I was curious why the “Titan Parts” available for practice lack GD&T (Geometric Dimensioning and Tolerancing) on the print.
Isn’t GD&T critical to “How” a part is machined. It may be just me and the work that’s around my town, but if you don’t understand the fundamentals of GD&T, you parts will not go out the door.
In my opinion, Prints with out GD&T, do no inform the machinist properly, as to what the designer/engineer’s intentions are with regard to FORM, FIT and FUNCTION of the part. In my experience. when GD&T is applied correctly to a feature, a machinist is able to bring the workpiece into FORM correctly, the parts then FIT properly, and lastly Function as intended.
What do you all think about GD&T?
Is my opinion “overrated” ? haha
Do you seen GD&T at work on the daily like myself?
GD&T applied wrong is horrible. There are too many engineers that do not understand GD&T and create parts that are more constrained than needed. There are some good GD&T drawings. A stand alone part that does not mate or fit something else does not need GD&T. I have found more often than not, having to call the engineer to see what is acceptable. Disclaimer, I would be lumped in with those engineers that do not understand GD&T as well as I probably should.
I get where you’re coming from. Yes in industry there should be a better understanding of GD&T.
But I don’t agree…
GD&T can be and should be applied to a stand alone part. It’s not only about how parts go together. But how the FUNCTION in FORM.
For example a laser optic mount. The optic rest against the mount in some fashion. But in order for the optic to sit squarely in the mount. Some sort of GD&T is needed to explain how that optic should sit. So the GD&T would explain how FLAT or PERPENDICULAR or even the true position rested to another area of the part let say an out side wall.
I’m probably losing because we don’t have a print to both look at.
Is there a way to post pictures I can draw something up.
You can insert images in your text box. It is html capable. A nice example of a drawing without GD&T are the Rocket Series parts. There are ten parts making one assembly. The part serves no other purpose but to create an assembly of parts, it (assembly) has no further interaction with any other part. Can it be GD&T’d, yes, but constraining the part with GD&T could make it more expensive to manufacture because of inspection methods or equipment utilized.
I guess what I’m getting at is yes your rocket will screw together, but you all are trying to teach how to machine PRECISION parts, right? If a customer brought me a part requiring full 5 axis work. I can almost guarantee you that there will be some sort GD&T on the print. Even if all there is, is a datum called out.
I read your profile and you should understand what I’m getting at.
GD&T describes the FORM and FUNCTION along with the FIT if need be.
The “aerospace connection” parts have GD&T on the prints, those parts are basic line fittings correct?
You say there"s not a need…?
If you don’t understand GD&T your not machining HIGH precision parts then i guess…
You will probably find they just have not had time to get the advanced stuff completed yet, you have rember titans doing this as skill base from nothing to something. He may be doing the GD&T as its own thing
I guess my issue is this.
I’m not the hiring manager here but I am the lead foreman for the Rapid Prototype Cell.
I’ve had a few guys now apply with the claim that they can successfully program a part requiring up to full 5-axis or some mill turn. GREAT!!! what we need!!! So i give them a print…
I ask about a 3 axis setup, I asked how they will relate a critical bore and c’bore, that are on the direct opposite side of the related datum (A) on this cube shape part. Datum A is called out with a flatness and profile of .002inch and the Bore C’bore are true positioned to .001 at maximum material condition.
To my surprise they didn’t understand a single word I asked…
They didn’t get the job unfortunately.
These types of FORUMS can be a great resource BUT the forum can also be misleading…
Its great to be able to learn to set-up a mill and lathe. I’m only recommending that maybe when @Titan
and his team are going thru their routines they explain why set-up is so important and needs to be PERFECT because they may be creating a direct geometric counter part.
I’ve learned that SET-UP is 85% of the job. Tooling and Programming make up the last 15%
We need to learn not only how to run Incredible tool paths but also how to correctly bring a work piece into form.
Forgive my frustration. Honestly I need true Machinist not just CAD/CAM professionals maybe…
GD&T, Metrology and Experience in both through repetition is everything. Also, there are levels to all… are you Machining and inspecting 4X4 parts or Aerospace parts under strict AS / Customer specifications.
