Drawing cleanliness

[CJJ]

Hand-drawn- drawing means nothing-text means eveything, but then there are grey areas like bend lines, hidden features, etc.. that break the rules extremely often

 

CAD-drawn- model means everything - text is secondary. The model creates the part, no ifs ands or butts.

 

CAD computer/workstation should be viewed like any machine out in the shop, commands are entered to "build" the part.

 

I agree with this, this goes along with what I just said about the final purpose of the drawing. If you're making a sketch that will be done by hand on a table saw and with a measuring tape, then the guy using the drawing the file will be reading the text, so that is the most important aspect, so as long as your dimensions say the correct numbers, it's not the end of the world if your model isn't exactly to scale. However, if you're drawing for a CAM or CNC machine shop, then the model had better be exact, regardless of what the dimension says.

[Dana W]

I've seen drawings that have everything on one layer, or that have boundary lines around the site that don't meet at the corners, or that aren't even aligned to north but instead rotated to fit in the title block. Even within the company, the CAD guys in the survey dept. are drawing just to get their plats made or just to do the bare minimum to get all of their points and data on the page, without regard to the planners and engineers who will be using the files next.

 

I think one of the most important things to keep in mind is the final purpose of the drawing. Who will be working on this file next? What parts should I pay extra attention to in order to make sure it's detailed enough and drawn to the right scale? Will the next guy who opens this file understand my layer naming convention? If I take a shortcut now, it may save me some time, but will it slow things down somewhere else down the production line?

 

First paragraph - Wow, that is scary.

 

Next Paragraph - I do some free lance civil drafting for my father-in-law, who is a Professional Land Surveyor here in Maryland. One of my drawing projects for him recently ended up in court as Plaintif's Exhibit "B", because it is an accurate drawing of a contested condition on some other recorded Plats fudged by a large developer.

 

Since our drawing makes it possible for the judge to understand the details better, the plaintif is likely going to win, and correct an injustice done to some local families. It seems a developer "conveniently" left a previously recorded access right of way dating back to underground railroad days off of a new subdivision record plat. This would have left some 3rd and 4th generation land owners high and dry with useless land and probably "convinced" to sell out to "some" developer for a seriously minimal amount of money.

 

Sounds just like the old west, huh?:wink:

 

Where is that drawing going to end up, indeed?

[jwkilgore]

My company's main problem is that we've historically worked with one main client. This client has been involved with CAD for decades, and had a few very sharp people involved early on. They have custom menus, scripts, buttons, routines, even their own custom-made font. Unfortunately, the main early developer (I've met him - he's still extra sharp) left the company a decade or so ago and his successors never updated their custom stuff to match newer capabilities of AutoCad. Layers are still PEN1, PEN1H, PEN1D, PEN2, etc. (for red cont., red hidden, red dashed, yellow cont., etc., from back when they used pen plotters). Dimensions are never associative. Things are rarely drawn to scale. There's no such thing as paper space or external references.

 

My problem is that we have drafters who don't know any other way to work. They have no idea how to set up text styles, dim styles, paper space layouts, etc. One guy had no idea that you could actually draw OUTSIDE THE TITLE BLOCK. They've never had to learn, because that's what the little buttons and drop-down menus are for. And as long as they're working for that client, then all is good with the world.

 

Unfortunately, I mainly work with our OTHER clients. Some of them have very strict drafting standards, some don't care. All it takes is one click on the wrong button and suddenly the drawing is filled with all these extra layers, dimstyles, and fonts. Even the clients that don't have specific standards start to care when they get all these "font not found" errors when they open the file.

[adamshive]

I agree with this, this goes along with what I just said about the final purpose of the drawing. If you're making a sketch that will be done by hand on a table saw and with a measuring tape, then the guy using the drawing the file will be reading the text, so that is the most important aspect, so as long as your dimensions say the correct numbers, it's not the end of the world if your model isn't exactly to scale. However, if you're drawing for a CAM or CNC machine shop, then the model had better be exact, regardless of what the dimension says.

 

Exactly- we've had a CNC punch for 16 years and the engineers have yet to catch on that the drawings need to be to scale, proportioned and annotative. Maybe I'm being too hard on them..let's give it until the 17th year...

[ReMark]

It's said that you can't teach an old engineer new tricks. Or was that a dog? Can't remember. Could be both.

[Dana W]

I agree with this, this goes along with what I just said about the final purpose of the drawing. If you're making a sketch that will be done by hand on a table saw and with a measuring tape, then the guy using the drawing the file will be reading the text, so that is the most important aspect, so as long as your dimensions say the correct numbers, it's not the end of the world if your model isn't exactly to scale. However, if you're drawing for a CAM or CNC machine shop, then the model had better be exact, regardless of what the dimension says.

