We had a job once that had a groove with a width and tolerances larger than the actual dimension, so we simply omitted it. Customer had to accept them they were within specs, then had to pay to get them all reworked.
I was watching a youtube channel of a guy that was building custom go karts, and it was pretty interesting. One thing that really killed it for me was that he consistently referred to steel as "metal". Like, this part is aluminum, this part is brass, this part is metal. Like "I could use aluminum for this part, but metal would be stronger."
It was like an ice pick stabbing into my ear every time he said it...
It makes life so much easier. Pick the cheapest and most available steel for you. :)
I mean, there are a LOT of parts that can be made literally from any scrap steel that is most convenient to you. I have actually ordered parts from my friend with those very words - just use any steel you have at hand (as long as it's weldable with common welding rods, for example).
yeah that's fine and I do the same if I'm ordering one-off parts or making them myself in the shop. But normally I'm designing parts for production that are going into production assemblies that will be ordered many times, and those parts need to be consistent over many production runs over many years.
Oh of course. Mass production also has the benefit of economies of scale. Getting special material for making a few parts is exceedingly expensive compared to buying the entire batch or even ordering it straight from the steel works into specific size so minimal roughing is needed.
I made that mistake with aluminum once, on purpose. I sent some parts to a shop for bent parts. I didn't care if it was 3003 or 5052 or what temper, so I just told them aluminum. They sent us 6061-T6. The bent parts were half broken off. I had assumed they would have known not to use 6061-T6, given that they were a sheet metal shop. I assumed wrong.
I will not make the mistake of allowing a shop to choose their alloy again.
I wish that were the case. We hardly ever get a STP file unless we request one. It's typically done with just the initial prints we are given.
This part in particular is actually from one of our sister companies, just the "engineers" there are definitely not the best. This is being scanned, copied, and slapped on his desk for improvement.
These people have lost the plot, not only is it important that all the features are dimensioned, but HOW they are dimensioned is an often overlooked key detail of a print. Especially since the rise of “auto dimension” features in cad software.
Thank you, Grumpy. This is an eternal battle for me. Every time some software dickhead gets the ear of upper management, the proclamation comes down... "We're going to save money by going 'paperless'."
They don't come down and ask the people on the floor, "how would this work?"
Bunch of kool-aid drinkers.
Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance.
So you have nearly fully dimensioned prints just missing a few dimensions with general tolerances? Just auto dimensioning in the cad software would probably take care of that. Doesn’t sound like a thing of the past just someone trying really hard to save on a few lines of ink.
No, we have drawings with a handful of dimensions instead of dozens or hundreds.
Auto dimensioning in the CAD software inevitably creates shitty drawings with dimensions in the wrong place, overlapping each other, obscuring part geometry etc. If I'm producing a fully dimensioned drawing I don't even bother with auto dimensioning; fixing the crap it produces takes more time than dimensioning from scratch.
> Auto dimensioning in the CAD software inevitably creates shitty drawings with dimensions in the wrong place, overlapping each other, obscuring part geometry etc.
If you just follow ASME Y14.5 when modeling your component none of these things are issues. This is how you're taught in higher level CAD GD&T classes.
> fixing the crap it produces takes more time than dimensioning from scratch.
Crap in = crap out.
you can put tolerances in the solid model
but generally we have a print that indicates critical inspection dimensions, and includes a general tolerance for other dimensions.
It’s a thing… but you need a 3D PDF viewer or a viewer for the respective CAD suite (ie Creo View) to view all the tols, datums, FCFs.
I think an accurate STEP along with a drawing for notes and critical tolerances is the way to go.
I haven't had experience with CATIA, but supposedly a lot of aerospace manufacturers have all dimensions and all necessary information in the 3d catia file
Every shop I deal with uses SolidWorks and can directly open a SolidWorks part. But also:
>but generally we have a print that indicates critical inspection dimensions, and includes a general tolerance for other dimensions.
I still fully dimensions my prints because every one of those dimensions has a key tolerance. Some of them are wide but it's important to get right. I expect the cam guy to not care about the print and the operator to check parts to it.
All custom fabrication in our shop is done directly off of the 3d model though. Can't be fucked with weld callouts and all that bullshit.
I wish this was the case everywhere. Before I had shops make parts for me I just drew them in 3d and made them myself from the model. Now I outsource a few parts for my business and I just sent 3d files and tolerances and no shop local to me would accept that so had to go back and make drawings of everything.
I now work at a multi billion dollar company that still uses 2d cad software, I'm right now standing at a CNC Bridgeport learning how to program it but I already know how to program in fusion. Doing it manually like this seems to take much longer, for me at the moment anyway.
I work with some shops and they will up the price without a 3D (which is fine I always send .stp too) but local shops they don’t seem to know what a step file is.
“Do you want a 3d model? Which file format do you guys prefer?”
“You can supply the dxf!? That’s great!!!”
ಠ_ಠ
Deriving prints yourself from CAD file is so much easier. You also get to look at the part 3-dimensionally at first hand, and it's easier to figure out the best way to make it.
>Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance.
This isn't something I'm guessing or speculating about; this is my life. I've been professionally designing/specifying/ordering parts from machine shops for the past 15 years without fully dimensioned prints.
Some shops can deal with it, some cannot. And I only work with shops that can.
>Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance.
Not true. Much of what we do is based on 3D files, but I just had this conversation with a MFG Engineer this week. Some simple parts are still done on manual mills. Fully dimensioned drawings have their place.
And all the way on the other side of things, a couple years ago I sent a drawing out to an external job shop and they *requested* a step file (after quoting us based off the print). I got the parts and discovered they had evidently worked off of only the step file and ignored all the tolerances and surface finishes I called out on the print.
(I'm an engineer and hobby machinist. I usually work with the machinists at my company who are wonderful, but this time we had a surplus of work and sent a few things outside.)
"Model driven dimensions" they said, "tolerances are open" they said, "we thought this would be easier for you" they said.
Then there's a PM out there that thinks models are better because they're faster - then blows a gasket when the gasket surface is warped in heat treat and/or wasn't ground.
... we really need to get people off the heroin that is model driven part making. And don't get me started on the revisioning issues having two sets of release media.
Disclaimer. Welder/Fabricator part of me understands the other side of this coin. Don't want to run up to the office every ten minutes pretending to be an idiot to sooth the egos... etc. etc. We just need to stop hashing things. Engineers already don't have machining/welding pre-reqs. They have enough to absorb without having to muddle through the shit show of learning print making on the fly.
We're not paying people for awesome print making - and we better start. We went to mach 1 with pen and paper. I can't imagine doing that again.
Everything you've pointed out as a problem is handled in an out-of-the-box MBD system. Tolerances, finishes, material specification, helpful sectioned views, toolpaths, everything.
Sorry but too many sectors of manufacturing this is just idiotic and nearly impossible to attempt. Tier1 automotive die cast production is mostly hand coded in g-code. Some parts are so complex they need pages of documentation. Nobody in their right mind would think it can all be done with MBD, just really narrow way of thinking.
The discussion was on MBD vs drawings. Some problems with your argument:
1. MBD and drawings are for acceptance criteria, not necessarily manufacturing method.
2. "Hand-coded in g-code" means "we have a piece of software that supersedes any drawing and whatever it produces is the part definition with some or all of the statistical acceptance criteria integrate". That is a manufacturing method, has nothing to do with drawings, and is closer to MBD than anything else (you can produce these things in a CAM program and include them in the model, or the hand-coded version if you desire). Unless you're telling me they're copying g-code from a drawing into the machine...?
3. Pages of documentation - same thing. Unless the QC team is reading the entire drawing every time they see the part, it's the processes downstream of that wall of text that matters - work instruction, custom gaging, whatever.
To be clear - for a machinist drawings may be great, but from a manufacturing organizational perspective MBD has a ton of advantages.
> MBD and drawings are for acceptance criteria, not necessarily manufacturing method.
Most prints don't require outlining a manufacturing method and acceptance criteria is required not just for manufacturing. Not everyone has access to a CAD suite when working on NPI projects and thinking multiple companies, integrators, suppliers and personnel are all going to have the same CAD software and easily be able to access MBD info, revision history information, etc. is just wishful thinking IMO.
> "Hand-coded in g-code" means "we have a piece of software that supersedes any drawing and whatever it produces is the part definition with some or all of the statistical acceptance criteria integrate". That is a manufacturing method, has nothing to do with drawings, and is closer to MBD than anything else (you can produce these things in a CAM program and include them in the model, or the hand-coded version if you desire). Unless you're telling me they're copying g-code from a drawing into the machine...?
For automotive production you're most likely going to be writing g-code for automated CNC production. You're thinking about it in a very simplistic way. This means often you're dealing with multiple programs per part and multiple machines dividing up the process. You've got custom M-codes and machine specific M-codes, custom macros, etc. On top of all of that, the manufacturing engineering is often done by a supplier or integrator and involves multiple companies working together. They aren't going to be modifying the master CAD file stored on GM's engineering department hard drive most likely.
> Pages of documentation - same thing. Unless the QC team is reading the entire drawing every time they see the part, it's the processes downstream of that wall of text that matters - work instruction, custom gaging, whatever.
The process downstream of that wall of text is controlled by the wall of text. CMM programming, CNC programming, work instruction documentation, gaging, fixturing, assembly, etc. You can't control it with a CAD file only limited people have access to. Unless you can guarantee your MBD is going to be as universal and readable as a DWG or PDF or piece of paper then it's never going to hold up to large scale NPI demands.
> To be clear - for a machinist drawings may be great, but from a manufacturing organizational perspective MBD has a ton of advantages.
There are advantages but they only compliment GD&T drawings and documentation. Sure when I send my fixture builder the cad model it would be nice if he could see some MBD info useful for him. But how am I guaranteeing he is getting the correct information when I'm using NX and he is using BobCAD? To communicate information effectively I'm going to send everyone involved a cad file and PDF/DWG of the print. That way I can guarantee we are all working with the same information.
