[EL34]

I had hijacked another thread so I thought I would start my own thread on my Extruder build.

I will be testing a 1.75mm PLA extruder on my CNC machine.
Once it's working and dialed in I will probably build a stand alone 3D printer.
My CNC machine is way overkill as far as the heavy frame and way slower than the speeds you can get with a super light 3D printer.

So my first bit of mock up is a a spring assisted idler pulley that uses a sealed ball bearing.
The ball bearing came out of an old hard disk drive. In fact there were two of them in the one I took apart

I plan on using my lathe to make a aluminum outer ring that will be pressed onto the ball bearing.
The outer ring will have a groove that will be shaped the same profile as the 1.75mm filament

Some of the items in my photos look warped but it's just the macro camera lens doing that

Here's a couple shots of that idler assembly with a round piece of aluminum that is just a stand in for the real gear.

[NSR_CIVIC]

That looks very simple and if it works correctly I think it may be a good open design for easy access for filament changes..

Kevin.
Nsr customs.

[EL34]

yeah, I think so too

The ball bearing idler turns real smooth and keeps lots of pressure against the motor shaft.

The addition of an outer aluminum band on the bearing with a 2mm groove should be the ticket

I have seen some people add a supprt bearing on the tip of the motor shaft because of the intense side pressure. That would give the motor shaft some relief

I am not sure that is needed. I see lots of CNC machines with gears and belts which is also side ways pressure on the motor shaft

[EL34]

I machined a couple items today
I drilled out a SS bolt to accept a PFTE tube
The 1.75mm PLA filament rides inside the PFTE tubing

The heater block is just a small square of 6061 AL
There's a tapped 1/4 hole for the SS bolt and a drilled hole for the 40 watt cartridge heater

That brass nut is just a dummy nut.
I have not received the extruder tip I ordered yet.

I would make my own but have not been able to find a .3mm drill bit yet
I could use a 1/64th inch bit but don't have one at the moment.
1/64th would be .39mm

[EL34]

Got some more machining done today

Machined the upper block and a motor mount
The motor mount is a piece of 1 inch aluminum angle
The motor mount will blot onto my CNC spindle mount

The upper block and heater block are 3/8" 6061 Aluminum

I have to find a new spot to anchor my idler bearing tension spring

On the idler bearing, I still have to machine an outer band with a grove for the filament to ride in

[Bob Adams]

Simple Design Good Job!!! Can we see some videos of it working?
Thanks
Bob Adams
CNC Programming Software Tools

[EL34]

Hi Bob,
This is all new to me, (3D printing) but I am getting a handle on it fairly quickly.

I'll shoot some HD vids once I get it working.

This is my first design and I am probably a week or so away from being able to extrude some plastic

I have also ordered some parts for an existing working design

So I will see which one gets up and running first.

The hardest part will be to figure out how to get a .nc file from a 3D .stl file that Mach3 can run

There's programs out there that can do that, but I have not even begun to work on that part yet.

Stay tuned

[Pplug]

I would use slic3r. It has a post processor for mach3 built in!

[EL34]

Thanks, I tested two pieces of software yesterday
I don't have my A axis running yet but I watched them extrude air and they seem to be working

Both programs work right inside of Mach3 as wizards
One uses slic3r and one uses skeinforge

You start the wizard in Mach3,
open a .stl file,
make any adjustments you need to make,
the Gcode appears in Mach3

The programs both change the E axis (3d printers use E axis) to A for Mach 3 usage

Both were written by the same guy and can be seen on this page
Mach3 Addon | Converting a CNC Machine to a 3D Printer

[EL34]

Got a test gear cut on the CNC. I cut it right on the shaft of the A axis motor.
I set the A axis motor to angular in mach 3 and tuned the motor so that Gcode A1 equaled one complete revolution of the motor.

The hard part was figuring how far away each cut should be so that you get a nice pointy gear profile.
I used a V cutter and cut grooves every .05 on the A axis
The v cutter tip was only .03" wide and I cut the grooves at .05" deep
I am basically engraving a short line at top dead center, then rotating th4 axis .05" and then cut another short line until I have gone all the way around the cylinder
I set this up into a loop on Mach 3 and it completed on it's own
I just clamped the A axis motor into a vise to get it nice and solid

I need to cut another gear and put the teeth slightly closer together to get sharper ridges
But the first test was good and it was very difficult to get the filament to slip.

You can see the gear in the image below
I also shot a quickie movie of the extruder pushing filament

Here's a link to the Youtube movie
[ame=http://www.youtube.com/watch?v=MWvxSvhAsw0]First text of 3D printer Extruder moving 1.75mm PLA filament - YouTube[/ame]

[EL34]

Got alot done this week

Cut a new extruder gear profile that is curved and grabs the filament way better (see pics)

Made two extruder tips from scratch and drilled the tips with a miniscule 1/64th inch drill bit

Did my first hot extrusion test yesterday.

I am still waiting on my temperature control board to arrive.

The 40 watt tip heater gets so hot that it boils the plastic and then it spurts out the end, but I did get some solid extusion before the tip got way too hot.

I won't be able to do a proper test until I can control the tip temperature
The temp control unit should be here next week

[keebler303]

A light dimmer switch would make a decent temporary heater controller. Just increase it slowly until it extrudes and then you are good to go.

Matt

[EL34]

Don't know if i have one of those around here and the 40 watt heating element runs on 12 volts

[keebler303]

Don't know if i have one of those around here and the 40 watt heating element runs on 12 volts

I guess that would limit the usefulness of a dimmer then, huh?

What are you using for a power supply? 5V would give you a "low" heater setting. There are other things you could put in series with the heater to reduce the power it gets. A car headlight would give you about half power.

Matt

[Bubba]

Use a light dimmer ahead of a 12V transformer. The "resistor" heater doesn't know the difference between AC and DC!

[EL34]

I have two variacs here, so I will give it a go

I just got one of these IR themometers, so I should be able to get a good idea about what temp the heater is putting out

Measurement Range: -76 to 932 °F (-60 to 500 °C)

[ame="http://www.amazon.com/gp/product/B0017L9Q9C/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1"]Kintrex IRT0421 Non-Contact Infrared Thermometer with Laser Targeting - Amazon.com[/ame]


The only problem is that the temp varies with how much and how fast you push placyic through the nozzle
And so the temp board can be set to regulate this

I can tray and do a manual temp regulate via a variac until the real deal arrives

[EL34]

Haaa, just finished my first test extrusion by printing a small cup object
It's ok for a first test but it will get much better after I get the temp control unit and dial in the extrusion rates and speed

I also need to mill a perfectly level bed and having a bed heater is the way to go, although the PLA plastic stuck to the blue painters tape quite nicely

All in all, not bad for a first test run
Here's 3 youtube vid's and some pics

[ame=http://www.youtube.com/watch?v=AAcvJH_UDSY]First print from my extruder - Part 1 - YouTube[/ame]
[ame=http://www.youtube.com/watch?v=A3Lo2bmS4y4]First print from my extruder - Part 2 - YouTube[/ame]
[ame=http://www.youtube.com/watch?v=TE00qGRiN5g]First print from my extruder - Part 3 - YouTube[/ame]

[Bob Adams]

Looks like your moving right along. Are you using Mach3 Controller?

[EL34]

Hi Bob,
Yes I am using Mach3 and Slic3r
Slic3r now has an option to produce Gcode for Mach3

[xairflyer]

Looks great, would like to have a go myself but totally green to the 3D process, also using turbocnc ver4 to run my router, I have been using it for the past nine years and too chicken to try somthing better!