I was wondering how cnc programmers program a complex casting or part from a blueprint?

Machining from a model is one thing. But to have to spend time creating a complex part is another. Will a company let the programmer spend 40 or so hours modeling just the part? I am refering to parts such as Sikorsky castings where the prints are .tiff files and no models available.

I guess my first question, would be, if there is no model, how are you supposed to machine the part? The second question would be, during the bid process, wasn't the drafting of a model included in the bid?
My third question would be, 40 hours????? You gotta be kidding!!! I do some pretty complex parts. I've never spent 40 hours on a model in my life. I realize some folks do things differently than I do, What software are you using to produce these models? I use Solidworks and Mastercam to design and machine. Mastercam has the ability to start with an STL file and define stock to machine to that.
What CAM system are you using?

My last job working for the other guy was doing exactly that, pin up a half dozen "E" size drawings on the wall and then run around with a laptop making solidworks models for the programmer. I dont recall ever spending more than about 6 hours on any given model (casting tooling for automotive), we did include the time in the bid. But, I always kept at least one cnc going while I was modeling, so boss got 2 for 1.....
Our customer could always supply us with hardcopy, but could not always supply a model. Even when they did, sometimes they were so big it took solidworks hours to open them, on a 8 gig workstation. We did switch to some software that did a better job opening the customer native files, but we still never stopped modeling some stuff from hard copy.
When you model it yourself you know what you have. And when customer wants to make changes you have something in your native format to work with. Plus it was great practice for when I opened my own shop!

I'd guess it should have been figured into the quote or absorbed in the quantity over the life of the part.

Jim, no kiddin. I have a 2D only part and I'll bet it takes no less than 25 hours to model it correctly. Thankfully I was for one of the first times given a model to work off of, but would have charged an additional 500 or so just for programming and modeling without it.
It has 7 sides with more than just holes, all interrelated to somewhere else on the model. A freakin' nightmare I tell you.
OTOH if you look at some Sikorsky parts and drawings, You'll see that a simple washer can be drawn in the likeness of the space shuttle. With all do respect to the engineers and draftsmen at Sikorsky, they make Hamilton and Honeywell's prints look good, and that's saying something.

Spock

Using your words, if it took Solidworks hours to convert it, I pretty much guaranteee you could not have drawn it in 6.

The Japanese we worked for would not always send you the specific part model from any certain die. You might only need to work on a small section or insert, but they send you the humongous file that contains everything but uphosltry on the car's seats. Those files take hours for solidworks to open. It is a software limitation. Solidworks does not like files that big. Period.
We saved time by modeling the specific insert/section we needed.
My six hour model was a piston die for Toyota engines. I spent about half a day trying to figure out how 6 drawings could work together to make one part, but once I got it in my head most (not all) of the modeling was pretty simple, that part took about 6 hours.

We have 2 guys that are responsible for making the models. We have some models of machined castings that will take at least 60 hours to make. Try to make a model of a part from a 23 page drawing. And that is only the machining drawing not the casting drawing.

40+ hrs of modeling isn't unheard of especially if you're looking at from a CAM perspective as opposed to simply a CAD one. STL won't matter either if a CAD doesn't exist. I've programmed many parts from a TIFF file (or other types of this nature) and many of them are a bitch. Did one not too long ago at 28 pages plus a 9 page BOM.... for a single piece part, not an assembly. Lost count at a 100+ hours on it.

Many times, machinists/programmers will approach this type of work with the actual process in mind as well. This adds time since you're considering all of your fixture options and machinability. Now, this may be rather extreme for an example, but it happens. If you can get money for programming and tooling, go for it. But many times, the "customer" considers that a wash so you have to hide and fudge some extra to pad the programming/modeling time. It's even worse if you have to turn in a 6 page report of missing dimensions, drawing discrepancies, "tribal knowledge" features, unclear leaders, or simply a poor copy of the file to begin with.

This is where you make your money or lose it. Machining is one thing, some machines are faster than other. But solid molding and programming is another thing. Having a trained machinist that can program and do solids is rare.

Can you help out an oldtimer ?
You guys are throwing me with the terms "model" and "complex casting" and "solid molding".
having worked with 4 and 5 axis CNC Boring mills years ago, I am trying to figure out what your problems are. ( just to stay up with the trade)
It sounds like the term model, is used for 'part"
When I hear complex casting, it means a raw part from the customer...why redraw it ?
and what is "Solid" molding... is it a term for 3 D contouring?
It sounds like the part drawing is so complicated, that "you" have to RE-draw it to confirm what you are looking at ?
But it sounds like you need to do it in "your" software, and not the customers ?

Stupid questions perhaps, but how in the world can you bid on a job, if you don't have all the info you need ( i.e. finished prints/CAD) at that time ?

This is blowing me away, because if i was a customer, I would be blowing money away on worthless prints that need redrawing.. Are they that stupid today ?
Help me out, am I outside the box ?
Rich

There are still people out there that will issue you a paper drawing. Then it is up to you to generate the geometry to machine from.
The real danger is that if there is an error in their model, it's their nickel. If there's an error in your geometry it's yours.
A solid modle is just that. It's a mathmatical solid. Not wireframe and surfaces although you can derive them from a solid.
Sometimes a comple casting model is requires to vastly reduce air cuts.

