Instructables

My plastic extrusion

Hi

I've made this little extrusion as a prototype: http://www.preciousplastic.com/little-extrusion/
It's for my graduation project at my school...(still in progress)
However, This is small..I want to make it big!
Does any of you guys have an idea where I can get a serious screw for inside the plastic extrusion?
Are where to get them second hand?
New price is around $2500...way to much for me...

Search for "earth auger" on EBAY the smaller diameter ones are 2 inches,3 inches,
and 4 inches in diameter. Lots of other larger sizes too.

You might even try having a very large supply hopper with a large feed screw
feeding the smaller extruder hopper.

delokaver1 year ago
a question ... if you are using a drill is that not way to fast ? since I am building my own extruder and get very nice and constant speed and enough torque with car wiper motor assembly ... as soon as I have a chance will uploaded in this web
davehakkens (author)  delokaver1 year ago
the drill is indeed quite fast, in the end I replaced it also with a car whiper motor :)
if you are interested here you can find more info and machines: www.preciousplastic.com
Toga_Dan1 year ago
Tear apart a vice? Have students in the machine shop make the screw on a machine lathe?
As I recall, pressure in those extruders is in the 10,000 psi range. Not that you absolutely need that.
One might expect to get higher pressures from a screw with more threads per inch (assuming it doesn't just jam)

May I also suggest that when prototyping somethin with BARE WIRES like this, at least put them on something NON CONDUCTIVE!!! LIKE CERAMIC, OR DRYWALL SCRAPS.
Toga_Dan1 year ago
Tear apart a vice? Have students in the machine shop make it?
As I recall, pressure in those is in the 10,000 psi range.
One might expect to get higher pressures from a screw with more threads per inch (assuming it doesn't just jam)

May I also suggest that when prototyping somethin with BARE WIRES like this, at least put them on something NON CONDUCTIVE!!! LIKE CERAMIC, OR DRYWALL SCRAPS.
May I also suggest
davehakkens (author) 1 year ago
thanks!
Sausage stuffer and old hand-turned brace-and-bits sounds like a plan, i'm going to look for one..
Kiteman1 year ago
I appears you are using a drill as a power supply, and a drill bit as your extruder screw.

In the UK, I have seen large-diameter drill bits for sale at steam fairs and car shows. They tend to be the bits from old hand-turned brace-and-bits, but only cost a couple of quid.
"Auger"
"Needlenose sharks", but only cost a couple of squid.
Hack42Moem1 year ago
Oh... you mean you made an extruder. Extrusion is the process; it's what an extruder does.
What do you mean by "A screw for inside the extrusion" ? Do you mean inside the extruDER ?

What is a "serious screw" ? Put some parameters on it. Pitch, diameter, length.
That wiring looks interesting. Remind you of anyone Steve?
Nah, this looks safe by comparison
davehakkens (author)  steveastrouk1 year ago
Hi Sorry for not being clear... Right now I just used a wood-drill.. but a 'real' extrusion screw looks more like this: http://en.wikipedia.org/wiki/File:Plastic_extruder_screw.jpg
o
ptimized for plastic-extrusion
It pressed the plastic better so you need less heat and have a more fluent/quicker output..
For me a length around 40 CM and diameter 30MM would be great.

I agree with Cdad, look at Sausage stuffer screws perhaps.
Why don't you put a heating element on a sausage stuffer or grinding machine? You are limited by the design of the nozzle on what volume/rate can push out and the pressure it can take. Viscosity and pressure of the molten plastic are other parameters to control.