Engineering Students

hum

hey just wondering what you all think of this years project!? the "marble machine"
many teachers in my school seem to agree that its the hardest one yet...
typical

yawn

last year i had to make an amphibious project

don't mind what the teachers say, every year they say it's the hardest one yet

Gone West

Yeah it was extremely hard. Only 1 or 2 people in my school actually got theirs to work.

Brendygg

did ye use pumps? i used a helix/screwlift it works perfect sud get an A hopefully.most of the lads in my class used pistons.all are working. what did ye make?

hum

i used a helix screw lift for mine too, then i split two tracks and used like xylophone steps for the novel destinations.
it works! loads of people in my class used the chain and bucket type lift,one used a ferris wheel kinda thing and one used pistons.
has anyone got any pics of theirs?

Brendygg

i just have mine going to 2 destinations.i took novel as "Strikingly new or different" dats wat a online dictionary said. so they cant take marks off if i have that in the brief.talkin of briefs how many pages[excludin headinds!] do ye have.iv about 25 and 5-6 pages of drawings.

ill have pics up in a few weeks bro has the digital.did u see the web page eddies mind.dats where i got the idea.

next thing is to try n get 20 plus percent in the practical we had a mock practical, 6 hours, very helpful.now know how to use time properly in the real 1

Errant11235

In hindsight I made mine far too complicated. My first thought was to use an Archimides screw type mechanism quite easy; but the brief did say a "lifting pump". In the end I decided on making a pump which runs off a motor. This in turn, inflates a balloon inside in a 65mm clear persex pipe. I then rigged up a piston type thing with the marbles going vertically. They then roll down a shoot when they come to a certain height. The first destination is on the shoot, simply the marbles being stopped by a "stopper" type yoke. The second dest. is just a tray.
For the two indicators I used an LDR (when the marble covers it, a LED is turned on) and tilt switch (I had they tray on a pivot).
Overall I wasnt too pleased with it. It barely works but looks quite good. Thankgod its only worth 25% of the total marks!
Anyone any ideas on what the day practical is going to be like? What sort of thing is it typically? It seems like a door lock type mechanism to me.

Gone West

Had my practical today.
It's a cam type yoke.
You need to file out a slot, so bring a junior hacksaw if you don't have them in school (we didnt!) Its very very easy. My teacher said it was one of the easiest ever. The two brass yokes move in different planes (X/Y) when you turn the big lathe piece.

If you are doing the practical, you will know what I mean!

OTOH, i used 2 rubber belts (inside of motorbike tube) and set them turning upwards diagonally, really slow. The marbles are gripped between them and are lifted upwards. I didnt have time to fit a motor or electronics, though because I was in the USA in feb+march. Still my teacher says you get an auto matic 50% for just handing up a project.

Brendygg

our practical is on next week.
any tips on marking out pieces any tricky things in it.from the amount of pieces we got i thought it mightnt b too hard.did urs work

Gone West

everyones worked(30 people). except for some idiot doing pass, who wouldn't know a file from a firebrick.

No, It's not really tricky. Just make sure that you do the aluminium bit well. Also, make sure that your plastic bits are at least 6mm thick. It would work better if they were thicker, like 8mm. Also, have a can of wd-40 handy, in case it gets a little sticky when you finish it. Also, make sure that your big lathe piece is *exactly* as the brief says it should be. If the front bit is even a mil too short, you will have to make it longer.

Brendygg

sound out. theres only going to be 10 in the room so it wont b packed. checked the big lathe piece and its spot on.the brass lathe piece is .2mm short but i doubt it will make a difference.

thanks for all the info any.

Gone West

the centre gap in the brass lathe piece has to be wider than your aluminium piece. because the brass pieces fit into slots in the aluminium and slide. the brass pieces have to slide!!! it fits like this -][-

the - being aluminium
the ][ being the brass bit
(cross section)

Brendygg

well,

checked it out doesnt fit will make a new one.twill only take 5 mins.thanks for that cause id be sickened if it dint work cause of that.

since there only 4 pieces id say its goin to be marked hard.theyll probably looking for accuracy,hopefully twill b grand.the mock practical we did a few weeks ago was a real help time wise

Gone West

make it nice and loose.
Also, make sure that those plastic bits are *at least* 6mm thick. If they are 3/4 mil, it wont work, at all.
Good Luck

Brendygg

ya they are 6mm