TOP_en

In this chapter, the parametric standard libraries provided by the TOP package are described.

What are parametric standard libraries?

The answer is simple: they are a set of functions designed to draw commonly used mechanical components (such as screws, nuts, set screws, bearings, etc.) according to UNI standards, whose parameters (object characteristics) can be customized by the user. Naturally, all choices must comply with standard regulations.

For example, it is possible to draw a screw with any length and diameter, as long as they fall within the tabulated values. The application ensures that all selected options are valid and consistent, so the user only needs to choose from the available parameters to obtain an object suitable for their design needs.

Among the available parameter options, those marked with the symbol “*” indicate less commonly used choices and are therefore not recommended. This is the case for certain screw or nut diameters.

Parameter configuration and dialogs

For each library element, a dialog box is available in which all key parameters can be viewed and modified by the user. There is no predefined sequence of choices, so the user can navigate freely within the dialog.

With the exception of holes, each library element can be turned into a part by enabling or disabling the corresponding option. For some elements, multiple parts can be created. For example, when designing a screw with several washers and a nut, separate parts will be created for the screw, the washers, and the nut.

For each part, the attributes Name, Code, Description, optionally Material, and the insertion point are defined. The Code attribute is linked to a text field in the dialog:

• If left empty, the code is generated automatically
• If filled in, the code is customized with the entered value

All functions described in the chapter “Parts” are available for each created part.

Types of dialogs

Each type of parametric library provides the user with two main dialogs, which differ in how they are used:

The general dialog, which allows the user to select drawing parameters from all standardized options provided by the application

The coded items dialog, which allows selection only among previously defined (coded) components

On the following page, both dialog types are shown for the specific case of screws, although their structure is similar for all other parametric libraries.

From the main dialog, by activating the Coding Menu button, it is possible to switch to the coded dialog.

The thread pitch used in drawings is of the coarse type, even when a fine pitch is selected in the dialog box. This choice was made purely for aesthetic reasons; in fact, in the object’s properties it will still be recognized as a fine pitch.

Within the coding menu, the list of codes is displayed in alphabetical order.

The thread thickness is determined by multiplying the pitch by a specific constant defined for ISO triangular-profile threads:

h3 = 0.61343 · P.

The length of blind threaded holes can be considered in two ways:

• From the seating point to the tip end (Total)
• From the seating point to the end of the thread (Partial)

To change the hole length type, you need to run the Top_TipoLungFr command described in paragraph 4.3, Customization Commands.

The protrusion of the non-threaded portion in blind threaded holes is determined according to UNI 5710 tables after calculating the pitch.

When the OK button is pressed in the dialog, the selected component is inserted into the active library.

However, when the main dialog is closed, the user cannot directly place the component, as an additional dialog appears, as shown in the illustration below. nella illustrazione sottostante.

This dialog allows the user to select how the desired component should be displayed within the drawing. It is possible to choose whether the part is fully visible or hidden (i.e., as if it were covered by another component). In the case of screws, there is also a partially visible option, which draws the part as visible but with the central threaded section between the head and the nut shown as hidden.

Another important feature of this dialog is that the user can choose to draw the selected component in multiple views at the same time, significantly speeding up the workflow.

To illustrate this, consider again the screw dialog: the user can draw a screw in a side view and, at the same time, in a top view by selecting the appropriate toggle. Naturally, toggles corresponding to views not available for that specific component type are disabled. This feature is available for all libraries in the application and is therefore described only in this introduction.

Note

For all library components, symmetry axes are drawn using the THIN DASHED-DOTTED linetype (configured via a dedicated command) and are always displayed unless they overlap with other axes.

In the library dialogs (Holes, Screws, Self-tapping Screws, Nuts, Washers, Profiles, Hollow Profiles, Bars, Bearings, and Eye Bolts), the catalog from which the components are taken is specified next to the name in the top-left corner.

The drawing of the AutoSnap reference marker is optional and can be disabled by setting the appropriate variable in the options:

Options > Top > Standards > Libraries > Insert AutoSnap Reference