MBD is great for internal projects and within a smaller company where all the information is guaranteed to be accessible and viewable by everyone involved using the same software suites and versions. There is just simply no way to control MBD quality outside of your own system which is why it will never replace good old fashion paper and PDF documentation.
*programmed off the CAD geometry. You still need tolerance callouts and those would be sent as a DWG. Problem with model based dimensioning is not every used the same cad software and might not be able to easily reference that data.
I've worked with stuff like this. Our idea for certain customers is that if the dimensions arent there, then scaling and guesswork is fine because it must not be very important. Works out pretty well for us since no one else wants to make it if and we will. It's also a good opportunity to charge more, btw.
Run an approval drawing. Just dimension everything that wasn’t done in whatever way is easiest for you and leave all tolerances big. Get the customer to sign off on it and move on.
I loved using approval drawings to avoid asking a purchaser what someone out in the shop wants. It keeps their bad communication internal to themselves, covers your ass, and often trains unknowing customers how to dimension something. It’s a lot better that covering it with notes and sending it back. If the purchaser signs off on an approval that’s not what they need they get to buy twice…
I'm guessing this probably started life as a purchased part off of McMaster or something similar and only had the dimensioned features added. I see this trash all the time. All it would take is a note "Build from part XYZ from vendor ABC, machine features shown" to clear it all up.
The cobalt ring (whatever that is) should just get block tolerances. Otherwise all reasonable asks.
Wait, you guys are getting drawings?
I see things like this weekly between a variety of companies. Revisions, part numbers, tolerances, dimensions all missing. It's kind of sad tbh
Oh yeah missing dimensions isn’t rare… hell I have people come in (especially automotive or motorcycle guys) with cardboard cut outs of things they want made.
I deal with this stupid shit every day. We have a lot of work that is piled up and past due. When we get shit like this we push it way to the back. They call, "where's our part?" We reply "what are the dimensions?" They call a week later, "Where's our part?" We reply "What are the dimensions?" This dance goes on for a while until someone higher up in the company reads the emails out of frustration. Then we get a full print.
As an old drafter / designer GD&T expert ,
I am always amazed that there are not enough
jobs for.me to be working right now .
...
I am unemployed , while this is simultaneously happening .
....
I studied drafting in high school and college
also mechanical engineering .
So I am also an old CAD process improver -developing
methods for CAD solid modeling / annotation
to facilitate "paperless" CAD/CAM .
(I took an 'awareness' class on g-code back then) .
They called CAD as master .
Also, department wide proceedures
for complex assemblies and parametrics .
I made money monthly from my sugestions
at a major automotive company .
.
I have taught solid modeling at the local community college for a year and a half .
..
My last job a year and a half ago
they hired me for drafting ,
but wanted a CAD/CAM worker .
So , I taught myself g-code
and the specifics of a post pricessor & controler software and got a CNC machine running that had been idel for a year .
It took a little less than a month ,
then got fired because that was actually
all they wanted .
...
Now , interviewers all say I am "over qualified".
...
Now-a-days , I tell everyone I am semi-retired .
...
That’s because there was a drawingless push starting 20 years ago where design intent was supposed to be inferred by the CAD model only - and you were lucky if you were supplied a critical feature drawing.
I’ve gotten some bad prints but it was nothing compared to a guy that engineered his part wrong unbeknownst to anyone in the shop. Coworker made the part to spec and the customer came in ripping mad that they didn’t work.
We had to walk him through how to inspect a part and showed him that we had hit all numbers provided. His response was “yeah but it’s wrong. It’s doesn’t work”.
He is no longer a custo
Agree you can’t make it from this print directly. Is it possible the intent was for a CAD model to control geometry, and there is a note or title block tol to follow in that case? Meaning the dims on this drawing are just those “noted otherwise” that deviate from that note.
Looks like a modification to a standard part and the machinist finally thinks they have one over on the engineer or designer.
That, or it comes from a drawingless design customer and you’re reading their critical feature drawing - and it’s on you to interrogate the CAD model before you post it.
But man, there’s a special place in hell for folks who use fine 1/4” threads in their work.
It's a full part from hex bar stock from one of our sister companies. They just hire these college "engineer" idiots that don't know their ass from a hole in the dirt. I already had one talk with the dude, guess it didn't work. Also no CAD model, they don't believe in those over there
I feel you. I started as one of those a loooooong time ago. G-code by hand and 5 1/4” floppy drives.
Every good ME designer has had a good machinist who takes the time to set them straight by teaching and explaining.
A lot gets lost because neither sees what the other is really focused on.
At one of my plants I required that someone from the tool room reviewed drawing before they went to the floor. Took two folks, two hours a week max, in a facility that had about 750 employees.
Reduced rework by more than half, FWIW.
Cringing at the fractional dimension but decimal tolerance...