When it comes to this Academy, I think we have to keep a few things in mind. First, it picks up on the ground level for a person who does not know anything. We start with Building Blocks projects and actually teach you how to design, program, set up a CNC, including Stoning a table, installing a vise, indicating, zeroing tools and fixtures and everything else needed to set up that specific job… with a check list that you have to go through before your able to dry run a part 6” above stock… videos teach everything, and holds teachers and students accountable. One the part is run and comes out of the machine you take your “FA” first article inspection sheet which was designed off one we created for SpaceX… and the students has to fill it out completely checking and documenting every dimension and call out… the teacher then signs each dim off.
So, now, the student has a problem… How do you check and document the part? That’s when the teacher introduces a caliper or mic, depth mic, thread gage etc.
The students learns quickly because he or she actually designed and programmed their own job and thus are intimate with every dim on the print.
Now as the parts get more complicated inspection and set up also gets more complicated.
Need to keep in mind that our Academy is still an infant and all will be covered in great detail. You can find inspection documents in related files to the right of each project.
Now, as I see more and more of your posts, it’s starting to look like your complaining, without actually doing your homework… and this your putting stuff out there that’s simply not true and starting to waste my time.
I am with my family right now but will answer this also. Set Up is huge and Fixturing is an Art. That’s why we created the “Art of Fixturing” where we teach about base plates and sub plates… many different types of clamping methods etc. The students learn different types of techniques… this has never been taught in school before because the curriculum didn’t exist, unless a specific teacher designed it for their specific class.
Have you seen all of our Fundamentals videos that we are creating? Videos on absolutely every aspect of set up.
You are completely right and I need to apologize.
I did jump to conclusions based on my own brief browsing of courses and such.
My intentions are maybe miss-understood, I asked a question about GD&T (not knowing the infancy of the courses) and why the “higher” level parts lack such on the prints.
The answers from the “host” were lacking in knowledge.
I have to honest I jumped to more conclusions and let my “passion” I’ll call get the better of me.
Ive watched your videos and they’re good. Really GOOD actually.
You’re post a bit ago led me to dig more and as to why I’m apologizing.
I never thought I’d be the grumpy old machinist.
I’d hate to be tagged as the GRUMP so if I may still lend my experience to an open ear.
I’ve come to realize that this is something other than a “practical” machinist forum.
MarcusMasrid, Upskilling and repetition is the name of this game.
There are a lot of people on here that need guidance from the older members into what works and what you know from years of exprecies does not work.
What I have seen so far haveing the GD&T on the high level stuff works as they get close to doing them the modeling and cam is at a level where it makes it easy (this is for the non uni or school guys that just don’t know what gd&t is to start with).
@MarcusMadrid my reply to your original post question “I was curious why the “Titan Parts” available for practice lack GD&T (Geometric Dimensioning and Tolerancing) on the print.”_ was probably best explained by Titan, in that at a beginner level where the new student is learning so many processes of CNC, a non GD&T drawing will help introduce them to basic inspection methods. After learning how to use those basic measuring instruments and experiencing the machining process and work holding methods, then more difficult measuring and inspection techniques can be introduced. The building block series is an excellent method.
I should have been more specific with my other responses and rationale. My other comments about GD&T being applied wrong matches your comments, that many drawings generated by engineers/machinists/draftsmen utilizing GD&T are often wrong and do not match the intent. Even today, there is accepted two standards for GD&T (ASME and ISO) that have differences of interpretations. GD&T is one of the most lectured instruction with hundreds of different presenters, that exponentially create more interpretations of the design intent. Do I believe it is important to understand and teach the new students about GD&T, my answer is Yes. My first experience with GD&T was in the seventies, following a revision that was so bad, everybody had difficulty matching up. Even the 1982 revision had discrepancies among professionals. Our problem with our industry, there are still working drawings out there that have not been updated, many not utilizing GD&T. Getting everyone onboard and all drawings updated will probably not happen in my lifetime. Yes, new drawings should be following the latest revision of GD&T practices if they are to be used to manufacture a part. The reason we revise the standards is because thru practice we find the debatable interpretations and improve the standard each time to improve the necessary communication needed at the shop floor. I am no expert using GD&T, nor am I a novice, I hope I never quit learning and will always seek ways to continuously improve.
More like the engineer. Even the primes can over engineer parts.
I also remember noticing the lack of GD&T on the prints in the Building Blocks, but I appreciate its simplicity since I’m just a beginner in CAD/CAM and trying to get straight to the point.