Carbon Arms (Again)

I really liked bgkdavis' idea of the Carbon Arms and as we have had some breakages with the Acrylic part we decided to have a go at making some too.

First I built a simple jig to make sure all the Arms were kept the same length. This consisted of a nice thick block of planed and square timber, and some 6mm dowl. I marked two holes in the timber using an acrylic arm as the template to get the centres correct. I then used my pillar drill to drill fairly deep 6mm holes (about 25 - 30mm) to hold the dowl. I then sanded down the dowl in the pillar drill to get them to about 5.5mm just enough to be a sung fit over the ball-end joints - no play. The bit of the dowl in the chuck stayed at 6mm to go into the jig holes.

I then made a small holder for the Ball-end joints to hold them still and vertical and drilled out the end by about 5mm deep to 4mm dia to accept the carbon rod.

Once I knew how tall I needed the down I trimmed them and sanded the top down a bit more so it would take an acrylic arm to keep the tops at the same distance apart (about 5mm dia).

Then it was just a case of doing a dry run to get one carbon arm the right length and then cutting the other 5 the same (A little difference in the carbon makes no odds as they are Epoxy'd into the ball-end joints).

Hopefully tonight the epoxy will be hard and we can test them out :-)

Some images attached showing the jig etc...

Very nice, wish I made a jig, I made mine by cut, measure, trim, repeat, which was time consuming to say the least.

I like your idea to use the original acrylic arms as a spacer.

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Got them on last night but man they were tight... I had to immerse the arms in a pan of boiling water for a few minutes to soften the plastic a little. Then quickly dry, grease and pop them on the balls. But we did a test print and they work :-D

Next will be to re-callibrate the machine I think before we print the new version 1.0 replacement parts.

Thanks for the idea. They "look" much better than the acrylic parts and I am sure will be more robust.

Were they just tight to pop on? do they move freely once they are on?

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Yes - they move fine once on but there was NO WAY I could push them on without softening them up a bit.

Maybe I just have stronger fingers , btw when you want to remove them, needle nose pliers work great as a lever.

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

To avoid loose joints, I suggest the following when using Traxxas rod ends:

1. Buy twice as many joints as you need.

2. Assemble them before attaching them to the rods. Soak the balls in the freezer and put the rod ends in boiling water. Then use this assembly tool [www.thingiverse.com] to snap them together.

3. When they are all assembled, check them for play and select 12 with no play.

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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
To avoid loose joints, I suggest the following when using Traxxas rod ends:

1. Buy twice as many joints as you need.

2. Assemble them before attaching them to the rods. Soak the balls in the freezer and put the rod ends in boiling water. Then use this assembly tool [www.thingiverse.com] to snap them together.

3. When they are all assembled, check them for play and select 12 with no play.

Mine have play as well hence I am moving towards IGUS DRYLIN KBRM-03 ends which come pre-assembled and have no discernible play in them. only issue is they are a little larger body than Traxxas joints and need a little bit of a trim on one edge at the effector end oh and the price but you get what you pay for (A set of 12 comes in at £34 when you add the VAT and Carriage).

You also have to use 3mm id tube for them but if you use 3K Weave tube they are plenty stiff enough at upto 350mm long

Doug

These are mugen seike Ball ends they are for 6mm balls, the traxxas are an imperial size, and about 0.2mm smaller

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

So I've got my Fisher up and running (kinda blown away at how I managed to get it working first go!)
I've read that carbon arms are a sensible upgrade, so I've been looking for what seems to be the most difficult thing to source, the ball-end connectors.

I've seen on ebay you can get a few 6mm ball-end connectors, and in most cases, it's about £4 ish for 4 connectors.

like this

So my question is (and please forgive me if this is a dumb question...)

Can I print my own?

Quote
RoboticMonk3y
So I've got my Fisher up and running (kinda blown away at how I managed to get it working first go!)
I've read that carbon arms are a sensible upgrade, so I've been looking for what seems to be the most difficult thing to source, the ball-end connectors.

