Manufacturing to CAD -without Drawings Yes/No 10

[Camille-starr]

I’m not new but an old user that can’t retrieve his login details due to emails change etc.

So, I have always produced full drawing packages with my CAD models and supplied them to the manufacturer for quote and production. I understand that most of the machinists I use programme from my models and use the drawings to check details and then the drawing is used for checking once the item is received.
The drawings I produce are full on manufacturing drawings with all details, I’m an old school draughtsman.

Am I working in the past, can we start to rely more on the model and lest on the drawing?

How do you handle this and what if any standards do you work to?

 

[SwinnyGG]

sure when you are using your program and apps, that is not the same for the manufacturers, if all the processing done in house, but what about the suppliers.

....vertical integration of this process is a requirement, as has been said already.

This isn't any different than paper drawings either- if your vendors can't read your paper drawings, you're also going to get bad product.

 

[CWB1]

The aerospace firm I worked at in college ~12'ish years ago used MBD exclusively for procuring prototypes, the only time we drafted prints was for documentation's sake when the boss sold the IP. It worked well but to be fair we did not sell products, only IP and a few prototypes. Since being back in the contract design world I have done several projects in MBD and never heard a complaint. Its certainly faster/easier than traditional drafting. For anything but early prototyping you need an inspection plan anyway, so your engineering team should be well aware of what/how the supply base is inspecting even without prints. Moreover, if you look on the bottom of modern prints most will say something to the effect of "CAD is master," which makes the print redundant at best and ignored at worst from both a legal and design perspective.

 

[IRstuff]

Just one caveat; printed documentation is superseded by their electronic files, per ISO-9000, which aren't necessarily the MBD.

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[mfgenggear]

incorrect, depending if it is a military or commercial contract. all records have to be retained for 5 years minimum, and all relevant requirements are flowed down from the prime.
quality requirements require an inspection first article, a detailed drawing must be drawn and show all the requirements for the first article. then all the certifications must be provided with the first article for all processes, Material, Heat Treat, NDT, Plating and on. a drawing and inspection plan must be submitted with the parts as well as the engineering with the requirements.
all dimensional requirements must be verified and recorded. a 3d model which great to be added for proper configuration, it does not meet all the requirements.

 

[drawoh]

mfgenggear,

One more thought here.

You have saved your production drawings and models in PDF and STEP formats respectively. Your company gets taken over by someone who insists on new CAD[ ]software, or perhaps your CAD vendor has come up with an excessively stupid business model. What do you do?

If you have good, complete drawings, you re-create the CAD models in your new 3D[ ]CAD software. You re-create your drawings, easily checked off the old PDFs. In the process, you get valuable practise at your new software. Everything is back under control.

--
JHG

 

[IRstuff]

It seems to me that one option short of a complete re-creation of the CAD models from scratch/2D drawings would be to back up the CAD in something like IGES, which would at least ensure that the new model can be directly compared against the putative original.

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[mfgenggear]

drawh
while I have the upmost respect for you all I can tell you guys really do a great job, and care about your designs.
most of all data is digital, mostly PDF even drawings, but simulates paper, even so a hard paper print is required and stored.
I mostly work on line, but my part is very limited as I am retired, and only work part time, and currently training younger engineers.
passing the knowledge in my tiny brain. since electronic data can easily be corrupted I believe in paper. but the trend is to be all digital.
and eventually that is the writing on the wall. after 44 years I am about spent.

 

[CWB1]

From the various jokes/discussions with mentors on how times have changed, my various employers all got rid of the filing cabinets and stopped keeping paper copies ~1990, about the same time smoking was banned from the offices. Prints aren't actually required for a quality plan, inspection, or contract, nor does industry "sign" prints anymore. Like it or hate it, digital 3d is the master and 2d (as well as printed copies) a simple subordinate nicety. Personally I'm a fan of technology and electronic signatures, esp when it comes to laborious tasks like releasing 300 prints/day or closing on a home purchase.

 

[IRstuff]

I don't think you can be ISO-9000 compliant using any paper documentation, since there's no demonstrable way of knowing whether any given copy is, in fact, the most recent and signed off version.

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[GregLocock]

We were ISO9000 in 1995ish using paper.

Cheers

Greg Locock


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[IRstuff]

Allowance for paper copies went out with the 2000 version, since the "Provide correct version of documents at points of use" requirement cannot be demonstrated with paper copies

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[3DDave]

It's always surprising to hear various descriptions of how well various methods work without a scintilla of context. My long-term favorite are those who make injection molded plastic parts and say they save huge amounts with their MBD. Upon further Q&A it's "We have been buying molds from the same company for 30 years and just send them the CAD file" because of course, after 30 years of making essentially the same parts they design to the mold maker's tolerances and finishes and boom - no drawings required. Not only no drawings, but no datums, no geometric tolerances, none of that expensive work. MBD perfection.

 

[drawoh]

IRstuff,

I am still traumatised by paper drawings and Xerox machines. I used to love the old diazo whiteprinters, because usable prints can only be made from the translucent originals. If they are methodically date-stamped, you can determine whether or not to trust the print. Even if they are not date-stamped, you can sniff for ammonia.

In-house, PDF and STEP files should be pulled directly out of PDM. There is nothing to stop disorganised, undisciplined people from creating their own document libraries that your ECR/ECO people don't know about. This is more likely if your PDM group is difficult to work with.

Where do your vendors go looking for drawings? There are lots of ways to mess this up.

--
JHG

 

[IRstuff]

Sure, but let's say your document/drawing is date stamped yesterday; while it's close, you don't know if there might have been a change in your PDM copy, unless you go there and check.

We typically do the usual bad thing of transmitting electronic copies that are divorced from PDM control, but allowing vendors access to our PDM is too big an ask. There are certain programs that do have tiered access, like DOORS, which allows read-only access to specific files or projects.

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[drawoh]

IRstuff,

Whiteprints have terrible UV resistance. If it looks yellowed at all, you don't trust it. This is why you track revision letters/numbers on the drawings and on the purchase orders.

--
JHG

 

[IFRs]

I routinely send files that are directly used with CNC devices, and also always send a PDF with dimensions. Every once in a while a shop may call with a question that involves the CNC file and the PDF being different, which is GREAT - it means they are looking, reading and trying to do the best job possible for all parties.

 

[drawoh]

Camille-starr,

I have come up with one more thought on this.

I worked at a place that converted to MBD. They issued a drawing without dimensions, and they shipped the PDF, plus a STEP file to the vendors. We found that at least one of the vendors was completing the drawing. They needed the drawing for their fabrication and inspection process. All MBD did was add to the vendor's NRE, and the price.

--
JHG

 

[Tmoose]

"They needed the drawing for their fabrication and inspection process. "

That is exactly what I would expect for anything but the simplest and crudest of parts.