Going to IMTS? Want to pass some time?

[Ron Branch @ 5th Axis]

DATE: Monday, September 10 from 2:00 PM - 2:55 PM ROOM: W193B

 

Here is what I will be speaking about:

 

Model Based Definition (MBD) is sweeping across all aspects of aerospace and defense. With the initiatives of several large companies and the programs of standards organizations, it is on its way to becoming a common practice for OEMs and suppliers of all types. MBD—as the sole design authority—removes ambiguity, doubt and contradiction when manufacturing products. By eliminating 2D drawings, it does the same for inspection.

 

However, many people question, what is MBD, what new tools and processes are required, and how does it benefit the inspection process. This presentation consolidates countless hours of industry research with aerospace OEMs, suppliers, CAD companies, GD&T experts and standards development professionals to answer those questions.

 

For the suppliers that no longer have the option to receive 2D drawings, MBI (Model Base Inspection) is essential because it is senseless to take on the effort and risk to generate drawings to perform inspections. For suppliers that control the product design, MBD/MBI is an approach that will reduce costs, labor, errors and ambiguity. Yet, few have fully embraced the practice simply because of the confusion and unnecessary complexity surrounding MBD and MBI.

 

Here is a link: My link

[Mr. M]

I wish I could, but I'll be working our booth that day

[Guest CNC Apps Guy 1]

Why create drawings? That what this is designed to eliminate. Ever open up a CATIA file with MBD in it? It just has special callouts/hole tretments that are not covered by the "standard" (Old School Block Tolerance). I've not seen what UG, Pro/E or SolidWorks does for this.

 

If I go to IMTS, I just may swing by. Personally I'm sick of drawings. That's so 1900's.

 

This is long overdue.

[Jeremy Herron@DBS Solutions™]

I will be there. Hey quick question. Does Mastercam or any another 3rd party software import MBD from UG, Pro/E, or solidworks the way Verisurf does for Catia?

[Ron Branch @ 5th Axis]

What is ironic is most people have been machining to models without prints for years. Biggest disconnect is understanding how the model can be the authority for inspection. "There is no tolerance for the part in the model" I call those hybrids where the PDF has all the notes about the tolerances and you have to go read the book to make it or it could be an system that does not output MBD. With FTA/MBD like CATIA using Moldplus the standard Mastercam programmer can bring all of that into Mastercam with no problem. The programmer can also take the MBD tools from Verisurf and you can go make a dumb model a live model inside of Mastercam. "Hey what do you mean by live? It can get up and walk away?" Yes I have been asked this question and what I mean is the MBD (Model Based Definition) is the intelligence of what needs to be manufactured to. A true position on a hole tells you were it needs to be relative to the Datums. The tolerance is all defined there and they days on a liner dimension from one edge to every hole are not needed. "But I do not use a CAM system" really and you want wanting to do MBD work? The model is the authority then you need to use something that lets you use the model for the manufacturing process. Mastercam machines to models all day long and with MBD you know where and how to machine the part to make it meets the quality requirements. Now Verisurf which works inside of Mastercam then takes that MBD uses the tolerances called out and then allows anyone to see to that model the deviation. Without the MBD then you need to get out a blue print and put the tolerances or read some 15 page PDF to put them in manually. MBD as a process if implemented correctly is a time saving money making process. Those that get MBD embrace it and make it part of the culture of their companies.

 

This is just a small idea of what goes on and hopefully I can shed light on this topic at IMTS.

[Ron Branch @ 5th Axis]

Does Mastercam or any another 3rd party software import MBD from UG, Pro/E, or solidworks the way Verisurf does for Catia?

 

Jeremy, It is Mold Plus that does this we only use it and allow someone to make MBD. Not that I am aware of maybe if enough people send that request to CNC it will make it into the software. :rolleyes:

[Jeremy Herron@DBS Solutions™]

Thanks Ron, enhancement request sent.

 

 

[Guest CNC Apps Guy 1]

Is MDB a fast way to tolerance for the designer/engineer? A lot of designers especially fresh out of school model everything line to line and then spend a bunch of time in re-work mode during assembly to get everything to fit.

SInce i'm probably only an intermediate CATIA user, I would say it is pretty easy. Again, you don't need to put a dimension on everything. Just critical features, then let the design standards handle the rest. Drawings are time consuming colossal wastes of time and energy. This all goes back to the push for DFM (Design for Manufacture) in the mid-90's IIRC. MBD is the next logical step in that evolution of conveying design intent in the model itself so that it cuts the time from design to market drastically.

 

JM2CFWIW

[Ron Branch @ 5th Axis]

Is MDB a fast way to tolerance for the designer/engineer? A lot of designers especially fresh out of school model everything line to line and then spend a bunch of time in re-work mode during assembly to get everything to fit.

 

If they understand it and apply it correctly of course. Problem is they will put a .000 true position on a .500 hole and the make it +/-.0001 on the diameter 40" deep and then wonder why the part cost $1 Million to make when it is a flange for a boat anchor.

 

When used correctly a MBD model can have 3 or 4 GD & T call outs and do the same thing as 50 to a 1000 dimensions. Profile tolerance of .01 using the overall symbol means than anywhere on the part nothing should be +/- .005 from the nominal model. So that old school 12.000 +/-.005 on the length and the 6.000 +/-.005 on the width can be one MBD on the model and do the same thing. So it there were 50 shoulders or steps old school would be 50 dimension for length and 50 dimensions for width. Again one MBD call out takes care of all of that. Which is easier when they do the same exact thing? You need a Hub to Match a Shaft then the Primary Datum needs to be Mating diameter on the Hub to Shaft. The secondary Datum needs to be the mating Face of hub the Mating face of Shoulder. The tertiary point is something to keep the relationship to each other important. So if the new graduate understands how all that works then he makes the correct Datum calls with the correct tolerances and the part is manufacture-able and it does not cost and arm and leg since it was done so with that in mind.

