CAD Blogs

Model-based definition or the perils of disconnected detours

September 27, 2021 By Leslie Langnau Leave a Comment

By Brian Thompson, DVP and GM, CAD Segment, PTC

When I speak with manufacturers, they often tell me that moving towards becoming more model-based is at the top of their priority list. Initially, they might have started down this path to eliminate the extra work required to build 2D drawings off of their 3D models. Now, manufacturers want to make the 3D model itself the gravitational center. The disconnect between the 2D drawing and 3D model is hobbling both their internal efficiency and external competitiveness.

More formally known as model-based definition, MBD is about creating rich “Technical Data Packages (TDP),” which include the 3D model and associated data elements. At the core of the TDPs is the 3D model, along with its associated dimensioning and tolerancing to clearly communicate design intent and geometric form control. Thanks to the TDP, users who sit downstream from engineering can understand and use that model without needing separate 2D artifacts – the information is in the model itself.

MBD is not another way of spelling ‘paperless engineering,’ as if mere convenience were the reason for such a strategic shift. The manufacturers we work with are talking about a broader and grander idea: a different way of approaching the product development, manufacturing, delivery, operations, and service processes so that the 3D model is the source authority.

By implication, these manufacturers are also talking about innovation, and how they might use breakthrough technologies such as simulation, additive manufacturing, and generative design to design better products faster. MBD is as much an approach to corporate strategy as it is an approach to design, product development and manufacturing.

That’s the exciting part – the vision that gets people to commit their time and resources to the effort. I would offer this advice to those who aspire to a model-based journey. Think of a rock climber scaling a cliff face. As he or she ascends, that climber will need to put an anchor in the rock through which to pass the rope.

Your 3D model is that anchor. Start there.

3D model as Anchor
This is no getting around it: every MBD journey starts by looking at your modeling practices and ensuring that your model truly reflects your design. One customer discovered, as they implemented MBD, that they had to train their engineers to know where and how to apply drafts to their injection molded parts, instead of relying on the manufacturing team to do it. Another found that simulation results would be inaccurate unless certain critical features were modeled in complete detail, instead of leaving some geometry details to notes.

Today, I look at the model itself as a precise database for all PMI rather than as a supporting item to create a 2D drawing quickly.

A geometrical product specification is gold for manufacturers.

A word of caution
Next, examine your own mental models and beware of outdated beliefs. We sometimes see those who have (unknowingly) gone halfway with MBD – only to stop on the manufacturing floor. In the past, a certain amount of rework was part of the design process, as was the willingness to accept change at the worst possible and most expensive time. Allow me to be candid. With MBD, your experts on the shop floor will need to learn to place the 3D model at the center of everything they do, too. This will surely help them streamline industrialization of the design, minimize mistakes, and produce the highest-quality output. This will definitely be a change for the manufacturing team, but everyone I’ve talked to has said this is worth it.

Disconnected detours
The worst choices in business are ones you don’t know you’re making. With that in mind, consider whether an MBD journey would, in fact, be less costly in time, money, materials and morale than situations such as the scenario described below.

At one manufacturer, final drawings were made into pdfs and put on a server where all could access them. Not surprisingly, CNC machines soon were decorated with marked-up pdfs showing late-breaking changes. As the model evolved, there was no way other than person-to-person to get the changes to the manufacturing floor. One employee jokingly referred to the ‘sneaker net’. The manufacturing engineers encountered the same situation, and the changes they made on the shop floor often didn’t get to the designers, who unknowingly proliferated errors.

In our opinion, becoming model-based is a journey. To prepare, commit to making the 3D model the source of all authority and then take a moment to reexamine your modeling practices. This will take time, but your reward will be more value for the investment you’ve already made, confidence that engineers can now spend their valuable time doing what you paid them to do, and circumstances more favorable to innovation. That’s what our customers are seeking.

PTC
www.ptc.com

CATIA V5: How to control video file size

March 15, 2021 By WTWH Editor Leave a Comment

By Iouri Apanovitch, Senior Technical Training Engineer, Rand 3D

The built-in CATIA video recorder is an essential tool when working with animations in kinematics, fitting simulator, human modeling, etc. When the default video settings are used, however, the resulting video files are quite large, making them difficult to share through a company.

Here’s how to control the video file size in CATIA V5.

Before starting the recording, select (Setup) icon to open the Video Properties dialog box, at the top of which you will see the Format pull-down list.

The default VFW Codec option records the video in an uncompressed AVI file. It provides the best video quality, at the cost of a very large file size. A one-minute-long video can be as large as 2Gb or more.

The DirectShow option lets you create smaller, MPEG-compressed files. Select the Movie tab and click Compressor Setup button to open the compression options.

If you don’t see the two compression options shown above (DV Video Encoder and MJPEG Compressor), it means that you need to install the codecs. To do that, run the file 3DSMJPEGVFWSetup.exe located in the \code\bin sub-folder of the CATIA install directory.

Using either of the two codecs creates smaller files, of course at the cost of quality. The MJPEG Compressor results in the smallest files.

