New CAD Modeling Tools for Pneumatic Components

Neutral vs. Native File Types

The problems with some CAD design tools start with their output file formats. If CAD capabilities are offered, they may provide only neutral or translated CAD files, not true native files. Such neutral, translated or generic files (in formats such as DXF, IGES or STEP) do allow viewing via any popular CAD program, regardless of the system on which they were created. These files may also be adequate for analysis, measurement, development of cutter paths and other limited uses.

However, neutral files can only create “dumb” models, without associated parameters, attributes or histories. Neutral files can also often be problematic to import and use. They almost always add extra time and trouble to your design process. Some engineers find them so frustrating and error-prone, they actually prefer to redraw a part instead of importing a neutral file!

By contrast, a true native CAD file imported into a CAD system might permit manipulation of the moving parts of an automation product such as a pneumatic cylinder. This makes it possible to watch the cylinder’s rod extend and retract in the CAD environment, through the product’s full range of motion, just as it would in physical space. This allows adjustment of the model to take advantage of its precise motion constraints and its dimensions in various positions.

However, when running a neutral or translated file of the same cylinder, vital data would be missing. The piston-moving feature would “break” and be unavailable for use or calculation. Such files can also fail to correctly model “mates” (geometric relationships between parts), can lose scalability or accurate dimensional data, might exhibit confusing “artifacts” not present in the actual pneumatics component, and can drop part numbers. They make it harder to properly verify design intent, perform assembly analysis and ensure correct part selection, so model building becomes a longer, more frustrating process. Additionally, the model created with a neutral file may lack critical features or functionality.

Many engineers now prefer a pneumatics manufacturer that insists on high-quality, native-file Web tools instead. For example, one Web-based CAD tool provides detailed files in more than 85 true native CAD formats, including Catia, I-DEAS, Pro/ENGINEER, SolidWorks, Unigraphic and more. So in the cylinder example above, the ability to “stroke” the cylinder (extend and retract the piston rod, etc.) would be retained no matter which of the CAD programs were used. It would include complete CAD functionality for the fastest, most efficient modeling experience.

Individual vs. Fully Assembled Files

One serious time sink associated with a number of web-based CAD tools stems from their inability to provide fully assembled files. Using tools with this limitation, only individual files can be accessed, meaning that detailed knowledge of each relevant component or product, and how each relates to every other part must be acquired. These elements must then be laboriously assembled into the final model to get the desired configuration.

With a multi-station valve manifold, for example, this is a complex and time-consuming undertaking. An example is a situation where a six-station valve manifold has been assembled. Then comes an all-too-familiar phenomenon in the manufacturing business: a change order. The customer wants to add functionality that requires another valve station.

Unfortunately, a limited CAD tool won’t permit the model to be disassembled. It requires a return to the configuration architecture, selection of new components, and the construction of a seven-station valve model instead.

Some users actually take the extra trouble to build in a workaround beforehand, just in case. They assemble their manifold with six valves—plus an extra blank station or two. That way, at least they can add extended functionality later, if the need arises.

Fortunately, a few pneumatics automation makers avoid these limitations. Instead of individual files only, their Web-based tools provide fully assembled models, but with each component in the assembly identified as an independent file. Therefore, even complex, “nested” models can be assembled or disassembled at will. For instance, to add a seventh valve to a manifold, simply replicate or “clone” a current valve element, move the end plate drawing component over, and add the new element to the existing six-valve assembly.

This allows maximum flexibility in CAD creation — plus finished models in a fraction of the time.

Part Numbers vs. User-Friendly Attributes

The easier the pneumatics component manufacturer makes it to use a CAD tool, the less time and effort it takes for the design engineer to accomplish the modeling task at hand. Also, user friendliness should extend even to seemingly minor features of the tool interface design. For instance, how does the program describe each part? In some cases, every step of the design process requires the engineer to learn and use the system’s proprietary, complicated part numbers or codes. Other manufacturers simplify things for the user. Instead of presenting only elaborate part codes, their tool’s user interface describes components according to their salient application attributes—employing terms related to performance characteristics that are familiar to the design engineer. The tool keeps track of the relevant part codes behind the scenes, and links these codes appropriately to the final model.

Rather than trying to remember a part number like JN77S5S or X511/R98(91)KQ-9C, the engineer simply selects clearly described manifold component attributes such as a terminal strip, push-in fitting and DIN rail mount, or chooses a given voltage requirement and lets the tool accurately code each part for final ordering purposes.

The User Experience

Product configuration using any Web-based CAD tool carries a baseline level of complexity. Naturally, attention and detail must be devoted to the modeling task. However, some systems seem to make the entire user experience more difficult than it has to be. Simply locating the configuration tool may take extra effort. Some CAD tool pages are buried several layers down from the home page in complicated Web architectures. The desired page also may be hard to pick out among multiple, poorly labeled menu items in a partial catalog that omits key components. Sometimes, even finding the CAD tool page doesn’t allow work to begin.

In some cases, the system is set up to require that all identifying information is placed on a registration form before any modeling may begin. Then, once configuration is finally allowed, the modeling process itself varies from site to site, tool to tool. Users report that some CAD tools demand more click-throughs than others. Offending sites may also suffer from illogical sequences of steps, confusing layouts or ambiguous instructions. In addition, rendering and downloading may also require extended waits.

If a site exhibits one or more of these problems, it’s probably advisable to seek out a manufacturer that provides the best and easiest possible user experience.

Avoiding Errors Through Design

Some manufacturers’ CAD tools may also make it easier to commit or harder to prevent errors. These can cause false starts and wasted time during the CAD design and configuration process. First, some errors or dead ends may develop simply because of incompatibilities between different generations or versions of the CAD tool software. By ensuring that the user’s and the manufacturer’s software are updated to the same (and/or latest) version, valuable time and effort can be saved.

Next, the basic quality and level of detail provided by their CAD tools can vary from one pneumatics components vendor to another. Features such as mountings or fasteners may lack precision, or may not be displayed at all. This may require the engineer to switch attention back and forth between the CAD screen and specifications in a paper catalog to figure out mounting plate requirements or bolt patterns to avoid making mistakes in the model.

Some software may introduce larger-scale errors as well. For example, when “plumbing up” a multi-valve manifold in a 3D environment and connecting it to cylinders or motion control components, a CAD tool with weak validation or rule-making capabilities may allow the creation of impossible or inadvisable configurations. In this instance the software could allow placement of a regulator on top of a speed control because the design tool doesn’t properly validate for manufacturability. To avoid these mistakes, this kind of system could require a great deal of time to learn assembly requirements, functionality, and other rules for each component or product.

Look for vendors using tools that reduce or eliminate all these error-prone situations.

Conclusion

Engineers should look for best-in-class manufacturers that offer complete online catalogs, interactive product configurators and CAD downloads. Such suppliers provide tools with fully assembled, native files, plus other thoughtful design features. These tools can help reduce time, complexity, effort and error while increasing accuracy, ease of use, speed of configuration and delivery, and productivity.

Mark Madsen is director of marketing for ASCO Numatics. Reach him at Mark.Madsen@emerson.com.