Technical drawings for pressure equipment, how do you do yours?

[KateMechEng]

Hi,

I've just started a new role a design and drafting office manager for a PV fabrication company, my first task is to look at optimising our technical drawings.
My background is mechanical design of PV so curious to see how others do their technical drawings and the software used.

Currently we produce a lot of detailed drawings which the workshop love, but the project managers are not happy with the time it takes to produce them (sound familiar?)
The team mostly use 2D CAD to do all their drawings inc exchanger tube bundles.

I think it would be good to move to 3D where we can produce the model and then take the details off that, and changes to the model will then be updated in the 2D dwgs.
However there is software such as Inventor which is a step more towards solid works.
Or even pV Fabricator to take pVelite models and use those to produce 2D technical drawings.

I'd really appreciate it if you could let me know what your thoughts are on this and also your experience of program set up / training

Thanks in advance

Kate

 

[danielpayne]

Hi Kate.

Are the technical drawings mostly generic in nature, e.g. are the assemblies mostly the same, but just slightly different sizes, or is it mostly bespoke design work? I may have just the solution for you if you have generic assemblies.

We have a system which I set up at our company for creating generic drawings easily and quickly in PDF format. If you are looking at inventor however (which we also use for bespoke design work), then you are looking at a significant investment and training period (unless you hire a graduate / someone experienced in 3D CAD). You also have to consider part control, as if you change one part in Inventor, it will update the change in every single drawing unless you save a copy of the part and insert it in a new assembly. This can become troublesome to then return to an old drawing and find it has completely changed. The natural progression then is to invest in part / drawing control software such as Autodesk Vault, which is then another significant investment.

If you are willing to make the jump to 3D CAD though its totally worth it in my opinion. Most standardized parts such as flanges, fasteners and basically any standardized component from bearings to long radius elbows are embedded within the content center. 3D CAD is becoming a necessity for serious design work in my opinion. As a designer, when i decide which supplier to use for a component, if a 3D CAD model is available its a massive selling point. Although the cost seems high for 3D CAD, it can potentially pay itself off within months, if not weeks, you just have to convince the accountants of that.

 

[KateMechEng]

Thanks for your response Daniel,

We do bespoke designs, but they do include a lot of standard flanges and pipe etc.
I believe that we tend to re-produce weld details. surely there is a better way?
Normally we draw 1:1 so to ensure that parts fit etc however I'm thinking it could be more time saving to have standard weld dwgs and then override the dimension to say what you need. Or is this a false economy?
Obviously I am speaking to my team about all this, however the most experience drafty (who is the only one who can do 3D CAD) has been here for 15years, so I m after some fresh eyes on this.
For all I know he isn't fully aware of capabilities if he has been doing things the same way for years.

As far as investments go, I totally agree it is going to have to be significant. However if senior management are telling me they want 'optimisations' in the drafting process to reduce hours, then my feeling is they have to suck it up! lol!

Really great to get your thoughts, thanks again!

Kate

 

[SnTMan]

These kinds of decisions should be, but rarely are (in my experience) be made on sound economic analysis. What's the value added? What's the pay back?

In my experience they are more often made on the gee-whiz factor of 3D modeling. Look at the pretty 3D rendering.

Don't get me wrong, solid modeling does have benefits. BUT, the required end product is most often paper shop drawings. Often better to proceed directly to their preparation.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[KateMechEng]

Totally agree Mike,

I've talked to everyone I need to at the office now and it looks like any changes to optimise will be with software and the actual hand over from pVelite to CAD.
I have used solidworks in the past and it's fantastic for distracting with the shiny 3D image. However I need something that is functional for the fabrication teams to use.

I do need to crunch the numbers, but for now I am interested in what the actual work flow would look like.
The way I see it the model is great for taking off 2D drawings quickly, however this is only going to be any good once the model is completed.
As we are often faced with a multitude of changes, this could mean a delay in the issuing of the 2D fabrication dwgs.

Usually we produce key drawings for the procurement office so they can order in our long lead items. This would not work with the model method.
I'm just curious to know how other offices are able to produce dwgs quickly and what other ways of achieving this are.

Thanks

Kate

 

[SnTMan]

KateMechEng, while never very good at it, I loved Solidworks modeling, but HATED trying to get drawings from it. Having the calcs in hand, I could modify an existing ACAD drawing much faster than producing a model and then getting drawings.

Another thing is I did a fair amount of proposal work, usually including a reasonably reliable outline. Generally not enough lead time for a correct 3D model, nor any certainty of a sale. If it did sell, I had an ACAD layout and outline ready to go. Shop drawings were fairly quick to produce at that point. It does put greater burden on the checking process though.

And yes, procurement drawings NOW is common.

Now if you need a lot of really accurate massprops and so forth, modelling can make sense.

Don't know what your class of work is, but for TEMA type shell and tube exchangers, you might take a look at RCS

Regards,

Mike


The problem with sloppy work is that the supply FAR EXCEEDS the demand