You can also use the Rate in Frames per Second (FPS) setting to further reduce the file size. However, be aware the very low FPS rate may result in your video appearing ‘jerky.’

Lastly, you can use either Area or Fixed Area options to limit the captured area and to reduce the file size even further.

The final recommendation – test the settings by yourself on a sample recording, to make sure you hit the right balance between the video quality and the file size.

About the Author

Iouri’s primary area of expertise is product analysis and simulation with FEA tools such as SIMULIA/Abaqus, Autodesk Simulation, Mechanica, including linear and non-linear simulations, dynamics, fatigue, and analysis of laminated composites.

Avoiding singularities in FEA boundary conditions

February 26, 2021 By Leslie Langnau Leave a Comment

FEA boundaries can usually be obtained using simple fixed constraints. But, this can result in singularities that produce erroneous results. To determine whether results show a real stress concentration or a singularity, an accurate solution can usually be obtained by either using elastic supports or modeling contact between components.

Singularities caused by sudden changes in boundary conditions can be harder to spot and resolve. In fact, setting up realistic boundary conditions is often the most challenging aspect of a simulation.

Dr. Jody Muelaner, PhD CEng MIMechE

Singularities in Finite Element Analysis (FEA) can cause real issues, even for an apparently simple structural analysis. Singularities lead to completely erroneous results and stresses that continue to rise as a mesh is refined. Many singularities are caused by stress-raising geometry such as holes and sharp internal corners, and this is generally well understood. Singularities caused by sudden changes in boundary conditions can be harder to spot and resolve. In fact, setting up realistic boundary conditions is often the most challenging aspect of a simulation.

What is a singularity?
A singularity is a point in the model where a value, such as stress, tends to infinity. As the mesh is refined, the increasingly small elements get closer to this point and the value therefore rises. As the element size tends to zero, the stress will tend to infinity. This produces nonsensical results and prevents mesh convergence.

Geometry that causes singularities
Singularities caused by stress-raising geometry such as holes and sharp internal corners are well understood. In the real world, there is likely to be a small radius on any internal corner, meaning the stress would not actually continue to rise. In any case, local yielding will limit the stress in such features. The location of these singularities can often be readily identified, excluded from convergence results and localized models used to predict the true stress in the features responsible. Singularities at corners are similar to cracks and the stress intensity factor can be calculated using the J-Integral, or considering the strain energy release rate – the energy dissipated during fracture.

There is, however, another type of stress raiser in FEA models that is talked about less often and which can be more difficult to deal with. Where there are abrupt changes in boundary conditions, such as a split line where a fixed constraint ends, this can also result in stress that continues to rise unrealistically and causes mesh convergence to fail. Let’s explore why this happens and how it can be avoided.

How can boundary conditions cause singularities?
The most obvious way that a boundary condition can cause a singularity is when a force is applied to a single node. Since stress is force divided by area, applying a force at a single point will give an infinite stress. If the area where the load is applied is not of interest, then it can be acceptable to use such a boundary condition. Due to Saint-Venant’s-principle, which states that, if the distance from the load is large enough, two different but statically equivalent loads create essentially the same effect. This can be easily seen where the same total force is applied to the sponges in two different ways. The fingers represent point loads and the flat hands distributed loads. Although the effects close to the applied loads are different, in the center of the stack, at a sufficient distance from the loads, the effect is virtually the same.

Saint-Venant’s principle states that, if the distance from the load is large enough, two different but statically equivalent loads create essentially the same effect. This image illustrates the point. The fingers represent point loads and the flat hands distributed loads. Although the effects close to the applied loads are different, in the center of the stack, at a sufficient distance from the loads, the effect is virtually the same.

When loads are simplified to point or edge loads, it is simply important to understand that the very high stress around the applied force does not represent reality. These regions must not be included in results, mesh convergence or adaptive meshing. Next, we’ll look at some more involved examples of boundary conditions casing singularities.

Abrupt changes to a fixed boundary condition
It is often convenient to fix a face of a model, to constrain a component that is loaded with forces applied in some other area. It should first be noted that such a fixed constraint can never truly represent reality. A fixed boundary condition essentially means that the face is bonded to an infinitely stiff body. In the real world, all solid bodies have some flexibility and often a part will actually be clamped rather than bonded. However, if the peak stresses are not expected in the region being represented by a fixed boundary, this may seem like a reasonable approximation. As with point loads, it can, therefore, be a good idea to simply exclude the stresses in this region from any mesh convergence. However, not all software allows this, and it is particularly problematic if automatic mesh refinement, or adaptive meshing, is being used.

A shaft can provide a good example of these issues. The shaft illustrated below has been cut in half and a symmetry fixture applied. The smaller cylindrical face at the right-hand end of the shaft has been split into three separate faces to allow a vertical force to be applied to a defined region. The other end of the shaft would be held by two bearings, with the outer bearing constraining axial movement against a shoulder and the end face.

