Drawing Practice.

[james.lynch]

Hi,


I was wondering of someone here could help me.. View attachment 610


Basically this is my question. First of all, when modelling this, should the different pieces (for example the2 bits of channel iron welded together at angles)be modeled as Parts or Features?and whataffectdoes this havewhen creating Drawings? As I'm sure you know, there is a dozen and one ways of actually manufacturing pieces like this and if I create them as parts then that limits theworkshop guys when it comes to manufacturing..


And if you are supposed to draw these as parts, wheredoyou draw the line? after all this isn't a precision machine and a lot of it would probably be cut with a gas torch, so not that accurate to begin with..


I've never modeled anything before with tha aim for manufacture (I'm still a student doing a masters). Everything I've done before was either outputted to a CNC or rapidprototype machine, so no real needto create drawings..


I've no problems creating the drawings, I'm just really wondering what's theindustry practice when it comes to this sort of thing? is EVERYTHING partbased bearing in mind the construction method will be rough?


I hope you understand the question, I kinda confused myself when asking it!

Thanks for the help,


James

 

[jeff4136]

Sort of a continuation of; napkin sketch vs. engineering drawing?

I will occasionally model simple weldments as parts, but other than that; detail parts are parts. All the old saws about taking shortcuts are founded in experiences. Some random, not necessarily perceptive, thoughts...

"...dozen and one ways of actually manufacturing pieces like this...". While there may be different ways of matching the envelope they may not be identical in strength, etc. and there may be times you don't want anything left to imagination or let others make the decisions. Where does the liability buck stop?

"...the industry practice ...". Which "industry"? Modeling all the detail, strictly as build may be a waste of time for some. Shortcuts can also come back and bite you; changing an assembly modeled as a part may be quite a bit more time consuming than if the little extra time were taken initially to model as parts and assemble. Different industries have different QA and safety standards. If it isn't defined on a drawing it can't be inspected and put into service. This doesn't mean that, for instance, my simple weldments done as parts are unacceptable, but it does mean that I have to be able to define all the details and processes without using detail part drawings.

 

[goosemonster]

A large part of my workload involves weldments, both simple and complex. I always create each part individualy, it gives you more options futher downstream.


This does not mean that you have to create individual drawings for each part, I would only do that for more complex example.


The main advantage, I find, for individaul parts is that you can assign parameters to each (mat type, dimensions, etc) this can then be used to generate a weldment BOM - very handy for the workshop guys.


Note - I create a weldment PART from the weldment ASSY by merging the seperate parts into one. This composite PART can have a single set of parameters for the assemble drawing BOM.

 

[james.lynch]

Well pretty much all of what's in the picture are individual parts, with the exception of just a few.. I do indeed takethe point about variations in strength etc.. The parameters used to generate weldament BOM is also indeed very benificial.


Thanks for yor help guys, it's appriciated! and hey, ya gotta learn somewhere, and here seems to be as good place as any!


James