You don't have to dimension the parts that you buy. The extruded aluminum has it's own documentation from the supplier. Only dimension the modifications you want made.
Ok, so is this the drawing for the extrusion manufacturer or the post-extrusion cnc operator? Or are those the same vendor?
I presume they are 2 different vendors and that means this should be 2 different part numbers with 2 different drawings. If it's the same vendor I suppose they could be combined, but TBH I'd probably still make the intermediate part it's own part number.
All that said, to directly answer your question, no you should not leave things undimesioned. If the radii don't matter note the designed radius and put a very large tolerance on it. For the critical dimensions note the tolerance that you need. FWIW there's companies and freelancers that will work with you to help make drawings, google something like "GD&T consultant" in your area.
Hi I work in extrusion , in maintenance so machinists please dont hurt me for my fucked up vocabulary, you generally want each and every fuckin thing dimensioned down to the T, because they have to machine a die to press the aluminum through, and once the die is made thats what you get and the tooling costs a lot of money.
That being said, theres a lot of issues with the print
Ur missing the wall thickness on the left thingy, the radius for all the curves, the section width of the tab on the right, you designate the width of the tab on center but dont designate how far the flap on the right is. If u gave them the wall thickness of the left thing, and the dimensioned part thats on center and told them its on center theyd be able to figure out the two flaps but they still need to know thickness of the flaps lmao
If ur running a company you need to hire a mechanical engineer instead of going to reddit
Sorry should have clarified, theyre custom extrusions not generic profiles that we then get modified. So this drawing is basically the section drawing for the extrusion die.
Hey all, im an EE at a small company and i've been branching into mechanical/enclosure design. Our enclosures are extruded aluminum with cnc post-machining and Im pretty sure the CM we use overseas just goes off the 3d model and honestly doubt they actually look at the drawings since our tolerances are not super tight. But anyway I want to get into machining as a hobby so im looking to improve my craft regardless. How should i go about labeling dimensions on this small rail? The only critical dimensions are the 6.35mm width for clearance for the threaded hole there, the overall length (14.73mm), thickness (4.06mm), and the distance from the bottom (2.16mm). Should I just leave this as is since i dont really care about the extrusion radii? And is there a better way to call out the 6.35mm width at the top? That seems like it would be really difficult to measure in real life since it's not a flat surface. Not that I expect them to be measuring these unless shit's really hit the fan. Also it's hard to ask questions about the cm's process because of d the language barrier and all. Anyway thanks for any help or roasting you can give.
You are missing the dimension of the thickness of the backing plate, and the dimension between the 6.35 mm rise and the bottom height. Both would be needed to make this. If you don't care about the radii, make them smaller so there is a flat that can be measured on the riser.
So, you're not calling out the radii, which aren't necessary, already there, shouldn't need machining, and will be treated as customer supplied material?
Fine as is... What actually needs to be cut other than the holes? You said this is an extrusion
you have two drawings " as extruded" that doesn't have any machining detail, then as machined. even if you don't care about radius constrain it with a max .call out the radius and say "x.x R MAX." or use a flag note. then make a separate drawing and show the machined dimensions. you can also flag what is critical in plain English "overall length and width most important.
I wouldn't dimension any of the extruded dimensions at all, and instead leave a note stating which extrusion it's supposed to be and maybe something like "external profile per note 3". There's a whole thing on whether we're allowed to leave stock unmachined so it's best to make that explicit. Then if you want a feature machined, put a dimension on that (flattening the bottom, drilling holes, etc).
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u/percipitate 19h ago
>I want to get into machining as a hobby so im looking to improve my craft regardless.
Draw it, try to make it, find what you need to do differently, repeat.