[GoetzInd]

Sounds really interesting Ron. Make sure to post in here again the week of IMTS to remind people

 

Mike

[Joe788]

This will get their attention on the design end

 

 

I'm not so sure about this one, +/-.005 all over the part doesn't guarantee form fit and function, hence the need for GD&T.

 

What would be really cool is if you could build in clearance specification(s) into the assembly level models, check all fits on the digital model and then output MBD data with each component for inspection during manufacturing. Kill two birds with one stone (check the design and the manufactured components)

 

The +/-.005 all over is more for the "filler" dimensions that clutter up a 100% dimensioned print. They still use the GD&T for form, fit, and function.

 

We make some parts where the customer's prints always have the first or second note as: "This is a minimal dimension component. The CAD model is the master for all dimensions shown."

 

Then when there's just a random slot or non FFF feature, it just has a surface profile callout.

 

For me personally, the benefit is more in the inspection than in the machining. As long as the customer is sending in good models, the parts are going to get machined properly. But using a 2D print to define even a simple feature like a curved slot, then measuring and reporting that on a CMM, is not exactly fun. Difficult? No - but still time consuming. With the surface profile callout and a DCC CMM, you just point and click. It takes the nominals right from the surfaces, and you get your surface profile data.

[crazy^millman]

I'm not so sure about this one, +/-.005 all over the part doesn't guarantee form fit and function, hence the need for GD&T.

 

That is a whole different conversation and that is where Datum call structure and the such become important. There there is feature frames, Modifiers, Max Material Condition regardless of feature size and the such. Why do they apply how do you apply them and what do they do to form fit and function? Like Joe said Verisurf take the MBDS then the model and gives you a good process to check the part. I see a PCMM at ever load station every cell in manufacturing in the next 10 years. I see people making real time decision with real time information to keep machines running without the bottle necks they use to have. The rub from inspection is this is replacing them. With the right system in place this is something to complement them and manufacturing. The whole North Korea/South Korea conflict most shops have with Quality Verse Manufacturing dissolve. Why well the quality guy has good insight into GD & T and the manufacturing guys have good insight into Manufacturing. Guess what one can help the other and use the system as the go between because both parts can get information from the same software. Most systems are closed loop Inspection is using this software and manufacturing is using this software. By having Verisurf such a part of Mastercam you bridge that gap and create an open platform all are using.

[Bruce Caulley]

Definately the way of the future. I had a drawing years ago done by one of the big US aerospace firms that was six A1 pages absolutely covered with dimensions and GDT. The CMM programmer almost had an aneurysm sorting it out. There were probably only half a dozen critical dimensions on the whole part when it all boiled down.

 

Bruce

[Jayson Kramer]

Ron me and Derek will see you at the show.

[Guest CNC Apps Guy 1]

I had a drawing years ago done by one of the big US aerospace firms that was six A1 pages absolutely covered with dimensions and GDT....There were probably only half a dozen critical dimensions on the whole part when it all boiled down.

 

That's usualy the case. If they had dimensions that only covered the necessary critical features, then they'd be done in about 1/4 of the time and we can't have that now can we?

[Chris Rizzo]

Philosophically speaking: I think a big difficulty in transitioning to this type of system (using the model with all-encompassing limited gd&t inspection), is that everyone learns the trade in a manual shop cranking handles.You usually need the classic highly dimensioned print to machine that way. That's how we've been brought up, that's how our world was defined. So it's a huge paradigm shift to go MBD. I think some nice classes or formal-ish training would be really beneficial in breaking through the barriers and figuring out how to think this way. It's such a big leap for alot of people...from my observations and personally.

 

m2c

 

ok going back to the RNC to learn how I'm gonna save all this ca$h on my taxes...and then of course I'll buy gold bullion and hide it under my mattress, to really stimulate my local economy

[Newbeeee™]

That's usualy the case. If they had dimensions that only covered the necessary critical features, then they'd be done in about 1/4 of the time and we can't have that now can we?

We have a couple of customers that supply drawings like this - they call them 'key point drawings'.

The drawing states part number, issue, title, mtl, finish/treatments, hole data table (to call out posn tol + thread size or whatever), length dim, width dim, height dim (so anyone in planning can look and see roughly what size the part is), and anything else that is 'tight' limit wise.

If nothing else is dimensioned, the general +/- ten thou applies, and we load the cad model and surface point check it.

What would have been a couple of A3 size dim sheets for a part can be fully checked in 10 minutes with the cmm doing it this way.

[Roger Peterson]

I wiish I had all the time back I went through prints with different color highlighters so you could easily identify different types of dimensions at a glance (Significant/critical, positive stock/negative stock, etc...). Digging through hundreds of dimensions to identify 5 "significant" and "critical" dimensions is painful. Critical dimension prints have been a useful intermediate step on our way to full MBD.

[Ron Branch @ 5th Axis]

Roger yes I have been breaking down the parts and think i have a good way to show people how to look at the MBD and MBI are part of the organization. I will throw this part of my presentation out there. There are 3 key parts of the method, People, Process and Technology. As the People become more involved and trained then the process becomes more efficient as the technology is used by the people the process improves again. When all 3 of these elements are aligned then a company will see more profit. Look at it the other way if the technology is not there then the process cannot grow for new work and the employees become complacent and feel like they are not growing. Engaging the technology moves the process along and as the process moves along the people will move along with it when given the right training and tools to do so.