Size Matters.... especially if you're a saw....

[phlyx]

Okay, warm up those brain cells and here's something to think about. We are required to place a note in the title block specifying the overall finished dimenions of the part so the shop folks can more easily determine what material to buy or pull and what size to cut. The problem is we've had people that accidentally put .5" for a diameter that should of been .25" and other not-so-fun things that cost. So here's the question.... is there any way to pull the overall maximum envelope of a part in the three major directions (X,Y & Z) and use that as a variable in the drawing so there is less potential for manual error?

Thanks!.... and Happy New Year!

~ Phlyx ~

 

[TheTick]

There is API to get this information. Possibly a "Macro Feature" could be used to put this into a form you can use.

"Great ideas need landing gear as well as wings."--C. D. Jackson

http://www.EsoxRepublic.com

 

[JahnEng]

Here is a solution that can only be applied to a part file:
In custom properties create a stock size field that would be driven by nominal dimensions of the part. Make this part a part template and use it for every new part you have to make.
One very important thing to keep in mind – you can only cut extrude, as if it were real material (that can’t grow boss extrusions here and there).
In my case I have templates for a Plate, Sq, tube, rectangular tube, round bar, round tube, Steel angle, etc. This allows me to change sizes of the parts as I need, keeping the real stock sizes.
Inconvenience is you always have to make sure that all the “important” faces are “machined” (cut extruded).

Hope this makes sense and helps…

Eduard F.

 

[ctopher]

Years ago our company tried the method of a note on the dwg for size of raw material/envelope. In the long run, it turned out to be more work for our machine shop and outside shops. They know what size they need and can find very easily if they are good and experienced.

 

[macPT]

Take a look at

http://www.trimech.com/solutions/techsprt-free-utilities.htm

(measure height macro)

Regards

 

[CorBlimeyLimey]

Also visit

http://www.MinBbox.com

I have not used this program but it may do what you want & is quite cheap.

Another possible method, when creating a new part, is to model it as if it were being machined from an actual block of material, in exactly the same way that it would be in a machine shop. ie. start with a block (rectangular or cylindrical) & remove what you don't need. It may not be the most productive way but does represent what happens in the real world. The starting block dimensions can then be referenced in your title block.


CorBlimeyLimey
Barrie, Ontario
faq559-863

 

[SBaugh]

I would have suggested the same approach as "JahnEng" did.

In custom properties create a stock size field that would be driven by nominal dimensions of the part.

I would make the custom property name different "overall_length" or distance. But hey that's just me .

Regards,

Scott Baugh, CSWP

http://www.3dvisiontech.com

http://www.scottjbaugh.com

faq731-376

 

[phlyx]

The problem I see with modelling the part as it would be machined is that during the design phase the part itself is not static. If I started making a part from 1/2" X 2" X 10" material but then due to design alterations decided it was best for it to be thicker and wider I'll just make it thicker and wider, not start over with new "raw material". Also, I may decide that the part should be made from 1/2" x 2" material and the 10" dimension gets faced off, while the shop may have 1/2" X 10" and prefer to face off the 2" dimension. Lots of variables there.

Our shop just prefers the finished dimensions of the part and they'll decide what material how to cut it. But having a guy running a steel saw have to stare at a detailed drawing of a complicated part and determine the raw dimensions from the drawing is asking a lot at times from a guy who recently learned that the end of his tape measure wiggles to change "0" for inside and outside measuring. :O)

~ Phlyx ~

 

[TheTick]

If you have a drawing, why not just add the overall reference dimension to the drawing itself?

"Great ideas need landing gear as well as wings."--C. D. Jackson

http://www.EsoxRepublic.com

 

[SBaugh]

I agree with TheTick.

If you don't start the file over from scratch then you can continue to change the dimensions and there will be no problem. If you do then you have to to work harder to please them by re-doing the custom property.

(No offense with below)

How do you want to do it? Do you want to work harder than them or you both decide on a valid solution.

Also if you haven't read it check out thread559-83520 - Start reading when they started posting on Jan 13.... It talks about Standards.

