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EL34
02-19-2013, 07:56 AM
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
02-19-2013, 10:14 AM
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
02-19-2013, 10:38 AM
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
02-19-2013, 04:36 PM
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
02-20-2013, 03:47 PM
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
02-20-2013, 04:46 PM
Simple Design Good Job!!! Can we see some videos of it working?
Thanks
Bob Adams
CNC Programming Software Tools (http://www.cad2gcode.com)

EL34
02-20-2013, 06:22 PM
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
02-21-2013, 10:13 PM
I would use slic3r. It has a post processor for mach3 built in!

EL34
02-22-2013, 06:15 AM
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 (http://cnc2printer3d.wordpress.com/software/)

EL34
02-22-2013, 02:57 PM
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
First text of 3D printer Extruder moving 1.75mm PLA filament - YouTube

EL34
03-01-2013, 01:17 PM
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
03-01-2013, 02:57 PM
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
03-01-2013, 03:10 PM
Don't know if i have one of those around here and the 40 watt heating element runs on 12 volts

keebler303
03-01-2013, 04:14 PM
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? :D

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
03-01-2013, 04:23 PM
Use a light dimmer ahead of a 12V transformer. The "resistor" heater doesn't know the difference between AC and DC!

EL34
03-01-2013, 05:24 PM
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)

Kintrex IRT0421 Non-Contact Infrared Thermometer with Laser Targeting - Amazon.com


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
03-02-2013, 11:12 AM
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

First print from my extruder - Part 1 - YouTube
First print from my extruder - Part 2 - YouTube
First print from my extruder - Part 3 - YouTube

Bob Adams
03-02-2013, 02:10 PM
Looks like your moving right along. Are you using Mach3 Controller?

EL34
03-02-2013, 03:13 PM
Hi Bob,
Yes I am using Mach3 and Slic3r
Slic3r now has an option to produce Gcode for Mach3

xairflyer
03-02-2013, 09:28 PM
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!

jlnading
03-02-2013, 09:43 PM
Very nice work EL. Looks very similar to the hotends I build, except I use Peek as a heat separator for the wades extruder and make my own block element along with the nozzle and barrel. Your design uses the least amount of parts, means less machining and cost. Way to go dude.

https://www.youtube.com/watch?v=x_F2OSymnS8&list=UU5MWkMsbXeqTSQGihR0is1Q&index=11

EL34
03-03-2013, 07:13 AM
Thanks,
A threaded rod seemed like a very simple solution.
I decided to drill out a Stainless Steel bolt because stainless has super low thermal transfer rate compared to many other metals.
Inside the hole in the SS bolt is a PFTE sleeve and it is glued in place with some high temp adhesive.

But, drilling out the stainless bolts is a major pain.

That little cup took 1 hour 40 minutes to complete and the heat never followed the bolt up to the upper section
Everything stayed at an acceptable temp.

Found this chart that shows thermal conductivity of a bunch of metals
Thermal Properties of Metals, Conductivity, Thermal Expansion, Specific Heat - Engineers Edge (http://www.engineersedge.com/properties_of_metals.htm)

Silver is highest at 247
Copper is 231
Aluminum is 136
brass is 69
SS is 8

jlnading
03-03-2013, 06:41 PM
Very nice design EL, I know what you mean about drilling the SS, I make the hobbed bolt out of SS. I also make a brass nozzle, out of solid stock, drill one end with a .5 mm bit and the other with a #7 bit then tap to 1/4" x 20. Lot of work but it sure does work. Good to know about the heat dissipation of SS. Thanks for the link.
https://www.youtube.com/watch?v=N0aZEXzT-m4&list=UU5MWkMsbXeqTSQGihR0is1Q&index=4

EL34
03-03-2013, 06:53 PM
I made my brass nozzles also.

I made an aluminum nozzle also

All were drilled with a 1/64th inch bit which is .39mm

There was no way any of my drill preses or lathe could grasp a bit that small
But I found out that my dremel tool had a chuck that would grasp the bits

jlnading
03-03-2013, 06:58 PM
Same problem I had, so I made a little arbor to fit the .5 mm bit then just chuck it up in a 3/8" battery drill.

robe_uk
03-07-2013, 12:44 PM
look for pcb drill bits, 1/8'' shank with tiny drill bit.

keebler303
03-07-2013, 12:52 PM
look for pcb drill bits, 1/8'' shank with tiny drill bit.

I'm not sure if they still have them but Harbor Freight used to sell packs of 10 random sizes of these drill bits. You can sort of see what sizes are in there before you buy.

