Vessel drafting: 2D vs. 3D
Vessel drafting: 2D vs. 3D
(OP)
Hello, I work for a fabricator of ASME code vessels and heat exchangers. We have been using 2D autocad to detail vessels for years, but people (mostly salesmen) are telling us we could save drafting time by switching to a 3D package such as Solidworks or ACAD Inventor.
Does anybody else in this industry have experience with this switch? Is the hassle of the initial learning curve worth the long term time savings (if any?)
Also, has anybody had success with semi-automated 3D models, for example outputting a solid model from Compress, PVElite, or Aspen Teams directly to Solidworks or Inventor?
Any help or advice would be appreciated.
-Bill
Does anybody else in this industry have experience with this switch? Is the hassle of the initial learning curve worth the long term time savings (if any?)
Also, has anybody had success with semi-automated 3D models, for example outputting a solid model from Compress, PVElite, or Aspen Teams directly to Solidworks or Inventor?
Any help or advice would be appreciated.
-Bill





RE: Vessel drafting: 2D vs. 3D
And when is the last time a salesman actually told you something that was true or something that would not make them a profit? ;)
Brian
RE: Vessel drafting: 2D vs. 3D
RE: Vessel drafting: 2D vs. 3D
thanks for letting me vent.
Rich
RE: Vessel drafting: 2D vs. 3D
RE: Vessel drafting: 2D vs. 3D
Also, these packages are going to generate standard 3 views and isometrics to whichever standard you wish (i.e. ANSI, ISO, JIS, etc.). I'm not exactly sure what a 3D drawing is, though. Also, if you're dealing with parts requiring NC work, you can often skip sending prints to the jobshop completely and just provide them a copy of the model file that their machines translate to a tool path if you so choose. But, other than special things like that, the prints these packages produce are standard engineering prints.
Where you see a real benefit for using some sort of solids package in designing things like S&T HXers would probably be in time to produce prints. Each exchanger requires its own prints specific to the exchanger, but on the whole, these exchangers are very similar in their geometries. These packages are pretty powerful and I'm fairly certain that you could set up a template model file with the basic geometrical relationships that go with each type of head, channel, etc. Then, you just parametrically set up a selection routine that allows you to tell it you want a flanged and dished head shell, 30" ID with a 5/8" wall thickness, 10 feet long, and provide it with a nozzle schedule and the program then uses your inputs to modify the model based on your pre-set rules and then uses previously created drawing templates and the information you provided to spit out prints ready for checking.
Granted, this is pretty advanced stuff, but it can be done.
RE: Vessel drafting: 2D vs. 3D
A&E firms are not fabricators. I work for an ASME fabricator and while 3D modeling is certainly beneficial when desiging a pressure vessel to check for possible interferences, 3D drafting is unneccessary as almost all pressure vessel/HX design programs already incorporate 3D modeling.
As far as detailing or drawing out the vessel/HX for fabrication, 2D AutoCAD is more than sufficient.
jistre - you readily admit you have done no vessel/HX design yet you want to talk about modeling a pressure vessel/HX? PV Elite and COMPRESS are two softwares I am familiar with and both model your pressure vessel/HX for you without having to use a 3D CAD program at all.
What works on paper or even the computer does not always work in the real world (fabrication).
Brian
RE: Vessel drafting: 2D vs. 3D
At the ASME fabricator I worked at we made vessels that were of similar design with minor changes to either nozzle sizes, locations or both. I could call up an old model that was close, make the changes to the model and be confident that all the sheets and the BOMS were updated.
The other advantage is being able to easily introduce complex new designs to fabricators. Nearly everyone can visualize a new design more easily in 3D. It is a lot harder to install that nozzle 180 out when given shaded isometric views to reference.
The 2D vs. 3D argument is a lot like the CAD vs. board drafting argument from so many years ago. Sure you have to retrain your drafters, but once they are trained productivity increases, mistakes decrease, and design changes are easier to make.
RE: Vessel drafting: 2D vs. 3D
Granted, they don't do code calculations, but as you said, you've got yet other programs to do that for you. I was specifically referring to bhuffman's question about saving drafting time in DETAILING the vessel. Nowhere in there did he mention doing any of the code calcs or vessel design that comes before the drafting of prints.
Of course, we all need to be careful when we're talking about models here to differentiate the strictly geometric solid models that I and others are and the models that waskillywabbit is talking about. The models he's talking about are actually modelling the performance and stresses in the operational exchanger, and for that, 3D packages are definitely the wrong tool.
RE: Vessel drafting: 2D vs. 3D
Thanks, Rich
RE: Vessel drafting: 2D vs. 3D
RE: Vessel drafting: 2D vs. 3D
As an engineer, in the old days (late 80s), I started by doing manual drafting/layout of vessels and exchangers on the board for a year before I was allow to handle a vessel package. Damn it, nowadays new grads are made Project Engineers; unfreaking believable!!! Few months later, I rolled out ACAD for 2D CAD for equipment layout. I have also been trained on 3D CAD and have done some FEA modelling. Although I have not done any CAD in the last 10 years, I guess I'm still qualified to comment on this.
I agree with 3dwaytogo. Many engineering software (Compress, HTRI, etc) all generate 3D models as an output. The 3D CAD software will generated your typical 2D plans complete with BOM. Although not all software are equal so research before purchase so it will suit your preference. The auto BOM update of the database is also the other bonus, and I believe this is a common feature in many vessel modeling package today. Of course, clash checking is so easy on 3D model. Also,the 3D model may be able to be transfered into ANSYS for FEA.
Long and short is, go 3D but chose the package carefully. I know some people, myself included many years ago, have a hard time accepting changes, but if you don't change then the world moves on without you.
RE: Vessel drafting: 2D vs. 3D
ISO 15926 Part 7 – Implementation of ISO 15926
Vessel drafting: 2D vs. 3D:
ISO-15926: Integration of lifecycle data for process plants including oil and gas production facilities
RE: Vessel drafting: 2D vs. 3D
However I would not recommend it to every pressure vessel fabricator.
Advantages of 3d:
- mistakes are reduced as designer is working with model, and each part is "assembled" into model same way as it will be in fabrication stage
- BOM is linked to the model, therefore less mistakes
- After you have a 3d model it is easy to create any draft view for detailing
- Weight and some other parameters are easy to get from the 3D model
- It is possible to modify similar design very quickly
- Sales pitch, customers loves 3d pictures of models.
Disadvantages of 3D for pressure vessel design:
- Most important thing, if 3D software is not implemented properly, all advantages becomes disadvantages.
- Good cad operator is not always a good pressure vessel designer. Designers with lots of an experience are used to work with 2d and sometimes are not willing to switch. They will be very slow at the beginning.
- Company database of old designs will not be as useful, as all designs shall be done again in 3D. There is no easy and smooth 2D to 3D transition.
I would still recommend 3D, however management needs to have realistic expectation. At beginning 3D will be slower and more complicated. But down the road it can generate better design and more profit.
RE: Vessel drafting: 2D vs. 3D
RE: Vessel drafting: 2D vs. 3D
I also learned drafting with a good old fashioned pencil before AutoCAD was even taught in college, so if that makes me an archaic old fart so be it, but I am not that old. Nowadays greenhorn graduates have no clue how to draw anything or do any calculations if the power goes out. Not all change is GOOD!
Brian