The shaft has been cut in half and a symmetry fixture applied. The smaller cylindrical face at the right-hand end of the shaft has been split into three separate faces to allow a vertical force to be applied to a defined region. The other end of the shaft would be held by two bearings, with the outer bearing constraining axial movement against a shoulder and the end face.

When standard inelastic fixtures are used, stress singularities occur where the fixtures end. This effect is equivalent to the edge of a stiff part digging into a soft part. This can be seen below, where a bearing support extends between a split line and an external radius. It also occurs on the face of the shoulder which was constrained using a roller/slider constraint in SolidWorks Simulation. When the mesh is refined on the radius it is clear the singularity occurs where the fixtures end and is not a real stress concentration in the radius. This is particularly problematic because the radius is also a stress concentration and this region cannot, therefore, simply be excluded from the results or mesh refinement.

When standard inelastic fixtures are used, stress singularities occur where the fixtures end, as shown here where a bearing support extends between a split line and an external radius. This effect is equivalent to the edge of a stiff part digging into a soft part.

Using elastic supports
One solution is to use elastic supports rather than fixed constraints. In a fixed constraint, each node on the constrained surface is forced to zero displacement. An elastic support consists of an additional spring element for each node on the constrained surface. One end of the spring is attached to the node on the surface and the other end of the spring is fixed with zero displacement. The actual stresses in the springs are not normally included in the results. Using elastic supports can eliminate the issues with stress singularities at the edges of boundary conditions, but care must be taken to select realistic stiffnesses for the supports. If the stiffness is too small, the model may encounter excessive displacements which cause the solver to fail. On the other hand, if the stiffness is too great, a spurious stress concentration may still be seen at the edge of the constraint. Although an initial value for the support stiffness may be calculated by considering the type and thickness of the actual material which would provide the support. The image below shows that, with correctly set elastic supports, the model properly converges on the actual high-stress region.

With correctly set elastic supports, the model properly converges on the actual high stress region.

Modeling contact
Another similar approach is to model contact between the supporting components and the component of interest. This can be the most accurate, but can also be seen as simply pushing the problem to another area, since the supporting components must then be constrained in some way. However, if the supporting components can be excluded from the mesh convergence and final results, the supporting components can be simply constrained by fixing faces.

Mesh convergence and adaptive meshing
Mesh convergence is one of the most important methods to ensure a reliable FEA simulation. The basic process is simply to rerun the simulation a number of times, refining the mesh around areas of interest and recording the relevant values for the simulation using each mesh. When the value of interest varies randomly, and by a small amount, in both directions, the model can be said to have converged. If there are large differences in the result, or the result keeps creeping in the same direction as the mesh is refined, then this indicates a problem, often a singularity. What constitutes a small change is somewhat subjective but can generally be considered as a few percent of the value under consideration.

When the value of interest varies randomly, and by a small amount, in both directions, the model can be said to have converged. If there are large differences in the result, or the result keeps creeping in the same direction as the mesh is refined, then this indicates a problem, often a singularity.

Adaptive meshing takes mesh convergence a stage further, automatically refining the mesh at areas of interest and rerunning the simulation until the model is converged, or convergence fails according to some criteria. There are two types of adaptive meshing: H-Adaptive reduces the element size and P-Adaptive increases the element order. SolidWorks Simulation does not currently support P-Adaptive meshing for elastic supports.

Conclusions
In many cases, it may be possible to obtain useful results while using simple fixed constraints. However, this can result in singularities that may prevent mesh convergence and produce erroneous results. It is important to be aware of this issue, since some judgment may be required to determine whether results show a real stress concentration or a singularity arising due to simplified boundary conditions. When this happens, an accurate solution can usually be obtained by either using elastic supports or modeling contact between components.

Reuse CAD data for technical documentation, split function and feature recognition

February 15, 2019 By Leslie Langnau Leave a Comment

KISTERS North America released version 2019 of its 3DViewStation product family. The new version features additions and enhancements that assist users in the area of repurposing their CAD data. For instance: V2019’s new technical documentation features include the splitting function, real-time wall thickness measurement, feature recognition and a user-friendly import dialog.

One challenging area in the reuse of CAD data lies in the creation of content for technical documentation purposes. Deliverables might be images, illustrations or interactive 3D geometry to be repurposed in printed manuals, online manuals or spare part catalogues.
“After reviewing our customer’s most important requirements for technical documentation processes, we created interactive and automatic BOM ID generation,” said Robert Collins, KISTERS North American Sales Manager.

“These BOM IDs will be reused to interactively and automatically generate balloon callouts in an exploded view of the assembly. In our new version, there are multiple new options to configure the arrangement of these balloons. For example: top and bottom, left and right, or in a rectangle. For further ease-of-use, we added the option to continuously recalculate the best possible layout, while rotating the 3D model.

“Another focus was to increase the value of 3DViewStation for our mold/die and casting customers. The splitting function complements our existing draft angle analysis tool,” he added. “Now you can easily determine the complexity of a tool, what will be required to produce a part and extract the face for the mold. Toolmakers will fine the feature recognition functions, such as the drill hole recognition tool, useful. Less experienced CAD users will have the new, easy-to-use import dialog. And all users will experience 3DViewStation rendering significantly faster once more.”