Regards,

Scott Baugh, CSWP

http://www.3dvisiontech.com

http://www.scottjbaugh.com

faq731-376

 

[drawoh]

phlyx,

1. Apply the overall dimensions on your part.

2. Create a note.

3. While editing the note, click on the dimension you want embedded in the note.

The resulting number will be parametric, and will follow the formst of your dimension. For example, you can control the number of decimal places displayed.

The disadvantage of all this is what I prefer to enlarge dimensions I apply to cutting lists.

When I specify things like material thicknesses on a material list, I apply a reference dimension on the drawing as well. This helps to catch errors.

JHG

 

[JJCPE]

Discipline works

One discipline that I have developed is that I always (in a drawing) prominently display the overall dimensions.

As I decide how the various views will be laid out, I start with the knowledge that the first thing a machinist (or CNC programmer) will do is figure out what raw material to start with, how to hold it. The questions are: where the datum surface(s) are, how good do they have to be i.e. flat, square, etc.

So laying out the drawing so that this information is, say, in the upper left hand view and the view below it, with those dimensions to the upper and left sides (as opposed to between two views), is good drafting practice. When filling out the title block, it’s a piece of cake to pull that information out.

This is a skill that isn’t easily handled by a software program (even one as good as SolidWorks).

For example: just because the overall part is 1 x 2 x 3, doesn’t mean that they can band saw a piece to those cut lines and go at it. Often they’ll start with a slightly larger piece, machine the datum surface(s), and then fit them up against the tooling surface(s) - the fixed jaw in a vice, for example - and then machine features and additional datum surface(s).

In CNC work, often the raw material is supplied as a pre-machined billet. It comes in to the proper overall shape, with the required surface specifications. In a case like that, a separate view on the drawing (or a separate sheet) would define the ‘make-from’ part.

I learned a long time ago that there is a difference between drafting, detailing, designing and engineering. The order doesn’t work both ways. An engineer may draft, but it’s unlikely that a drafter will engineer.

As an engineer, I’ve learned to wear all the hats, and know when I’m wearing what hat.

When I have my designer hat on, I don’t care about the starting material size, I’ll use every tool in the SolidWorks Crib to develop the design.

When I put on my detailing hat, I’ll look at how the part might be produced.

When wearing my drafting hat, I’ll concern myself with how the machinist or fabricator, or inspector, will use the drawing to do their job.

While SolidWorks is a great set of tools, they are just tools. It’s the knowledge, skill, experience of the professionals using those tools that is important.

 

[CorBlimeyLimey]

phlyx
"If I started making a part from 1/2" X 2" X 10" material but then due to design alterations decided it was best for it to be thicker and wider I'll just make it thicker and wider, not start over with new "raw material"."
The suggestion to use a "Raw Material" block was given as a possible solution to your problem. I have only experimented with it once, but do not understand why would you have to "start over with new raw material" if the part "gets thicker or wider". If the part changes size, then simply enlarge the raw material block accordingly, or start with an oversize block and reduce it after the part design is finished.

"Also, I may decide that the part should be made from 1/2" x 2" material and the 10" dimension gets faced off, while the shop may have 1/2" X 10" and prefer to face off the 2" dimension. Lots of variables there."
So don't list the sizes as WxLxT just list them as 1/2" x 2" x 10". That leaves whoever to decide what size is what. Admittedly that is allowing for all sides to be machined or faced-off.

"But having a guy running a steel saw have to stare at a detailed drawing of a complicated part and determine the raw dimensions from the drawing is asking a lot"
Didn't you say you were putting the sizes in your title block??? If your "saw men" are that inept, why are you giving them drawings anyway? Most compaies I have worked for would issue a simple cutting list showing Job #, Qty, Material & Length.

Another, simpler, alternative would be to add the max X,Y,Z dimensions to your finished part & link those to the title block note. The dimensions could be hidden via the View Annotations switch.

Did you look at the MinBbox website?


CorBlimeyLimey
Barrie, Ontario
faq559-863