Yes and No. At least its becoming more prevalent. As more and more companies go "electronic", "digital", whatever, .... the requirement for programmers to learn and adapt modeling to their use is becoming much more of a necessity. It's tough just finding a good programmer period.

Often a customer may supply you a casting (and possibly a model or 3D part file of the cast) but the machining issues are all on paper. This may require a model to be created for the machined condition. If the machining is relatively simple (in terms of the shops capability), than you're correct, why create a model. But many parts can be very complex or simply "busy". In this case, a model can help identify problems in machinability, fixturing, toolpathing, etc. On top of that what PBMW stated about program efficiency. But, I've also had to create casting models as well because it didn't exist or maybe has deviated so much from the original form that what is there isn't worth anything.

Many machines or machining aren't the simple 4 axis or 5 axis types either (I use "simple" loosely). Machine centers that have a dozen or more programmable axis, multi-task machines that can combine a number of operations in one set up, simultaneous multiple spindles, etc, etc. Models can help to optimize the programs from before cutting chips and avoid certain destruction to both part and machine from bad moves. Several machine builders are also continuously developing software to import models directly to the control to program conversationally.

Just make sure that it's stated that way or that there is a company spec (yours or theirs) to control this distinction. I've been in several arguments over models on this because something didn't come out right.

I think some terminology issues were created by mis-spelling and mis-reading properly spelled words, such as MODEL, MODELING, MOLD and MODLE.

In the case of this thread, the question was regarding SOLID MODELING.

I think Rich is talking about SOLID MOLD, which is not to be confused with SOLID MODEL.
And to answer that question, having a real finished part supplied by the customer is useful for paperweight at best. For machining purposes on CNC equipment, the part MUST still be drawn up, which makes a proper SOLID MODEL in CAD invalueable in comparison.

In pattern and mold making we spend 40hrs + on many jobs. We spend that on jobs with models sometimes. Alot of times we get a perfect model..perfectly straight...which does us no good. Depending on native format and what system we use (may or may not play well together) we can draft and add offsets and change radii and such. CAD has made things so much easier on the guy making the job. We used to program G code to do all our 3D stuff. We used Sharnoa machines because the control was great for programming with variables using parameters. We used to have 5 pages of trig and parameters before we even started the G code. Now the cad/cam systems do all the smart work.
But back to the topic, I have seen 80hrs on design time and that is without mistakes and backtracks!

Barry

I had a customer that dropped of a bunch of castings and wanted drawings. I did the solid modeling to create the drawings. I got through 2 parts and was working on the third when they pressed me for 2d drawings for the pattern maker. The customer just couldn't understand that solid models would speed the pattern making process up and ultimatley give them a better part. The pattern maker told them he didn't want the drawings and he would work from the castings. I had a ton of hours in these parts and with their approval I tweaked the part here and there to create symetry etc. The job got ugly so I walked away from it when they couldn't understand that if the pattern maker didn't use my drawings it wouldn't work. I ate the whole rush job. I hope one of you guys didn't get my drawings with the patternmakers castings. I did hear some roomers that they were having to weld the castings and stuff to get them to work.

Here is a link if you want to take a look:
http://www.gtprototype.com/casting/

This (8 GB) would only be even possible if you were running a 64 bit workstation WITH 64 bit Solidworks. (highly unlikely, as most companies still have not adopted 64 bit infrastructure) If you were running Windows XP, it is impossible that you had 8 GB RAM. If you had NT, you may have had the RAM, but SolidWorks would still only see 3GB, at best, unless you actually had 64 bit SolidWorks to go with it. So not matter if it were 8GB workstation or not, it's probably a moot point.

Besides, SolidWorks, and all other mid-range CAD programs, are limited in the size of file that they will open, especially if translated by some other program. Any 32 bit application is limited in what it will or won't open. 64 bit will open anything, but sometimes still at quite a premium on time.

Dale, before I looked at your pics I figured it was some of the castings I have sitting here. Or at least some of the castings in the same assembly.

This customer has screwed up so many times its not even funny, they paid 9k to the mold maker for the solid model (investment casting), then they turned around and paid the place machining it 13k to make another model. They never got the solid model. It was a nasty bastard, 180 piece mold for one casting, and the machining was miserable, thin walled aluminum, machining on 9 different planes that all had to line up within .001, and it just kept moving and moving and moving, approx 10"X10"X14", lots of deep internal stuff on thin walls that had to line up, and it just moved and moved and moved.

Bob,
I feel for you man. I know the machine shop that got my drawings with the patternmakers castings really went through some greif. I did everything first rate, I'm a perfectionist by nature, the problem arrose when the customer just wanted it close. He even said to me that it's normal to weld up the castings and make adjustments on the first article before production. Not in my world! It seemed more important to be moving than moving in the right direction. I could see the problems down the line. Certain disaster prompted me to eat all the time and costs just to get away from the project. It was costly for me but I didn't get any of the headaches. I did buy some nice inspection equipment though.

I have found in modeling a print from a drawing the interpretation can take a while depending on the presentation of the drawing.

I have seen a video by Solidedge and Solidworks where a 2d drawing is develope into a 3d model.

So basicly it would require the drawing to be recreated in 2d as is. Then you would apply the tools to go from 2d to 3d.

I find it to hard to do it that way. But I admit more practice is always a good thing as long as its using the tools right.

Has anyone tried this 2d to 3d or used it and found certain draw backs?