecification for common properties like weight or material for all component types.
- PlaceableElementSpecification for components that have an explicitly defined position in the harness topology lik wire protections, connectors or fixings.
- LocalGeometrySpecification for information about the component’s geometry model, e.g. the bounding box, transformations, segment connection points.
Component Characteristics: Specifications in this group describe properties that are very specific for a certain component type, e.g. WireSpecification for wires or ConnectorHousingSpecification for connectors. In most cases, a part can be clearly assigned to one of these categories. However, there can be cases of “hybrid” components that fall into more than one category. In this case, the PrimaryPartType defines the primary character of the components. A detailed description can be found here: “Description of Parts”.

Unclassified / Custom Component Types

The VEC natively supports a wide range of component types and attributes for them. Nevertheless, this list is probably not exhaustive when considering which component types could potentially appear in the BOM of a wire harness and could also be added by future developments.

Currently, the list of directly supported types is derived from the specific requirements of the VEC and is focused on those components that have a specific relationship with other components in the harness (e.g. wires/connectors) and whose attributes play a strong role in the selection processes during development.

However, following its principle of openness and extendability, the VEC provides a possibility to add such components, that are not specifically supported by it, in a defined way as user/process defined components. The necessary elements to do this are:

The PrimaryPartType to use is Other.
“General Component Data” can be added with corresponding specifications analogous to a regular component (see above).
The “Component Characteristics” is expressed by an instance of PartOrUsageRelatedSpecification itself (no subclass).
The concrete type of the component (for regular components expressed by the PrimaryPartType), is defined in the PartOrUsageRelatedSpecification.SpecialPartType-Attribute.
Specific attributes of the “new” type (not available via “General Component Data”) can be added as CustomProperty to the PartOrUsageRelatedSpecification.
Instancing is done via a SpecificRole (see chapter “Instances of undefined Components” in the Specification for Details).

An example in XML of such a custom component can be found in the XML Listings section at the end of this page.

Gripping Features

This section applies to VEC 2.3 and later. The class GrippingFeature and the attribute GeneralTechnicalPartSpecification.SupportedGrippingFeatures were introduced with version 2.3.

The handling of components in an automated assembly process (e.g. by a robotic gripper) requires that the gripper can engage the component reliably. Standards such as DIN 72036 therefore require components - connector housings in the first place, but grommets, covers or fixings just as well - to provide standardized geometries for the form-fitting gripping during handling and mating processes.

Since this is a property of any component and not of a specific component type, it is part of the “General Component Data” and described with the SupportedGrippingFeatures of the GeneralTechnicalPartSpecification. A GrippingFeature is identified by a Key, whose meaning is defined by a ReferenceSystem - the same pattern that is used for Material or Color (see Physical Properties).

In contrast to Material or Color, the values of SupportedGrippingFeatures are not alternative representations of one and the same value. They are the set of features the component actually provides. A component may therefore declare several entries for the same ReferenceSystem, as long as their Key values differ. The combination of ReferenceSystem and Key must be unique.

It can be assumed that two components declaring the same Key in the same ReferenceSystem can be handled by the same gripper. This is what makes the information usable for a variance analysis: counting the distinct ReferenceSystem / Key combinations over all components of a harness yields the number of different grippers a production line has to provide.

If a component supports no standardized gripping geometry at all, the attribute is simply absent. There is no dedicated “no gripping feature” value - an empty list is not distinguishable from “not specified”, which is the regular VEC behaviour for optional information (see Content Requirements).

Reference Systems for Gripping Features

The ReferenceSystem is a free string, so the same standard can be written down in different ways. For the variance analysis described above to work across suppliers, the spelling has to be agreed upon. The following values should be used:

Reference System	Value of ReferenceSystem
DIN 72036	`DIN 72036`
A company specific system	The company name, consistent with its usage for `Color` and `Material` (e.g. `ACME Inc.`)

XML Listing

The listing below shows a connector housing that supports two different gripping features of the same reference system and one company specific feature. The gripping features are located in the GeneralTechnicalPartSpecification, the connector specific data in the ConnectorHousingSpecification. Both describe the same PartVersion.

