Manufacturing

Solid Edge's Goal Seek: The Next Best Thing to Hindsight (On the Edge Solid Edge Tutorial)

1 Oct, 2007 By: Russell Brook

Tool helps you design right the first time without using costly prototypes.


If there are two things most engineers could use when designing anything for the first time, they are hindsight and experience, both of which reduce learning curves, design errors, and costly prototypes. As you know, hindsight is great, but it's always too late when you really need it. Hindsight does lead to experience though. Unfortunately, experience must be earned, not bought. Fortunately, Solid Edge now provides the next best thing -- Goal Seeking.

This month, we'll look at how Goal Seeking lets you do up-front engineering to get your design right the first time by combining the parametric capabilities of Solid Edge with 2D sketches to more easily visualize your design scenario and efficiently calculate your desired design parameters. .

What is Goal Seeking?
Goal Seeking lets you perform what-if calculations by finding a desired target value in an engineering calculation by defining critical parameters and varying other factors to arrive at your target value. The key here is 'varying other factors.' Goal Seeking removes all the hard work of iterative design calculations to quickly arrive at your goal.

For example, you can specify a force required at the fulcrum point on a cantilever crane while lifting a desired load to find the safe working angle for the crane jib. If the maximum load, distance between the mounting points, and jib length remain constant and you specify the maximum force at the fulcrum, Solid Edge Goal Seek finds the maximum angle at which the crane jib is safe to operate.

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Here's an example of Solid Edge Goal Seeking being used to find the minimum angle for safe operation, given a maximum force the fulcrum points are designed to withstand.

Simple, Yet Powerful
Goal Seek concepts have been in spreadsheets for some time. Solid Edge takes this concept and combines it with its 2D parametric drawing capabilities. By sketching out your design, you can visualize problems that are best expressed graphically, much like free-body diagrams commonly used to describe problems. Design values that would otherwise be hidden or unobtrusive in a table are linked directly from your 2D sketch to the goal-seeking capabilities in Solid Edge. If you later change your target value, other chosen variables are forced to reflect your new goal, and your sketch updates dynamically, helping you solve engineering problems graphically and before any design detail have been done.

Saves Labor-Intensive, Iterative Design Calculations
As you can imagine, manually transposing design variables to find a target value is repetitive and time consuming. Solid Edge Goal Seeking takes graphical engineering problem solving to a new level and does all the labor-intensive iterative calculations for you allowing you to quickly perform 2D 'what-if' calculations using a combination of 2D parametric geometry, mathematical formulas, variables, and properties to find a safer or more cost effective alternative design solution.

Easily Repeat Design Knowledge and Reuse Data
Establishing a desired result is only part of the story. Designs captured using 2D sketches can be used as templates and quickly applied to similar scenarios. If you want, you can add another dimension to goal seeking. Using Solid Edge's powerful hybrid 2D/3D design capabilities, goal seeking can be used to control part and assembly sketches to drive positions of 3D parts or features, so you can check for component clearance as they are moved to a new position.

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Goal seeking in assembly sketches is combined with powerful 3D parametric constraint solvers in Solid Edge to drive the position of 3D components.

Design Right the First Time and Remove Costly Prototypes So is Goal Seek the next best thing to hindsight? You bet, and in today's competitive market where design cycles and margins are being reduced, and designs must be developed faster and cheaper, Solid Edge Goal Seek offers a great alternative to building costly prototypes, by allowing you solve engineering problems upfront and get it right first time.

And Now for the Really Good News . . .
Goal Seek is free. It's included in Solid Edge Free 2D. Give Goal Seek a try by downloading a copy of Solid Edge V20 Free 2D and follow this exercise to become acquainted with Solid Edge Goal Seek, Once you have the basics I bet you will find many more uses for this powerful yet versatile capability in Solid Edge.

How to Use Goal Seek
The best place to start using Goal Seek (new in Solid Edge Version 20) is to create a simple line sketch of your design in principle. Then add all the parametric dimensions, locking down all degrees of freedom to move, just as you would for any other parametric design. To save you some time and to get you started, I've included a simple example of this belt and pulley arrangement. Click here to download.

Also, I completed Steps 1 through 3, but I have included them here so you appreciate how Goal Seek works.

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Solid Edge Goal Seek example draft file.

In this example, you are going to determine the position of the idler pulley, or jockey wheel as it's sometimes known. Rather than specify a custom belt, which is expensive and hard to replace, use a stock size of 12", 15", or 18". Fit the components to the pulley and then determine the location of the idler pulley to accurately position its mounting holes and brackets.

Step 1. With the drawing open, select the Layer tab from the pathfinder. Click to get to Belt and the Area Hatch layer, then right-click, and select Show only.

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Turn off layers, so only the belt outline is visible.

Step 2. Select the Area tool from the Solid Edge Inspect menu. First use the Area tool to find the area inside the belt profile. The perimeter is one of the properties of the area and determines the belt length. The area and perimeter (as well as other useful properties such as area center and principle x,y positions) are automatically captured in the variable table.

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The area command is first used to expose properties, such as the perimeter to the variable table, to find the belt length.

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The perimeter is exposed in the variable table. In this example, I renamed it to something more meaningful to this example.

Step 3. Shift-select the Belt layer and then the Area Hatch layer and then with the CTRL key pressed deselect the Constrained Dims 2 layer.

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Select the highlighted layers and with the right-mouse options, choose Show only.

Step 4. After you capture the Area properties, you're ready to start goal seeking. Under the Inspect menu, chose Goal Seek.

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Select the Solid Edge Goal Seek command.

From the Goal Seek SmartStep ribbon toolbar, select the Belt Length as the Goal variable (the value to determine) and key in the target value (15"). Next, chose the variable that needs to vary to find this 15" target. Select the variable called Angle from the list on the toolbar. Alternatively, you can select the icon next to the list and physically choose the dimension for the Angle directly from your drawing.

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The Goal Seek smart step ribbon bar provides easy access to Goal Seek options.

As soon as you're ready, press Enter or select the green tick and the system quickly arrives at your Goal.

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The Goal Seek results are shown on the right, and the left shows what it was before. Note how the angle changed to arrive at a target of a 15" belt perimeter.

If you enter a value that can't be physically solved, Solid Edge Goal Seek pops up a polite failure warning dialog. Select OK, and your diagram resets and is ready for a new target value.

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The Solid Edge Goal Seek failure dialog box provides feedback if a target value can't be physically solved.

See you On the Edge, next time.


About the Author: Russell Brook

Russell Brook

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