Archive for June, 2012

Don’t Get Filled Up

Friday, June 29th, 2012

Here’s a feature that you might not use too much or even know about.  The “Fill Pattern” patterns a feature or a predefined cut shape in a defined area.  This is great for weight reduction or ventilation.

In the image below, you can see that you can pattern selected features or create a seed cut.  The seed cut has the 4 predefined shapes that are created on the fly.  You just need to specify the size of the seed and it can take care of the rest.

You can specify the “buffer zone” or “margins” that the pattern can be created in.  That is the area of clearance around any of the edges.  In the image below you can see the holes are no closer than 0.25″ to the model edges.  This option is set in the “Pattern Layout” and is the third box down.

That great but what if you only want the pattern in a certain area and there are no model edges around.  Well all you need to do is create a closed sketch and select just the sketch and NOT the face.  You don’t need to split the face with the sketch or anything.

If you would select both the face and the sketch, it will create the fill pattern on the face and NOT inside the sketch.

*The large circle is just a sketch that is shown and not a model edge.

 

The fill pattern was added in 2006 and hopefully will help you be more productive.

Josh Spencer

Elite Application Engineer, CSWE 3DVision Technologies

Should your Simulation files go into the EPDM vault?

Thursday, June 28th, 2012

SolidWorks Enterprise PDM’s integration with Simulation is pretty easy.

 

(Though as you can see from above SolidWorks hides it in the “Display” menu.)

If you click this option, when you check in a SolidWorks part or assembly that has the simulation report file still available, EPDM will offer to check in the report file along with the component.

But should you do it? Some of those report files can get pretty big.

My advice is that unless your IT guys are falling over themselves, taking turns screaming at you because their precious vault is too big. (Why do IT guys always think it is their vault?) Do it.

Assuming you ran the analysis to ensure the design is good, having a record that you did your due diligence and checked your designs can come in very handy down the road. Doubly nice is that each Simulation report file is associated with the version of the file that you ran on it. So with EPDM, you not only have a history of how that file has changed over time, you additionally have all the analysis report files related to each version.

Never underestimate the power of a good paper trail.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

NEW SmartDimension functionality in SW2012

Monday, June 25th, 2012

Wondering why sometimes in SolidWorks 2012 you have to hit the ESC key multiple times to exit out of the Smart Dimension command ?

Think there is something wrong ?

Turns out you are just missing out on some new functionality with the Dimension command in SolidWorks 2012 !

The ESC key will let you “back up” thru your picks that you have made in the Smart Dimension command.

Let’s say you selected two things to dimension between and then decide you don’t like what you selected for one of them… In 2011 and before you would have to just ESC to exit out of the Smart Dimension command, then hit the Smart Dimension button again to start over, and then pick what you wanted.

NOW in SolidWorks 2012, if you have “mis-picked” (or changed your mind) you can hit ESC once to UN-pick your last pic, ESC again to UN-pick the previous pick, etc. etc. until you have un-picked what you don’t want and then just pick the correct items.
All without exiting and restarting the Smart Dimension command !

Pretty great when you know how to use it !!

Randy Simmons

Application Engineer, CSWP 3DVision Technologies

Flow Simulation and the 75 Dollar Question

Friday, June 22nd, 2012

Is it worth the extra 75 dollars for a long tube header versus a short tube?

Let’s start answering this by examining how an exhaust header works, and why you would want one.  Headers are one of the easiest bolt-on accessories you can use to improve an engine’s performance. The goal of headers is to make it easier for the engine to push exhaust gases out of the cylinders.

 

To further understand why the exhaust manifold has an impact on performance let’s review the  combustion cycle of a gasoline engine.

  1. The intake stroke-  Starts with the piston at the top of the cylinder.  As the piston moves downward the intake valve opens allowing the air fuel mixture to enter the cylinder.
  2. The compression stroke-  Moves the piston back up to compress this air fuel mixture, causing the ignition of the air fuel mixture to be more powerful.
  3. The combustion stroke –  When the piston reaches the top of the cylinder, the spark plug emits a spark to ignite the gasoline. The gasoline charge in the cylinder explodes, driving the piston down.
  4. The exhaust stroke- Once the piston hits the bottom of its stroke, the exhaust valve opens and the exhaust leaves the cylinder to go out the header.