<DocumentVersion id="id_00001">
 <DocumentType>PartMaster</DocumentType>
 <ReferencedPart>id_part_4711</ReferencedPart>
 <Specification xsi:type="vec:GeneralTechnicalPartSpecification" id="id_gtps_1">
 <Identification>GTPS_4711</Identification>
 <DescribedPart>id_part_4711</DescribedPart>
 <SupportedGrippingFeatures id="id_gf_1">
 <Key>AR-1</Key>
 <ReferenceSystem>DIN 72036</ReferenceSystem>
 <Description>
 <LanguageCode>en</LanguageCode>
 <Value>Automation rib, type 1</Value>
 </Description>
 </SupportedGrippingFeatures>
 <SupportedGrippingFeatures id="id_gf_2">
 <Key>AR-3</Key>
 <ReferenceSystem>DIN 72036</ReferenceSystem>
 </SupportedGrippingFeatures>
 <SupportedGrippingFeatures id="id_gf_3">
 <Key>GRP-A</Key>
 <ReferenceSystem>ACME Inc.</ReferenceSystem>
 </SupportedGrippingFeatures>
 </Specification>
 <Specification xsi:type="vec:ConnectorHousingSpecification" id="id_chs_1">
 <Identification>CHS_4711</Identification>
 <DescribedPart>id_part_4711</DescribedPart>
 </Specification>
</DocumentVersion>

`PartMaster` - DocumentVersions

Part Master Documents

A part master document describes the properties of a component or a group of components (a PartVersion or a set of PartVersions). It can be recognised with the DocumentType = PartMaster. A schematic illustration can be found in the figure on the right side. It contains some general purpose specifications (highlighted in light blue) and component characteristics (highlighted in strong green), in most cases one. Those specifications are not mandatory and only necessary if the corresponding information aspect is relevant in the use case and can be provided.

Additionally, the document could contain auxillary specifications that are required for a complete component description (in the illustration the CavitySpecification and SlotSpecification highlighted in light green).

The emphasis here is on “could”, as this is a quite common case, but a process-specific interpretation of component definitions. For example, if the cavity system is described and released together with the connector (in the same document), it makes sense that the corresponding specification is included in the same DocumentVersion. However, if the cavity system is defined and released independently, i.e. in a separate document, and used by multiple connectors, it would be appropriate to place it in its own DocumentVersion and reuse the information in the document of the connectors (see Reuse of Documents).

Content Requirements

In an omniscient view of the world, it would be possible to formulate logical constraints and minimum requirements for the content of a PartMaster-Document, such as mandatory content or a logical relationship between the PrimaryPartType and the types of descriptive specifications that have to be used. For example, it could be stated that each component should have a GeneralTechnicalPartSpecification and one PartOrUsageRelatedSpecification corresponding to its type (e.g. a ConnectorHousingSpecification when the PrimaryPartType = ConnectorHousing).

However, a given VEC file can only be a fragment of this complete picture. The availability of information in a VEC depends on the specific use case, the process, the point in the process, the degree of maturity of the tooling, “need to know” and IP-protection policies and many more. Therefore, even if there are logical constraint, they are not enforced in the VEC.

XML Listings

The listing below contains an example of the general structure of a PartMaster VEC, additionally it does not contain a regular VEC component, but also illustrates the usage of “Custom Component Types”.

