technical design

[Greta99]

I am new on this forum, I wanted to ask you for help on an exam I have to give technical drawing, the exam consists in drawing a particular and assigning quotation, tolerances and roughness.
I have long studied (and I am continuing) how to put roughness, tolerances and quotas and know that 90% depends on the type of object and function, and here comes a first question, where can I look for how to assign certain values to important pieces?
Moreover I would like to know how I can make to understand how to draw the parts of the particular when I have the overall, how do I "imagine" how the particular is done, there is a way to better understand how to draw the particular?
I have many gaps on the drawing, I followed the course 2 times and the professor unfortunately from many things for granted that I do not know so I hope you know to disappoint me a little more everything, even banal comments are well accepted
Thank you in advance

 

[Vittorio]

Hello Greta99
Maybe you better put some picture of the job you were assigned.
Just so we can figure out what to recommend.

start posting some pictures of what you have already done

about .. when I have the overall, how do I "imagine" how is the detail that I have to draw ... in this case the total must give you all the information to get your details, you do not have to invent almost nothing

 

[Greta99]

This is one of the last exams, it was necessary to draw particular 3 , but the difficulty in some exams is greater

 

[Vittorio]

bhe.. You were lucky, it's a simple piece
as soon as you can, send the image of what is according to your logic.
also a hand sketch.. It's fine.

 

[MassiVonWeizen]

the subject of the technical design has been treated countless times and the extrapolation of a particular from an overall was also treated.
in the forum find some dispenses of Mr. Galluzzo in which the technical drawing is explained (the link Direct)
an object is listed according to the function, so you have to ask what the total you have in front of or, reducing the analysis in the specific case, what the particular 3 serves.
always in the forum it is explained that to extract a particular from an overall like this one must consider, and know, that two adjacent details have different fields, by direction or by size, besides the fact that some elements (pins, gears, tabs, viteria...) do not dissect if not partially.
said this print the design and with the highlighter marks the contours of the particular 3 keeping in mind the concept of the samplings; then make the table as if I had to introduce it to the teacher and allegala that comments together.

 

[MassiVonWeizen]

I know that 90% depends on the type of object and function, and here comes a first question, where can I look for how to assign certain values to important pieces?

I add a comment to this phrase: 100% of the details should be sized according to its function. However, you must initially dimensional, i.e. insert the quotas, for its construction and then there must be all those for which whoever takes the design for the first time knows what size has every single area of the particular.
then enters into play the functionality that allows you to spare as areas of the particular and consequently that dimensions must be tolerated specifically (remember that for the un tolerated size is the en-22768 iso-2768 regulations that defines the deviations for dimensional range) and with what precision; roughness is a direct consequence of this precision.

 

[MassiVonWeizen]

some discussions that might help you

https://www.cad3d.it/forum1/threads/quotatura-e-tolleranze-di-un-complessivo.57753/https://www.cad3d.it/forum1/threads/tolleranze-geometriche-di-un-complessivo.57747/

Tolleranze geometriche di un complessivo

Salve a tutti, mi presento, sono Luca, studio ingegneria meccanica presso l'università di tor vergata e questo è il mio primo post sul forum. Sono alle prese con un'esercitazione su tolleranze geometriche sulle quali ho molte perplessità riguardo sia la rappresentazione che il loro utilizzo. Mi...

www.cad3d.it

Estrazione particolari: disegno industriale

Buongiorno a tutti! Sono un nuovo utente del forum, studente di Ingegneria meccanica ai primi anni e quindi al primo approccio con il disegno industriale, solo su carta per il momento senza l'ausilio di software da disegno. Mi perdonerete nel caso, non ho ben capito se ci fosse una sezione del...

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[Greta99]

I don't know.

 

[MassiVonWeizen]

I don't know.

I'd say no. even as proportions
as I said, print, or alternatively open with paint, the overall design and track the contours of the object considering that the nut is screwed on the particular 3, what you have to extract.

 

[Greta99]

.

 

[MassiVonWeizen]

That's right.
edit: mi correggo, the terminal part of the pin must be corrected, where the nut should be screwed.

 

[MassiVonWeizen]

being a low nut, position 16 of the distinct, what you see under the hexagon is not a collar that is part of the nut, but it is part of the pin from which it is deduced that narrowing is a threaded discharge throat.
detail not easily recognizable for a student who does not have much experience of overall.

 

[Greta99]

Can I therefore deduce that when there is this "double line" it is an exhaust throat?
then if I do not go out on the trees after there is a hole for the tongue you do the drain throat
in general where it is "obligatory" and necessary to make gorges? so that even if I do not see the piece well I can deduce that there is a throat

 

[MassiVonWeizen]

Can I therefore deduce that when there is this "double line" it is an exhaust throat?

No, because there is no double line.

and I do not err on the trees after there is a hole for the tongue you do the drain throat

a tab does not need a hole, but a seat which in this specific case is semi-rounded for a tab uni 6606. and never requires an exhaust throat

in general where it is "obligatory" and necessary to make gorges?

There are thread and grinding exhaust gorges which are standardized

 

[Greta99]

Thank you for all the clarifications you're giving me.
I have another question, for the section of in particular, how should I move? I'll explain better if the piece doesn't know how I know how it's done inside.

 

[MassiVonWeizen]

i'll explain better if the piece doesn't know how i know how it's done inside.

reading the drawing. if the detail to be represented has an internal geometry is highlighted by section or with lines drawn to indicate hidden entities; if neither of them means that the detail is full to you. in your case you have everything you need to represent also the inner part of the pin

 

[MassiVonWeizen]

@greta99, don't take it, but a week to make a pin like this is definitely too much. even the timing of your interventions, one per day to ask all things trivial, from the idea that you do not care or expect the drawing already made.
If this discussion has for you lost value maybe it would be worth reporting it.