3DViewStation ships with current and mature importers for a range of 3D and 2D formats including Catia, NX, Creo, SolidWorks, SolidEdge, Inventor, JT, 3D-PDF, STEP, DWG, DXF, DWF, MS Office and more.

V2019 Upgrades Include:

– New and updated file formats:
– Import 3D: Inventor 2019, SolidWorks 2019, Solid Edge 2019, Parasolid V31, Revit 2019, FBX, glTF, JT 10.2, OBJ
– Import 2D: Catia V5 R28 (V5-6R2018), Catia V6 R2017x, Creo 4.0 / ProE, NX12, SolidEdge ST10, Solidworks 2018
– Export: JavaScript for 3D-PDF, IFC, FBX, JT 10, OBJ
– New and updated functions:
– Import dialog (quick settings)
– Structure tree: Remove empty nodes
– Neutral axis calculation with tesselated data
– Real-time wall thickness measurement
– Drill hole recognition
– Split
– Technical documentation:
BOM table: interactive BOM ID generation
BOM table: automatic ID generation
Ballooning: arrangement as line, rectangle, circle
Ballooning: automatic re-arrangement during rotation
Options for shapes and lines for balloons
Replace existing SMG files by 3DVS counterparts, limited to supported objects & properties
– Printdialog:
Print range
Autorotate document
Tiled printing
– Selection of all instances of a geometry
– Filtering option: include / exclude unvisible objects
– Rotation mode “Turntable”
– 2D text search enhanced
-Transformation: Align move circle center to circle center
– Export PNG with transparent background
– PDF template: configurable date
– New options for license borrowing
– Performance optimization:
Tremendous increase in rendering speed of ultra large assemblies
Calculation of Level of Detail (LoD)
Ability to remove normals (space-saving)
Optimization of instancing

KISTERS AG
www.3dviewstation.com

“3D Evolution Simplifier” simplifies the handling of large CAD data models

October 3, 2018 By Leslie Langnau Leave a Comment

The “3D_Evolution Simplifier” of the German-French software manufacturer CoreTechnologie is software for the fast and fully automatic simplification of CAD data. The tool converts and handles the reading and writing of all popular formats such as Catia V5 and V6, NX, Solidworks, Creo, Inventor, Step, IGES, JT, XT, FBX, DWG and DGN. In addition to conversion and simplification, the models can be checked and optimized in terms of quality.

Envelope geometry improves CAD performance
With the increasing level of detail and the size of CAD models, the number of entities to be displayed is in most cases beyond the capabilities of today’s CAD workstations. Automated simplification and data reduction is essential for the control of large volumes of data to create layouts or VR models in the field. The fast and fully automated generation of envelope geometries is a viable solution to smoothly work with the large amounts of data, especially in plant construction.

Preparation of customer or supplier data
The Simplifier simplifies and converts supplier data. The removal of internal geometry for the calculation of envelope geometries can be achieved within seconds by pressing a button. For efficient reduction of the file size, solids are produced automatically without any inner workings. The “Healing” technology ensures the automatic analysis and repair of the 3D models. The automatic correction functions improve data quality to optimize data exchange, especially for imported data.

The result of the simplifier process and quality optimization is higher performance in the CAD system and in all downstream processes. Particularly suitable is the method for Digital Mock Ups. In addition, problems in the drawing derivation are eliminated by the significantly reduced amount of data and the high data quality.

Automated product release with know-how protection
The model simplification is automated in batch mode and can be performed for any number of files and directories. Attributes in the CAD data, colors and names of the components allow precise control of the simplification process. Thus, certain components are specifically excluded from the simplification, completely removed or replaced by highly simplified, that is approximate envelope contours.

The envelope contours provide the replacement of the original geometry for an additional reduction in file size. Sheet metal parts can be replaced, for example, by boxes, threads or gears by cylinders or more complex geometries with cooling fins by polyhedra. In addition, Enterprise Datamanager offers various automation options. Web-based client / server solutions, multiprocessor operation, command-line operation and the optional directory scanner provide seamless integration into existing PLM environments as needed. The directory scanner monitors defined folders and processes data stored in them.

Another option for integration into existing PLM systems is the command line. The integration enables automation for the provision of product data, for example for catalog systems such as Docware or Engineer-to-Order systems such as Siemens PLM Rulestream.

Preparation of CAD data for VR / AR
When processing CAD data for visualization in virtual or augmented reality, the 3D_Evolution Simplifier is used to reduce the number of polygons without quality disadvantages, i.e. by 90% or more, in typical models from the mechanical and plant engineering sector. The process is based on removing the internal geometry and drilling based on optimized B-rep solids. After reading the original CAD geometry, the simplification of the exact B-Rep data takes place. Subsequently, the conversion to formats such as obj and fbx with definition of the polygon size as well as the reduction of the tessellation by up to 98% is accomplished. Since Simplifier simplifies simplified B-Rep geometry with topology, no holes or unwanted geometry deformations occur.

