Mythical Specifications: Non-accumulative tolerance

This entry is part 4 of 4 in the series Mythical Specifications

Mythical specifications come in many forms.  One realm they seem to haunt is that of repetitive features, also known as patterns.  Many attempts to shorthand pattern callouts are continuously made.  Bad habits die hard as old mistakes are passed down from one generation of engineers to the next.  One particularly bad habit is the use of linear dimensions with the term “NON-ACCUMULATIVE TOLERANCES”, or something similar.  There is no such thing.  Trying to use this shorthand leads to tolerance issues.

Pattern non-accumulative tolerance callout

In the example above, the dimensional callout attempts to simply dimension a pattern without considering tolerance stack-up.  However, this attempt fails since any two non-adjecent holes cannot avoid accumulation of tolerance due to the dimensioning scheme.  Tolerance stack-ups on linear dimensions have accumulation.  There’s no way to avoid it without dumping linear dimensions.

I had originally planned on a short article about this topic.  However, once I started delving into it, I found out that there is a lot of ground to cover.   So, this topic will be addressed in detail within a future article (Feb 23, 2011) where examples of different pattern dimensioning schemes will be explored.

Also see How to dimension feature patterns on drawings.

SolidWorks World 2012 is on Valentine’s Day (luvification letter included)

HeartYes, it is true. SolidWorks World 2012 will be from February 13-15, 2012. It’s on Valentine’s Day! Maybe SolidWorks Corp is trying to schedule the event around other major conferences in southern California? Maybe someone didn’t think about the fact that many of us not only have to get approval from our boss at work, but now we have to get special approval from our boss at home?

Well, SolidWorks Corp has decided to help out. They created a new justification, or luvification, letter to help potential SolidWorks World 2012 attendees get approval from their spouses to be away on Valentine’s Day.

From their new weblink:

DS SolidWorks Corporation understands that SolidWorks World 2012 will fall on Valentines Day in 2012. Unfortunately, scheduling around other major events in southern California, such as the MD&M show, requires us to push our conference into mid-February next year. We are sympathetic to the many spouses that may be away from their loved-ones on Valentines Day. This justification, or luvification, letter was written to aid in getting spousal approval for attending SolidWorks World 2012.

SolidWorks World Luvification Letter

Dear madam or sir,

I am writing to you [spouse’s name here], who I love, to request permission to attend the SolidWorks World 2012. It is highly important that I attend this significant event because I believe the conference’s opportunities for technical training and networking with SolidWorks users worldwide can help me accelerate my career. In turn, that will help me bring home more bacon (and other such required groceries).

Don’t worry about me enjoying myself. I’ll be too busy with more than 150 technical training sessions and three long General Sessions. Then there’s the Special Event where I will congregate with other individuals who are missing their spouses. Yes, dear, I will miss you something fierce. The pain and agony of being away from you on Valentines Day will not be bareable. Therefore, the very next weekend, I’m taking you on a very special trip to [insert appropriate location and activities here] without the kids.

Thank you in advance for your consideration, and please let me know if you need additional information on specific conference opportunities and activities. I look forward to your positive response to my request.

With great love,

[insert your pitiful name here]

I originally posted this “luvification letter” in the SolidWorks Forum. And in case someone missed it, this is a joke. 🙂

 

Hidden SolidWorks Commands – compiled by Scott Baugh

SolidWorks Help file is notoriously unhelpful at times.  It has evolved over the years to improve its usefulness.  However, there are still many under-documented functions within the Help file or commands that are completely undocumented.  One day in January 2011, Scott Baugh asked a sincere and innocent question in the SolidWorks area on Eng-Tips.

Does anyone no (sic) where I can find a document with hidden SW commands. There are some key strokes and commands in SW that are not always listed in the help, or if they are they are overlooked very easy (sic).

From there, a long thread of comments grew.  Someone mentioned that users can print out a list of keystroke assignments.  This isn’t what Baugh was looking for. 

