The Technology Database (TDB) is the core of Creo Elements/Direct Sheet Metal. It holds the information about the sheet metal fabrication processes at your manufacturing sites and provides this data to ensure Design for Manufacturability (DFM). Without the TDB, you cannot use Creo Elements/Direct Sheet Metal.
At Creo Elements/Direct Sheet Metal runtime, the TDB data is displayed in selection tables to be used by the designer.
• Fabrication cost information. See
Cost Estimates for details.
Creo Elements/Direct Sheet Metal is supplied with the following default TDB files in LISP format:
sha_shopstable.lsp
Defines the text literals displayed in the column headers of your shop file. You can edit this file to create custom column headers for use in your organization.
sha_demoshop.lsp
This file provides the core information for TDB customization. It contains the definitions (including ID codes, descriptions and dimensions) of all materials and tools used in the demoshop. This file can be copied and customized in order to define custom shops.
sha_demoshop_func.lsp
Includes all bend, hem and offset allowance formulas as well as check functions for tools etc.
sha_costmodel.lsp
Defines parameters and formulas used to calculate fabrication costs.
By default, the English versions of these files reside in the following directory:
For the punch and stamp processes, Creo Elements/Direct Sheet Metal provides further default TDB files in LISP format. See
The Punch Process and
The Stamp Process for details.
Structural Overview
The TDB data is provided to the Creo Elements/Direct Sheet Metal user by shop definition files. A sample shop definition file named sha_demoshop.lsp is supplied with Creo Elements/Direct Sheet Metal. Sample allowance formulas are contained in the sha_demoshop_func.lsp file supplied with Creo Elements/Direct Sheet Metal. The following figure illustrates the structural hierarchy of processes, tables and formulas defined in this sample file.
Figure 1. Functional Structure of the TDB -- General Overview
You can draw upon this structure (including DFM rules and calculation formulas for the fabrication process) when creating your own TDB files.
Customizing the Technology Database
By creating and editing copies of the sample TDB files supplied with Creo Elements/Direct Sheet Metal, your TDB administrator can define a custom TDB to meet the specific requirements of your engineering organization. Refer to the Creo Elements/Direct Modeling Integration Kit for more detailed information:
The following figure summarizes the procedure of adding entries to the TDB.
Figure 2. Maintaining the TDB -- General Procedure
Stage #
Description
1
Create a working copy of a given default TDB file.
2
Use the Technology Database Browser (see
The Technology Database Browser) or any standard text editor (such as vi) to make the required changes in your working copy. For example, you can add your own material stock as well as custom tool types and tool sizes to the database.
3
Load your customized TDB file(s) into Creo Elements/Direct Sheet Metal.
4
New materials and/or tools are now available for selection by the Creo Elements/Direct Sheet Metal user.
Implementing Customized TDB Files
To ensure that Creo Elements/Direct Sheet Metal uses your customized TDB files, you have to create and edit a working copy of the following customization file:
$INSTALLDIR/personality/sd_customize/SheetAdvisor/sha_customize For example, you can create a copy named sha_customize. In this file, specify the customized files you want to load when Creo Elements/Direct Sheet Metal starts. For a customized shop definition file named my_shop.lsp, you would have to add the following line to the sha_customize file:
(sha-tdb-load "my_shop.lsp")
Structure of a Shop Definition File
The TDB is built of one or more shop definition files. By default, the TDB contains only the sha_demoshop.lsp file as a sample shop definition file. Additional shop definition files can be added by your organization's TDB administrator. The default sha_demoshop.lsp file can be used as a reference template for this purpose.
The TDB can contain a single or multiple shop definition files. Each shop definition file represents a real manufacturing site and the materials, tools, and processes used at this site. A shop definition file can have the following structure:
Item
Description
:MATERIALS
Name of the material table for this shop.
:BEND-PROCESSES
List of bend processes supported by this shop.
:CUT-PROCESSES
List of cut processes supported by this shop.
:STAMP-PROCESSES
List of stamp processes supported by this shop.
:BEND-RELIEFS
List of punch tools suited for bend reliefs.
:CORNER-RELIEFS
List of punch tools suited for corner reliefs.
:MITER-BEND-RELIEFS
List of punch tools suited for miter bend reliefs.