During the exhaust stroke, back pressure robs the engine of power. The exhaust valves open at the beginning of the exhaust stroke, and then the piston pushes the exhaust gases out of the cylinder. The more resistance there is to the piston expelling the exhaust gases, the greater the power loss.

Once the exhaust gases exit the cylinder they end up in the exhaust manifold. In a four-cylinder engine, all cylinders utilize the same manifold. From the manifold, the exhaust gases flow into one pipe toward the catalytic converter and the ­muffler. The idea behind an exhaust header is to eliminate the manifold’s back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. Old hot-rodder intuition, gut feel, and experimentation lead to each pipe being the same length, and using a two into one set up. Two into one specifies that the pipe leading from two cylinders merge into one.  In the case of a four cylinder, pipes from cylinders 1 and 2 lead to one pipe, and pipes from cylinders 3 and 4 lead to one pipe.  Those two pipes then merge again into the collector. The two into one method “smoothes” the flow through the pipe causing less turbulence when the flow fields merge.  These pipes come together in a larger pipe called the collector. By making them the same length, it guarantees that each cylinder’s exhaust gases arrive in the collector spaced out equally so there is no back pressure generated by the cylinders sharing the collector. Basically Header=Power, and we all want more power.

The 75 dollar question arose from my sister.  She is considering replacing her stock exhaust manifold with an after-market header, and was wondering what was the best “bang for the buck”.  After researching the topic extensively we found that across all the after-market brands the designs seemed to be the same regarding pipe routing, materials, etc.  So the main question came down to should she buy the “short tube” or “long tube” header?

Both the “long tube” and “short tube” headers have equal length pipes from the engine block to the collector.  Both ran a two into one method.  The long tube header however claims that since it is longer by design there would be less back pressure due to a smoother flow.  The differentiator was about 75 dollars, and the fact that the “long tube” header would need the catalytic converter to be moved and remounted by a muffler shop.  The “short tube” header is a direct bolt in.

I couldn’t resist turning to Flow Simulation to solve this question.

We purchased the long and short tube headers, and removed the stock manifold to be able to accurately take measurements from them.  The models are close but not exact without a reverse engineering tool such as a scanner or arm.

After the models were completed the next step became the boundary conditions.  I was able to find a good reference guide located on line from www.donaldsonexhaust.com.  Given the engine Horsepower, cubic inch displacement, and operating RPM I was able to determine Intake airflow, and exhaust gas flow in CFM.

This calculated the exhaust gas CFM to be 520.00 CFM, or 130.0 CFM per port. Please see the hand calculations below.

Yes Engineers Still Do Hand Calcs

Knowing the CFM of the exhaust leaving the cylinder allows us to compare pressure drop from the inlet to outlet across the three manifold models.  The stock exhaust will be the base line for comparison.

 

Model Set Up:

 

Inlet Condition:                130 CFM per inlet port

Outlet Condition:             Environmental Pressure

Surface Goals:                   Each Inlet Goal – Static Pressure / Mass Flow Rate

Outlet Goal – Static Pressure / Mass Flow Rate

Results:


Stock Flow Path

Stock Pressure Gradient

Short Tube Pressure Gradient

Short Tube Flow Trajectories

Long Tube Pressure Gradient

 

Summary:

 

The “short tube” header is hands down the best value.  Both after-market headers showed a drastic decrease in pressure drop over the stock manifold however, the “long tube” header only had an edge over the “short tube” pressure by 0.019 PSI.  As a bonus the “short tube is a direct bolt in, not requiring the existing catalytic converter to be moved.  As Engineers we are always worried about time and money, and are often faced with a decision regarding these two factors.  From my engineering background and proof provided by flow I recommended the “short tube” header.

Robert Warren

Elite Application Engineer CAE Technical Specialist 3DVision Technologies

Dissection – Quickly Reuse SolidWorks Design Data

Wednesday, June 20th, 2012

I love to find things that help me keep from having to do something over again. Calculators. Assembly instructions. Programmable lawn mowers.

A great SolidWorks tool in this area is Dissection – SolidWorks dissects files to make their components available for reuse. When SolidWorks files are dissected:

  • Parts are dissected into features (extrudes and cuts)
  • Features are dissected into sketches
  • Drawings are dissected into general tables and blocks
  • DWG/DXF files are dissected into tables, blocks and views

To use this functionality, first use File and Model search to search the folders you have specified in: Tools > Options > System Options > File Locations > Show folders for: Search Paths. Your search results will show in the Search tab of the Task Pane.