CoreTechnologie
www.coretechnologie.de/produkte/3d-evolution

6 ways Onshape helps you dump your Laptop!

January 30, 2018 By Leslie Langnau Leave a Comment

Phil Foley, guest blogger

1. You no longer have to travel with a laptop

Engineers, designers and other users of Solidworks, Inventor, Creo and Rhino, it’s time to dump your laptops. Onshape is the first web-based 3D Computer-aided-design package.
Can a web-based package handle or even compete with your custom built, rock solid Workstation? Yes.

For the short time I’ve been using Onshape I have seen several updates and new videos added to their site. The site also boasts a Learning Center that offers self-paced learning videos that I found to be very good. You can also obtain Instructor led training videos that range from $150, $250 to $500 USD. Their free video offerings will get you up to speed.

Solidworks and Inventor users will feel at home with this product due to its similar workflow and terminology. The learning curve is not steep at all. I was up and running in an hour, and after two weeks I was teaching students how to design using Onshape.

2. Free and easy signup

I went to Onshape and it was a simple free signup. They offer Student, Teacher and Hobbyist accounts that are free. The only catch here is that your files are part of their Public library. For professional users, Onshape offers only a flat $125 per month, paid annually, which equates to $1,500 per year in a single payment.

The six founders of Onshape helped build Solidworks into a world leader in 3D design software. So, Solidworks users will feel a similar work flow. You can find info on the founders here.

The image in Figure 1 shows the login screen.

You will be happy with the intuitive User Interface mixed with CSS stylings and talented java scripting.

3. The interface is smooth and quick

I surfed in the Public folder for a file that looked interesting and found a Nvidia Geforce GTX-980 Ti Video Card designed and uploaded by Zoran Simeonov. I could not find any meta data on the file so I decided to test the Export functions. I exported this file by Right Clicking (RC) on the Assembly tab located at the bottom of your screen and then selecting Export in the options menu as shown in Figure 4.

Exporting to Solidworks format creates a 13 Mb file, exporting to an STL file created a smaller 6.18 Mb file and Rhino created a whopping 38.32 Mb file size. Just for fun I imported the files into Rhino and they came in clean and with no noticeable data loss.

I wanted to add some stress to Onshape to see what it could handle so I created an assembly file and added 12 GTX Video Cards. Based on the file sizes I mentioned, a Solidworks assembly file with 12 video cards would be in the neighborhood of 163 Mb, STL roughly 74.16 Mb and Rhino bloating out at around 459.6 Mb. I closed the assembly and reopened it. It took a long 15+ seconds to open, however, it seemed to do all the heavy lifting upon opening.

After the assembly file loaded I was able to rotate it as if it was a single Socket Cap Screw. By Right Clicking and holding, I was able to rotate the entire assembly without any video pixilation, video drag or delay; it was smooth.

4. Sheet Metal Modeling is intuitive, quick, and fun to use

Sheet Metal Modeling in Onshape couldn’t be easier. I sketched a quick Center Point Rectangle, clicked OK, then selected the Sheet Medal Model button. The following image shows the 2D sketch on the top plane with two edges selected. The two selected edges are new Sheet Metal flanges.

Figure 6- Sheet Metal Tool Bar

Figure 7 – Two edges selected to create the first Sheet Metal Flanges

The real power of the Sheet Metal Modeling comes when you want to look at multiple views. Selecting the Sheet Metal mode, two new Icons appear.

Figure 8 – Two new Tabs appear when you enter Sheet Metal Model mode

The Tab and Flat View bring up a LIVE 3 view display (Fig. 10)

Figure 10- Sheet Metal Table and Flat View

The image in Figure 10 shows the multi view layout. You can interact or modify any view. Let’s assume for a moment that I wanted to change the Bend Radius of Joints A through D. When bent, these four bends represent the base of this chassis. I have typically gone back into the 3D model to make this edit. I know Solidworks and other Parametric Modelers also show bend tables, and they can be edited. I do however, feel this visual interface allows for rapid edits and updates. Looking at Figure 10, notice when I select Joint C in the Bend Radius Table, the actual bend is highlighted in all three views as well.

One of my favorite features in Sheet Metal modeling is the Automatic Mitering. You can toggle this feature on/off by selecting or deselecting the checkbox Automatic Miter box. See Figure 9.

Figure 9 – Adding Flanges and Automatic Miters

Figure 11- Live Editing with Bend Radius Table

5. Creating Drawings with all associated data at your fingertips

I was pleased when I started to add drawings. The typical dimensioning tools were available including the ability to add your BOM, Insert a DXF/DWG or Image files too. The presentation of information was done well. As you can see in Figure 13, I had more than ten files open. My entire design was displayed nicely using Tabs located across the bottom of my screen. My entire design was at my fingertips.

