Category: Part

June SW Legion Contest: Create an Ellipsoid model

The June SW Legion Contest is a different kind of challenge!  The task is to submit the simplest SolidWorks model of an ellipsoid possible.  The person with the least combined number of features and sketches wins.  Use of equations is highly encouraged. 

The submitter must be the author of the file they submit. 

Contestants may email their entry to me at my email address by the end of July 6, 2009 PDT.

Ellipsoid

The prize is one CSWP test of your choice (CSWA, CSWP, CSWP Sheetmetal, CSWSP FEA, etc).   

Past winners of the Legion Contest are eligible.  In the event of a tie, tie breaker will be in the form of email roshambo.

Best of luck to everyone!

Dimensioning of Slots in SOLIDWORKS for ASME Y14.5

This entry is part 4 of 8 in the series Dimensions and Tolerances

Ever since the additions of the slot sketch tool for 2009 and the Hole Wizard Slot for 2014, SOLIDWORKS almost seems like a whole new software for the those who design machined parts.  Adding these tools were long overdue.  Additionally, SOLIDWORKS supports the standard methods for dimensioning slots when they are created by using these tools.

ASME Y14.5M-1994 paragraph 1.8.10 and figure 1-35 provide three methods for the dimensioning of slots, with no stipulation regarding which is preferred for particular scenarios.   (Note: all three methods require the insertion of a non-dimensioned “2X R” note pointing at one of the slot’s end radii.)

In one fashion or another, SOLIDWORKS supports all three methods, though it does have a default for both simple slots and arc slots.  For brevity, this article will only cover simple slots.

The first slot dimensioning method (a) provides the width and the distance between the end radii center points.

Dimensioning Method (a)

Method (a)

The second method (b) is the easiest and simplest to dimension.  Simply state width and overall length, and use an arrow to point to the slot’s object line.  Though originally reserved for punching operations, ASME Y14.5M-1994 (and later versions) allows for the use of this method on any simple slot.  When using Hole Callout to dimension a slot in SOLIDWORKS 2009 or later, this is the type of dimension that is inserted.

Dimensioning Method (b)

Method (b)

The third method (c)  provides the width and overall length of the slot in linear dimensions.  This method is preferred if the slot has positional tolerances that use the boundary method (see ASME Y14.5M-1994 figure 5-47).

Dimensioning Method (c)

Method (c)

For all of the above methods, add the “2X R” separately by using Smart Dimension tool.

Side note: of the three choices, the ASME board almost left out (a) and (b).  The original release draft of ASME Y14.5M-(1994) only shows method (c) in figure 1-35.

New type of SaveAsPDF macro

SolidWorks is able to save drawings and current model views as a PDF format file.  SaveAsPDF with Folder SelectionThere’s been a lot of macros written over the years that cut the process of saving as PDF down to as few steps as possible. One of the long standing requests for this type of macro (and many similar types of macros) is to allow the user to pick the save location. Just uploaded is a macro (SaveAsPDF with Folder Selection) that does just this, and simplifies the location selection process for default folders. This new macro also uses more modern API techniques to save the file (using modelext::saveas instead of model::saveas4).

This macro does many things that previous macros haven’t.  While allowing the user to establish a default save location folder, it also provides automatic alternative choices when the default is not available.  Yet, even with all of these, the user can still override automated selection and pick a new location.  It does all of this without the use of VB6 forms.

As with other macros that do similar tasks, this will work best when assigned to a keyboard shortcut or a toolbar icon.   Also, as with all SolidWorks macros, there is a chance it will not work “out-of-the-box”.  This is normally due to the fact that SolidWorks updates core reference libraries with each release.  If errors are encountered, simply re-reference to the libraries that are available to allow the macro to function.  More information about that is available in this previous article.

Model Based Definition (MBD)

As we move further into the realm of 3D CAD software, something that is still catching on is the idea of driving all specifications directly from the model file, instead of having a separate drawing.  There are various terms for this, but I’ve seen Model Based Definition (MBD) most recently.  I personally am not critical of this idea.  I am critical of moving 100% to this form of documentation without better support from our 3D CAD packages and ASME/ISO standards.

Models are generally considered basic.  All this means is that the tolerance is derived from some “other” specification.  This is normally in the form of associated Geometric Tolerances. To fully define a part in MBD, you’ll need a GD&T scheme, often supplemented by traditionally dimensioning and tolerancing where needed.  The difference is that if drawings are not used, this has to be done within the model itself and then is somehow communicated to the manufacturer.  The task to communicate this information to the manufacturer via the model is harder than it might seem as first glance.  This is due to the myriad of 3D CAD formats and versions now available.  GD&T information may not translate to other formats, such as STEP and IGES. 

