Reference Articles:

“Redefining 2D/3D”

"The Embedded Title Block! A PLM Solution!"

"The Worst to Best CAD System and Why!"

"The Death of the Drawing"

The 3D MCAD MODEL?

 COMPARE AND VALIDATION PROGRAMS?

BAND-AIDS FOR SELF INFLICTED WOUNDS!!

Apples to Apples?

VALIDATION PROGRAMS

3D CAD model validation software is probably a bit foreign to you. Only the larger manufacturing companies that have based the authority of their engineering documentation on the 3D model have required their suppliers purchase it. Most smaller companies have stayed with conventional documentation which includes the 3D model and the fully detailed AID (Associated Information Document (drawing)). This is one of the unintended consequences of the MBE (Model Based Enterprise) and throws the engineering documentation to manufacturing process into a tizzy.  

Validation programs were released a few years ago. They were created to compare solid models to make sure what the supplier was machining was what the customer sent. They program cost over $7,000.00 and produced an 8.5 x 11 "PIECE OF PAPER" that said it was a good part. Which a Boeing supplier would stick in a file. Now you would think the actual inspection of the finished part would be the final validation. But no, Boeing demanded the supplier to assure the solid model was just like the solid model they sent. Apples to Apples??? Of course.

Can the 3D Model Be Used as the Design Authority?

I have been translating parts between systems since 1986 while at Boeing, I transferred files between CADKEY and Catia 2 using IGES. With the entry of solid modeling, Boeing has put in a requirement that the parts must be validated. The reason is that Catia 5 translation cannot be trusted. Catia 5 can basically only output STEP. The problem is not with the receiving CAD product but with Catia 5. Catia 5 produces some of the most corrupt parts I have ever seen. Yes I have also seen corrupt parts from Pro/e and Solidworks but not at the level of Catia. I believe it is the Pro/E paradigm of history based solid modeling that allows this corruption, trying to create parts that are beyond the products limits. Many CAD products directly read native Catia 5 file, yet Boeing does not even trust these translations.

Corrupt 3D CAD Parts

Talking to Catia! and other Popular 3D CAD Packages

Is 3D CAD Productivity an Oxymoron?

COMPARE PROGRAMS

WHY WOULD WE NEED PROGRAMS LIKE THESE??

You may not be old enough to have ever made or even seen a complete drawing. Drawings were documents that completely defined the part with separate unassociated orthographically projected views. Notice I didn’t say 3D part because that would be silly. Of course there are no such thing as 2D parts.

Please read my articles "To Draw or Not to Draw?" and “Redefining 2D/3D”.

These drawings not only defined the shape of the parts but they also gave all the information necessary to create these parts, material, tolerance, finish, etc. All the pertinent information in one place also for inspection. There was also a very complete revision system. Each DCN (Drawing Change Notice) noted all the change history of the part. An ADCN (Advanced Drawing Change Notice) was a description of the change done on 8.5 x 11 sheets of paper so as to not require the amount of time to directly change the drawing every time a small change was made. These were simply stapled to the blue print (a print of the drawing). When a few of these accumulated they would be incorporated into the original drawing as a DCN and a new revision letter would be assigned.

The ADCN (Advanced Drawing Change Notice) vs MBE (Model Based Enterprise)

Can you imagine doing a change to the drawing and not defining it?? Just sending out the drawing with a different date and name. No, of course not, that would be insane. Let’s say you changed a hole size and the drawing had hundreds of holes, you would have to look over the complete drawing comparing it to the old drawing. That is what the necessity of a Model Compare Program is indicating that is happening in the industry. It is data out of control.

Enter Solid Modeling

Today the engineering industry is trying to eliminate drawings. We can now directly give manufacturing a solid model of the part. They can now take the solid and create tool paths to drive a CNC mill. Absolutely wonderful. But we still have to qualify the features that mate with other parts. We have to inspect the parts and the CNC programmer and machine operator may have to put more attention on what is important when programming the code. So there is still some tolerances or GD&T data required.

Now the part is programmed and the parts are made. Now comes the revision. What do the manufacturers send the supplier? Now that the solid model is the authorizing document, they send a new solid model. Is there a description of the change?? Well obviously not. They do have a format call PMI (Part Manufacturing Information) which has a bastardized form of minimized GD&T dimensions and annotation in 3D space (see PMI vs AID). I am not sure it even has the capability of describing the change. But it requires the native software or a 3rd party program that reads this data. But many of the companies are not getting this data and are only receiving a STEP file with a name. Now the file name probably includes the revision letter. So you now need a program to compare the parts. Why? So you can see the difference and be able to utilize the original complex CNC program so you don’t have to reprogram the complete part.

Free PMI Importer?

PMI vs AID (Associated Information Document)

What does this tell us. The originating company does not have an effective way to communicate the changes. Imagine spending virtually millions of dollars on a CAD system, and it does not have the capability to document the revisions of the part to an outside supplier. Each of the large systems like Pro/E, Catia and NX have and brag about their PLM (Part Lifecycle Management). There are even 3rd party PLM programs to make matters worse. There is a huge vested interest to keep this non-standardized. This is costing companies like Boeing millions of dollars in scrapped parts and missed schedules.

Don't believe me!! Here are 105 programs that claim to be PLM.

Product Lifecycle Management Software

Solutions

1. Have all of your suppliers on the native system.
But what small supplier can afford all of the high end systems? Not only is the cost prohibitive, but all of these systems are complex and require huge learning curves, demanding an expert user on staff.

2. Use the Validation or Compare program.
So you spend extra money to buy a program that is nothing but a Band-Aid to fill a gap the customers software does not supply. Opening doors to errors by not having a direct communication with the client.

3. Just ignore it and build the parts.
This is the solution many of my customers have used. Just treat the revised part as a new part and charge accordingly adding thousand$ to the price of the parts.

4. Do all your manufacturing in house.
I am not even sure this solution works without a lot of support.

True Solution – A New Standard