<vec:VecContent id="id_00000" xmlns:vec="http://www.prostep.org/ecad-if/2011/vec">
 <VecVersion>2.0.1</VecVersion>
 <GeneratingSystemName>VEC Samples</GeneratingSystemName>
 <DateOfCreation>2022-10-07T00:00:00</DateOfCreation>
 <GeneratingSystemVersion>0.0.1</GeneratingSystemVersion>
 <DocumentVersion id="id_00001">
 <CompanyName>prostep ivip</CompanyName>
 <DocumentNumber>D-213454-143-31</DocumentNumber>
 <DocumentType>PartMaster</DocumentType>
 <DocumentVersion>1</DocumentVersion>
 <ReferencedPart>id_00007</ReferencedPart>
 <Specification xsi:type="vec:GeneralTechnicalPartSpecification" id="id_00002" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
 <Identification>P-213454-143-30</Identification>
 <DescribedPart>id_00007</DescribedPart>
 <ColorInformation id="id_00003">
 <Key>RD</Key>
 <ReferenceSystem>IEC 60757</ReferenceSystem>
 </ColorInformation>
 </Specification>
 <Specification xsi:type="vec:PartOrUsageRelatedSpecification" id="id_00004" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
 <CustomProperty xsi:type="vec:NumericalValueProperty" id="id_00005">
 <PropertyType>power</PropertyType>
 <Value id="id_00006">
 <UnitComponent>id_00008</UnitComponent>
 <ValueComponent>1.21</ValueComponent>
 </Value>
 </CustomProperty>
 <Identification>P-213454-143-30</Identification>
 <SpecialPartType>FluxCapacitor</SpecialPartType>
 <DescribedPart>id_00007</DescribedPart>
 </Specification>
 </DocumentVersion>
 <PartVersion id="id_00007">
 <CompanyName>prostep ivip</CompanyName>
 <PartNumber>P-213454-143-30</PartNumber>
 <PartVersion>1</PartVersion>
 <PrimaryPartType>Other</PrimaryPartType>
 </PartVersion>
 <Unit xsi:type="vec:SIUnit" id="id_00008" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
 <SiUnitName>Watt</SiUnitName>
 <SiPrefix>Giga</SiPrefix>
 </Unit>
</vec:VecContent>

Connectors

Thu, 29 Nov 2018 00:00:00 +0000

Modular Connector

A modular connector is a type of electrical connector designed to support flexible, configurable assembly using interchangeable subcomponents, typically called contact modules or inserts. Instead of having a fixed internal structure, a modular connector provides modular slots into which different contact modules can be inserted, depending on the application’s electrical or mechanical requirements.

This approach allows for highly adaptable connector designs that can accommodate different pole counts, signal types, or layout constraints—all while reusing standard housing and interface components. Modular connectors can also serve as a means to break down large wiring harnesses into smaller, automatable subassemblies, enabling more efficient and scalable manufacturing processes.

Modular Connector (Illustration)

The figure above illustrates an example connector used in this implementation guideline. The collector housing 4711 has a regular slot A with a single cavity 1. It has two inserts (also referred to as contact carrier or contact module) 4712 & 4713 have one or two cavities respectively. On the right hand side, you can find a possible mating connector for the assembly variant using 4713.

Component Description

Modular Connector

The object diagram above shows the component master data definition of the example. Each element (4711, 4712 & 4713) is primarily defined by a ConnectorHousingSpecification. The collector housing 4711 defines the two inserts as valid accessory with a PartRelation. This is done with generic part relation modelling (see Accessories). The semantic of the illustrated example is, that you have to choose between 4712 or 4713 to achieve a valid assembly configuration of 4711.

As explained in the corresponding implementation guideline, the PartRelation represents a position in the accessory parts list of the collector housing. By referencing this position from the ModularSlot as allowedInserts, the elements referenced by the PartRelation are identified as such.

All relations between the collector housing and the inserts are only based on PartVersion links and ID matching. This supports the distribution of part master data with one VEC file per component.

The next paragraphs apply to VEC 2.2 and later.

In addition to that, the ModularSlot can define a CavityLayout for each valid assembly variant to define an indidivdual Cavity numbering for inserts when used in this ModularSlot. On the left hand side, a MappingSpecification is used to create link between the insert 4713 and the CavityLayout 2 (the mapping of 4712 is omitted in the diagram).

The CavityLayout and the virtual Cavitys in it could be also used to create a Mapping with a mating connector (not shown in the diagram).

