need help for coursework? design?

[ash-kennard]

I have been instructed to research "information about materials, processes and constructions that could be used in the production of the product". my product will be a bicycle frame made from aluminium at the end, but i need to know what the process is for making a frame. will be a similar design to the echo control 04/new pure/caisso.

help will be much appreciated.

[tomacropod]

well first they dig the bauxite out of the ground in western australia. From this the company Alcoa make aluminium, which is then formed into assorted aluminium alloys by adding other things. u6 or whatever proprietary name they give it is one of the alloys made. This is bought up big by a factory in South east Asia called Pulo. They extrude it into tube and tube-like shapes, and weld a bicycle frame out of it.

Someone else can do the design bit.

- Joel

[ash-kennard]

thanks alot matey, but i've heard of heat treating too, what is that about.

i know about the design aspect, and how to draw it up, i just needed to know what was involved for making it thanks.

[tomacropod]

well heat treating typically happens after the frame is built. Bascially it involved heating the entire, welded frame in an oven to a particular temperature. At certain temperatures the molecular structure of materials changes. At this point you can either let it cool down naturally, which allows the molecular structure to go back to pretty much the way it was, or you can cool it down quickly, which will "freeze" the molecular structure in a particular arrangement.

In the case of aluminium and steel and probably many other things, this rapid cooling will make the material harder, more resistant to deformation, scratching or denting, but will also make it more brittle and less able to absorb vibration or shock without fracturing. Consider the difference between wood and glass. Glass is hard, but brittle. Wood is soft, but doesn't shatter (it's not brittle). This is what heat treating is generally about.

For instance I had an aluminium frame modified - I had a disc tab welded onto it. The tab was plenty strong, and wasn't about to crack, but as it wasn't heat treated after the modification, the new material was soft and it deformed with the pressure of the disc brake and the bolts holding the brake on. This sort of deformation is almost never seen on correctly heat-treated frames - they fracture or crack instead.

- Joel

[ash-kennard]

thanks alot for your answers, they are going to come in very useful and i am very appreiciated

[tomacropod]

I can only presume that you're right.

- Joel

[jmkimmel]

I have been instructed to research "information about materials, processes and constructions that could be used in the production of the product". my product will be a bicycle frame made from aluminium at the end, but i need to know what the process is for making a frame. will be a similar design to the echo control 04/new pure/caisso.

help will be much appreciated.

There are also CNC machined or forged bits that make up various parts of the frame (specifically dropouts, chainstay yokes, brake bridges)

http://en.wikipedia.org/wiki/Forging

http://en.wikipedia.org/wiki/CNC

Or...for a more Specialized approach, there's always cold forging :bigthumb:



Lastly, don't forget paint/ano!

[xALmoN]

Hehehe, hydroforming too.

[capin]

They extrude it into tube and tube-like shapes.
- Joel

Are you sure about this bit?
From what i have always red, bike manufacturers buy premade tubesets. stock ones or custom made especially for them. Then some of them manipulate them further.. bending, ovalizing, hydroforming...
But its the Alcoa, Easton, Columbus, Reynolds companies ,that actually make tubes.

cheers
jan

[kieldp]

Tomac,
To be correct... Alcoa mine bauxite which they refine into Alumina not Aluminium and then send it to be turned into aluminium ;)

[tomacropod]

oh ffs. I was being general. Anyway Capin, I'm not sure if the larger factories extrude their own tubesets. Given how far they are from standard diameters and buttings, I would imagine they do. Tubesets from easton, columbus etc tend to come in standard outer diameters (34.9/31.8/28.6 etc) which are smaller than the tubesets on these damnfangled trials bikes of y'alls.

- Joel

[stocktrials]

is there anything joel doesnt know? honestly
amazes me everytime

[capin]

Well, im not sure either, but my guess is that its just too much work for bike company.
I dont think they do it in house.
In fact, most of bike companies dont even make things such as dropouts! Concerning alu makers. I think they do all sorts of things. Not just plain tubes. One example on the top of my head is easton's RAD tubing (rectangle to circle profile)
Cannondale uses Alcoa. And its Alcoa that makes special pyramid downtubes for them. They even make special type of aluminium for them! optimo.
A lot of things are done using hydroforming these days. But even this i doubt that its made inhouse by bike companies. I think that they just send drawings somewhere and then truck with finished tubes comes..

cheers
jan

[Rodmunch]

I worked at Mountain Cycle during summer 2000 and they did alot of their own forming. However, since their frames were mostly monocoque designs at the time, the only real forming they did was with sheet metal.

The owner designed and built his own hydraulic press and forming plates, so all we had to do was cut out a shape in sheet metal on the CNC, put it on the forming plates with some rubber sheeting on top, place that whole assembly in the press, and whamo...you have half a frame. Of course, there was still some handwork to be done to smooth it out and get the edges straight for welding. The San Andreas mainframe and swingarm were made like this. I think we cut the headtubes and seattubes in house, and also CNCd the dropouts in house too. Pretty much the only thing we didn't do was thread the BB shells, those were sourced out.