I've seen on ebay you can get a few 6mm ball-end connectors, and in most cases, it's about £4 ish for 4 connectors.

like this

So my question is (and please forgive me if this is a dumb question...)

Can I print my own?

Not answering your question - but I used these ones from ebay - [www.ebay.co.uk]

You'll need two packs (they come in 10's) and will work out at £12.50 delivered and you'll have 8 spares.

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DC42 Kossel 330mm x 2meters
My Thingiverse Creations

Quote
DADIY
Not answering your question - but I used these ones from ebay - [www.ebay.co.uk]

You'll need two packs (they come in 10's) and will work out at £12.50 delivered and you'll have 8 spares.

Thanks for the link!

I also found this thread
[forums.reprap.org]
Which seems to not only answer the question, but have a link to the stl file.

As always seems to be the case with tinkering, I seem to find myself asking more questions, like "how accurate are my prints?" and "do I need to make sure I'm all calibrated before taking on the task of printing out a part?", which leads to asking "what's the best way to calibrate?"

I think I'm falling down a rabbit-hole...

A common choice for delta printers is Traxxas 5347 rod ends, 20mm M4 set screws, and 6mm o.d. carbon fibre tube. The Traxxas ends are widely available on eBay and from RC shops.

There are several existing threads in this forum about calibrating a Fisher.

---

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].

The traxxas ball ends are imperial sized, where the fisher balls are metric, because of this the traxxas are too loose (I tried them), there may be alternative metric ball ends, but after visiting half a dozen rc model shops and looking at a great many ball ends, the Mugen Seiki ones are the best I could find by a long mark.

---

RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

The Traxxas 5347 ends take M3 screws through the ball ends and M4 screws in the tails. I didn't find them loose.

Edited 1 time(s). Last edit at 01/27/2016 04:02PM by dc42.

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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].

I ended up going for Carbon arms myself too.
Before even finishing building my printer I'd managed to snap one of the arms, conveniently, the day after RepRapPro ceased trading.
From what I'd read, carbon was the way to go anyway as helped improve stability and reduced chances of future breaks.
I'm very happy how solid it is now I swapped them over!

I had a search for the "Traxxas 5347" and even found a UK supplier, which is great. (here is a link, in case anyone like me is looking to try this out)
Where I'm stumbling, is if I look at the picture of the product, I can see that you get the hollow ball-ends as part of the pack, but they appear to be completely smooth on the inside.
I can't understand how you would fix them in place as I don't seem to recall there being a massive amount of thread left coming out of the effector, certainly not enough to hold the ball in place with a nut on the other side.

Maybe if I do get this bits, I'll see about taking some step by step pictures and pop them up for other people to follow

As Ive already said, I dont recommended the traxxas, they are a bad fit, use mugen seiki they are much bettter, see my original thread for the part details.

Btw just checked the details and I made a mistake, the traxxas were not the sloppy ones, they were one of those that are way too tight, they are used on a 5.8mm ball, you could possibly use them with the supplied balls, but that will mean reworking the mounting structure.....Mugen seiki are way better.

---

RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Quote
bgkdavis
As Ive already said, I dont recommended the traxxas, they are a bad fit, use mugen seiki they are much bettter, see my original thread for the part details.

Btw just checked the details and I made a mistake, the traxxas were not the sloppy ones, they were one of those that are way too tight, they are used on a 5.8mm ball, you could possibly use them with the supplied balls, but that will mean reworking the mounting structure.....Mugen seiki are way better.

Definitely agree. The Mugen Seiki are perfect fit for the existing metal ballcaps that RepRap supplied.

Quote
ByteSlinger

Quote
bgkdavis
As Ive already said, I dont recommended the traxxas, they are a bad fit, use mugen seiki they are much bettter, see my original thread for the part details.