If you search returns a part, for example, you are ready to drag and drop that part into an open assembly.

Go back to the Search tab and double-click on the part and you will be presented with a list of features that SolidWorks dissected (extracted) from the part – you can drag and drop one of these features onto the existing geometry of an open part.

Go back to the Search tab and double-click on the dissected feature and you will be presented with the sketch that was used to build the feature – you can drag and drop this sketch onto a plane or face of an open part.

The source files are not changed when dissected and there is no associativity created if you were to drag a dissected feature onto a new part.

Design reuse made easy!

Follow this link to read more about it in the Help file: http://help.solidworks.com/2012/English/solidworks/sldworks/design_clipart.htm

Chris Snider

Application Engineer, CSWE 3DVision Technologies

EPDM users across the world love sldsetdocprop

Friday, June 15th, 2012

A few years ago Bill mentioned how you could use “sldsetdocprop” to take a Toolbox part and make it behave like a normal part. However you can use this tool to do the exact opposite – take a normal part and make it a Toolbox part.

SolidWorks Enterprise PDM users all across the land think this is cool -here is why:

Checkout this screen shot from EPDM’s “Copy Tree” command:

HomeMadeToolbox

See the part cleverly named: “I want this part to work like a toolbox part.sldprt”? This part is just a simple part like all of the others except I changed it into a Toolbox part with the sldsetdocprop command. Now, by default “Copy Tree” does not try to copy this file! I don’t have to dig through my copy list trying to figure out which are my standard/toolbox parts that I don’t want to copy, Copy Tree does this for me now!

Sldsetdocprop can work on an entire directory, so if you have a directory of commercial parts, it may be worth your while to change all the parts in that directory to become a “toolbox” part.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Group Members for your Datacard

Monday, June 11th, 2012

You’ve designed the perfect folder datacard for your SolidWorks Enterprise PDM setup. It is a great little folder card listing project due date, description and even have a nice little droplist for your users to pick the proper project manager.

But wait! You’ve noticed there is no way to get a list of just your project managers! What’s a girl to do?!

List Properties

The solution is easy with Engineering Data Specialist Man! Create a new list, make it a SQL query and enter in this SQL statement:

 

SELECT Users.Username
FROM GroupMembers INNER JOIN
 Groups ON GroupMembers.GroupID = Groups.GroupID INNER JOIN
 Users ON GroupMembers.UserID = Users.UserID
WHERE (Groups.Groupname = 'Engineers') AND (Users.Enabled = 1)

Now, assuming you have assigned your project managers on the root level, you have a list for your card that will update as your project managers come and go.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Expand 3D Printing Value Across Your Organization: Explore the new Mojo 3D Printer

Tuesday, June 5th, 2012

You are personally invited to attend a free webinar June 14 at 2pm EDT introducing the new Mojo 3D Printer.

This introduction to the new Mojo 3D Print Pack, including how to save time processing files with Mojo Print Wizard software, sending jobs to the 3D printer, loading materials, and removing supports from finished models is a great way to see the new Mojo 3D Printer in action.

Get a look at how you can get the most out of your 3D-printing investment by expanding use beyond concept models and functional prototyping and into surprising applications throughout your organization, such as fixtures and finished goods and all at a price that you will not believe.

Who should attend?
- Designers
- Educators
- Engineers
- Product-Development Professionals
- Project Managers
- Supply-Chain Managers
- System Engineers

So don’t miss this introductory webinar, June 14 at 2pm EDT. Click the following link to register http://bit.ly/KMjNN9

Carrie Patrick

Marketing Manager 3DVision Technologies

Need more bandwidth

Saturday, June 2nd, 2012

Funny story: A few days ago I was at a customer’s site to install SolidWorks Enterprise PDM. They only had service pack 0 on DVD and I wanted install service pack 3. We started the download -it was very slow.

I ran over to McDonalds, connected to their WiFi and was able to download the entire install and get back before their download was complete.

Interesting that a fast food restaurant takes Internet bandwidth more seriously than an engineering based company.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

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