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Inspired by Angus video "Reverse Engineering the 101Hero 3D Printer" I did some experimental design with the 28BYJ-48 to see how they might be used for an extruder. As already said its experimental and even as I have used two of the 28BYJ-48, they might even not be strong enough. But its fun to try. Lets see how it will end up.
Inspired lately by different sources (vlogs, kickstarter campains etc.) I tried to design an extruder driven by lightweight and unexpensive stepper motors 28BYJ-48. While one of them is definetly to weak, I aranged two of them to push the filament. BOM: 3d-printed part "ex28byj-by.stl" x2 3d-printed part "ex28byj-fila.stl" x1 stepper motor 28BYJ-48 x2 (apply bipolar hack to drive them with ramps) screw M3x10 x6 nut M3 x4 screw M5x16 x2 locknut...
Antonio beta's profile photoTinkering On Steroids's profile photo
Well I have a working prototype, but not yet a valid testenvironment. I just attached it to one one of my existing printers but did not want to mess there configuration to much up (especially the current of the stepper drivers). So I just had a small time windows for testing to prevent the steppers from overheating. Not enough to get an hotend heated up. However the torque of the two steppers was surprisingly strong. I was not able to hold the filament with my fingers. Also: the setup of two extruder gears is amazing there is no slipping.
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Kevin Criqui

Questions/Help  - 
I'm getting horribly inconsistent first layer thicknesses on my Metal Plus with the dual extruder. Chain of events is like this

- try to print, first layer is way too thin
- adjust z offset up a bit with M212, M500 and M501 to make sure it stuck
- print successfully
- try another print, first layer is way too thick
- adjust z offset down a bit
- etc.

This was never a problem with the original firmware. Not sure the version, but what was shipped with the very first units made (I bought mine in the Black Friday release). I updated to the latest firmware (Rev F v5) to try and solve a problem with Simplify3D's buggy USB code. I notice that the G29 bed leveling uses different points on the bed than before. I've also noticed that it is inconsistent on what 3 point it uses - sometimes it's 10mm further in the X axis.

I'm wondering if the proximity detector, which is a rectangular green box unlike the metal cylinder used on all their other printers may be to blame. Or maybe a bug in V5 firmware. Has anyone else noticed this behavior?

Kevin Criqui's profile photo
Here is something strange. The results from a G29 bed level are different depending in where the print head is when I issue the G29. It seems like if the print head is anywhere in the left rear quadrant, G29 reports values that are about 0.5mm too big. i changed my start G-code from G28 X0 Y0 Z0 to just G28, which inexplicably moves the print head to the middle of the bed before homing the Z axis and it seems to be better. I'm in the middle of a 2hr print so I'll have to confirm all this later.

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Florian Ford

Development  - 
I have started designing an #XCarriage for #Bowden setups and Horizontal Rods that overcomes most of the static and dynamic errors that affect printing during the accelerations/jerks/etc of a 3D printer (discussion here:,668254).
I hope to improve it and want to get some input from the community.

I have added explanations to each photo so they should be pretty explanatory. If you click each photo you will be able to see the explanations.

Sketchfab model here :
Brook Drumm's profile photoFlorian Ford's profile photo
I might replace the blower fans with axial fans for a more compact design ... 4 30mm axial fans, 2 cooling the hotend and the other two cooling the part...
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Show-n-tell  - 
Dat hamster castle ^^
 ·  Translate
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When you play the game of thrones, you win or you die.
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I decided I need a small desktop CNC-Mill for PCB prototyping.
So this is what I came up with after 6 hours CAD tinkering on a rainy Sunday afternoon.
Milling area: 174 x 128 52 mm, Footprint: 348 x 354 x 350 mm
Daniel Kruger's profile photoJohn Bump's profile photo
+Andreas Hölldorfer -- it doesn't. It's a purely two axis machine, with the z axis set up to just drop and be held down with a combination of spring force and the solenoid. Very fine manual z-axis adjustment screw so you can adjust depth of cut for v-shaped cutters. It'll easily do even very fine pitch smd stuff: snake three traces between the pads of a 1206 resistor, for instance. I love having a pcb mill. I suspect you will not regret building one.
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Shai Schechter

General discussion  - 
Is it just me or did Maker Shed stop selling 3d printers?
Alexander Pritchard's profile photo
I can't find any either.
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All you need to know to set your slic3r, when you custimize your New or Old #3DPrinter. The Part-3 of Beginner tutorial on How to get started in Slic3r is out - Printer Settings in #Slic3r

