Functions - Assembly Nesting, First Part

This function is used to start a nesting of an assembly part. The name of the nest job is given and if OPERATION COMPLETE is given the name of the nest job will be the same as the name of the assembly part. The user can then select the assembly part to be nested.

The assembly part is presented on the screen with the side turned upwards which contains most blasting contours. In this process the assembly part may have been reflected in the x-axis. The user has then the option to rotate the assembly part 180 degrees before it is automatically nested.

The circumscribed rectangle of the assembly part is used as a temporary raw plate. To this raw plate is added the excess of type EXC_TYPE_3 for the piece parts. If no such excess has been defined default excess values are used, given by the default parameter ADDITIONAL_EXCESS.

If a station for preparation of the piece parts is available (controlled with the default parameter IND_PART_NESTING) the PLMC now enters the individual parts nesting mode. Otherwise the temporary raw plate is used as the final raw plate.

Individual Part Nesting

To facilitate the welding of the piece parts to form the raw plate to the nesting of the assembly part, it is necessary to define one side as a reference side. This side must always be straight. To do this the user simply points on the outer contour. If the x-coordinate of the closest segment on the outer contour is smaller than the x-coordinate of the mid-point of the circumscribed rectangle of the outer contour, the left side is chosen as reference side.

The system will now sort all piece parts belonging to the assembly part in ascending y-coordinate order. In this way the piece parts will be treated in the correct order.

For each piece part the user now has to defined the raw plate to be used. The selected raw plate is automatically positioned around the piece part. The default part to plate distance is also taken into account. If the raw plates are selected from a list, only the raw plate which are big enough are listed.

The least size is determined by the size of the piece part itself, the default part to plate distance, the welding tolerance for 'small' piece parts. It must be possible to have room for the welding tool, so the raw plate for small piece parts which not are rectangular in shape need to be somewhat larger then the piece part. The welding tolerance is given by the default parameter WELD_TOLERANCE.

The size of the raw plate is also dependent on the reference side. If one of the piece parts has half the length of the assembly part and is placed to the left on the assembly part, the necessary length of the raw plate will be the length of the assembly part if the reference side is to the right.

When the raw plates for all piece parts have been defined, the user has an option to let the system create rest plates automatically. This is only done if the size of the rest is large enough. The size is controlled with the default parameters for this station. A vertical cut will be created at a distance from the piece part. This distance is dependent on the presence of EXC_TYPE_3, cf above. For small piece parts the welding tolerance is also used.

Before the final raw plate is created the system adjusts the individual raw plates so that the reference line will be straight. The temporary raw plate is then replaced by the final one.

Each piece part is nested on one raw plate, so the individual nesting ends up with a number of nested plates. The name of an individual nesting is

<assembly nest><order><ind number>

where <assembly nest> is the name of the assembly nesting, <order> is the order number for the current individual nesting (starting at 1) and <ind number> is the total number of piece parts for the current assembly part. The assembly nesting ABC with 5 piece parts will result in the individual nestings ABC15, ABC25, ABC35, ABC45 and ABC55.

There is however only created one burning sketch for all the individual parts. The sketch is automatically updated with the following data:

• individual part geometry

• the geometry of the rawplates

• texts with individual part dimensions

• texts with individual nesting data

• texts with raw plate dimensions

• side indication

The PLMC now resumes the assembly nesting mode.