:CHECK-DISTANCES
Name of check distance matrix for stamps and punches.
Minimal text at the bend line in the flat drawing. For details see:
Bend Line Text.
:OFFSET-FLAT-TEXT
Minimal text at the offset bend line in the flat drawing. For details see:
Offset Line Text.
:HEM-FLAT-TEXT
Minimal text at the hem bend line in the flat drawing. For details see:
Hem Line Text
:CONTACT
Contact person at manufacturing shop, e.g. "Mr. Moore".
:PHONE
Phone number of contact person, e.g. "007126".
The following parameter is defined implicitly:
:SHOP-NAME
The first parameter of the 'sha-define-shop' function, e.g "demoshop".
Please note that most of these parameters are optional. They can be omitted if you decide not to use the associated functionality. At a minimum, your shop definition files need to contain the :MATERIALS and the :BEND-PROCESSES together with an allowance fallback strategy (formula or table based) and the appropriate text information for the flat drawing (:UP-FLAG, :DOWN-FLAG, :BEND-FLAT-TEXT).
The following example shows the associated section of the sha_demoshop.lsp which complies with the structure described above.
; shop definition
(sha-define-shop "demoshop" ;; Some lines of comments ; materials :MATERIALS
"sheet_metals"
; must ; processes : 'optional' means: ; if not existing: ; for bend/offset/hem/reliefs/corner-reliefs: ; unadvised function parameters entered by hand ; for punch & stamp: ; no functionality available :BEND-PROCESSES ("air_bending"
3. Save the my_shop.lsp file in the appropriate directory.
$INSTALLDIR/personality/SheetAdvisor
4. Append the following line to your sha_customize file:
(sha-tdb-load "my_shop.lsp")
5. When you start Creo Elements/Direct Sheet Metal the next time, the new manufacturing shop definition is loaded automatically so that it is available for selection. If you want to load the new manufacturing shop definition during your current Creo Elements/Direct Sheet Metal session, enter the appropriate load command, e.g.:
6. To use the new manufacturing shop definition, select my_shop in the Shop box of the Shop Based Settings dialog box.
General Structure of Shop Tables
All tables contained in TDB shop definition files have the same general structure. When building your own tables for a shop definition file, be sure to use the structure described below.
Item
Description
:TABLE-TITLE
This line specifies the displayed table title. Use a meaningful name, for example "Material".
:COLUMNS
This line specifies the necessary parameters for a complete material, tool, or allowance description. Use keywords like :RADIUS. Additional columns are possible.
:COLUMN-NAMES
This line specifies the displayed column headers. Use meaningful abbreviations like "Rad" for radius. The column names can be freely modified.
:UNITS
This line specifies the parameter units, for example :mm for millimeter, or :deg for degree; the term nil implies that no unit of measurement is associated with the given entry.
:CONTENTS
Each line defines a specific material, tool, or allowance. Lines can be freely added, modified, or deleted. If you want to use the existing table structure, this is the section where you add your specific materials, allowance values, and tools.
:KEY
This line specifies the key columns. The key column values define one unique table entry such as a tool. If the :KEY line does not exist, Creo Elements/Direct Sheet Metal defaults to the first column as key column. Otherwise enter a sublist of the :COLUMNS entries such as (:RADIUS :ANGLE) for bend forming tools.
:DISPLAY
This line specifies the columns displayed in the tables. If the :DISPLAY line does not exist, all specified columns are displayed in the tables. To limit the display to four columns, enter a four-column statement such as (:RADIUS :ANGLE :PREFERENCE :ADVICE)
:FLAT-TEXT
This line specifies the information displayed as an annotation in the flat drawing in Creo Elements/Direct Drafting or in the MI file, for example (:TOOL-ID). In general, the :FLAT-TEXT keyword consists of a list of :COLUMN entries that the :FLAT-TEXT entry belongs to. For further information see
FLAT-TEXT. For details on the minimal text, see the following section in this chapter:
Shop-Wide Definitions and Fall-Back Strategies
:HELP
This line specifies the name of the Help page called by the table's Help button.
:DISABLE-SORT T
This switch can be used to suppress the sort buttons in the selection table headers.
