Cad model or Print

[Frank]

Oh I know I have the geometry, and also know I have it right. But he doesn't want me to tell inspection the dimensions that are missing, he needs a hard copy (fax) from the engineer. I guess liability is an issue. Probably if the engineer was asked, before the quote, if the cad model is up to date, and can we use it, if we find missing dimensions on the print. That would be a move in the right direction.

[Thad]

quote:

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IMHO when engineers can't/won't create a 3D SOlid model that is correct it's 1 of 2 things, they are inept or they are lazy.

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James,

 

This just makes me want to puke! Our designers have UG but they "don't have time to learn/use it." So we continue to get 2D die designs in Autocad. Who wouldn't jump all over the opportunity to start modelling in solids, instead of 2D drawing in Autocad? Fricken morons!

 

CAD is master. Period. If the model was created electronically, then you should be receiving electronic files that are master, and correct. If they are hand drawn (trans cases, engine blocks, etc...I doubt it), they, including your boss, need to get with the program. CAD is superior. End of story.

 

Thad

[MetalMarvels]

CAD models rule.... As a job shop owner, I always state in my quotes that the CAD model takes precedence and I make sure that the customer understands exactly what that means. I have been burnt one too many times on the delta between a print and an electronic model. I greatly prefer to receive the electronic model that has the "print" embedded as simply another "sheet" in the same file as the model (or linked files - like SolidWorks). I also make it known that I charge less for work received that way - there are too many opportunities for error with a flat file or paper copy and I charge accordingly. How many times have you machined the item exactly to Revision F of the drawing/model and delivered it - only to get a frantic phone call about "what version did you use?" "The one I quoted, the version you delivered a model/print to me, and the version I confirmed to you that I was making - exactly what SHOULD I be making....."

 

In my role as engineer, I simply won't do the design job if I can't model it in 3D with the parts available and sitting in front of me. I really, really, really hate looking like an idiot. Especially when I went from the cut sheet of product A and purchasing went and bought product B because it was a little less expensive - guess what - different hole pattern, different diameter, always something.... We are going through this problem in a major way on a large project.

[Jack Mitchell]

“In my role as engineer, I simply won't do the design job if I can't model it in 3D with the parts available and sitting in front of me. I really, really, really hate looking like an idiot. Especially when I went from the cut sheet of product A and purchasing went and bought product B because it was a little less expensive - guess what - different hole pattern, different diameter, always something.... We are going through this problem in a major way on a large project.”

 

Gary, I prefer to follow the print every single time because it ensures that I will get paid. So you get caught up with constant rev changes or competitive bidding etc!

Let’s say that you deliver exactly what the drawing called for and that there is a problem.

You cannot ever be the idiot but you can always be the hero and do the job a second time all while charging overtime rates. I don’t look for this at all but I absolutely love fixing up the mistakes and charging a small fortune correcting this; funny thing is the customer actually appreciates this immensely. So many times this has happened and I immediately tell the customer that I will ask the guys to work a double shift on the weekend in order to accommodate the customer’s needs. When you call him back in about an hour’s time he thanks you profusely; charge it up as overtime rates that are completely justifiable.

 

Sure I could make the call and say that I think there might be a problem etc! But why would I risk getting all those professionals into a bind; you and I know how long it takes to explain why you believe something is wrong with the print. We also know that we basically have to educate engineers and purchasers exactly what it is we are requesting; all the wasted time just gets brushed off and any potential profit goes down the drain.

 

Rarely do I come off as anything less than the hero and that is exactly what I am trying to be - in my customer’s eyes.

 

To me the only thing better than sex

Is getting the job after the customer goes with the cheaper quote - the cheaper quote really screws the job - then the customer comes back at you two weeks later begging for a quick delivery.

 

 

Regards, Jack

[Dan Schnars]

Frank,

 

I use the model when I'm programming anything on the cylinder blocks here. We check everything per the print when I'm done though... If I've got the model of something, especially the cylinder block, You can bet that we use that vs. re-drafting it.... Set t/c planes and go...

[Frank]

Dan:

 

 

"We check everything per the print when I'm done though... "

 

Does that mean your inspection department checks the part to the print. Or do you double check everything you've done to the model...to the print ? Because if I have to double check everything on the model to the print...I might as well draw the whole thing and skip even looking at the model except for some face mill paths.

 

I feel some of the prints we recieve, were done half a...., and the designers figure, just give it to them they'll call us if there is something missing !!! So I spend my time looking for, and fixing screw up's created by the engineers, instead of writing toolpaths. And to top that I have to write a whole sheet of corrections that need to be made, submit it to the boss, he forwards it to the engineers, then wait for the corrections to continue programming. And finally when the job is complete, I am constantly asked "WHY I TOOK SO LONG TO PROGRAM THIS JOB" So thank you for all the responses and please keep them coming, because I want to be able to machine the part in the time I am expected to do so, and hopefully after printing all your processes, and submitting them to the big guy it will somehow turn on a light, and we can as James said "get on the 21st century bus"

 

Thanks,

Frank

[robk]

Hey Dan,

Must be a helluva celebration at the shop this morning

Congratulations on a great weekend

[Frank]

Hey wait a minute......a CHEVY won yesterday's race !!!