Btw just checked the details and I made a mistake, the traxxas were not the sloppy ones, they were one of those that are way too tight, they are used on a 5.8mm ball, you could possibly use them with the supplied balls, but that will mean reworking the mounting structure.....Mugen seiki are way better.

Definitely agree. The Mugen Seiki are perfect fit for the existing metal ballcaps that RepRap supplied.

I used the Traxxas ends, they were very tight, but I have found them to be much quieter and no problem on movement. They were *very* tight however and are a pain to get off easily so bgkdavis is probably right about the mugen being better. But Traxxas (or as I used) traxxas knockoffs (£7 for 12 pack) were acceptable alternatives.

Quote
dc42
A common choice for delta printers is Traxxas 5347 rod ends, 20mm M4 set screws, and 6mm o.d. carbon fibre tube. The Traxxas ends are widely available on eBay and from RC shops.

I made some like above for one of my Fishers. The rod ends weren't even offial traxxas, but matching dimensions and part number. I don't find them loose, you just have to assemble them correctly. (Edit: Used these: [www.ebay.com])

I had the plastic parts in hot water, froze the metal part with -55c cold spray a second before assembly, and mated them using an M3 screw, nut, and a spacer. Just to clarify, I ditched the threaded balls that came with the Fisher, and used a nut in their place to hold the rod ends. I needed to print spacers to avoid rod hitting effector and carriers.

Edited 1 time(s). Last edit at 02/24/2016 11:30AM by StupendousMan.

Quote
StupendousMan

Quote
dc42
A common choice for delta printers is Traxxas 5347 rod ends, 20mm M4 set screws, and 6mm o.d. carbon fibre tube. The Traxxas ends are widely available on eBay and from RC shops.

I made some like above for one of my Fishers. The rod ends weren't even offial traxxas, but matching dimensions and part number. I don't find them loose, you just have to assemble them correctly. (Edit: Used these: [www.ebay.com])

I had the plastic parts in hot water, froze the metal part with -55c cold spray a second before assembly, and mated them using an M3 screw, nut, and a spacer. Just to clarify, I ditched the threaded balls that came with the Fisher, and used a nut in their place to hold the rod ends. I needed to print spacers to avoid rod hitting effector and carriers.

If you had to use spacers, what is the distance between the centres of the balls now, I assume you've used spacers on both the carriages and the effectors to keep the arms parallel?

Just open question, not sure I've seen this anywhere but is there a reason why carbon is being used instead of 4mm aluminium rod?

e.g. Alum Rod - Wickes

Edited 1 time(s). Last edit at 03/24/2016 09:44AM by geeksarebeta.

Having used some of that rod from wickes, I would expect the carbon fiber to be much straighter. Also I only used 3mm rod and have not had any issues with it.

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DC42 Kossel 330mm x 2meters
My Thingiverse Creations

What should be the exact length of the carbon fiber rods without the ball ends?

The length without the ball ends doesn't matter its the length with the ends that is critical.

If you think you can precisely cut the rods and assemble the arms and get them perfect then you are probably going to be dissapointed

---

RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Quote
bgkdavis
The length without the ball ends doesn't matter its the length with the ends that is critical.

If you think you can precisely cut the rods and assemble the arms and get them perfect then you are probably going to be dissapointed

How precise I can cut is my problem. It would be great if someone could just answer a simple question: what should be the carbon fiber rod length without "Mugen Seiki" ball ends to get print volume similar to the original.

Have you guys seen this?

Rod ends kits

comes as 180 instead of 160, but its a complete kit. though i know these are the imperial sized ends rather than the metric.

Edited 1 time(s). Last edit at 03/30/2016 05:29AM by Sean.kennedy.

Quote
Sean.kennedy
Have you guys seen this?

Rod ends kits

comes as 180 instead of 160, but its a complete kit. though i know these are the imperial sized ends rather than the metric.

* If you choose "preassembled" option, it says they don't have it in stock

* Ball ends might not fit on Fisher's small balls

Edited 1 time(s). Last edit at 03/30/2016 05:34AM by hakimio.