‪#3DPrinting ‎ ‬ ‪#reprap ‬ ‪#gcodes ‬ ‪#prusai3‬
#iltms +Ultimaker +MakerBot +3Ding 3D Printers
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Volker Klaffehn

Show-n-tell  - 
Z axis again :-) Experimenting with a dual motor Z axis for the next iteration of my CoreXY, trying to get away from canitlever design.
Thomas “Balu” Walter's profile photoBrook Drumm's profile photoalain frenois's profile photo
Yes, I think do. I've built a few of this design... 1-offs. The alignment has to be perfect so a z motor doesn't jam and lag lower. After doing a few, I am thinking the two z acme rods should be linked to one motor. Laser cutters do this to good effect. Ultra low cost was the reason two z motors were introduced, but now, reliability and repeatability are more important.
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Andreas Thorn

Show-n-tell  - 
After a gazillion revisions I finally got to mount my 3D printed handwheels on my mini lathe (MJ-189, Emco Unimat 4 clone) and try them out.

It's great to have resettable dials which the originals lacked and the larger size really improve the surface finish. I am using carbide tools on aluminum so mirror like finish isn't to be expected but with the new handwheels in place it is much easier to maintain a constant feed and surface finish is actually beyond my expectations.

Very happy with these.
11 new photos · Album by Andreas Thorn
Kurt Meister's profile photoAndreas Thorn's profile photo
+Kurt Meister nice :)

I'm not sure about Emco. I got my lathe used recently and the model was sold new around 2001 here in Sweden.

Lathes named Unimat do exist new from a company called thecooltool (duh...)
But they look more like toys or very low end entry models even compared to my little lathe which can handle quite a bit if handled accordingly.

The thing about the real/clone Unimats from the time is that unless you get lucky accessories are pretty expensive and can be hard to find compared to other machines in the segment on the current market. If I'd start over from scratch I'd probably look at a Taig/Peatol (with larger spindle bore upgrade and brushless motor), Proxxon or Sherline. Proxxon seem most capable out of the box but Taig/Peatol sure is the most hackable/extendable and most value for money of the three.
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Questions/Help  - 
Any suggestions how I can get rid of this?
Wood filament seems to crumble even with 0.85 extrusionmultiplier. Diameter set correctly, e steps are correct. I only have this with laywood. Turning down temp to 205 deg helped a bit but not much...
René Jurack's profile photoLord_Vader's profile photo
+René Jurack like old jhead nozzles mhh
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About this community

A community centered around 3D Printing which is accessible to everyone. This includes open source designs, home built printers, and the sharing of information which helps everyone gain access to this wonderful technology. The people here are very enthusiastic about 3D Printing and always willing to help. Ask questions! Show us your ideas! Help advance what is possible! We have a strict policy on spam and irrelevant content; which includes closed source, patent encumbered development, and self-promotion - if the users cannot replicate what you're posting, it probably doesn't belong here. No analytic URL shorteners. This includes,, etc. This just goes to show that you're not interested in participation, but only how this community can benefit you. Links:

Brook Drumm

General discussion  - 
Harmonic Linear Actuator / Drive

Ive been enamored with harmonic drives for things such as robot arms. But it's patented and expensive. Models exist on thingiverse that allow you to print one but after printing emmet's design, it's not robust.

Then I found this a couple days ago..

It's patented but a simple way to make a harmonic linear drive to power Cnc / 3D printers with very high drive ratios and zero backlash! Just belts, different sized pulleys and gears

Has anyone used this setup in a 3D printer or Cnc application? I will build one to test. It seems that it offers improved accuracy, specifically no backlash. The drive rations mentioned are pretty low nothing like harmonic drives for robot arms, but the hardware needed is at our fingertips for cheap. I will probably try first with steppers. But if it's really no backlash, it could work with servos (closed loop brushless motors).

Ive dreamed of open source hardest/firmware for years, haven't we all?! But lacking this, I bought teknics servo killers :

They offer closed loop in a self contained package and are quite nice. I've tried them with belts, but I was using dual y belts and their support said this was impossible to tune... Back to drawing board. Then we tried them with acne screws but the torque seemed to be lacking since my y axis was incredibly heavy. This linear harmonic drive setup would offer increased torque with zero backlash and looks like a good solution to couple with the tekinic servos... Maybe there would be increased accuracy and faster movement with steppers alone.