Figure 12- Onshape offers a robust set of Drawing tools

Figure 13- Highlights of all the information at your fingertips

The Feature Tree showed all parts, assemblies and drawings associated with my design. I was dimensioning the Sheet Metal Frame and located just below the feature tree was a nice rendered view of my chassis. In, all, the amount of information I found at my fingertips was surprising and efficient. I quickly forgot I was using a web based Parametric Modeler, as it had the feel of any 3D package I’ve used during my career.

Onshape felt powerful during part modeling, even though as the assemblies grew I noticed a slight delay of roughly 9-14 second. However, it was clear they spent a lot of design cycles to handle the video buffering up front, hence, the user experience and workflow didn’t suffer. Drawings also offered a slim list of Export options. You have the choice to export out to PDF, DXF, DWG and DWT. I would like to see them add an option that allows users to select multiple formats for export out at one time. You will find the typical line weight options, hidden lines, centerlines and a host of other standard CAD features within Onshape’s Drawing module.

6. Inserting new elements

My final exploration into Onshape was using the Inserting New Elements option.

By selecting the Plus sign located at the bottom of the screen you will see the menu shown in figure 15. Select the Go to App Store and browse around for some goodies. They had apps for rendering, simulation, manufacturing, data management, CAM, utilities and import and export apps too. There is a large selection of free apps so I decided to download Power Surfacing, One Render, 3DX Certified Models and Onshape Explode Sample Utility.

Figure 15 – insert New Elements Dialog Box

In testing the One Reader app, I found the integration was seamless, the user Interface was simple to navigate, and I was happy to see the app didn’t come along with annoying advertising billboards. The rendering tools let me create my own materials, lights, and cameras. This app also had the option to create video. Throughout my career I’ve been called upon to create assets for Sales and Marketing so I was happy to see a full set of tools in a free app.

My experience learning Onshape has been positive and I hope this quick introduction ignites your curiosity. I see this product as a game changer or a market disrupter that will challenge the pragmatic design and require all major 3D software companies to roll out their own web-based product.

Only time will tell.

Is SolidWorks CAM Better Than an Integrated System?

December 15, 2017 By Leslie Langnau Leave a Comment

When the engineering software vendor announced it was moving from integrated CAM to a total CAD/CAM solution industry watchers took note.

Jean Thilmany, Contributing Editor

For engineers and design companies, it’s not difficult to find integrated computer-aided design and computer-aided manufacturing technologies. Yet, the announcement of SolidWorks CAM, released in October as a SolidWorks 2018 add-on, has created a small buzz in engineering technology circles.

Why?

It’s no secret that engineers struggle to create designs that are easy to manufacture while machinists complain about receiving unworkable CAD models.

An imperfect fit

CAM software uses the CAD models to generate the toolpaths that drive computer numerically controlled manufacturing machines. Engineers and designers who use CAM can evaluate designs earlier in the design process to ensure they can be manufactured, thus avoiding product costs and delays.

Without CAM, manufacturers can be on their own when programming machines to make the CAD model. And not all those who design in CAD enter design features into CAM to control the machine tools. Without CAM, manufacturers use the CAD design to program the tools themselves.

SolidWorks CAM could create codes for the end machine used for manufacturing.

“The general idea has been that engineers design something and then the manufacturing people eventually figure out how to manufacture it,” says Sandesh Joshi. “With integrated CAM, they’re not as disconnected as that, but there’s still a disconnect. This SolidWorks tool could close that disconnect.”

Closing the CAD/CAM disconnect

Joshi is chief executive officer at the CAD outsourcing firm Indovance. Previously, he spent six years on the SolidWorks research and development team.

The SolidWorks offering could ramp up the number of CAM users by making the tool available to more engineers and designers, Joshi says. The SolidWorks 2018 release marks the first time that SolidWorks is providing the CAM product as part of its design solution.

SolidWorks CAM is “powered by” CAMWorks, in the vendor’s parlance. Before the October release, CAMWorks, from HCL Technologies, was one of many third-party CAM tools available for integration with the vendor’s CAD program.

Of course other CAD vendors offer integrated CAD and CAM solutions.

Siemens PLM Software, for example, also offers CAMWorks as an embedded solution within its Solid Edge CAD program. NX CAM, also from Siemens PLM Software, is integrated with other NX solutions, which allows NC programmers and manufacturing engineers to associatively access design, assembly and drafting tools in a one part-manufacturing environment, according to that software maker. And CAM features are integrated into the Fusion 360 design tool from Autodesk.

But rather than taking on two separate software solutions, CAD and CAM can act as one system within SolidWorks CAM, Joshi says. That could make CAM easier and more straightforward to the software’s users.

The solution is fully integrated with SolidWorks so users need not leave the familiar SolidWorks environment, says Mike Buchli, senior SolidWorks product and portfolio manager. It supports feature recognition and can generate machining operations directly from native SolidWorks files or from imported data. Toolpaths are automatically updated based on changes to the model.

If SolidWorks 2018 engineers and designers feel they’re working within one integrated system–rather than two separate but connected software systems—they might begin to automatically use CAM and to consistently consider manufacturability as they design the product, he adds.