 

I spent some time as a drafter for a very high end custom cabinetry and millwork shop. While they had CNC machinery all over the place, I mainly did AutoCAD drawings for the Master Cabinet Maker who made everything by hand, of course using appropriate power tools.

 

We were not permitted to use hand drawn sketches, even for one-off keepsake boxes. Everything had to be kept in a *.dwg.

 

Now this MCM would have been in the casting auditions for the Travelosity Gnome. I think he even knew Merlin, but the MCM was much older.:wink:

 

Anyway... Invariably, this guy would lay a scale on the drawings and measure stuff, then if a discrepency turned up, go to the Boss instead if me, and ask which measurement to use. Of course I would be questioned as to the validity of the whole drawing. He would even check the molding profiles against our custom shaper knives even though there was a catalog number callout pointing to the molding on the drawing, and the same number engraved into the knife. Note: Not one single CAD molding profile block in that shop matched the custom hand ground knife for that molding exactly. Some inside corners just refuse to be ground into shaper knives.

 

I learned to treat EVERY drawing as though Commander Data of the Starship Enterprise NCC-1701-D was in charge of Quality Control. I still make mistakes, but simply don't take obvious shortcuts when it's so easy to do things the right way.

 

From day one, 40 years ago, at my very first architectural drafting position for a major local ticky tacky builder, I was taught that Rule Number One for the trades people out in the field was NEVER MEASURE a drawing.

 

On day number two, I went out to a jobsite and learned that Rule Number Two was apparently ALWAYS MEASURE a drawing rather than use math to figure out the ONE missing dimension. This was, and is still, done using a 1/4" scale drawing and a folding carpenter's rule.

 

My moral is use some sort of standards and QA checking.

[MikeScott]

I had a problem where as part of the engineering staff, we'd set-up holes for a CNC punch that simply didn't have the proper tooling. I'd think nothing of passing along a drawing with a .469 hole on it, because the CNC guy would say "Sure, I can do ANYTHING" and wouldn't get me a list of punches. As a result, I had holes with ragged edges (nibbled edges) or substituted hole sizes, and it'd sometimes be MONTHS before anyone found-out that our client was redrilling some of the holes in the field.

 

Sometimes, the hole sizes were arbitrary, and we had punches that were a slightly different size, and so the CNC programmer would manually make corrections/adjustments that we weren't aware of, and so when components or modules were added, it looked sloppy as hell, and took all kinds of extra time to program.

 

That's unacceptable.

 

You cannot work properly in a vacuum. Positive and negative feedback is essential. I'm there to do a job, and I make it my business to do it correctly.

 

Later, I started working with the client's quality control crew, and finally got a list of availible punches, and availible clearance dies from the CNC guy. When I place a hole, it's either the correct size, or the client is informed, or we order the stuff we need.. there's no fourth option of "oh well.. maybe this is good enough"

 

The guy bending the metal on the brake, was also having problems because he was making adjustments to my bend calculations in-order to get the required dimensions. He'd never spoken a word of it before. I was using bend deductions taken from recordings of piles of test material, but it had been bent by a previous operator, who apparently did things differently.

 

I also discovered that the brake operator ALWAYS assumed the part was being illustrated face down, despite proper rotations, notations, etc. He'd grab a piece of metal from the punch operator, and use the burr as his guide as to which face to use, irregardless of instructions to the contrary. That meant that my orders stating "other side bend opposite" was rarely followed until an extra part was discovered, and it's opposite match missing. Sometimes that wasn't discovered until after welding and powdercoating, and assembly was underway, with a looming deadline.

 

The shop foreman HATED me.. his guys were wasting time, and generating improper parts that didn't match drawings, and he was getting complaints from the sales department who was fielding complaints from the client. I then simply went through every stage and determined exactly what was needed, and adjusted my drawings accordingly.

 

I finally started getting feedback from everyone, and I smoothed-out all the production kinks without taking any significant extra time to do it.

 

None of it was my fault.. I had inherited a system (and a lot of re-used prints/drawing files) from a predecessor that had no clue why everyone hated the engineering department, and apparently no inclination to do the job right for anyone actually using the prints, instead merely placing blame on the shop for not following his prints.

 

Hell, I even discovered that our brake operator rounded to the nearest 1/8th (sometimes up, sometimes down).. he had a computer driven brake, and still only used 1/8 because it meant he could check his work easier. Once I knew that shortcoming, I catered to it and saved everyone a lot of headaches when it came to sizing/adding weldments, assemblies, door hanging, and any other number of processes some of the parts had to go through.

 

Soon I received word that when a Mike job came through (something I'd drawn up), they were happy to get it and knew it'd have exactly what they needed to do their jobs correctly and by the prints... and that's what a drawing is supposed to do, no matter the company size.

 

Sure, sometimes they nitpicked, but in the end, it was totally worth the effort, and gave them the power to take pride in, and responsibility for, the quality of work and the resultant end products. We also regained control over what we produced.