Since I don't know if any open source electronics/firmware that run servos (I assume the host software / slicer would be unchanged), maybe this configuration offers advantages.

The use of belts on Cnc, with very heavy carriages/hardware could benefit from both the torque and accuracy. But there would be a limit to speed with steppers, I would think. I found video examples of the harmonic linear drive in use with a large Cnc using servos, though. I assume it saves money to use belts over acne rods and acme rods are practically limited in length to 3 meters from what I can tell... Shipping sizes, I presume.

So is anyone up to design and build a machine with this setup to test accuracy and other benefits?

The example diagrams show a rather low drive ratio. I know there is always a trade off in design... So I assume the higher drive ratio you use, the less speed you could have access to. But you would get increased torque. I suppose that finding a sane amount of torque / drive ratio for a 3D printer or Cnc would be the goal that translates into increased speed... To meet the limits of hardware and rigidity that you have on that machine.

I think Cncs will run up against the limits of cutting speed for a given router, spindle or cutting bit, but cheap, 3D printable robot arms always run up against torque issues first... Ok, and arguably rigidity comes into play.

Robot arms are an interesting study for these linear harmonic drives... Kuka arms do use harmonic drives. They need high speed (low torque) motors but require low speed movement with very high torque at the joints... Thus, the combination of fast motors or servos (closed loop using encoders at the motor?) and high ration harmonic drives for converting that speed into manageable torque with the magic of (near) zero backlash.

I assume that you can license the patents for harmonic drives, but the hardware is very tough to build and therefore expensive. I also assume you can license the patents for linear harmonic drives, but the simple, lower cost hardware seems to give it an advantage if you are looking for cheap, high speed motors to deliver the high torque at the joints due to the potentially huge drive ratios in a cheSp mechanism you can build at home.

So why has no one, to my knowledge, build a home brew version of this? Or licensed the tech for a Cnc or 3D printer? Since we use belts and it's all about linear motion, it seems a good fit.

I found a 2009 RepRap post asking the same thing but it didn't go far.

I also found the patent.

Of particular interest is also fig. 12, 18, 22 which show other embodiments - although I didn't understand if it was prior art/inventions or derivatives of the new design. All are interesting. They specifically call out the use of this applying to robotic arms.

Note: I saw a YouTube video of a Kuka robotic arm tear down and was surprised at the extensive use of belts. I didn't investigate further, but I assume they are used to get the weight of the motors off the arm... Not to use this type of system. Anyone who can confirm this?

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Dead Pool

Questions/Help  - 
Hi guys, I seem to be having an issue with my wanhao duplicator i3 V2. For some reason as it lays down pla it switches lines to quickly making the ends turn up, and as it passes through again it catches it pulling the print off the bed. If you guys have any suggestions that will be great. Also I have leveled the build plate and cleaned out the nozzle.
Dead Pool's profile photoJustis Saayman's profile photo
No on the printer itself - Configuration -> acceleration -> Jerk and Move, go back and click on Save to EEPROM +Dead Pool 
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Steven Cadd

Custom-built & Reprap  - 
Being a Boy Scout in your youth often helps later in life.

Case in point: this morning as I read the news and had a cuppa there came a thunk from my Tricolour Mendel. Peering bleary over my monitor I find the y rail holder has decided to give up the ghost after two + years of unswerving support.

Having given out my last pack of spares I was a bit stuck. Until I remembered I can do knots.

I have no idea what the basis of this knot is (a sheep shank?) but who cares - with a bit of lashing it's enough to get a new set of clips printed!
Steven Cadd's profile photoBrook Drumm's profile photo
Man, I love reprappers.
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dstevens lv

Electronics  - 
Import RAMPS DOA Stats

There has been discussion from time to time about how the low cost import boards fare. Here are is a breakdown of DOA and failure returns. I do a basic test when they are flashed but some failed shortly into use. Most live long including the ones I've used here with hundreds of hours duty cycle.

118 iduino ATmega 2560 clone boards, Geeetech
7 total bad 5.9% USB connection or power reg issues

2 Arduino clone boards for evaluation Aliexpress vendor 100% loss, both needed bootloaders flashed. They work now, I didn't sell them. When they got here they were counterfeit. The listing pic showed plain green board.
The parts and boards look good but there are obvious issues in the silkscreen making it obvious they are counterfeit. Pretty good for US$8 each, they didn't need to go counterfeit.

