yang686526

how the present a "liner"
hi,
today, i prepared an assembly drawing in which basicly two pieces will be assembled together, the problem is, there should be a liner material in between. the thickness of the liner will be at most 0.1mm. so, what i did is, in bill of material on the drawing i gave the three components, i.e the two pieces that will be assembled and the liner material. but on the drawing i only put ballons to the two pieces, and in the notes i wrote, "before assembling part 2 to part 1, the liner will be applied to the part 1 according to the document xyz. " and i did not put a ballon to the liner. and this caused a little (!) argument with my project manager.
so is there a problem in what i did?
because of the argument, i was asked to prepare a formal report on this problem. so i need to refer a standart while explaning this. could you please help me?
thanks in advance...
the title should be
how to present a "liner"
sorry...
i don't see a big problem with what you did....
if document xyz clearly identifies things like:
what side of part 1 does the liner go on?
does the liner go on the entire surface of part 1? if not, then where?
does a specific side of the liner have to be against part 1?
how does the assembler determine what thickness of liner to apply?
is there any surface prepartion of part 1 or part 2 before the liner goes one?
are then any time, temperature or other process constraints?
after the assembly is complete, how can you tell if the liner is there?
of course all of these questions apply regardless of the existence or non-existence of a ballon on the drawing.
all parts and materials should be listed on a bom and balloons called out. materials such as your liner would be listed including any epoxies, solders, etc. the quantities for these materials can be drawn to show size, listed in weight or ar (as required). these are just some examples.
ever do any military dwgs? all materials are listed.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 06
the guy who buys the liners doesn't read the drawing notes, and doesn't dig out referenced drawings. nor should he be expected to do so.
so when your assembly reaches the production stage, there won't be any liners available to assemble.
mike halloran
pembroke pines, fl, usa
thanks for your replies...
well, document xyz clearly identifies the details.
i agree that all the materials should be listed on a bom , but does it really necessary to put a balloon for every part/material listed on a bom??
thanks.
yes. have ever assembled something that listed the part but didn't show you where it goes?
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 06
thanks chris,
is there a reference document on this?
here another example, say we are going apply an adhesive before fastening it, in bom we listed all three parts, i.e the part 1 (the body) part 2 (the bolt) and part 3 (adhesive, loctite 410 etc) and in the notes we said
"before fastening the bolt apply 1 gram of loctite 410 to the threads, then fasten the bolt using ....., the applied torque should be 5 nm, wait 6 hours before any futher operation"
should i put a "balloon 3" with the arrow pointing the threads on the drawing?
information like that can get lost in an assembly drawing. your bom and associated asembly drawing just defines the components and their spatial relation to each other. if something like torque and loctite application is critical, you may want to create a new document. they have various names- process sheets, assembly procedures, etc.
art without engineering is dreaming; engineering without art is calculating.
steven k. roberts, technomad
mike correctly points out that the purchasing department doesn't read the drawings, they just buy what is listed on the bom. you've got your liner listed, so no problem there.
for things like loctite i've seen either an item number call-out along with the hardware, or a note with the hardware call-out, or both. the note either needs to spell out the correct process for application, or refer to a document that does. since you must have the process info, the item call-out seems redundnt, although i would include it.
one other thing to consider is, do the assemblers work to the drawings, or do they work to a work instruction?
there probably isn't a standard which states that, in your situation, what you did was right. which also means that their isn't one which says that you were wrong.
however, there is the "unwritten" standard that any drawing must contain sufficient "idiot-proof" information to clearly and unambiguously convey its intended message.
i am guessing that the liner was omitted in one or more assemblies & that you are being blamed for underestimating the quality of "idiots" the company employs to assemble its product. just when you think you have an idiot-proof solution, better idiots appear.
in future drawings, i suggest creating cut-aways so that the liner is clearly visible, even shaded if necessary. if ballooning, either show [u]everything[/i] ballooned or nothing ballooned. no halfway measures. and don't forget you can use stacked balloonsfff">. (if your cad program allows).