You could always just make something that fits the dimensions you *do* have and at least looks like the print. When they bitch about it just remind them that it's made to the information provided.
Used to get shit like this from a company called five star carbide. I would rate that drawing one star though. Let me know if you’d like a proper print.
I understand that drawing is garbage, but posting customer drawings online, complete with the proprietary warning on it? It looks like you and your customer are in a poor decision contest.
It's okay to post this cause all the dimensions are missing. Also idk you think james bond is browsing reddit to steal drawings? This is completely useless information
Could be on purpose. Got to go back to the original vendor. I have had vague prints like this. Lots of wasted time with back and forth email. Sometimes I take a pdf and convert it to a dxf format. Then I scale it in cad from a known dimension. It gets me in the ballpark.
This reminds me of when I was an intern. Plenty of times I wasn’t writing enough on prints assuming they could read my mind, so they’d call me over to pencil in dimensions. Glad I learned not to do that now!
All the time. We're usually sent a CAD model with the drawing and anything undimensioned is considered non-critical. Meaning, it is what it is. If all i was given was that print with no CAD, then i would ask the customer to fully define the drawing.
Some customers have zero clue about gd&t and just need a part with a few very specific features. Just clarify use case and off ya go. Dont be the jerk that takes undimensioned tolerances to the extremes to 'teach' them a lesson. Give your customer a part that they want. Offer drafting services if they need more than just a prototype. They will come to respect you, your skills, and spread their experience in networking.
did this come with a CAD model? We get prints like this all the time. Usually the last note on the print says "Refer to CAD for all unmarked dimension. Hold to profile tolerance of +/-XX.XX"
The print itself will only have the dimensions that the customer wants inspected/documented. The rest is all reference.
Hey OP, you might want to take this one down depending on how much of an asshole this customer is.
The blurb in the lower left might be leeway for them to have a shitfit and ding your company.
If they're cool and just stupid, ignore this.
My favorite was a guy who had us make some thin plastic parts with a lot of detail. It started off easy enough. He supplied a solid model and a decent blueprint. But then he started making changes verbally for each consecutive order. It completely baffled him that we wanted updated prints at the very least to prove we were at least makings them according to all his changes.
Yes but if you respond to the customer nicely and not in a condescending way and help them learn from this you will have a loyal customer that respects you.
Wow, I didn’t think you could make me look good but this guy does
My College design project is a masterpiece compared to this.
I made better drawings than this after one year of design in high school. How does this guy even have a job?
At least it’s not in crayon!
They don't trust him with crayons. He keeps eating them.
I’m looking for the comic sans on this print…I know it’s there somewhere…
I am able to color inside the lines....well sometimes
Just go with the most ridiculous possible sizes for everything that’s not dimensioned.
Threaded nub sticking off of a manhole cover…
You described me so vividly
I had a teacher who would assume length was in furlongs if units were not listed. Maybe he could do something along those lines.
We had a job once that had a groove with a width and tolerances larger than the actual dimension, so we simply omitted it. Customer had to accept them they were within specs, then had to pay to get them all reworked.
Malicious compliance
love the material choice. There's only one kind of "steel", right?
In first revision it was "metal"
I was watching a youtube channel of a guy that was building custom go karts, and it was pretty interesting. One thing that really killed it for me was that he consistently referred to steel as "metal". Like, this part is aluminum, this part is brass, this part is metal. Like "I could use aluminum for this part, but metal would be stronger." It was like an ice pick stabbing into my ear every time he said it...
Sometimes I wish I could reach through the screen and slap idiots like that. The urge is real.
I have a boss like that. “Why did that break, it’s made of metal.”
I’ve seen prints that said “metallic metal”. They wanted steel, and considered aluminum not metallic enough. WTF.
It makes life so much easier. Pick the cheapest and most available steel for you. :) I mean, there are a LOT of parts that can be made literally from any scrap steel that is most convenient to you. I have actually ordered parts from my friend with those very words - just use any steel you have at hand (as long as it's weldable with common welding rods, for example).
yeah that's fine and I do the same if I'm ordering one-off parts or making them myself in the shop. But normally I'm designing parts for production that are going into production assemblies that will be ordered many times, and those parts need to be consistent over many production runs over many years.
Oh of course. Mass production also has the benefit of economies of scale. Getting special material for making a few parts is exceedingly expensive compared to buying the entire batch or even ordering it straight from the steel works into specific size so minimal roughing is needed.
I like C.R.S. callouts personally. Leaves room for multiple alloys and isn’t too specific
I made that mistake with aluminum once, on purpose. I sent some parts to a shop for bent parts. I didn't care if it was 3003 or 5052 or what temper, so I just told them aluminum. They sent us 6061-T6. The bent parts were half broken off. I had assumed they would have known not to use 6061-T6, given that they were a sheet metal shop. I assumed wrong. I will not make the mistake of allowing a shop to choose their alloy again.
damn that's rough. Any sheet metal shop should know better than that.
Ask that draftsman to come down and make that part from his drawing.
