NEWSUG Meeting Minutes
December 7, 2004, 5:00 p.m.,
While this report generally covers the meeting events, they have been arranged into a logical sequence and refined with the purpose of making them helpful without necessarily precisely representing the facts as they happened.
20 people attended this meeting.
Click on links for easy navigation
Rapid Prototyping with Fused Deposition Modeling
Announcements—Bob Braun
Upcoming Events
SolidWorks World will be held in
The next NEWSUG meeting will be held on March 1, 2005. We tentatively plan to focus on large assemblies.
User Interests
By show of hands, NEWSUG members have only modest interest in large assemblies presentations.
SolidWorks Tips
Enhancing Windows XP Performance – Moshe Saraf Up
While Windows XP has an attractive interface, the rounded corners on the dialog boxes and elaborate, bright color schemes come at a performance price. If you can accept the interface appearance from the earlier Windows versions, it will help with SolidWorks performance.
To make this change, follow these steps:
- Under
the Start button in the task
bar, select Settings from the
menu.
- Under Settings, select Control Panel.
- Double
click on the Systems icon.
- Select
the Advanced tab. The form should look something like the
above illustration.
- In the Performance region, select the Settings command button.
For best SoldiWorks performance, select the option button Adjust for best perfromance shown here.
Print Only a Select Area of a Drawing – Carol Beard
This tip will help you efficiently print only the parts of a drawing that you are interested in. Note that while this is a great solution for drawings, it does not work with part or assembly models.
Here are the steps:
- Zoom
so that you can see the entire drawing.
- Select
Print from the File menu (Or [Ctrl + P]).
- Choose
the printer and paper size and orientation that you want.
- Choose
the Selection option button.
- Select
the OK command button.
- A Print Selection dialog box will
appear and a frame will appear on the drawing. The frame illustrates the print
area.
Select the option button in the Print Selection dialog box to match your desired print scale or select the custom scale. The frame on the drawing will reflect the area that is to be printed with the printer and paper that you selected in step 3. Drag the frame around and adjust the scale until the frame reflects the area of your drawing that you want to print.
When
you have framed the area that you want to print, select the OK command button on the Print Selection dialog box.
Rapid Prototyping with Fused Deposition Modeling – Dean Sommerfeld Up
Rapid prototyping is a tool that permits early design evaluation, market research and tests. It can help speed a product to market and help insure that the product meets customer needs but it cannot replace designer responsibility.
Major types of rapid prototyping include these:
- Fused
deposition (3-D printing)
- Stereo
lithography
- LOM
(Laminated Object Modeling)
- Sintered
powder
- Glued powder
The technologies have wide variations in these parameters:
- Equipment
purchase price
- Finished
part size
- Demands
for a special (or routine) operating environment
- Finished
item cost
- Finished
part resolution. In some
applications, parts may need no finishing operations and other
technologies in other applications may need extensive secondary finishing
operations.
- Finished part mechanical properties and material selection flexibility. Some systems produce parts that can be plated.
Stereo lithography was singled out as having particularly high equipment purchase price and offsetting finished part properties. FVTC selected fused deposition because of modest purchase price and suitability for use in a student environment. Some of the processes permit finished parts to be made from wax or plaster so that they can be used in subsequent casting processes for fully functional parts. Some offer flexible materials that are suitable to illustrate a squeeze bottle.
Dean made these comments about the fused deposition system that FVTC has.
·
A number of materials are available.
o ABS
o Polycarbonate
o Wax
In the particular model of machine that FVTC has, only one structural material
can be used.
·
The raw material feeds as a plastic wire from a
cartridge. Various colors are available.
·
This system prints a second, brittle material to
support the finished part. When the part
is fully made and it has had a chance to cool, the support material can be
broken out by hand or with an ultrasonic cleaner and a special solution.
·
Assemblies can be built as assemblies in
SolidWorks with the volume between moving parts formed in the fused deposition
machine with the support material.
Later, the support material can be removed.
·
Accuracy is ± 0.005 inch in the build area.
· The system is clean and quiet so that it is suitable for an office environment.
From the assembly file, here are the rapid prototype model creation steps:
- Save
the SolidWorks model as a STL file with the Save As command under the SolidWorks File menu.
- Open
the file with the post processing software.
- Orient
the part in the virtual enclosure to minimize the required support
structure in order to minimize cost and build time. Multiple parts can be made
simultaneously, provided that they fit in the virtual enclosure.
- Permit
the post processor to mathematically slice the model in 0.010 inch thick
layers. This is a menu pick or an
icon selection.
- Send
the processed data to the rapid prototype machine. This is a menu pick or an icon
selection. The machine will
automatically begin processing the file.
- The model will start to build on top of a disposable foam platform. After printing each layer, the platform drops 0.010 inch and the next layer is printed. Material is only printed where the finished part is or support structure is only printed where the finished part will be above it.
Rapid and Virtual Prototyping – Ed Eaton Up
Ed’s full presentation can be downloaded from http://www.dimontegroup.com/Tutorials.htm. Scroll down until you see the part of the
page like the below illustration and download the main presentation and the
associated movie files as separate downloads.
The 13 and 23 Mb of respective compressed file sizes will take at least
several minutes to down load, even with a high speed connection. The balance of this section will summarize
the contents of the presentation.