 

[Guest CNC Apps Guy 1]

quote:

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...So I spend my time looking for, and fixing screw up's created by the engineers, instead of writing toolpaths...

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[rant]

Welcome to my world. Once I had a part. It was given to me in DWG format. SO I take my views, extrude the cross sections and build me a nice solid model. So I do some cursory checks (mind you some of the stuff is not that close (±.030") anyway, I'm doing some cursory checks and I'm finding the DWG is out like .020" - .025" in some spots, so I go and ask the engineer and he says "... it's in print...", I say yeah but at the very least is shoudl be drawn exact, preferrably nominal but I'll accept exact, he starts spouting off about "...tolerancing..." yadda yadda, yadda, so I left with "...Tolerance is for Manufacturing NOT for drafting..." Didn't win that battle. MORONS I thank God daily that some of these guys are not designing cars, airplanes, or something else that if failure were to occurr would result in loss of life.

[/rant]

[Guest CNC Apps Guy 1]

quote:

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...Hey wait a minute......a CHEVY won yesterday's race !!!...

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So much for First On Race Day

[Dan Schnars]

We have the inspection depart stick the block up on the cmm and inspect it per the blueprint. We are lucky in the fact that the print came from the model we use and we know both are gospel. Any changes or updates get done to both print and model so they are always as accurate as possible.

 

We aren't machining the raw casting from ground zero though... We are machining decks and cam tunnels and finishing the main lines and any custom work we do, so we are probably machining a whole lot less than you are and probably checking a lot less stuff...

 

I agree with you if you have to spend all that time verifying model to print, then yeah, I'd draw the whole thing too. That's where the engineers doing their job comes in... We've fought that battle with poor models and NO prints... That's getting alot better though... I'd just show the boss what you have to go through to get enough information to do your job and make toolpaths... Hopefully he understands and helps you out.

[Dan Schnars]

I thought we were tight James...

 

4 outta the top 10 isn't too bad... I sure would have liked to see the 88 and 38 first and second... And I hate that Kenseth and Martin had tire troubles...

 

Man, #24 was on fire wasn't he?

 

 

That's racin I guess...

[Guest CNC Apps Guy 1]

quote:

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...I thought we were tight James...

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We are ... I'm just a Chevy man, course, these days, I'm considering going back to my first cars... Honda, where the milage is better and the reliability is phemominal.

[Dan Schnars]

I've always been Chevrolet at heart too... Never owned anything but Chevys... Not popular here in the Ford camp but thats my story... I'm stickin' to it.

[Guest CNC Apps Guy 1]

[Tim Johnson]

Dan,

Which NASCAR engine is better? Not after Henricks or Yates is done with them, but before the magic gets machined into them. Just curious how close the engines are to start with.

[MACHINEMASTERG]

im no enginear ...but i play one at work EVERY DAY!!!!!

[Dan Schnars]

I think they are all pretty close Tim. Used to be that the Ford stuff had the induction system to beat, then Chevy came out with the SB2 and kind of leveled up the playing field, then Mopar got back into things and they did they're homework and they have a decent product... So honestly, from one manufacturer to another I'd say they are all right in the same ballpark...

[Frank]

We run the SB2,s and now R99's blocks and heads for the Nascar teams. Also.....

 

http://www.snapfish.com/slideshow/AlbumID=...2842/t_=5978627

 

http://www.snapfish.com/slideshow/AlbumID=...2842/t_=5978627

[Frank]

[Frank]

[Don S at Barefoot CNC South]

Hi,

I agree with James, in the aircraft field the solid model is the bible. 2d prints are mostly created from these solid models latter for inspection purposes, quoting and so forth. Just my two cents.

 

Don S

[MetalMarvels]

quote:

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To me the only thing better than sex [big Grin]

Is getting the job after the customer goes with the cheaper quote - the cheaper quote really screws the job - then the customer comes back at you two weeks later begging for a quick delivery.

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Jack, I hear you on this one - had this happen many times. I usually charge them 20 - 30% more to "break into" the production schedule I already have. More if it is a "hurry up we are way behind now because the other couldn't make the parts" - type of job.

 

The "I hate looking like an idiot" part is when I am the one designing the part to be made - and making the model/prints. It really sucks when you get everything just right (and machinable) just to find out that a completely different part was purchased....

[billystein]

I have found that you must get your customer to put in the purchase order that they will buy the part to the cad model. normally they will give you a blanket tolerance and list only the critical dimensons. I have had some customers that only use cad files. If you get a chance look at Verisurf.com The software runs in mastercam design. i use on my cmm. it is also good for inspection arms and laser trackers.

It is very easy to use for mastercam people but the owner of Verisurf is a wiener.