Then, the list of “hidden SolidWorks commands” began as people submitted commands they felt were obscure or impossible to find in the SolidWorks Help file.  It wasn’t long before Baugh offered to compile the list into a document.  At first, the idea was to build the list in a discrete document.  However, Deepak Gupta suggested GoogleDocs. 

From there, Baugh built the list of “hidden SolidWorks commands”.  There were three types of items added to the list:  commands that are truly undocumented, commands that are under-documented (full functionality isn’t described), and commands that were too hard to find within the documentation.

Baugh then brought the topic over to the SolidWorks Forums, where the discussion further exploded.  SolidWorks staff chimed in to address several points, but also to learn.  Jim Wilkinson provided several detailed responses to help bring clarity to the conversation.  Through his efforts, he also discovered several areas where improvement to the SolidWorks Help file is needed. 

The Hidden SolidWorks Commands list is now a treasure of numerous golden nuggets.  It’s not long, yet it can take awhile to fully explore.  Check it out.  If you have any further suggestions, feel free to leave a comment here, or in either the SolidWorks Forum thread or the Eng-Tips thread.

Hidden SolidWorks Commands

InspectionXpert for SolidWorks review

Refresh ProjectInspectionXpert for SolidWorks is an inspection report automater and ballooning application that runs within SolidWorks FeatureManager pane.  Its tight integration with SolidWorks has earned it SolidWorks Gold Partner status.

InspectionXpert helps users to automatically generate inspection report forms in conjunction with automatically ballooned inspection drawings.  The user can choose to create an inspection report for every dimension (for First Article), or choose particular dimensions to inspect, such as those identified with the rounded outline box.  InspectionXpert displays identified information in something called Characteristic Tree (it includes dimensions, geometric tolerances, notes, hole callouts, weld and surface finish symbols extracted directly from the SolidWorks drawings).  Report forms created from the Characteristic Tree are created in Excel.

Inspection data points within the Characteristic Tree can be saved directly inside of the SolidWorks Drawing for added convenience.  InspectionXpert has a project refresh function that may be used if dimensions are added or if a drawing is changed.

InspectionXpert can be particularly useful for Incoming Inspection, Manufacturing, and other groups by allowing them to generate accurate and highly specialized reports based on information directly pulled from the SolidWorks drawing.  This seems like a good solution that can simplify and streamline the inspection process.

Senseless Sunday: the long and the short word

  • The word hippopotomonstrosesquippedaliophobia means fear of long words.
  • Flint, Michigan is the largest city in the U.S.A. to have just one syllable in its name.
  • An urban legend defines a twit as a pregnant gold fish.   Gold fish do not get pregant.  They lay eggs that get fertilized afterwards.  A twit is also not a comment on Twitter.  That is a tweet.

SolidWorks World 2011 Top Ten requests

Each year, SolidWorks users vote on the changes they’d most like to see included in SolidWorks.  This year, voting was conducted in a special area on the SolidWorks forums.  For the amount of attention this list gets, it should be noted that the top vote-getter on the Top Ten List didn’t get much more than 120 total votes.  There are several important requests in this year’s list.  There are also some that leave me wondering, “what’s the big deal?”

Top Ten Freeze FeaturesTop Ten List

  1. Angle mates that don’t flip at random (Yes, we need this!)
  2. Better utilize processor cores (Yes, of course!)
  3. Option to dangle instead of deleting (A cool option that could be useful.)
  4. SolidWorks should cleanly uninstall itself (Done! …supposedly in 2012.)
  5. Freeze Features (Again, done! …supposedly in 2012.)
  6. Enhanced Equations Input & Editing & Linking (Again again, Done! …supposedly in 2012.)
  7. Convert a Solid Body into a Surface body without having to delete, offset, or knit faces (Ok, cool idea, but aren’t there more critical changes needed?)
  8. Make the ideas section (in the forum) available all year, not just for SWW (huh?)
  9. File compatibility between versions (Every year this is on the list.  Every year this is not implemented.)
  10. Pressing Escape key should immediately return control of the interface (This ESC key request again?  Yes, but let’s move on already.)