Additionally, any information that would’ve appeared on the drawings now has to appear within the model itself.  So, shortcutting the drawing step doesn’t mean one gets to ignore the information that would’ve been included on a drawing. It just means all of that now needs to appear in the model.

With that said, ASME Y14.41 supposedly standardizes this effort.  In my opinion (and yes I’ve read it and “own” a copy), it is lacking right now.

If considering a MBD program, just make sure everyone understands that the model is now the drawing; and that means it will need to be as accurately detailed as the drawing would’ve been; and since this information is now in the model, a method of communication will have to be established with the manufacturer if they don’t have the ability to use the format where the GD&T information resides. 

An alternative is to use the drawing in conjuction with the model, which together provide the complete specification.  In this case, the drawing will still be the primary specification (usually for critical-to-function specifications), but it makes use model to complete the specificaiton.  The model can either be basic, or used with some traditional tolerance.  Where the model is basic, I’ve seen companies place a generic profile feature control frame in the general notes.  This FCF is applied to the model for any dimensions that are unspecified on the drawing.  If such as system is employed, it is important to clearly state this on the drawing to prevent ambiguities.

SWW09: Focus Groups (Drawings and Sheet Metal)

As previously mentioned, I attended two focus groups (also called roundtable discussions) this year.  These are generally held on Sunday before all the major SolidWorks World activities begin on Monday.

Sheet Metal

The first group I attended was for sheet metal functionality.  Though attendence was very light, the number of different methodologies and opinions was high.  My own interest in the topic is the problem with being forced to use assemblies to fully document sheet metail parts with inserts.  This is an issue because if you start a drawing of a part, you cannot later replace that part with an assembly.  So, if you create a sheet metal part with no inserts and then you need to add inserts on some later revision, you are forced to recreate the drawing practically from scratch.  This is a horid time and resource sink.

Others in the group talked about using K-factors to determine the material used by the sheet metal part (for flat patterning), while others disregarded K-factors in favor of bend reduction techniques.

One request that seemed to get common acceptance is the idea of creating a table of all the bends of a part with their full characteristics, with the ability to highlight each bend by clicking on it within the table.  When this table is on a drawing, it was suggested that details be added to a specific layer.

The session  also revealed that some used work arounds to use the SolidWorks model to instruct sheet metal tooling to perform certain actions (either via direct or translated input).  Some use alternative features which do not match the final design in order to instruct a tool to produce the feature desired in the final design.

One work around solution did come out of this session.  Right now, the material mass number changes from bent state to flattened state.  Although this difference is minor, over a large quality of parts, the error multiples and can create issues in part handling.  Use a non-configuration custom property to link to the the material property (of a specific configuration?).  Use this custom property as the source for the mass regardless of the configuration or part state.

Drawings

A large portion of the drawings discussion revolved around printing and saving issues with Drawings.  It seems many people are experiencing similar problems.  When saving as a PDF, views randomly disappear.  When printing as a PDF, text locations get shifted.  Also, changes to parts at lower levels of an assembly may cause errors and view changes in higher level assembly drawings; meaning the the company has to open up all levels of a product’s assemblies to make sure that any change did not affect the drawings in unexpected ways.  It seems more people are having these kind of issues that I originally thought.  Many of the problems are magnified by use of PDM’s.

The meeting also focused on DimXpert and how to handle its dimensions.  One comment is that it should place dimensions per current standards within the model.  Another comment noted that datums and feature frames should drive the model.

I voiced my other major concern as well.  Symbols from the Gtol.sym library file should be stored within a drawing.  Right now, I cannot give native drawings to others outside of my organization because they will not be able to see symbols that we employ.  When a symbol is used within a drawing, it should be included in that drawing’s file and not require editing of any other user’s Gtol.sym file.

SWW09: Wednesday General Session (Part 1: Annual Top 10)

Each year at SolidWorks World, SolidWorks Corp announces the top 10 enhancement requests, as voted upon by the users.  It is claimed that there has been a 70% implementation rate for the top 10 requests over the past 8 years.  It was implied that his years list comes from the new service on SolidWorks.com called Brainstorm (though I don’t remember this being explicitly stated):

10. Excel behavior for tables.

9. Abort any running command using ESC key.

8. Add lock points.

7. Dual monitor support.

6. On-the-fly equation creation and editing.

5. Faster rebuild on complex models and drawings.

4. Rename configurations that are in use.

3. SolidWorks backward compatibility

2. Clear memory when file is closed.

1. Increase program stability.