:SORT-OFF T
This switch can be used to enable or disable the table sort function when the selection table pops up for the first time. Unless this switch is explicitly set, Creo Elements/Direct Sheet Metal uses the default Sort ON setting which enables the sort capability.
:SORT-BY <:COLUMN>
This line enables you to specify a column by which the associated selection table will be sorted (if sorting is enabled). By default, tables are sorted by the first column.
:SORT-BY <:COLUMN> REVERSE
This line enables you to specify a column by which the associated selection table will be sorted in reverse order (if sorting is enabled). By default, tables are sorted by the first column.
The following are special entries for punch and stamp tools:
Item
Description
:PROF_FNC
:PROF_FNC entries specify a parametric punch tool function. This is usually a unique, non-display column entry which appears as a single entry at the end of a table definition.
:TOOL_FNC
:TOOL_FNC entries specify a parametric stamp tool function. This is usually a unique non-display column entry which appears as a single entry at the end of a table definition. Please note that stamp tools need both the :PROF_FNC and the :TOOL_FNC entry.
:PROF_WP
:PROF_WP entries specify non-parametric punch and stamp profiles.
The :MATERIALS statement in the shop definition file points to the table of sheet metal stock available for the associated shop. A sample set of sheet metal definitions is included in thesheet_metals table in the sha_demoshop.lsp file supplied with Creo Elements/Direct Sheet Metal. For details see:
To add a sheet metal material to a shop definition file, either use the Technology Database Browser (see
Adding a Material) or add the new material specification to the "Sheet_Metals" table. The relevant section of this table is shown below.
(sha-define-shop-table "sheet_metals"
:TABLE-TITLE "Sheet Metals" ;; :MAT_ID
Ident. number/string of the material e.g. "7144-0503" ;; :MATERIAL
Under :CONTENTS, add the line which specifies your additional material. In the sha_demoshop.lsp file, each material specification consists of entries for the following columns:
:MAT_ID
Material identity number.
:MATERIAL
Material description or name.
:THICK
Material thickness.
:MIN_BEND_RAD
Minimum bend radius.
The following line is an example of an additional material specification.
("3458-1209" "AA 5067" 2.00 0.6 )
The material ID number of this new material is 3458-1209. Its material description is AA 5067. The material thickness is 2.00 mm. The minimum bend radius is 0.6 mm.
For materials you must not edit the :KEY line. :MATERIAL and :THICK are used as unique keys.
When you have added a new material to your TDB, be sure to define an appropriate allowance mechanism. Refer to the following topics for details:
To change a material of a shop definition file, use the Technology Database Browser (see
Editing a Material) editing the following entries in the CONTENTS section of the associated material table:
• MAT_ID
• MATERIAL
• THICK
• MIN_BEND_RAD
For example, you can replace the "UST 1203" string by "Steel Grade B".
Removing a Material from a Shop Definition File
To remove a sheet metal material from the selection table of a shop definition file, either use the Technology Database Browser (see
Deleting a Material), or use one of the following manual methods:
• Delete the material specification line from the "Sheet Metals" table in the shop definition file.
• Comment out the tool specification line by placing a semicolon (;) in front of it. The advantage of this method is that you can retain existing material definitions for future use and/or for use in other shop definition files.
For example, if you want to exclude 1.6 mm aluminum from the material selection dialog, place a semicolon in front of the associated definition line. The resulting line in the :CONTENTS section of the "Sheet Metals" table is shown below.
;("8888-0003" "AA 5052" 1.60 0.4 )
Shop-Wide Definitions and Fall-Back Strategies
For certain situations, Creo Elements/Direct Sheet Metal provides shop-wide definitions and fall-back strategies.
Creo Elements/Direct Sheet Metal automatically checks for distance violations during punch and stamp operations.
The system checks the punch or stamp tool you apply against other existing punch and stamp features, against the edges of the sheet metal part, and against any existing bend.
The distance check is based on a TDB table which contains the minimal distances. For each combination of two processes the table lists a factor and a minimum distance. The formula specified next to :DISTANCE-FORMULA in the table uses these entries to calculate the real minimum distance which is valid for the actual material.
