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By Ron Green, December 17, 2012
As a CAD application developed in China by ZWSOFT, ZWCAD has slowly made its presence noticeable over the past decade. ZWSOFT recently launched a mechanical flavor, naming it ZWCAD Mechanical. Because Ralph Grabowski provided a detailed overview of the ZWCAD+ base application in www.caddigest.com/exclusive/ZWCAD/101112_vs_autocad_grabowski.htm, I’ll jump directly onto the mechanical design aspects of the application.
ZWCAD Mechanical is easy to set up. It installs the vanilla ZWCAD+ version along with the mechanical add-on. In ZWCAD, the mechanical workspace is set up automatically by the installation process, which defaults to the profile named zwcadm_ENU. The suffix (ENU = Europe, in this case) represents the localized environment where ZWCAD Mechanical is installed. Note that ZWCAD is a 32-bit application, and so might not take full advantage of 64-bit computers.
It is important to point out that none of the parts drawn by ZWCAD Mechanical are drawn in 3D; rather, this software produces 2D representations of mechanical parts, just like AutoCAD Mechanical. (To get 3D objects, users would use ZWCAD’s native 3D commands, or else acquire ZWSOFT’s ZW3D CAM/CAM software.) For simple day-to-day work, these 2D representations should be sufficient, especially when used with the extensive Parts Library included with the software.
The learning curve seems easy for operators already familiar with other CAD environments. For instance, the graphical user interface and the function names are similar to those of AutoCAD; AutoCAD users would require hardly any training to get used to ZWCAD Mechanical.
ZWCAD Mechanical provides a library of commonly used mechanical parts. The mechanical CAD-related functions are accessed from two extra ribbon tabs, Mechanical Design and Mechanical Drawing. (See figure 1.)
|Figure 1: A sample project in ZWCAD Mechanical|
In addition to the ribbon, mechanical CAD related functions can be accessed from tool bars; these can be customized to the user’s preference.
To review the functions of ZWCAD Mechanical in greater detail, I decided to concentrate on the following areas:
I was pleased to see that ZWCAD Mechanical comes with an exhaustive library of mechanical parts. The library has an interface that I found easy to understand: on the left side, the explorer view lists all the parts available in the library; on the right hand side, the view shows the part dimensions. (See figure 2.)
|Figure 2: The user interface of ZWCAD Mechanical, showing its parametric parts library|
The preview window shows how the selected part looks in 2D. Many parts have more than one view associated with them, and so the user can choose which one to see.
There is a set of tabs along the bottom. These provide access to part descriptions, properties, and the scripts that are used to draw the parts in ZWCAD Mechanical. The bottom right side offers a very useful set of options of how to draw the part, such as setting the drawing scale and toggling the display of dimensions.
Once sent to the drawing, the part’s information is stored in xdata. (Xdata = extended entity data is used to store information about the entity in the entity itself. This is kind of like attributes, but xdata is available to programmers only.) To edit the part, the user just double-clicks it; this action brings up the library to edit any of the part’s properties.
There are separate parametric tools for build up shafts and gears; they are named Shaft Generator and Gear Generator, respectively. See figure 3 for a typical shaft designed with ZWCAD Mechanical.
|Figure 3: A sample shaft drawn using Shaft Generator|
With the Shaft Generator, the user builds up shaft parts of different lengths and diameters. There are options to specify chamfers and keyways. As data is entered, the built-up shaft can be previewed in the same dialog. (See figure 4.) Once the shaft is drawn in the drawing, it retains its properties and so to edit, the user double-clicks the part to invoke the same dialog. The user may modify the dimensions, as required to change sizes. This is a very useful tool, because change is quite normal during actual design and execution phases.
|Figure 4: The Shaft Generator dialog box in ZWCAD Mechanical|
The Gear Generator is partially parametric, building up different types of gears in a manner similar to what is available with the Shaft Generator. The primary difference is that once the gear is drawn, double-clicking to edit it does not invoke the Gear Generator dialog box. This is because the generated gears’ parameters are not saved; once gears are drawn, the only way to change them is by editing the individual line and arc entities. It is probably faster just to erase the gear, and then go back to the Gear Generator dialog box to re-specify the options.