In his presentation, Ed invited us to look at prototyping, why we prototype and related technologies from the broadest perspective in order to most efficiently create value. While this includes the rapid prototype technologies of the earlier presentation, it includes other technologies and techniques that may be more suitable in some situations.
Why do we make prototypes?
- Check
- Various materials
- Fit
- Finish
- Balance
- Mass or weight
- Confirm function
- Sell
- Product internally to Marketing, Sales, officers and investors
- Product to customers to get advanced interest
- Explain
- Assembly issues
- How to use the product
- Experiment with design variations
- Explore injection molding details
- Insure that the mold fills correctly
- Look for sinks
- Identify weld line locations
In an example of a virtual prototype, Ed’s company made a SolidWorks model of a product and took a photo of a human hand holding an object with similar shape in a realistic context. With PhotoWorks, they were able to blend the two into a rendering that was subsequently used on a web site, seen above, to get customer interest and input. No physical prototype was made.
In a second example, SolidWorks Animator was used to show the assembly and function of a time delay chemical delivery system for a swimming pool. This assembly could not be explained well with 2D illustrations and the virtual prototype saved the cost of injection molded tooling. The video communicated how the assembly worked with no ambiguity. Anyone who saw the video understood why it was a superior product without seeing the physical parts. The client was able to get orders before the product existed!
In the swimming pool device, another type of virtual prototype was used in CosmosWorks. In this application, at least three parts were analyzed for strength, including strength after a snap fit assembly and stress through the snap fit. While software limitations force them to be conservative in their required safety factors, they were able to avoid the time and expense of physical parts and tests. On this project, DiMonte estimates that they saved 14 days in their design schedule and $5,000 in prototype tooling with CosmosWorks.
In the swimming pool device development, they eventually
created physical prototypes. In this
case, the end customer dictated the stereo lithography (
- Select
your rapid prototype vendor carefully.
- Visit
their facility to make sure they are competent.
- Make
sure that communication goes both ways between you and the vendor.
- Consider
the vendor location. Can you visit
them quickly if a problem comes up?
Will you loose days shipping samples back and forth?
- Be
particular or you may pay the price in delays.
- Don’t
be afraid to “fire” your vendors if they cannot meet your quality needs.
- Good model makers can do incredible work!
A combined ketchup and mustard dispenser served as an illustration of several virtual modeling technologies and techniques.
- Cosmos
Motion was used on the levers and pump system to calculate loads that were
input into CosmosWorks for stress and deflection analysis. One result of the Cosmos Motion analysis
was the discovery that moving the mustard
only lever also caused some ketchup leakage. That would have been difficult to
identify, even if physical prototypes had been made.
- The ketchup and mustard were modeled as solid models
in the container. This was helpful
to get exact volume information, center of gravity information and
accurate location for the refill marks.
- In order to meet an end customer request, the client made a last minute change to a molded part. After the change, a failure was observed in the changed part. Services by EPS Flotek (www.epsflotek.com) were used to look at how an injection mold filled in the molding process. With this technique, DiMonte determined that the molding knit line was at the failure point. They were also able to look at changes that can be made to enhance this part in that critical area.
The last example project that Ed presented was to design a grill scraper (illustration below). This project had these requirements, only some of which can be directly addressed with SolidWorks.
1.
The tool had to be comfortable to use correctly
and uncomfortable to use incorrectly.
2.
The new tool had to work with an existing blade
sharpener, which had been designed for an obsolete grill scraper.
3.
There had to be room to work inside a clamshell
grill.
4.
The scraper had to protect the operator from
heat from the clamshell grill.
5.
The scraper had to clear a flip up tray that is
on the front of some grills.
6. The design had to be made from heavy gauge wire.
A proposed deign was laid out in SolidWorks to potentially meet all clearance and other fit requirements. CosmosWorks was used to look at component strength and rigidity.
In order to get an ergonomic back handle, a rough physical model was made out of Castelene based on subjective feel. Gaspardo (www.gaspardo.como) scanned the model into a point cloud that was then converted into SolidWorks surfaces. From there, it was tweaked to give a smooth shape. Below is an illustration of the physical model and the finished handle.
First sample parts from the handle vendor showed them to be weaker than
expected. By scanning the physical parts
and comparing the results to the SolidWorks model, it was determined that the
wall thickness was about half of the specification. Because of delivery time pressure, there was
not time to have the vendor to make the parts match the design specification. DiMonte was able to model the actual part in
SolidWorks and analyze it in CosmosWorks.
From there, it added internal ribs, which could be added quickly, and
verified that this design modification was adequate to meet the performance
requirements.
In summary, DiMonte has been able to use SolidWorks, SolidWorks Gold Partners and other related technologies to efficiently design parts and assemblies that fully meet customer demands.
Other Meeting Details
In addition to the formal presentations, Dean Sommerfeld also demonstrated how a SolidWorks part or assembly file can be converted to the format of their rapid deposition machine. He sent a sample part to the machine and the NEWSUG members were able to watch it build.
Both VAR’s, CATI and Graphic Systems, each sell a brand of rapid prototype machines. Since each brand is a different type of technology, interested parties should contact both. Contact information is on the NEWSUG web site. Other rapid prototype machines are available from other vendors.
Next meeting
Our next meeting is scheduled for Tuesday, March 1, 2005. Tentative topics will be Large Assemblies.