Instancing

Instanciating Modular Connectors

The diagram shows the instantiation of modular connector (previous example). On the left hand side of the diagram the component description of the modular connector is shown (similar to the previous example). On the right hand side the instancing of such a modular connector is shown.

Both parts of the modular connector (the housing and the insert) have their own PartOccurrence. The ModularSlotReference defines which inserts are actually used in the specific context and references their ConnectorHousingRoles to name the concrete housing instance directly.

Note: As a wiring harness is often described in a 150% scope, it is possible that a ModularSlotReference references more than one ConnectorHousingRole as usedInserts. In these cases the variant management mechanisms have to ensure, that in a concrete case only one insert is used. This can be either done explicitly with PartStructureSpecifications or implicitly with a VariantConfiguration.

Segment Connection Points

Example of Multiple Segment Connection Pints

The picture above shows an example of connector with multiple segment connection points (sometimes also called bundle postion / connection points). The segment connection points are marked with red circles. Such connectors have multiple entry points for wires, that can be used alternatively or at the simultaniously. The geometric position of the segment connection points is different, that they have to be treated individually, so each segment connection point is accessed via an individual SegmentConnectionPoint

Instanciating Segment Connection Points

The example shows a connector that has two cavity, that are only reachable through different segment connection points. By associating these SegmentConnectionPoints with corresponding PlacementPoints the SegmentConnectionPoint become ‘placeable’ on nodes in the topology of a harness.

Wire Addons

Cavities

Cavity Add-Ons

This example shows how add-ons for cavities in a connector could be defined. In this example, the ConnectorHousingSpecification has two different SegmentConnectionPoints. Each of them is defining it’s own CavityAddOn. So depending on the SegmentConnectionPoint used, a Cavity can have for example 50mm as well as 150mm as Add-On.

Modular Slots

Add-Ons for Modular Slots

If a ConnectorHousingSpecification has ModularSlots, the Add-ons are not defined individually for all cavities for all possible inserts, but only per ModularSlot. The Add-On defined in the ModularSlotAddOn, is the Add-On need to reach the ModularSlot from the corresponding SegmentConnectionPoint. The add-on needed to reach a certain cavity in an used insert, can be obtain from ConnectorHousingSpecification of the used insert.

ConnectorHousingCap

Wire Add-Ons for the Usage of Caps

Wire add-ons caused by cap’s are defined in the ConnectorHousingCapSpecification. The specified value is the add-on required to reach the SegmentConnectionPoint of the ConnectorHousing from the entry point of the cap.

Gripping Features and Reference Surfaces

This section applies to VEC 2.3 and later. The class GrippingFeature and the attribute GeneralTechnicalPartSpecification.SupportedGrippingFeatures were introduced with version 2.3.

Connector housings are the primary driver for the description of gripping features, because they are the components a gripper has to handle and mate in an automated assembly process. Gripping features are however not a connector specific property: they are described with the SupportedGrippingFeatures of the GeneralTechnicalPartSpecification of the component, which allows the same information for grommets, covers or fixings. See Component Description for a detailed explanation.

A connector housing typically carries two pieces of handling relevant information, which shall not be confused with each other:

Concept	Located at	Describes
SupportedGrippingFeatures	`GeneralTechnicalPartSpecification`	The features (e.g. an automation rib) that allow the form-fitting gripping of the component by a gripper during handling and mating processes.
`ReferenceSurfaceDefinition`	`ConnectorHousingSpecification`	The contact surfaces of the housing towards a work piece holder, including their tolerance limits. They support the accurate determination of cavity positions, e.g. during the insertion process.

A connector housing can, and typically will, be described with both.

Gripping | ECAD WIKI

Component Description

Unclassified / Custom Component Types

Gripping Features

Reference Systems for Gripping Features

XML Listing

PartMaster - DocumentVersions

Content Requirements

XML Listings

Connectors

Modular Connector

Component Description

Instancing

Segment Connection Points

Wire Addons

Cavities

Modular Slots

ConnectorHousingCap

Gripping Features and Reference Surfaces

`PartMaster` - DocumentVersions