The vendor’s tool opens the way toward making CAM ubiquitous on engineers’ desktops, much as 3D CAD is now more-or-less used across an industry that once relied on 2D drawings, he said.

The part process from CAD to machining will never be a “one-click process,” Joshi says. But it certainly can become more streamlined through the use of a common CAD and CAM system.

“The difference is engineers would be using CAM as they design so manufacturability is easier,” he says.

“When we build assemblies, we have clash detection. Similarly, CAM gives us red flags for manufacturability right at he design stage, saves a lot of time and money,” Joshi says. “Today all design engineers don’t necessarily deal with CAM, so having access to that will help engineers design for manufacturing way ahead in the product design cycle.

SolidWorks CAM holds the potential for both designers and manufacturers–the possibility of a key to the elusive quest for CNC standardization.

“Some kind of machining cannot be done, and if that’s true it’s better to change the design right away rather than during the manufacturing process,” he says.

The system offers tools to validate and improve part and tool designs, including part-manufacturability checks and tool-motion simulation, Buchli says.

In a blog post introducing the tool, he outlined other benefits, such as the capability to:

–Recognize certain types of geometry to understand how those features will be manufactured, and how much it will cost to manufacture.

–Read tolerances and surface finishes and make decisions about how to manufacture the product

–Automatically apply best manufacturing strategies so manufacturing processes faster and more standard

–Automate quoting and compare it to traditional methods to ensure all aspects of the part are accounted for ahead of time

Fewer codes in the future?

The introduction of SolidWorks CAM holds the potential for another big benefit for both designers and manufacturers: the possibility of a key to the elusive quest for CNC standardization, Joshi says.

If the CAM tool becomes popular among SolidWorks users, Joshi can envision a day when the software automatically produces the G-codes that drive the machines that manufacture the part.

Right now, manufacturers struggle to drive their machining processes directly from their design software. The CAD systems don’t “speak the language” of various machines such as cutters and laser cutters, CNC mills and lathes.

“There are different flavors of G-codes depending on the CNC controller,” Joshi says. “The basic commands and operations generally will work on all machines but there are particular specialties and differences.

If SolidWorks CAM becomes widespread with designers who already use the vendor’s CAD program, the vendor “could potentially create codes for the end machine used for manufacturing,” Joshi adds. “The designer may not have to worry about that up front, but it makes manufacturing a lot smoother.”

With enough popularity, others will adopt those same end-machine codes, he says, creating a more-or-less-standard manufacturing-machine programming code.

And he knows of what he speaks. Currently, designers often rely on machinists and production engineers to develop strategies to effectively make the part.

“Job shops and manufacturing generate G-code for their CNC machine tools based on the CAD models they receive,” Joshi says.

Technologists at his company help interpret “on the back end” how to machine CAD designs, he says. He sees the issues manufacturers have with CAD designs.

“These companies get models from anybody and everybody and they don’t necessarily have all the types of CAD software. So they’re importing raw data rather than inclusive parametric models,” Joshi says. “It still works, but it’s more work.

“If the process is more integrated from end to end, it’s more likely to be seamless,” he adds. “If something has to be changed or modified it can be done quickly rather than going to engineering and coming back and being modified for machining.”

At SolidWorks World 2017, held last February, at which SolidWorks CAM was teased, Buchli related the benefits integrated CAD and CAM can mean for a company, specifically CP-Carillo, of Irvine, Calif., which makes pistons and connecting rods for high-performance race vehicles. The company saw a “significant increase in throughput” when using the then-integrated SolidWorks and CAMWorks, Buchli said in February.

Before using CAMWorks, the manufacturer input SolidWorks model geometry into the Mastercam program to create toolpaths and generate G-codes.

“We programmed each custom piston order manually, slowing down manufacturing,” says Karl Ramm, former CP-Carillo senior technology manager and project developer.

“Each job would take about 10 minutes for non-complex pistons and up to 40 minutes for complex pistons–and that’s programming time alone,” Ramm adds.

When the company brought in the integrated CAD and CAM solution, “custom orders that took days to design and program went down to hours,” Ramm says. “What used to take five to 15 minutes takes seconds now.”

The time-savings comes because the process is automated. Designers load custom criteria into a database and launch SolidWorks. The design application automatically pulls in that criteria and the designer can then create the new piece, which it transfers into CAMWorks. The CAM program then automatically generates new toolpaths and posts them to CNC machines in the shop, Ramm says.

The capability to share that kind of design and programming knowledge between engineering and manufacturing speaks to one of the biggest benefits of an integrated CAD and CAM system, Buchli says.

Another benefit is consistency of workflow. At CP-Carillo, custom orders always follow the same path. Design engineers and manufacturers know what’s expected of them when creating and manufacturing custom orders, Buchli adds.

SolidWorks CAM is much too new to see if any of Joshi’s predictions about standardization and popularity will play out.

But product lifecycle management consultancy CIMdata Inc. says it welcomes the decision to package and offer SolidWorks CAM.

