Double Helix Extruder Gears - iamburny Style

Following on from yesterdays double helix Z Gears [forums.reprap.org], I thought i'd have a bash at some extruder gears too (just so it all matches!!)

I'm pretty pleased with the results, I have also started a new Github repository for the STL's and scad files for my Upgrades, most of the files are now too big to be attached to posts, plus github has a lovely STL viewer =)

Ormerod Upgrade Github

---

Limited Edition Red RS Ormerod 1 #144 of 200 - RRP 1.09fw
iamburnys Ormerod Upgrades Github
Follow me on ThingiVerse My Designs

I'm a novice when it comes to gears (and mechanical engineering generally), so can you tell me what is the advantage in this application of double helix gears over single helix gears?

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Apart from looking very pretty, I found there to be significantly less play in the gears, I believe the technical advantages are to do with smoother delivery of power so ideal for the extruder if you have a high retraction setting.

the wikipedia page is sparse but confirms my thoughts [en.wikipedia.org]

Matt

---

Limited Edition Red RS Ormerod 1 #144 of 200 - RRP 1.09fw
iamburnys Ormerod Upgrades Github
Follow me on ThingiVerse My Designs

Single helical gears give smooth drive, but also have axial forces on them. Simple trigonometry on the angle of the helix, will turn the torque into that force.
The double helix is slightly less smooth (the length of the gear tooth is half), but it does cancel out any axial forces.
Greg

---

Ormerod #17

Thanks, Matt.

May I suggest another part for your upgrade library? It would be useful to have a version of the y-motor bracket that has a hole and nut trap in the back to take the 4mm screw from the Duet enclosure. That way, the Duet box could be slid further along, making more room for fan inlet ducts etc.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
Thanks, Matt.

May I suggest another part for your upgrade library? It would be useful to have a version of the y-motor bracket that has a hole and nut trap in the back to take the 4mm screw from the Duet enclosure. That way, the Duet box could be slid further along, making more room for fan inlet ducts etc.

I had a shock when I first tried to zero X axis with my newly printed fan backwash clip on and it hit the Duet enclosure!

@dc42 - fixed the support of the Duet enclosure by adding another vertical support inside, it clashes a bit with the backs of the header pins and ive been meaning to add some stand-offs on the internal duet mounts, but it is fine of you dont screw the duet board in tight.

Custom Duet Enclosure

Matt

---

Limited Edition Red RS Ormerod 1 #144 of 200 - RRP 1.09fw
iamburnys Ormerod Upgrades Github
Follow me on ThingiVerse My Designs

Hi Matt'

How do you access the stl viewer in github please as I could not find it.

Cheers

Dave

Edited 1 time(s). Last edit at 02/10/2014 05:26AM by davetech.

davetech just click on any .stl file in github like viewing normal source files. If your browser do support WebGL it will be rendered in a viewer automatically.

I've come to the conclusion that I'm just plain thick, cos I have problems with github to.....
Sometimes I can get the files a treat if there's a big download button, else I'm lost.....
Or going blind..... Oh no that's it...I'm Doomed!!!!..... Not to worry.... I wanted a dog anyway.....
Always look on the bright side of life....

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

PS it was doing those herring bone gears that made me realize my Z axis had slipped out of line....
They don't turn out so nice if it's 5' out... That'll be one of the mods I'll be doing....

And the other reason that herring bone (double helix) gears are used is there is always a section of one of the teeth
engaged in driving the other gear wheel. Which is why they are used in Marine Gearboxes as they
give a very smooth transmission of power (unless your Z axis is out that is.....lol).
[Used to have to blue the teeth and check the mesh of the gears when I was an apprentice...]

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Hi, and thanks for the gears. They work great... now... But printing these made me aware of something I wasn't previously. For example, the large gear has a profile for the hex screw head, but the exact dimensions turn out incorrect, and the head simply doesn't fit. I believe it's about 1 mm to small and I have to file it up. The print appear to be good otherwise. It's like I missed a setting in both Cura and Slic3r. (I tried both) I made measurements in both the STL and in real life; it's not your model, but my print.

Does anyone have an idea if I made a software configuration error?

Are you sure to have done correctly the axis compensation?

Could it be the layer thickness and the over extrusion into the open area, i.e. the hex nut profile?

---

Ormerod #007 (shaken but not stirred!)

Quote
michaelljunggren
Hi, and thanks for the gears. They work great... now... But printing these made me aware of something I wasn't previously. For example, the large gear has a profile for the hex screw head, but the exact dimensions turn out incorrect, and the head simply doesn't fit. I believe it's about 1 mm to small and I have to file it up. The print appear to be good otherwise. It's like I missed a setting in both Cura and Slic3r. (I tried both) I made measurements in both the STL and in real life; it's not your model, but my print.

Does anyone have an idea if I made a software configuration error?

My first couple came out like yours, I changed the 'Filament settings>Extrusion Multiplier' in to 0.95 in Slic3r and the next one was perfect.

Regards,

Les

Thanks for the suggestions. I'll try experimenting with the extrusion when the kids have gone to bed.