Oh, and the quality control was shit, but that's another story altogether. :)

[capin]

Cool experience!
I always liked Mounain Cycle. I almost bought ful susp.Moho about ten years ago. It has never been an average company. Reisinger did it his own way. Very creative, Ahead of the time. Id love to see some MCycle trials frame. Hmm Iguess they had a bmx though.
Its a pity they r out of bussines.

[ash-kennard]

also anyone know how cnc works, i tried the wiki link but found it quite hard to understand, a dumbed down version would be helpful thank you

(Y)

[dkoppric]

as far as the heat treating process, look into what molecular pattern it puts the particles in. It will either be FCC (face centered cubic) or BCC (body centered cubic), which is a way of describing how close together the spherical molecules are.

I could be completely wrong but I think the BCC has more voids (percent of volume that is air) and therefore the heat treating process trying to put the molecues in a FCC position, thus reducing the voids and making the overall material stronger.

Pretty much just do a google search on heat treating with respect to FCC and BCC and see what pops up.

[eturt9]

also, if you want more specifics into how they actually get aluminum from alumina. Look up the Hall-Heroult process or just Hall process. I'm lazy and don't feel like explaining but wikipedia should do a good job at it.

http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process

also i wouldn't worry too much about atomic arrangement. It's probably a little out of the scope of the project. A general understanding of heat treating probably will suffice. If you want more in depth, specifcially look for quenching, tempering, aluminum phase diagrams.

[jmkimmel]

A CNC mill works just like a regular mill. However, all the things you control by hand on a mill (x, y, z position of the workpiece) are controlled by a computer, which is using a file that the operator creates beforehand.

Think 3D Etch-a-sketch, but with metal.

http://en.wikipedia.org/wiki/Milling_machine

[dkoppric]

also i wouldn't worry too much about atomic arrangement. It's probably a little out of the scope of the project. A general understanding of heat treating probably will suffice.



ehhh, a basic understanding of heat treating is basically atomic arrangement, and yes, quenching, ect....

[heatsink]

On the machining of Aluminium to make parts, here is some basic info that is a good starting point. Hopefully more complicated descriptions will make sense after you've looked at the bit below! I have my own Alu Vee and Magura backings, Vee adapters and booster all "CNCed". When you've seen one clear example then it should help too.

http://heatsinkbikes.com/content/Alubackings/recessmachl.jpg

The milling machine has a rotating cutter which moves around according to the program/manual control. The rotating cutter is like a drill bit really, but is shaped so that it can cut moving across whilst drills only want to make vertical holes.

If the milling machine is running a program rather than relying on an operator to move it around, then it's called a "CNC" milling machine. Computer Numerically Controlled. The machine either has a basic computer in it with a small display to enable you to program the shapes for the cutter to move in, or the modern ones will accept 3D cad files from a PC's CAD program. Not only does the machine automatically cut the shape, but it changes cutting tool as well via a head that clicks around. There are cutters with rounded tips (bullnosed cutters) or not (the pad recess in this Heatsink magura backing is cut using one of these because there is no requirement for no base radii in there.) There are also tools for creating chamfers (see the edges of the backing), or external radii. Plenty of special cutters too such as the one we use to machine the o-ring annular recess because the material needing removing is hidden away.

Typically you need to hold the block of alu in a vice and machine one side before turning it over and machining the otherside. In the photo the first part of the program has just taken place to machine the top form of the backing. Then the part will be turned over by hand and placed into a custom made clamp to grip the cross shape, so the remaining lump of alu used to clamp around previous can be machined off leaving the back of the backing where the o-ring recess form is added and external chamfers around the edge.

Some more photos which show stuff mentioned above:

http://www.heatsinkbikes.com/content/Boosters/b2l.jpg

^ Pile of Heatsink Boosters following machining of the front.

http://www.heatsinkbikes.com/content/Boosters/b3l.jpg

^ Booster in custom clamp following machining of rear.

http://www.heatsinkbikes.com/content/Boosters/b1l.jpg

^ The Booster on the CNC mill

http://heatsinkbikes.com/content/Boosters/sunbooster640.jpg

^ Finished Booster after anodising.

Steve

[Free-Ride-Junkie]

Interesting thread. Now how much for that booster??

[JHuskTrials]

^^ Ah a Haas Mini Mill, I run two of those at work. However, I do not get to make bike parts all day.

[Rodmunch]

Cool experience!
I always liked Mounain Cycle. I almost bought ful susp.Moho about ten years ago. It has never been an average company. Reisinger did it his own way. Very creative, Ahead of the time. Id love to see some MCycle trials frame. Hmm Iguess they had a bmx though.
Its a pity they r out of bussines.

Well yeah I guess he did things his own way, like yell at us for standing too long in front of the swamp cooler when it was 90 degrees outside and over 100 degrees inside (he had no ventilation in the production area). And paid dirt, around $6.50/hr for production work. He wasn't the easiest person to talk to either. I used to blare my death metal once in a while, just to make his asshole pucker a little bit. BUT, the experience was worth it. I worked there for the summer and learned how a frame is made from the first step to the last. He had his own heat treating tank too, so I learned about that as well. There were some cool guys working there too. I thought he sold the business to Kinesis...are you sure they're out of business?