“It protects the investment of CAMWorks users and adds proven CAM capabilities to SolidWorks,” according to a CIMdata statement.

While it remains to be seen if SolidWorks CAM is a step beyond the type of integrated CAD and CAM systems that exist today, Joshi and CIMdata are certain the engineering software vendor has taken a step in the direction down which the industry must travel to iron out disconnects between engineering and manufacturing and to save manufacturers costs and development time in the future.

Dassault Systemes SolidWorks Corporation
Solidworks.com

Do designers need to get physical?

October 3, 2017 By Leslie Langnau Leave a Comment

As powerful and feature-rich as CAD programs have become, you can argue that there’s a missing element to the design experience. Even augmented reality does not deliver the needed experience, yet.

The experience is actually touching a physical, three-dimensional model of the designed object.

The digital world is working hard to replicate such an experience as best as it can, but nothing quite succeeds like holding the object in your hands and examining and testing it. Simulations are great, and quite mature, but something is still lacking.

That is one of the reasons behind the trend to offer a fabrication lab experience to CAD designers. Dassault Systemes in Waltham, Mass., recently gave a tour of its new fab lab within the headquarters building. Noted Abhishek Bali, 3DExperience Lab manager, this facility helps CAD software designers, as well as customers, test and play with equipment to learn more about how a design could or should be manufactured and what future features to include in SOLIDWORKS to make the process more efficient. Part of the focus of the new features in SOLIDWORKS 2018 is on shrinking the steps it takes to go from design to actual product production.

This lab has a range of equipment, notably several versions of desktop 3D printers, such as Formlabs and Ultimaker, a Tormach mini CNC mill, a Roland SRM-20 for circuit design and test, a Shopbot CNC router, and even a small robot arm.

Said Bali, “Engineers are doing more physical prototyping, rather than just working with software.”

The trend for design engineers is to become multi-faceted, performing a range of tasks more involved with physical product development. So in a sense, everyone is becoming a “maker.”

Some of this shift into making is due to 3D printing / additive manufacturing. “3D printing has made a lot more engineers think about manufacturing,” said Craig Therrien, senior product manager for SOLIDWORKS.

With this increase in skills, comes the need for better communications between design and manufacturing. The two groups still often speak in different “languages.” Dassault hopes to change that by promoting SOLIDWORKS 2018 as a common language between manufacturing and design, even across the enterprise.

One takeaway from the meeting is that everything—from design through manufacturing through use—is connected; we just need to figure out how to fully benefit from this connectivity. This is where future advances lie.

Leslie Langnau
llangnau@wtwhmedia.com

Water pump design: Geometry optimization for a shrouded impeller

April 7, 2017 By Leslie Langnau Leave a Comment

Bruce Jenkins, Ora Research

For CFD-driven shape optimization of water pumps with shrouded impellers, it’s essential to have an efficient variable-geometry model defined by a set of relevant parameters (design variables). This case-study example focuses on geometry modeling of a typical water pump, with the goal of attaining maximum flexibility in shape variation and fine-tuning.

To begin, the geometry was set up in CAESES (CAE System Empowering Simulation), the software platform from FRIENDSHIP SYSTEMS that helps engineers design optimal flow-exposed products. CAESES provides simulation-ready parametric CAD for complex free-form surfaces, and targets CFD-driven design processes. Its specialized geometry models are ideally suited to automated design exploration and shape optimization.

The animations shown below were generated in CAESES by varying all design variables simultaneously. The geometry variations in these animations are exaggerated to make clearly visible how the shape is being varied; in a real-world use case, the changes that engineers would make to their initial design would likely not be as large.

Meridional contour

The hub and shroud contours, as well as the leading-edge curve, were designed in the Z-X-axis view. Variables were created and connected to these curves—for example, to the control vertices of the B-spline curves or to an angle control—so that they could be varied through the automated process of design exploration. The entire shape can also be controlled and adjusted manually based on engineering intuition, if needed.

Variation of meridional contours.

Blade camber and thickness

The camber surface of the blade was generated using a theta function in the (m,theta)-system. The function graph shown above is a 2D curve definition for which additional design variables were created and connected. From this function and from the leading-edge contour in the meridional plane, the camber surface was derived.

Theta function for generating camber surface.

Next a user-defined thickness distribution was applied normal to the generated camber surface. To control the shape, additional design variables were introduced to change the leading-edge region to be more elliptical than circular, and to vary thickness from leading edge to trailing edge. In addition, the thickness could be varied in the radial direction—that is, while sweeping from hub to shroud.

Variation of impeller blade.

Boolean operations and filleting

After the blade surface was generated, it was combined with the hub and shroud surfaces. CAESES’ Boolean operations were used to merge these geometries. Fillets were created at the intersection of the blade and the remaining geometry. The model shown above has two fillets: one between blade and hub, and another between blade and shroud. Below is an animation from the top view of the final impeller:

Water pump variation (top view).

And a final view, zoomed in:

Water pump variation (zoom).

Friendship Systems CAESES
www.caeses.com

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