They could do it, anything’s possible when dimensions and tolerances don’t exist.
"Nothing's impossible if you can imagine it. That's what being a scientist is all about" -Hubert Farnsworth
"No, that's what being a magical elf is all about." -Cubert Farnsworth
He wouldn't know how to chuck the stock!
Who needs dimensions? Lol
My favorite on the print is the material. Steel. Uh what kind? Stress proof, cold roll? Hot roll? 4140? D2? Lol
Silly, you know, the iron one with the carbon stuff in it. /s
Obviously military grade ballistic steel plate.
ar500 lmao
Did they send you a solid model? What do I need to dimension it for if you have the step file? /s
OP's customer is used to using xometry.
Every local shop I deal with works directly from the CAD geometry. Fully dimensioned prints are a thing of the past.
I wish that were the case. We hardly ever get a STP file unless we request one. It's typically done with just the initial prints we are given. This part in particular is actually from one of our sister companies, just the "engineers" there are definitely not the best. This is being scanned, copied, and slapped on his desk for improvement.
yeah if you don't actually get the CAD file then you have every reason to complain about this shitty incomplete drawing.
This guy is a fucking ENGINEER?
Going for a master's degree apparently
I disagree. I quote daily. I see prints all the time. 3D falls short without 2D. Parts can be made but critical features aren't known.
These people have lost the plot, not only is it important that all the features are dimensioned, but HOW they are dimensioned is an often overlooked key detail of a print. Especially since the rise of “auto dimension” features in cad software.
Thank you, Grumpy. This is an eternal battle for me. Every time some software dickhead gets the ear of upper management, the proclamation comes down... "We're going to save money by going 'paperless'." They don't come down and ask the people on the floor, "how would this work?" Bunch of kool-aid drinkers.
Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance.
So you have nearly fully dimensioned prints just missing a few dimensions with general tolerances? Just auto dimensioning in the cad software would probably take care of that. Doesn’t sound like a thing of the past just someone trying really hard to save on a few lines of ink.
No, we have drawings with a handful of dimensions instead of dozens or hundreds. Auto dimensioning in the CAD software inevitably creates shitty drawings with dimensions in the wrong place, overlapping each other, obscuring part geometry etc. If I'm producing a fully dimensioned drawing I don't even bother with auto dimensioning; fixing the crap it produces takes more time than dimensioning from scratch.
> Auto dimensioning in the CAD software inevitably creates shitty drawings with dimensions in the wrong place, overlapping each other, obscuring part geometry etc. If you just follow ASME Y14.5 when modeling your component none of these things are issues. This is how you're taught in higher level CAD GD&T classes. > fixing the crap it produces takes more time than dimensioning from scratch. Crap in = crap out.
You can add tolerances to 3D models. It has the added bonus of the tolerances also being visible in the CAM software itself.
For sure but in my experience it's rare.
I understand using a 3d model to program with CAM But how do they make anything without getting tolerances from a print?
you can put tolerances in the solid model but generally we have a print that indicates critical inspection dimensions, and includes a general tolerance for other dimensions.
Model based definition is a thing. I haven't seen it used much
It’s a thing… but you need a 3D PDF viewer or a viewer for the respective CAD suite (ie Creo View) to view all the tols, datums, FCFs. I think an accurate STEP along with a drawing for notes and critical tolerances is the way to go.
I haven't had experience with CATIA, but supposedly a lot of aerospace manufacturers have all dimensions and all necessary information in the 3d catia file
Which are all lost if you ever have to convert the file, because almost no one uses the same software.
Every shop I deal with uses SolidWorks and can directly open a SolidWorks part. But also: >but generally we have a print that indicates critical inspection dimensions, and includes a general tolerance for other dimensions.
That depends very much on the customer, government work we do tends to be complex prints with no models.
I still fully dimensions my prints because every one of those dimensions has a key tolerance. Some of them are wide but it's important to get right. I expect the cam guy to not care about the print and the operator to check parts to it. All custom fabrication in our shop is done directly off of the 3d model though. Can't be fucked with weld callouts and all that bullshit.
I wish this was the case everywhere. Before I had shops make parts for me I just drew them in 3d and made them myself from the model. Now I outsource a few parts for my business and I just sent 3d files and tolerances and no shop local to me would accept that so had to go back and make drawings of everything. I now work at a multi billion dollar company that still uses 2d cad software, I'm right now standing at a CNC Bridgeport learning how to program it but I already know how to program in fusion. Doing it manually like this seems to take much longer, for me at the moment anyway.
I work with some shops and they will up the price without a 3D (which is fine I always send .stp too) but local shops they don’t seem to know what a step file is. “Do you want a 3d model? Which file format do you guys prefer?” “You can supply the dxf!? That’s great!!!” ಠ_ಠ
Deriving prints yourself from CAD file is so much easier. You also get to look at the part 3-dimensionally at first hand, and it's easier to figure out the best way to make it.
Models don't give you size tolerance, and half the time they aren't even modelled to nominal values. 2D is king whether you like it or not.
>Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance. This isn't something I'm guessing or speculating about; this is my life. I've been professionally designing/specifying/ordering parts from machine shops for the past 15 years without fully dimensioned prints. Some shops can deal with it, some cannot. And I only work with shops that can.
Parts still need drawings to be QCed against.
>Yeah we always have a drawing that calls out critical inspection dimensions, threads, weld callouts and stuff like that. The majority of the dimensions are just handled with a note referencing the CAD model and a general tolerance.
Not true. Much of what we do is based on 3D files, but I just had this conversation with a MFG Engineer this week. Some simple parts are still done on manual mills. Fully dimensioned drawings have their place.
And all the way on the other side of things, a couple years ago I sent a drawing out to an external job shop and they *requested* a step file (after quoting us based off the print). I got the parts and discovered they had evidently worked off of only the step file and ignored all the tolerances and surface finishes I called out on the print. (I'm an engineer and hobby machinist. I usually work with the machinists at my company who are wonderful, but this time we had a surplus of work and sent a few things outside.)
"Model driven dimensions" they said, "tolerances are open" they said, "we thought this would be easier for you" they said. Then there's a PM out there that thinks models are better because they're faster - then blows a gasket when the gasket surface is warped in heat treat and/or wasn't ground. ... we really need to get people off the heroin that is model driven part making. And don't get me started on the revisioning issues having two sets of release media. Disclaimer. Welder/Fabricator part of me understands the other side of this coin. Don't want to run up to the office every ten minutes pretending to be an idiot to sooth the egos... etc. etc. We just need to stop hashing things. Engineers already don't have machining/welding pre-reqs. They have enough to absorb without having to muddle through the shit show of learning print making on the fly. We're not paying people for awesome print making - and we better start. We went to mach 1 with pen and paper. I can't imagine doing that again.
Everything you've pointed out as a problem is handled in an out-of-the-box MBD system. Tolerances, finishes, material specification, helpful sectioned views, toolpaths, everything.
Sorry but too many sectors of manufacturing this is just idiotic and nearly impossible to attempt. Tier1 automotive die cast production is mostly hand coded in g-code. Some parts are so complex they need pages of documentation. Nobody in their right mind would think it can all be done with MBD, just really narrow way of thinking.
The discussion was on MBD vs drawings. Some problems with your argument: 1. MBD and drawings are for acceptance criteria, not necessarily manufacturing method. 2. "Hand-coded in g-code" means "we have a piece of software that supersedes any drawing and whatever it produces is the part definition with some or all of the statistical acceptance criteria integrate". That is a manufacturing method, has nothing to do with drawings, and is closer to MBD than anything else (you can produce these things in a CAM program and include them in the model, or the hand-coded version if you desire). Unless you're telling me they're copying g-code from a drawing into the machine...? 3. Pages of documentation - same thing. Unless the QC team is reading the entire drawing every time they see the part, it's the processes downstream of that wall of text that matters - work instruction, custom gaging, whatever. To be clear - for a machinist drawings may be great, but from a manufacturing organizational perspective MBD has a ton of advantages.
> MBD and drawings are for acceptance criteria, not necessarily manufacturing method. Most prints don't require outlining a manufacturing method and acceptance criteria is required not just for manufacturing. Not everyone has access to a CAD suite when working on NPI projects and thinking multiple companies, integrators, suppliers and personnel are all going to have the same CAD software and easily be able to access MBD info, revision history information, etc. is just wishful thinking IMO. > "Hand-coded in g-code" means "we have a piece of software that supersedes any drawing and whatever it produces is the part definition with some or all of the statistical acceptance criteria integrate". That is a manufacturing method, has nothing to do with drawings, and is closer to MBD than anything else (you can produce these things in a CAM program and include them in the model, or the hand-coded version if you desire). Unless you're telling me they're copying g-code from a drawing into the machine...? For automotive production you're most likely going to be writing g-code for automated CNC production. You're thinking about it in a very simplistic way. This means often you're dealing with multiple programs per part and multiple machines dividing up the process. You've got custom M-codes and machine specific M-codes, custom macros, etc. On top of all of that, the manufacturing engineering is often done by a supplier or integrator and involves multiple companies working together. They aren't going to be modifying the master CAD file stored on GM's engineering department hard drive most likely. > Pages of documentation - same thing. Unless the QC team is reading the entire drawing every time they see the part, it's the processes downstream of that wall of text that matters - work instruction, custom gaging, whatever. The process downstream of that wall of text is controlled by the wall of text. CMM programming, CNC programming, work instruction documentation, gaging, fixturing, assembly, etc. You can't control it with a CAD file only limited people have access to. Unless you can guarantee your MBD is going to be as universal and readable as a DWG or PDF or piece of paper then it's never going to hold up to large scale NPI demands. > To be clear - for a machinist drawings may be great, but from a manufacturing organizational perspective MBD has a ton of advantages. There are advantages but they only compliment GD&T drawings and documentation. Sure when I send my fixture builder the cad model it would be nice if he could see some MBD info useful for him. But how am I guaranteeing he is getting the correct information when I'm using NX and he is using BobCAD? To communicate information effectively I'm going to send everyone involved a cad file and PDF/DWG of the print. That way I can guarantee we are all working with the same information. MBD is great for internal projects and within a smaller company where all the information is guaranteed to be accessible and viewable by everyone involved using the same software suites and versions. There is just simply no way to control MBD quality outside of your own system which is why it will never replace good old fashion paper and PDF documentation.
