Whats The Trick To Extruding PLA?

It is very possible. While I have not tried extruding PLA, this user did a wonderful job outlining how he did it.

http://www.soliforum.com/topic/7648/bas … s-request/

I was extruding tons of PLA with filastruder in the past with factory quality and good speed.
I would make as much as a spool in around 1.5 days of extruding.

But this machine is so touchy that small little thing will get you off balance so much you going to end up with no filament for a long time unless you fix it.
And if you do get lucky to fix it, you most likely work know how LOL.

After years of extruding PLA and ABS, i cant wrap my head around why my filastruder is suddenly extruding very slow.

I have some tips for you.
Heater band location is critical.
Closer to the nozzle=more stable temperature
It will also cause problems such as less preheat.
Preheat is the area before nozzle where plastic is not melted but soft enough to produce good pushing force.
Preheat area is generally achieved with full insulation.

If you move heater band further from the nozzle, you will have better preheat but temperature will start to jump higher and lower deviating more and more the further away you move.

I think ideal setup would be to have 2 heaters and have them adjusted individually.

Also, Pellets must be dry.
When i say dry, i mean (before you put them into the hopper, put them into the over for 212F for 2hrs)
Then its dry.
Any other way of saying "dry" is not good enough.
THats PLA for you.
If its not dry, it will cause all sorts of problems..

Once dry, you have no more then 2 weeks (assuming it was closed in an air tight container kept at room temperature) to extrude it all.

yep i cant agree more.
I have one nozzle for each material.
For ABS i use 1.6 (like most)
and for PLA i use 1.9 (not sure why but it seems to do the trick since i run my motor on 24v or double the speed.)

I have found that there is a fine balance to motor current, filament droop, nozzle size, and temp.

If you are running 4043D (which is what most people run) then the key to success is to use a more scientific way to measure what is happening while extruding.

Case and point; If your thermocouple for the nozzle is in the path of your cooling fan it will report an incorrect temp due heating losses in the thermocouple wire. You can verify the temp using a multimeter with thermocouple capability.

I have insulated my thermocouple with high temp fiberglass insulation to keep any transient breeze away. I know some people haven't done this and they instead turn up their temp to compensate. This is ok as long as the fan is always in the same place on the barrel insulation. But you will eventually run into a wattage barrier where the barrel consumes all the available power from the power supply and can't get hot enough

I have made many adjustments to my machine to make 1.75mm filament as fast as possible. My nozzle is drilled to 1.9mm. I have increased the motor speed by using a buck/boost converter found on ebay:

https://www.ebay.com/sch/sis.html?_nkw= … 2749.l2658

The converter is installed before the current limiting board, NOT AFTER!! This is very important!

I run the motor at 17V, but I also turn down the current (since the motor can only handle about 20watts). With the larger nozzle diameter and increased speed, The filament diameter at the nozzle before droop is about 1.87mm.

The three largest factors that contribute to filament diameter while extruding are:
1. how much filament droop
2. extrusion temp
3. extrusion speed

The best droop distance from the nozzle I've found is 15 inches (381mm), and 26 inches (660mm) between nozzle and spooler.

The best temp I've found is 175c (insulated with fiberglass), and 182c (without fiberglass).

Methods for getting correct extrusion diameter: (pick only one method)

1. Set the motor at one voltage and leave it, change either droop distance, cooling fan speed, extrusion temp, or distance between nozzle and spooler.

2. Set one extrusion temp, the either change droop distance, cooling fan speed, or motor voltage.

3. Maintain fan speed and droop distance, and only change extrusion temp.

I personally choose method 1. I get about 1 spool every 8 hours.

Another thing to be careful of is the motor current. Anything over 20 watts and you are likely to strip the internal gears. So if you are running anything other than virgin resin (recycled material for example), then make sure to mix some virgin material in. This is done for two reasons: 1. The resin degrades after multiple heat cycles (and thickens), 2. virgin material decreases compaction causing the flow to be more consistent and consumes less motor power.

Last but not least, DRY YOUR RESIN!!!
You won't get anywhere if it is wet. Even a little wet will cause problems.

You can dry resin using a food dehydrator like this one:

https://www.amazon.com/Presto-06300-Deh … B008H2OELY

This is the go to dehydrator for drying because it dries at the perfect temp, no temperature changes needed.

The other way to dry is in an oven.

Dry at 175F (80c) for 4 hours.

I hope this helps those who are trying to get started extruding.

Happy extruding!
Fusion Filaments
fusionfilaments.com

You are partly correct! The voltage determines the speed, watts determines the torque. Watts is a measurement of work performed.

https://www.magtrol.com/motor-power-calculator/

What I meant was that you should limit the wattage of the motor to about 20watts (since watts = V * I(amps)) so no matter what your voltage is, you should adjust the current to match 20 watts.

Thanks for the tip on the DIY materials forum, I will get my info in there THANKS!

The current limiter board included is excellent, Ian knows his stuff.

I put the buck / boost board in between the power supply and the current limiter board.

A good way to set the current limit is:

1. Disconnect voltage from the input.
2. Disconnect the output to the motor.
3. Apply voltage to the input.
4. Set the output voltage to about 17v while buck / boost is connected.
5. Turn the current pot down to very low (until you hear the click on the pot).
6. Disconnect voltage from the input.
7. Short the + and - wires on the output together (ONLY THE OUTPUT!!!!)
8. Apply voltage to the input
9. Slowly turn the current pot up until you get to about 1.17 (this is 20watts)
10. Disconnect input voltage.
11. Reconnect motor to output.
12. Apply input voltage.

Now your current is set.

You are allowed to "short circuit" the output from current board, this is normal. Think about it, if your motor starts to get up to the current limit and the motor stops, the voltage is going to drop from 17v to something around or close to 0v which is effectively a short circuit.

Tim (myself) made the Filastruder and stall protection board, not Ian.

Never a good idea to short circuit anything. Better to use the included heater, it will be plenty of load.

I'm not Tim, but if you run more voltage at the same current you would be heating the motor up more (possibly wearing out the brushes faster) is what my understanding was.

If you happened to talk to anybody at Natureworks when you bought your 3D870 (or wherever you got it), could you ask them what the melt strength of 3D870 is like compared to 3D850 and 4043D?  High melt strength has always indicated to me a material far easier to extrude in the Filastruder. 

Too bad nobody will sell melt strength additives in small quantities - it would certainly make 4043D easier to extrude.  Imagine something like this: https://www.ptonline.com/products/addit … t-strength making PLA stay closer to the exact size it was when it came out of the nozzle.