5 ATmega 2560 clones for evaluation Taobao vendor. 100% loss, not flashable, would not power. Assuming bad or counterfeit parts particularly at US$4 each, including ePacket from Shenzhen. Board quality and PCBA was bad. At US$20? Why not, was worth the gamble.

118 Geeetech RAMPS 9 total bad 7.6% mosfets and connections, some shorting when driver boards inserted. On two in the field the bed fet was so poorly installed they fell out under heavy duty cycle.

10 Bigtree RAMPS from Arduino counterfeit guy. All are good, no issues, boards were a bit rough, connector shrouds easily pulled off.

500 plus Stepstick boards, under 2% mostly due to screw pots failing though I don't know if it's user caused. I did have a couple that wouldn't allow the RAMPS to boot , when I removed them and replaced them the boards booted fine.

40 Genuine Pololu Black driver boards. 0% failure,

We're at the point now where like most of the other entry level kits the entry level electronics have been commoditised. 
ThantiK's profile photodstevens lv's profile photo
The point is to show that in general my experience has been positive with entry level electronics. If you are having assemblies fabbed in the thousands the prices are dirt cheap for good parts. Overall I'm pretty pleased with the results.

If the Smoothie based boards (or any other board) gain traction and are built in 10k runs, the prices will plummet. At this point though I see the non kit DIY segment slowing (that is where you self source your parts) to where what allowed RAMPS to be ubiquitous are no longer in play.

The low buck kits add more new users due to price but not new features or technology. We are witnessing another shift in the entry level printer market. It's shifting to a market where people want the functionality of the tool rather than building and tinkering with the tool itself.
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Anthony Martin

General discussion  - 
Paul Gross's profile photoLord_Vader's profile photo
Does anyone manufacture a tungsten-carbide nozzle? 
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Adrian Ciubotariu

General discussion  - 
sooooo I found this channel, small but fun and the guy has a good vibe to his work. he printed this beauty:

and here is the video (to check some things on his channel)
Commercial Use / No Derivatives  Please respect the model and the artist and do not post their work on other sites   I am VENGENCE, I am the NIGHT, I am BATMAN!!!! Fight crime and save your neighborhood from all the evil doers lurking in the shadows.  One person can make a difference    Click below and watch this cowl come to life by awesome DIY'er UncleJessy4Real . AMAZING VIDEO!!!  WATCH...
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Alex Skoruppa

Custom-built & Reprap  - 
#CarbonoidD1 just started replicating itself! I spent around 2 hours to find the settings where the #HDGlass filament keeps sticking to the #Filaprint surface: 225°C for the nozzle and 70°C for the bed.
christophe malvasio's profile photoMike Miller's profile photo
Don't be pedantic. 
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Panayiotis Savva

Show-n-tell  - 
Calibrated with specs from M8 data sheet.
I calculated 304 steps that was needed.

Nozzle 0.4mm
Layer height 0.2mm
Extrusion width 0.48mm
2 shell Parameters
180Deg temp
PLA 1.75
Extrusion multiplier 1
The cube is a 20 x 20mm

0.48 per outer parameter X 2 parameters = 0.96 expected shell thickness.

I think I'm on the right road now.

Anything obvious you notice that needs further refinement, please post.

Thanks everyone for your advice and help.
Keith Applegarth's profile photo
+Trhuster I stand corrected!
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Alex Skoruppa

Custom-built & Reprap  - 
I just installed the Filaprint surface from +Filafarm on #CarbonoidD1  no. 2. I am very curious if it works as good as Filafarm claims!
Step Cia's profile photoAx Smith-Laffin's profile photo
Just looked at the pricing on this.. ouch.. €63.89 shipped for a MK2 size piece. Over a 4 years, it's going to be a saver, but for an initial outlay on something that may work over buying a can of hairspray a month and repacing a cheap glass pane once a year, which I know works, (being generous on that, btw, should last a lot longer, just compensating for of it should crack etc), think I'll stick with the glass and hairspray.
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Panayiotis Savva

Questions/Help  - 
Advice needed.

Some Calibration done.
180 Deg PLA
6mm retraction
355 Esteps
0.95 extrusion multiplier.
First photo is the bottom.
Second and third are sides
Last is the top layer.

Any advice to make it better?

You'll notice that the seam (where Z lifts for the next layer is pulled upwards.

Any advice in that?
Panayiotis Savva's profile photo
I calibrated again. Posting a new thread now with results.

I followed +Trhuster​'s advice with the youtube link.
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