Next to the Part Library control is an option labeled "Part Builder." When invoked, it lists parts commonly used in mechanical drawings, such as bolts, screws, and fasteners. This tool is used to quickly add relevant accessories without the need to search through the entire part library or draw them from scratch. (See figure 5.)
|Figure 5: Symbols Library provided with ZWCAD Mechanical|
A customizable tool palette is also available where users can add their own parts and entities for quick, drag’n drop addition to drawings. The palette is shown on the left in figure 6.
|Figure 6: A sample mechanical part drawn in ZWCAD Mechanical|
I found that the easiest way to draw parts was to follow these steps:
Overall, I found that creating and modifying parts with ZWCAD Mechanical was easy to learn and use. The part library is very effective in providing commonly-used mechanical parts. I could not, however, find any way to add custom parts to the library. The workaround would be to create my own ZWCAD blocks with attributes, and then reuse them.
Bills of materials can be generated from the drawing with proper part referencing. The BOM data can be exported to text files or to ERP systems using separate plug-ins.
ZWCAD Mechanical supports many commonly-used drawing standards, such as ISO (international), ANSI (American), DIN (German), JIS (Japanese), and GB (Chinese). To support these standards, it has an exhaustive library of symbols, which can be accessed through the ribbon’s Mechanical Drawing tab. Another option configures a variety of drawing representation styles.
Once the drawing representation styles are set up, the software generates the layers, dimension styles, and text styles. It can identify the objects you created, select the right styles, and then lay them on the correct layer. The annotation symbols are readily used for representing individual elements, such as welds. For example, the weld representation for different instances of weld in the same drawing can be changed as per user requirement.
There are various representation styles available for commonly-required drawing entities, such as feature control frame, surface textures, break lines, and round hole mark. (See figure 7.) These drawing representations are stored as xdata, and so the user can double-click them to edit the representations at later stages.
|Figure 7: Symbols displayed visually in ZWCAD Mechanical|
There is a function for generating bills of materials, and then placing them in the drawing with appropriate annotations. (See figure 8.) These annotations can be customized, based on drawing requirements.
|Figure 8: Sample bill of material inserted in a drawing|
Drawing representations that are found normally in CAD, such as dimensions and leaders, are customized using the DimStyle function. A large number of dimension styles are included, of which users can choose to customize by modifying existing ones. (See figure 9.)
|Figure 9a: Sample bill of material inserted in a drawing||Figure 9b: Customizing dimension styles|
Overall, a large number of options are available for users to customize and finish drawings as per their office’s drawing standards.
One of the first questions that may well comes up in your mind is, "How does ZWCAD Mechanical compare to similar offerings from companies like Autodesk or Bentley?" Every software product has its own identity. Because Autodesk and Bentley were two companies that spearheaded CAD software on microcomputers, it is obvious to draw comparisons with their product lines. It is true that many of the features in ZWCAD Mechanical look and feel similar to AutoCAD Mechanical. With the training overhead being low for users migrating from other products, then the other big plus is the lower cost of the software package itself.
A comparison table with AutoCAD Mechanical is provided by ZWCAD in their website. http://www.zwsoft.com/products/zwcad_mechanical.html#!tab=3.
Design firms often rely on specialized vertical products built on top of CAD applications. There are a quite a number of partner products already available for ZWCAD Mechanical. You can view these at the ZWCAD Website, http://zwcad.org/zdn/plus/list.php?tid=7&keyword.
ZWCAD Mechanical performs adequately the job it is meant to do. ZWCAD has come a long way since its inception, and ZWCAD Mechanical is a mature product that can be used effectively for drafting 2D mechanical drawings.
|Ron Green has written extensively about computer-aided design for nearly three decades. He was a professional engineer for a number of years, and has his degree in engineering. More...|