User instructions

Prior to starting to build a Nest table, go to 'Console \ parameters \ material management' and first check that the material to be used exists in the material library. If not, then enter the material characteristics as required and save. Material widths entered should be less than the actual roll width to allow for edge salvage. Note also that automatic nesting seems to require that the material width entered is wider than the parts by at least 2mm, for successful automatic placement of patterns .

5.1 New Nest Tables

Now start compiling the new Nest table(s) of the material(s) which make up a single part. Open 'Console' icon, select 'Programs \ Nest management'.

• If starting a new Nest table enter its name in the Nest name field. Due to the limited number of characters available in this field,(8), the following convention for part number abbreviation should be adopted:- e.g. Boeing part number 116A5441-25, Lightweight plies, rev A become B44125La.NST C-17 part number 17P6W8409-2, Standardweight plies, rev B become C40902Sb.NST The .NST extension must be included otherwise the table will not be correctly saved. Any more than 8 name characters entered will cause an error at the Postprocessing stage.
• Next, enter the material to be used. The material must be present in the material library, see above. If a part comprises different materials e.g. Standard and Lightweight cloth, then a separate Nest table must be generated for each set of plies within the part which use a common material.
• Next, enter the ply identity. Completion of the 'IGES file transfer record' will assist with correct ply identification. Enter the ply number in as brief a form as possible, e.g. '1', not 'ply1'. As this field will be printed on each individual piece of material, it will eventually include the part number as well as the ply number. However, if the Nest table will comprise many plies, it is far easier to edit-in lengthy part numbers as a block, after the Nest table is completed, rather than type them in individually for each ply at this stage, see below. The id. number allocated to each ply should reflect the position of the ply in the part as a whole, not its position within the nest of plies, which use a common material Use a letter to follow ply number where a single layer of material in the lay-up has been divided into individual pieces, i.e. if layer 1 has 3 plies, these are:- 1a, 1b, 1c.
• Set the quantity or number of copies required of a given ply, this will usually be 1
• Set the rotations allowed for the particular ply, usually 0, 180 deg.
• Select the shape file required. In the 'pattern' field, click the lower of the two selection buttons, this opens the grafic_b directory. Change the 'files of type', to IGES and select the individual IGES file required for the particular ply and open it. This IGES file id. will now appear in the pattern field.
• Next press 'Add line', this initiates Pre-processing of the IGES file. A small black DOS screen will appear whilst this occurs. This converts the IGES file to a GEO file. The GEO file identity will now appear both in the pattern field and its full details in the lowest large field at the bottom of the page, to which the details of each individual pattern file are automatically added as they are converted.
• Enter the identity of the next ply required, change the allowed rotations as necessary, select the appropriate IGES file, then "Add line" and continue to build the Nest table ply by ply in this manner
• Include the machining test piece (IGES file no B00196), at 0 deg only, in every Nest table produced and identify this as "QA". This may be used as a routine check on the function of the cutting machine.
• Once the table is complete save the nest before doing anything else The success of pattern transfer can now be checked by selecting each line in turn, then 'Grab line \ Menu \ Geoviewer'. This should then display the pattern. Normal conversion of an IGES file of identity e.g. B00123.igs will produce 1 GEO file of identity Gb001230.000. If no pattern, or a pattern fragment is displayed, or if more than one GEO file has been created, i.e. Gb001230.000 & Gb001231.000 etc, then there is either a problem with the IGES CAD data format, (which should then be rechecked for the errors described in Section 2 ), or the Pre-processor is incorrectly set, see Section 4.
• The full part / ply identifications can now be included using the 'Edit as file' function. Selecting this displays the text of the saved Nest table. To now edit-in the full part number to the 'ply field', select the first line. Type in the full part number ahead of the ply identification already present (e.g. 6a), to a maximum of 12 characters, thus for Boeing 116A5441-22 ply 6a , type: B5441-22/6a The first part of this number i.e. B5441-22/ may now easily be highlighted, copied and pasted onto each subsequent line as required, using the edit function.
• Any typographical errors may now also be edited
• Save the edited table
• Print out the table, select File \ print

5.2 Existing Nest table, additions to

This may be necessary, for example, to add new plies to a Nest or to replace one of the existing plies contained within the Nest table with a new IGES file. Again access the table from "console \ nest management" In these cases double clicking the button to the right of the Nest name field opens the partdef directory from which the required existing Nest table, (******.nst) may be selected and then loaded. Additions can then be made to the table by the same pre-processing method as above. Again, save the modified table.

5.3 Existing Nest table, editing of

This may be required if, for example, part or ply identities are revised. The table may be accessed and edited directly from the partdef directory, or as above and edited using the "Edit as file" function.

Editing of the Nest table is now completed and should be saved. This table may now be used for generating Nest results, and machine part programs, either by the Automatic or Interactive (manual) method.

Prior to starting Interactive or Automatic nesting, which will both call up the Post- processor, the settings of this may need to be first checked. Exit "Nest management" .

Interactive (manual) nesting will usually result in a better material utilisation for the variety and complexity of shapes likely to be encountered in many aircraft parts and this will normally be the next stage.

However, if Automatic nesting is to be used, and both the Nesting sequence selection method and the Post-processor parameters are known to be set as required, then Automatic nesting may now be started, directly from the Nest management screen, (call this up as necessary from console), by selecting "Menu \ Start scheduler" (now go to section 7.2).

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