The sample formula check-dist provided in the sha_demoshop_func.lsp file calculates the minimum distance as follows:
(declare (ignore sheet_material)) ; to keep compiler quiet until it's used
(let ((dist (* factor sheet_thickness)))
(if (< dist min_value) min_value dist ) )
The example below shows the distance check table for the demoshop provided with Creo Elements/Direct Sheet Metal. The "anonymous" row in the table refers to all outline edges of the sheet metal part, or edges that were created with Creo Elements/Direct Modeling machining commands.
Currently the distance check treats all bend processes, the offset process, and the hem process in the same way. Therefore, the table contains only one bend process entry ("air-bending").
Bend Line Text
The fall-back text for bend lines is defined in the column :BEND-FLAT-TEXT.
This text is written at the bend line in the flat drawing if the regular bend tool could not be found in the bend tool tables.
The following properties are allowed:
:RADIUS
:ANGLE :ALLOWANCE :UPDOWN
The corresponding units are optional, for example:
:mm :RADIUS :deg :ANGLE :mm :ALLOWANCE :UPDOWN
The default units are :mm for length and :rad for angles. The units must stand before the corresponding property. Numbers specify the number of decimal places (to the right of the decimal point) to which the system approximates the following value; for example:
:deg 1 :ANGLE
{#} entries in the leading string refer to the corresponding property in the following list; the first property is {1}. Units and numbers are not counted for the {#} entries. For example:
The minimal text for offset bend lines is defined in the column :OFFSET-FLAT-TEXT.
This text is written at the offset bend line in the flat drawing if the regular bend tool could not be found in the bend tool tables.
The following properties are allowed:
:OFFSET_HEIGHT :ALLOWANCE :UPDOWN
The corresponding units are optional, for example:
:mm :OFFSET_HEIGHT :mm :ALLOWANCE :UPDOWN
The default units are :mm for length. The units must stand before the corresponding property. Numbers specify the number of decimal places (to the right of the decimal point) to which the system approximates the following value, for example:
:mm 2 :OFFSET_HEIGHT
{#} entries in the leading string refer to the corresponding property in the following list; the first property is {1}. Units and numbers are not counted for the {#} entries. For example:
The minimal text for hem bend lines is defined in the column :HEM-FLAT-TEXT.
This text is written at the hem bend line in the flat drawing if the regular bend tool could not be found in the bend tool tables.
The following properties are allowed:
:HEM_DIST :ALLOWANCE :UPDOWN
The corresponding units are optional, for example:
:mm :HEM_DIST :mm :ALLOWANCE :UPDOWN
The default unit is :mm for length. The units must stand before the corresponding property. Numbers specify the number of decimal places (to the right of the decimal point) to which the system approximates the following value; for example:
:mm 2 :HEM_DIST
{#} entries in the leading string refer to the corresponding property in the following list; the first property is {1}. Units and numbers are not counted for the {#} entries. For example:
Any tool table in the TDB undergoes a number of checks to verify that the tool is valid for a given combination of material, thickness, radius and angle. The result of these checks is written to the Advice column of the tool selection table in the Creo Elements/Direct Sheet Metal user interface. The system can also check for minimal lip length, maximal bend force, and maximal bend length.
The appearance of each tool selection list in the Creo Elements/Direct Sheet Metal user interface depends on the setting of the Advice column in the associated tool table:
• If the Advice column in the TDB tool table exists and if it is specified in the :DISPLAY row, the associated Advice column plus the result of the validity checks will be displayed in the tool selection table in the Creo Elements/Direct Sheet Metal user interface. The :CONTENTS section of the Advice column should be filled with "-" (dash) entries.
• If the Advice column does not exist in the TDB tool table or if it is not included in the :COLUMNS statement, the associated Advice column will not be displayed in the tool selection table in the Creo Elements/Direct Sheet Metal user interface. All tools will be displayed if no Advice column is provided.
An example of the use of this Advice toggle is provided in
Adding a Bend Tool.
The Advisor check functions implemented in Creo Elements/Direct Sheet Metal are included in the sample sha_demoshop_func.lsp file. Each of these check functions is called with the complete context information of the selected tool as well as the sheet material and the sheet thickness.
Depending on the outcome of its Advisor checks, Creo Elements/Direct Sheet Metal returns either t (LISP "true") if no rule violation was found or f (LISP "false") plus an associated error message if a rule violation was found.