Matt

vger
04-01-2013, 11:39 PM
Yes Harbor Freight still carries those bits... It's a mix in the boxes, and not all boxes are the same. Some of them are really tiny, like .010". Work great in Dremel tool. Sizes are marked on the colored collar. Take a close look at the tip of some of the larger sizes as they may be mill bits.

EL34
04-03-2013, 07:12 PM
Not interested in PCB mixed size bits

I am able to use 1/64th inch bits no problem in a dremel tool with a 3 jaw chuck
I can buy a whole pack of 1/64th inch bits at Mcmaster for a fraction of the price of one PCB bit

billcat
05-09-2013, 10:06 PM
Looking forward to more progress.....!

I am grateful of your generous effort to provide your findings, document your work, and explain things in a straightforward fashion. Enough to warrant my first post on cnc zone.:D Nice to have clear pictures and video, I don't seem to find that too often.

I would like to attempt a router to 3d printer conversion myself shortly, but I have lots of questions.......to the point of still being on the fence about the whole matter.

I have a hobby lathe I can toy with, but I have found that I am not much of a machinist. I attempted to make a nozzle today....snapped a few small drill bits, etc, but maybe it will work. I turned down an old copper solder tip then pressed it into 6061 alum then turned some more. Smallest drill bit I had was .028" (keyword....had), can't imagine using a 1/64"!

NSR_CIVIC
05-10-2013, 02:23 AM
The key to small bits is super slow feed in and very small pecks best way is sadly by hand with a pin vice although that does not make a very strait hole but you can feel the bit binding before it snaps. Also keep some rapid-tap or similar cutting fluid on hand. It helps move the chips out of the way.

Kevin.
Nsr customs.

EL34
05-10-2013, 05:07 AM
Looking forward to more progress.....!

I am grateful of your generous effort to provide your findings, document your work, and explain things in a straightforward fashion. Enough to warrant my first post on cnc zone.:D Nice to have clear pictures and video, I don't seem to find that too often.

I would like to attempt a router to 3d printer conversion myself shortly, but I have lots of questions.......to the point of still being on the fence about the whole matter.

I have a hobby lathe I can toy with, but I have found that I am not much of a machinist. I attempted to make a nozzle today....snapped a few small drill bits, etc, but maybe it will work. I turned down an old copper solder tip then pressed it into 6061 alum then turned some more. Smallest drill bit I had was .028" (keyword....had), can't imagine using a 1/64"!


Hi,
I update this page with my projects. You can see more info on my 3d printer and extruder here
EL4's CNC projects Main page (http://www.el34world.com/Misc/Cnc/CNC0.htm)

This post has info on my build
http://www.cnczone.com/forums/general_3d_printer_discussion/175337-new_printer_build.html

I am not using my router, I built a stand alone 3D printer
The router was just used as a first test of an extruder
I have improved my print quality greatly since the first test I did on my CNC machine

My CNC router is way slow compared to my DIY super light weight 3D printer
The print times are 5 times or more faster because the moving parts are very light weight
I can print at very fast speeds

Here's a pic of an object I printed
The two outside pices are after another extruder nozzle upgrade using a makerbot style extruder tip
They are much smoother than the middle one
184330

billcat
05-10-2013, 09:51 AM
Thanks for the links, at a quick glance it looks like I will enjoy spending some time there. Again, very well documented.

I just began researching extruders about 3 days ago, but your homebrew looks like just the ticket......simple and functional. And those available commercially seem awfully pricey for what you get, maybe I am not looking in the right place.

I still have much to learn about the cam software, have not even seriously looked into it yet. But I am fairly comfortable with mach3, seems to make more sense as a means to an end, than going the arduino route, which I have no experience with whatsoever.



The key to small bits is super slow feed in and very small pecks best way is sadly by hand with a pin vice although that does not make a very strait hole but you can feel the bit binding before it snaps. Also keep some rapid-tap or similar cutting fluid on hand. It helps move the chips out of the way.

Kevin.
Nsr customs.

Thanks for the suggestions. I tried by hand with a pin vise, but was making no progress, so I chucked the pin vise in the lathe tailstock. I then attempted slow feed and small pecks, but snapped bits nonetheless. Perhaps the cheap china drill bits were to blame. Or the alloy of the copper. I noticed it kind of just wanted to mush up when turning the outside, even with sharp carbide bits and aluminum cutting fluid. I guess it really makes little sense to make your own nozzle, when they are quite inexpensive to purchase online.

EL34
05-10-2013, 10:29 AM
Don'y use my acorn nut idea
It is not pointy enough and it drags the plastic around instead of depositing it nice and clean

I show the new makerbot type tip in my build post
Much better design