I just fitted mine along with Mr Burns extruder block, (the upgraded extruder block has flap to secure the tongue if you need to, and allows you to get the ptfe tube 40mm inside)

On the first test print the motor started stuttering, but after I upped the extruder current to 1amp it's all working beautifully.

Regards,

Les

While trying to find a similar post on hole sizes I found this thread that could be of interest.
[forums.reprap.org]

And just because it was interesting someone got improved prints (different printer) with a change to the nozzle cone shape
[forums.reprap.org]

Excuse the randomness of the above, but worth a look!

[Edit] and this one....
[forums.reprap.org]

Edited 1 time(s). Last edit at 04/12/2014 04:00PM by Treth.

---

Ormerod #007 (shaken but not stirred!)

Quote
Pointy
I just fitted mine along with Mr Burns extruder block, (the upgraded extruder block has flap to secure the tongue if you need to, and allows you to get the ptfe tube 40mm inside)

On the first test print the motor started stuttering, but after I upped the extruder current to 1amp it's all working beautifully.

Regards,

Les

Hi Les, good luck with upping the motor current. I tried it yesterday, and set everything back to 800mA
As for the stuttering, I think you might find your nozzle might have been a fraction low. When it's to low, the table blocks off the nozzle, and then the pressure is to much for the motor, and it stutters.... Have a look at the print you did at the time and see if the first layer was splade out.
It's a trick game getting the height right... With the tall Fan Ducts I use here, I watch the top like a hawk and I can see the top just start to lift as it rests on the the table. As soon as it moves, I go back 0.1mm and set the Z to zero using G92 z0.

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

I think the head level is fine Kim, I had been printing since 8am without issues, until I changed the parts.

I just had a few more stutters, but think I can see why. I didn't pull the hex nut right into the large gear and it has done it itself while printing. I can see about 2mm of thread before the nyloc nut on the other side. DOH!

I also had some twist in the filament, and since I straightened it, I have had no more stutters, but best I tighten up the nut after this print is finished.

Regards,

Les

If they are IamBurny's then they are good gears. But it took me a while to realise my Z-axis was slightly out which messes them up, and you can get tight pots then.

I had my X-carriage bearing fall out from the carriage today.....
I ended up super gluing it back in as I wanted to get a test piece printed in a hurry.
The accident happend halfway throu a long print so I wasn't happy... I was right beside it when it happend, and managed to get the bearing back in on the fly, but it knocked out the X-axis alignment and I had to scrap the piece.... So I tried printing again.... Nope.... No matter what I did it wasn't going to print. I leveled my bed again as it had knocked that out, tried all sorts of temps. Then decided to give up and replace the Nozzle Mount as is was falling apart...
Then I saw the Nozzle wasin't square to the axis... I didn't realise that that could stop it printing till I had put the new mount in place....
It printed first time after that, and the print is nearly finished now.... And it's turning out to be a first class print to....
I must add it to my things to check when it won't print....

Kim

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Well Kim, you will be pleased to know you were correct.

I noticed that the stuttering got less frequent after a few layers, so decided to check everything, I should have just listened to you in the first place!

Something had moved by 0.2mm during all my tinkering, and the head was hitting the glass.

No stuttering so far this morning.

Regards,

Les

iamburny

Thank you for sharing the double helix gears for the Omerod Z axis. Very nice work indeed. I printed a set for my Omerod using the default settings and after removing a few 'nibs' they fitted perfectly.

Incidently I think the Omerod is an amazing little printer, I could not be happier.

RayC40

Hi Ray,

Thanks for posting your experiences, I'm very glad they work well for you.

I've been using mine for over 2 months and nearly 6kg of PLA now and they are still virtually unworn and still backlash free =)

have you tried my Z-Axis gears also? [forums.reprap.org]

Matt

---

Limited Edition Red RS Ormerod 1 #144 of 200 - RRP 1.09fw
iamburnys Ormerod Upgrades Github
Follow me on ThingiVerse My Designs

I made some modifications to the "big extruder gear", might as well share it: http://www.thingiverse.com/thing:306252
(STL file too large to attach here)

When I first tried to make this, my machine had some issues getting things done neatly, so I couldn't get a clean print. The "outside rim" of the gear teeth was very thin and would fall off, and the infill would be pretty messy since it was a lot of individual "stops and starts".

I changed iamburny's gear so the rim is a bit thicker (to make it easier to print cleanly and maybe make it a little stronger), while the central parts are a bit thinner. Instead of having holes in it, it's solid so you can just control the amount of material with infill density. Also made the center hole round instead of hexagonal.

The gear teeth themselves are identical to the original, so it should be 100% compatible with the original design

I've printed it but not actually mounted it since the original gears work fine (there was some play in the original Z-axis gears, but none in the extruder gears so I haven't bothered taking the extruder apart).

Edited 1 time(s). Last edit at 04/22/2014 07:29AM by jstck.

I am looking for a set of these to buy.
I would like the grub nut collar on the small gear.
Any for sale out there?
My replikeo gears were nasty and misprinted. So I am replacing them.
I cant even print a decent set with them to upgrade so I have a unusable printer.
They originals were pla but I would prefer abs if possible. Either kind would be ok if I have to settle.

Where do you live?

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.