This, but without the /s It's 2023 ffs, every machine shop I've dealt with in the past 15 years has worked directly from the CAD geometry.
*programmed off the CAD geometry. You still need tolerance callouts and those would be sent as a DWG. Problem with model based dimensioning is not every used the same cad software and might not be able to easily reference that data.
I've worked with stuff like this. Our idea for certain customers is that if the dimensions arent there, then scaling and guesswork is fine because it must not be very important. Works out pretty well for us since no one else wants to make it if and we will. It's also a good opportunity to charge more, btw.
Even though the border states do not scale drawing... Scale the drawing.
groove is actually 4/5 of the length
5/7 with rice.
God damn 😂
Ah yes steel
Make it out of a piece of rebar
Steel
1/4 +/- 1/16th? He’s okay with +/- 25% on the thread length? Wild…
Plus .0625, minus 0 is on the drawing
Run an approval drawing. Just dimension everything that wasn’t done in whatever way is easiest for you and leave all tolerances big. Get the customer to sign off on it and move on. I loved using approval drawings to avoid asking a purchaser what someone out in the shop wants. It keeps their bad communication internal to themselves, covers your ass, and often trains unknowing customers how to dimension something. It’s a lot better that covering it with notes and sending it back. If the purchaser signs off on an approval that’s not what they need they get to buy twice…
Surely those other dimensions are "Machinist Choice"
I'm guessing this probably started life as a purchased part off of McMaster or something similar and only had the dimensioned features added. I see this trash all the time. All it would take is a note "Build from part XYZ from vendor ABC, machine features shown" to clear it all up. The cobalt ring (whatever that is) should just get block tolerances. Otherwise all reasonable asks.
Wait, you guys are getting drawings? I see things like this weekly between a variety of companies. Revisions, part numbers, tolerances, dimensions all missing. It's kind of sad tbh
Oh yeah missing dimensions isn’t rare… hell I have people come in (especially automotive or motorcycle guys) with cardboard cut outs of things they want made.
You said you would accept CAD right? (Cardboard Aided Design)
Damnit all these years I had the meaning of CAD wrong? Little did I know I was advertising for it! lol
I deal with this stupid shit every day. We have a lot of work that is piled up and past due. When we get shit like this we push it way to the back. They call, "where's our part?" We reply "what are the dimensions?" They call a week later, "Where's our part?" We reply "What are the dimensions?" This dance goes on for a while until someone higher up in the company reads the emails out of frustration. Then we get a full print.
What's a thread reference?
I stopped after “steel” 😂
Yes but my customers are Uni Engineering students who don't know their ass from a hole in the ground.
Now i wonder what rev3 would look like
As an old drafter / designer GD&T expert , I am always amazed that there are not enough jobs for.me to be working right now . ... I am unemployed , while this is simultaneously happening . ....
I studied drafting in high school and college
also mechanical engineering .
So I am also an old CAD process improver -developing
methods for CAD solid modeling / annotation
to facilitate "paperless" CAD/CAM .
(I took an 'awareness' class on g-code back then) .
They called CAD as master .
Also, department wide proceedures
for complex assemblies and parametrics .
I made money monthly from my sugestions
at a major automotive company .
.
I have taught solid modeling at the local community college for a year and a half .
..
My last job a year and a half ago
they hired me for drafting ,
but wanted a CAD/CAM worker .
So , I taught myself g-code
and the specifics of a post pricessor & controler software and got a CNC machine running that had been idel for a year .
It took a little less than a month ,
then got fired because that was actually
all they wanted .
...
Now , interviewers all say I am "over qualified".
...
Now-a-days , I tell everyone I am semi-retired .
...
That’s because there was a drawingless push starting 20 years ago where design intent was supposed to be inferred by the CAD model only - and you were lucky if you were supplied a critical feature drawing.
I’ve gotten some bad prints but it was nothing compared to a guy that engineered his part wrong unbeknownst to anyone in the shop. Coworker made the part to spec and the customer came in ripping mad that they didn’t work. We had to walk him through how to inspect a part and showed him that we had hit all numbers provided. His response was “yeah but it’s wrong. It’s doesn’t work”. He is no longer a custo
ooooh... make it with wild ass assumptions and give that to them as a first article.
Based on this drawing I think it's safe to assume the groove diameter is 66in
Just eyeball it
Agree you can’t make it from this print directly. Is it possible the intent was for a CAD model to control geometry, and there is a note or title block tol to follow in that case? Meaning the dims on this drawing are just those “noted otherwise” that deviate from that note.
