SolidWorks

Validate Manufacturability (Solid Thinking SolidWorks Tutorial)

1 Nov, 2007 By: Richard Doyle

How to Use DFMXpress in SolidWorks 2008.


SolidWorks 2008 introduces a new tool powered by Geometric Software that is fully integrated into SolidWorks. DFMXpress is an analysis tool that validates the manufacturability of SolidWorks parts. You can use DFMXpress to quickly identify certain design features that could cause problems in fabrication or
figure
The DFMXpress interface.
increase the cost of production.

DFMXpress Overview
DFMXpress features a basic set of tools to help design better parts in SolidWorks. You use the simple DFMXpress interface to check your design for manufacturability, identifying areas that are expensive, difficult, or even impossible to machine. DFMXpress checks parts against several categories of rules that you can adjust to suit your environment. For example, you can check to make sure that all of the holes in a part are of a standard size or to make sure

figure
Rule parameters.
that blind drilled holes are not excessively deep. Other checks such as tight tolerances and difficult-to-machine features are also supported.

Setting up Rules
To set up DFMXpress rules, open the part to be checked and click Tools / DFMXpress. The DFMXpress dialog box appears in the task pane.

Click Settings to enter rule parameters. You can set rule parameters for either Prismatic or Turned parts. You can set your own values or accept the default values. Other parameters are already integrated into the database, such as checking for inaccessible features, standard drill sizes, and expensive machining operations. See the figure below for configurable rule parameters.

You can restore the default values at any time by selecting the Restore Default Values button.

Running the DFMXpress Check
After you set the Rule Parameter values, click Run to begin the check. DFMXpress uses Automatic Feature Recognition to parse the model and report the results. The model shown below breaks nearly all rules of manufacturability.

figure
A poorly designed model.
figure

Analyzing the DFMXpress Results
DFMXpress reports the results in a tree view, and shows the rules that have failed and passed. As you can see, there are 11 rules set for this model, and we have failed 8 of them. Expanding the Rules Failed tree lets you view each failure instance. A tool tip explains each failure and the problem feature is highlighted in the graphics area.

Click for larger image
This hole fails the Hole Depth/Diameter Ratio rule check. (Click image for larger version)

Take a look at the other features in this model. Various manufacturability issues are present, including features that would be inaccessible to a tool or tool holder and a deep pocket cut that would be tough to machine using traditional milling methods. DFMXpress reports on these conditions as well.

Click for larger image
A feature that may be difficult to machine. (Click image for larger version)

Fixing the Model
After the results are reported, its time to do a little cleanup. You don't have to close DFMXpress to work on the model. Take each failure in order and modify the features using normal SolidWorks commands. Let's start with the Hole Depth/Diameter Ratio failure:

  1. DFMXpress reports a depth to diameter ratio of 4.864, which is out of the range we have specified in the settings (2.75). The feature is a #4 clearance hole with a diameter of 0.1285. To meet the criteria we set, the depth must be reduced to no more than:
    1. 0.1285 x 2.75 = 0.353
  2. Edit the feature and set the proper depth.
  3. Rerun DFMXpress.
DFMXpress now reports that the Hole Depth/Diameter Ratio has passed.

Click for larger image
The check passes. (Click image for larger version)

Next, we'll modify the milled pocket that failed because of tight corners. Adding a radius to the inside of the pocket makes it easier to machine.

  1. Edit the feature and add a radius of 0.25 to each corner.
  2. Rerun DFMXpress.

Continue with the other failed checks, running the DFMXpress check after each update. After DFMXpress reports that all features have passed the checks, you will have a part that is easy and cost effective to manufacture.

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All checks passed leaving an easily manufactured model. (Click image for larger version)

Reduce Manufacturing Costs
Using DFMXpress combines a high-level of functionality with ease of use and can help reduce manufacturing costs and spot hard to manufacture parts before they get to the shop. The ability to set specific values for rules allows for flexibility -- you decide which values and checks are important to your company. With the tight integration with SolidWorks 2008, you have the confidence that DFMXpress will help you design better parts.


About the Author: Richard Doyle


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