876

Re: Filament Extruder - Convert pellets to filament

Ian - what you want to do is use a detector for the loop and the output of the detector varies the control voltage on the motor controller to cause the motor to speed up or slow down.  This is dynamic control based upon the position of the filament's location.  Since you are using a pot to vary the speed now you should be able to use that point as the voltage control point for loop control.

Bob Teeter

877

Re: Filament Extruder - Convert pellets to filament

bteeter wrote:

Ian - what you want to do is use a detector

What type of detector do you recommend? Closed loop control is no biggie, picking the right type of sensor is. It is not as simple as monitoring shaft speed, as some have suggested. It cannot interact mechanically with the filament or it will disturb it. That leaves optical and ultrasonic solutions...

878

Re: Filament Extruder - Convert pellets to filament

Optical is the simplest type to do.  Simply break the light beam at the bottom and speed up.  Break the Light beam at the top and slow down.  Limit the amount of change over any length of time.  Easiest way would have an Arduino monitor the light beams and shift the reference voltage up or down at some specific rate to solve the problem.

Bob Teeter

879

Re: Filament Extruder - Convert pellets to filament

The problem with just a pair of beams is that if the filament strays above the top beam or below the bottom beam, control is lost. I like the linear photocell arrays, but have not had a chance to play with one yet.

Btw - shooting video now for kickstarter!

https://dl.dropbox.com/u/1786359/Photo%20Mar%2006%2C%206%2037%2048%20PM.jpg

880

Re: Filament Extruder - Convert pellets to filament

Jeez, Tim, that seemed fast...

Oh, well, there goes my tax refund.... smile

881

Re: Filament Extruder - Convert pellets to filament

elmoret wrote:

Btw - shooting video now for kickstarter!


Is that the new case/cover?

SD2 with E3D, SD Press, Form 1+
Filastruder
NYLON (taulman): http://www.soliforum.com/topic/466/nylon/

882

Re: Filament Extruder - Convert pellets to filament

I don't think that you will loose all the control that you think you will.  I remember working on 1/2" mag tape units with vacuum columns for control.  They were moving tape at 100's of inches per minute and were able to keep up just fine.
Now the old geezer part - This was before you were born from the looks of the picture you just posted.  But I think that you will be surprised at how valid the control loop will be  just from using 2 points of control for the loop.  If you only use a 10% speed change on the loop your response will still be just fine.

Bob Teeter

883 (edited by elmoret 2013-03-07 01:30:51)

Re: Filament Extruder - Convert pellets to filament

Bob - my point is that if you don't catch it in time, it will drop through below the beam of light. I agree it would work, probably 99.99% of the time, but I don't think it's necessarily the best solution. It's certainly the simplest, and therefore the one I'll try first.

For what it's worth, I'm only 27, but I've worked on pneumatic control systems at a nuclear power plant. That stuff that was invented "before my time" is still around, so it's worth understanding!

884

Re: Filament Extruder - Convert pellets to filament

One question - How many posts are need so that links to photos can be made from a posting.  I just tried and 5 is not enough.  And can photos be uploaded to the forum for display?

Bob Teeter

885

Re: Filament Extruder - Convert pellets to filament

@elmoret and IanJohnson

What type of plastic is the "clear" that you are using and where are you getting it?

886

Re: Filament Extruder - Convert pellets to filament

d.mositner1 wrote:

@elmoret and IanJohnson

What type of plastic is the "clear" that you are using and where are you getting it?

Here's everything I've ever run through the Filastruder:

https://docs.google.com/spreadsheet/ccc … sp=sharing

The clear Ian and I use is at the bottom, with ebay links on the right.

887

Re: Filament Extruder - Convert pellets to filament

bteeter wrote:

One question - How many posts are need so that links to photos can be made from a posting.  I just tried and 5 is not enough.  And can photos be uploaded to the forum for display?

Bob Teeter

I thought it was 5 or 10. Upload somewhere like dropbox or imgur, and then enclose the URL in image tags... like this:

[i mg]https://dl.dropbox.com/u/1786359/Photo% … 8%20PM.jpg[/i mg]

Only without the space between the i and m in the first and last tag.

888 (edited by elmoret 2013-03-07 01:39:07)

Re: Filament Extruder - Convert pellets to filament

DePartedPrinter wrote:

Is that the new case/cover?

Yup. OS Printing overnighted me a copy of the enclosure off their CNC router. I got it assembled just in time for the video:

https://dl.dropbox.com/u/1786359/Photo%20Mar%2006%2C%203%2056%2029%20PM.jpg

Pardon the cell phone picture, still in the middle of shooting. I'll have better stuff later. Big thanks again to OS Printing, they threw in some masterbatch as well, so I'll be able to test that as well.

889

Re: Filament Extruder - Convert pellets to filament

For a pair of photocells, I would need to mount them somewhere below the edge of the table and be able to adjust them.  The filament is rigid enough that it doesn't always make a neat symmetrical loop like a piece of string, so the bottom of the curve can wander a bit. 

I found a tutorial on taking the optical sensor out of a mouse and wiring it into an arduino, and someone wrote a library for it.  Others have used them to track the speed of robots rolling over a floor, so I can probably get it to read changes in filament speed.