The bend tool check function is called when a bend tool table is generated and/or when the unfold operation scans a bend. The sample bend-tool-check function provided in the sha_demoshop_func.lsp file checks if:
• the given bend angle can be produced by the current tool;
• the minimum and maximum material thickness limits are being complied with;
• the bend radius is equal to or greater than the minimum bend radius defined for the current material.
Offset Tool Check Function
The offset tool check function is called when an offset tool table is generated and/or when the unfold operation scans an offset. The sample offset-tool-check function provided in the sha_demoshop_func.lsp file checks for compliance with the minimum and maximum material thickness limits.
Hem Tool Check Function
The hem tool check function is called when a hem tool table is generated and/or when the unfold operation scans a hem. The sample hem-tool-check function provided in the sha_demoshop_func.lsp file checks if the minimum and maximum material thickness limits are being complied with.
Punch Tool Check Function
The punch tool check function is called when a punch tool table is generated by a PUNCH command. The sample cut-tool-check function provided in the sha_demoshop_func.lsp file checks for compliance with the the minimum and maximum material thickness limits.
Stamp Tool Check Function
The stamp tool check function is called when a stamp tool table is generated by a STAMP command. The sample stamp-tool-check function provided in the sha_demoshop_func.lsp file checks for compliance with the minimum and maximum material thickness limits.
Minimal Lip Length Check Function
Creo Elements/Direct Sheet Metal can check the minimal lip length of the currently used bending tool. If the inquired or calculated minimal lip length is smaller than the planned lip length (for example, with the Add Lip command) the system issues an error message.
The sample check-tool-min-lip-length function provided in the sha_demoshop_func.lsp file looks for a column named :MINIMAL_LIP_LENGTH in the table of the currently used bend process. If the column exists, the system inquires the value of that column. If the column does not exist, the system looks for a column named :DIE_WIDTH. If one of these columns and a corresponding value entry for the selected bending tool are available, the system calculates the minimal lip length using a simple formula. Therefore, to use this formula, every bend tool table should have a :MINIMAL_LIP_LENGTH or a :DIE_WIDTH column.
Maximal Bend Force Check Function
Creo Elements/Direct Sheet Metal can check the maximal bend force of the bending machine and the maximal bend force per meter of the bending tool. In case of problems, this will be shown as advice in the bend tool table. If the Advice button is pressed, the tools that fail on this check are not shown in the bend tool table.
The sample check-tool-max-bend-force function provided in the sha_demoshop_func.lsp file first checks in the bend tools table for columns named :MAX_BEND_FORCE and :MAX_BEND_FORCE_PER_M. If one or both of these columns exist in the table of the currently used bend process, the system inquires the value(s) of the column(s).
With the use of the additional bend table columns :DIE_WIDTH and :PISTON_RAD and a column in the material table called :TENSILE_STRENGTH, the formula calculates the actual bend force values and compares them to the maximal possible force values.
To use this formula, every bend tool table must have a :MAX_BEND_FORCE and a :MAX_BEND_FORCE_PER_M column. Additionally the material table must have a column called :TENSILE_STRENGTH (see examples in file "sha_demoshop.lsp").
Maximal Bend Length Check Function
Creo Elements/Direct Sheet Metal can check the bend length against the maximal bend length of the currently used bending tool or machine. In case of problems, these are shown as advice in the bend tool table. If the Advice button is pressed the tools that fail on this check are not shown in the bend tool table.
The sample check-tool-max-bend-length function provided in the sha_demoshop_func.lsp file first checks in the bend tools table for a column named :MAX_BEND_LENGTH. If this column exists in the table of the currently used bend process, the system inquires the value of the column and compares it to the bend length derived from the model.
To use this formula, every bend tool table must have a :MAX_BEND_LENGTH column (see the examples in file sha_demoshop.lsp).
Producing the Same Sheet Metal Part in Multiple Shops
Even if two shops use exactly the same tool geometry (based on identical :KEY columns and identical dimensions), different bend radii may result. Such differences are due to the specific conditions in the production environment (different material grades, different oils, etc) of each shop.
To compensate for such deviations, Creo Elements/Direct Sheet Metal derives the radius annotation in the flat from the bend allowance calculation and the tool radius data in the local shop definition file but not from the part geometry.