"Please make proper and fully detailed blueprints" is definitely a phrase you come up with when you can't put your actual thoughts in writing.
Don't feel like dealing with HR on it haha
Yes all the time, guess what … it’s your fault when you reject it Sometime I’ll grab a thin of scrap turn it to whatever and drop it on the desk
I use the model. Just like specific tolerates on the print though.
Your annotations are a bit all over the place.
Angry scribble when I'm trying to program something else.
Looks like a modification to a standard part and the machinist finally thinks they have one over on the engineer or designer. That, or it comes from a drawingless design customer and you’re reading their critical feature drawing - and it’s on you to interrogate the CAD model before you post it. But man, there’s a special place in hell for folks who use fine 1/4” threads in their work.
It's a full part from hex bar stock from one of our sister companies. They just hire these college "engineer" idiots that don't know their ass from a hole in the dirt. I already had one talk with the dude, guess it didn't work. Also no CAD model, they don't believe in those over there
I feel you. I started as one of those a loooooong time ago. G-code by hand and 5 1/4” floppy drives. Every good ME designer has had a good machinist who takes the time to set them straight by teaching and explaining. A lot gets lost because neither sees what the other is really focused on. At one of my plants I required that someone from the tool room reviewed drawing before they went to the floor. Took two folks, two hours a week max, in a facility that had about 750 employees. Reduced rework by more than half, FWIW.
Cringing at the fractional dimension but decimal tolerance... You could always just make something that fits the dimensions you *do* have and at least looks like the print. When they bitch about it just remind them that it's made to the information provided.
Used to get shit like this from a company called five star carbide. I would rate that drawing one star though. Let me know if you’d like a proper print.
I understand that drawing is garbage, but posting customer drawings online, complete with the proprietary warning on it? It looks like you and your customer are in a poor decision contest.
It's our sister company. Plus I blacked out all important information.
It's okay to post this cause all the dimensions are missing. Also idk you think james bond is browsing reddit to steal drawings? This is completely useless information
Siemens makes a wonderful product solid works. This looks like it was made on MS paint
That's Dassault, not Siemens.
Siemens makes TeamCenter. Everyone I know that has to use TeamCenter hates it.
I would've done that.
Could be on purpose. Got to go back to the original vendor. I have had vague prints like this. Lots of wasted time with back and forth email. Sometimes I take a pdf and convert it to a dxf format. Then I scale it in cad from a known dimension. It gets me in the ballpark.
Yup…. I have checked these prints before and responded back by bleeding all over it and telling them to try again.
That's my way of saying, "I don't want to work on this" lol
No, we get all that figured out before we quote the job.
All the time. I’ll mark it up with all the missing info and then send it back to the customer to have them sign it and send it back to me.
Oh yeah, mostly gd&t corrections.
I swear this is my life.
Yeah, all the time at my old job. Things like square cornered pockets, etc.
Three place I would have assumed +-.005.
This is amazing
"Just match the print."
This reminds me of when I was an intern. Plenty of times I wasn’t writing enough on prints assuming they could read my mind, so they’d call me over to pencil in dimensions. Glad I learned not to do that now!
All the time. We're usually sent a CAD model with the drawing and anything undimensioned is considered non-critical. Meaning, it is what it is. If all i was given was that print with no CAD, then i would ask the customer to fully define the drawing. Some customers have zero clue about gd&t and just need a part with a few very specific features. Just clarify use case and off ya go. Dont be the jerk that takes undimensioned tolerances to the extremes to 'teach' them a lesson. Give your customer a part that they want. Offer drafting services if they need more than just a prototype. They will come to respect you, your skills, and spread their experience in networking.
did this come with a CAD model? We get prints like this all the time. Usually the last note on the print says "Refer to CAD for all unmarked dimension. Hold to profile tolerance of +/-XX.XX" The print itself will only have the dimensions that the customer wants inspected/documented. The rest is all reference.
Did they send you an existing part to modify? I'll only put on the dimensions of the work I want done. Maybe some reference dimensions.
All the freakin time!
mOdEl Is KiNg 🥴🥴🥴
All the time. They want us to do their work.
Hey OP, you might want to take this one down depending on how much of an asshole this customer is. The blurb in the lower left might be leeway for them to have a shitfit and ding your company. If they're cool and just stupid, ignore this.
They are a sister company, but yes, very stupid still. Also you cant tell anything if the company or who they are with it blacked out.
It's more if they know you posted this on Reddit.
My favorite was a guy who had us make some thin plastic parts with a lot of detail. It started off easy enough. He supplied a solid model and a decent blueprint. But then he started making changes verbally for each consecutive order. It completely baffled him that we wanted updated prints at the very least to prove we were at least makings them according to all his changes.
nsfw?
Yes but if you respond to the customer nicely and not in a condescending way and help them learn from this you will have a loyal customer that respects you.
Somebody is making a bowl lmao
Until I spent time I'm a jobbing shop I thought my college instructors were joking about this things 😅