890

Re: Filament Extruder - Convert pellets to filament

IanJohnson wrote:

For a pair of photocells, I would need to mount them somewhere below the edge of the table and be able to adjust them.  The filament is rigid enough that it doesn't always make a neat symmetrical loop like a piece of string, so the bottom of the curve can wander a bit. 

I found a tutorial on taking the optical sensor out of a mouse and wiring it into an arduino, and someone wrote a library for it.  Others have used them to track the speed of robots rolling over a floor, so I can probably get it to read changes in filament speed.

I was thinking the same thing with the mouse.if we develope the puller a little more we should be able to pick up any drop in speed and even help with dia control.

I guess a question that I would have is how much speed would you increase it by. By changing speed the dia will change too. Soo keep that to a min would be a big deal.

Could maybe mount 4 sensors. 2 in th horizontal montering the filament dip and one mounted just above the die exit to see any diametrical change.

Elmoret enclosure is look great. Will def help with air movement and temperature changes.

891

Re: Filament Extruder - Convert pellets to filament

Guys thank you for the motivation to make a version of your Filastruder.  I was able to use the information from the Filastruder, Luman's and Filabot stuff to create this:

Picture 1: The basic parts of a no cut extruder except for wood.

Picture 2: Picture of Drive Train

Picture 3:  Picture of complete hardware items

Picture 4:  Because I do not like to mix plastic types and I have ABS and HDPE pellets I have made TWINS!

Just a note I will be getting PLA shortly and have started getting the parts for another extruder.  TRIPLETS!!!!!

Bob Teeter

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892 (edited by bteeter 2013-03-07 02:32:23)

Re: Filament Extruder - Convert pellets to filament

I also will be building the spooling section for each unit.
Also for information the pipe parts are 3/4" in size. 
Pellets fall into the auger real nice.
The bottles in the pictures are 2 liter and will hold about 1350 grams of pellets.
I really did measure the weight on my scale.

Bob Teeter

893

Re: Filament Extruder - Convert pellets to filament

Based upon the best extrusion stats in the spread sheet.  To extrude  1 Kg of plastic takes about 13 hours.
Is this correct?

Bob Teeter

894

Re: Filament Extruder - Convert pellets to filament

bteeter wrote:

Based upon the best extrusion stats in the spread sheet.  To extrude  1 Kg of plastic takes about 13 hours.
Is this correct?

Bob Teeter

Not sure what stats you're going off of? 1kg in 13 hours would be faster than I've ever done reliably.

Good luck with your project!

895

Re: Filament Extruder - Convert pellets to filament

Ok here's my bad math.     Based upon the white/natural at 12g/10min to make.  1000g / 12g = 83.3333 units based upon 10 minutes per unit.  83.3 * 10 = 833 time units to make 1Kg.  833 minutes / 60 minutes = 13.88 hours to make 1 Kg of Filament.

OUCH that hurt.  I would rather calc in British units like (furlongs / fortnight) *phase of the moon / the number of times the sun has come up since I was born.   

Bob Teeter

896

Re: Filament Extruder - Convert pellets to filament

12g/10min is the results of the ASTM D1238 Melt Flow Rate Test Method. It does not mean the Filastruder extrudes that amount in that time period.

897

Re: Filament Extruder - Convert pellets to filament

Bob, how long has it just taken you to put that together?
I've been reading this all for a month or more and haven't got to the garage yet, it looks like you've just jumped right on it.
I feel so lazy now. :-( Congrats on the progress though.

Currently waiting for a call back about ABS pellets in the UK. It is surprisingly hard to find.
So far I can get a ton of black pellets for £1320 delivered which isn't too bad if I wanted a ton of the stuff! Not sure I could print that much.

Anyone from the UK know of a place to get pellets?

898

Re: Filament Extruder - Convert pellets to filament

elmoret wrote:
DePartedPrinter wrote:

Is that the new case/cover?

Yup. OS Printing overnighted me a copy of the enclosure off their CNC router. I got it assembled just in time for the video:


Pardon the cell phone picture, still in the middle of shooting. I'll have better stuff later. Big thanks again to OS Printing, they threw in some masterbatch as well, so I'll be able to test that as well.


OS printing came through with that enclosure.  Very cool.  Logo looks good.

SD2 with E3D, SD Press, Form 1+
Filastruder
NYLON (taulman): http://www.soliforum.com/topic/466/nylon/

899

Re: Filament Extruder - Convert pellets to filament

Zarni wrote:

So far I can get a ton of black pellets for £1320 delivered which isn't too bad if I wanted a ton of the stuff! Not sure I could print that much.

That's a lot of plastic...

SD2 with E3D, SD Press, Form 1+
Filastruder
NYLON (taulman): http://www.soliforum.com/topic/466/nylon/

900

Re: Filament Extruder - Convert pellets to filament

DePartedPrinter wrote:
Zarni wrote:

So far I can get a ton of black pellets for £1320 delivered which isn't too bad if I wanted a ton of the stuff! Not sure I could print that much.

That's a lot of plastic...

Maybe he want's to build a plastic beach... or have plastic ball fights, while plastic falls from the sky.