My Robo3D upgrades (Smooth rod bed, z-axis stabilization, direct drive extruder)

Hi to all the Robo3D users,

I own a Robo3D for about a year now, during this period, I added some changes which I would like to share at the forum. All files are available on Thingiverse as well as some pictures of the mods. Each of the mod helped me to achieve a better print quality.

1. My first upgrade was the y-axis smooth rod upgrade. I own a Robo3D with the old rail system, it was very weak, I could easily move the bed up and down with only a little force. Since the balls were moving along the axis, the height was not very stable. Robo3D already offered the upgrade, but since I am from Germany I wanted to avoid the shipping time, cost and the disassembly of the whole printer. Thats why I designed my own version, the goal was to reuse the stock bed, not to change the rest of the Robo, keep it simple and affordable and maybe gain a bigger printing area. After some parts (2 40mm Rods, 4 linear bearings, GT2 belt, some standard me screws) for only a little money, I ended up in a quite sturdy printbed which moves nicely over a area of ~280mm.

Thingiverse link:
http://www.thingiverse.com/thing:386602

2. After replacing the printbed, I did some tesprints (off course) without closing the Robo, I found that the z-axis was moving around, not only the threaded rod, but the smooth rod also a little bit due to the threaded rod. For small parts no problem, but higher parts would be definitly be worse. I checked for the available z-axis stabilizers, all of them had in commen that they were glued and mostly only catch the smooth rod. I wanted something to adjust, to be removed easily during disassembly and to catch some of the movement of the threaded rod. I ended up in a simple block with ball bearing and linear movable dampeners. Its very simple, but I was able to print a tiny tube with the height of 15cm without a problem of displacement which was not possible before. Because of the long holes, the displacement from center requires only one part which could be printed four times.

Thingiverse link:
http://www.thingiverse.com/thing:393955

3. Last (and maybe least necessary) mod I did so far, is a direct drive extruder with E3D hotend. The wade extruder is well proven, but I had jams from time to time, and I found the direct drive extruders are way more compact. There are a lot of direct drive extruders on Thingiverse, but each one for different carriages, before creating an adapter, I decided to create the extruder + E3D hotend mount that fits directly to the Robo3D carriage. I am runing the Robo3D in this configuration for a while now without any jam at all, I had to increase the print temperature for about 10° but I think the reason is a different temperature probe, maybe some offset or different location at the hotend. Only negative aspect is, the surface is not as smooth as before at the outer perimeters, due to the missing gear, the resolution of the steps is not as detailed as before.

Thingiverse link:
http://www.thingiverse.com/thing:519320

Keep creating,
Stargrove1

 

Already had your bed upgrade but gave it a twist (few actually that am sure you are aware of)
Thanks allot man, your design made my prints look awesome.

Also working on your direct feed. Looks very promising but does need small adjustments. Springs on ebay are typically 25mm long, but the clearance you have is about the same so there simply wont be enough tension. Diameter is kinda big but ok in case of a larger spring is used.

You were not very clear on instructions of this design as you were for the bed upgrade, it would be awesome if you would provide details on the bearings, washers, nuts and screw size and length required to put it together.
Maybe some existing material can be used ?

Thanks for your work.

 

I am glad to hear that it improved your printer as it did for me.

I went to the local hardware store (Obi ) and bought one of the available springs, then I designed the lever for it. But a simple way to make it adjustable is to add a hole and a hex pocket for a nut, then you could use a screw to adjust the distance. Or create your own lever. If I find some time at a weekend, I could add it to the thingiverse fileset.

I updated the BOM and added some instructions, I hope that answers your questions. Some parts could/should be reused, especially the Nema17 stepper and the fan, this also avoids the rewiring of the components .

 

Cool, thanks !
Am not so sure about the pocket being the best way, maybe design an insert that can be printed separately from the lever ?
That way to match up the height of the spring can be solved by scaling up the insert part rather then redesigning entire lever or having nuts and bolts involved.

I think there is plenty of room to simply make an insert that would fit into existing setup at the base "spring space"
Ill try to come up with one sometime my self since i already have an idea.

 

Love your work guys.

 

Ill test it when the red thing finish printing.

 

I guess a simple cylindrical design would do the trick as well, but your quick in CAD I must admit . I would be happy if could do that too, would make the realization of my ideas a lot easier lol.

 

Am not much on ideas, i am more on perfecting them or simplifying.
I wish i had anything in my head of my own, but i dont.

 

Next time I have an idea of an extruder or something else, I hand it to you for the 3D design ;-)

 

Here is what i came up with using bigger bearing that i had.

The cylinder inside is printed in such a way that allows it to be flexed just enough to go into the the hole thru the bearing and exit the other end flash against the surface.
It then expands and stays in place as a retainer.

However, i dont think its possible with your version because yours is smaller and you can only go so small with 0.4m nozzle.

I used 8x16x5 bearing.

I also thought to design the spring area to match up to springs ROBO's extruder is using.
Those springs can b e moved one into another making them as one and perhaps strong enough.

 

Nice cylinder to fix the bearing, its ok for me with the M4 screw, easy to use as well.

Good luck with the spings, but I am not sure if they stay in place since they are very unstable and may move to the side. The springs I got are very strong and do not move to the side. You may have to add a bolt like in the Robo setup to ensure they remain in position.

 

I guess posting few versions of same thing to accomodate for possibly available hardware is a good idea.
Like my bed, designing i use screws that were left from rails.

 

Here is what i came up with.
My goal is to use as much left over hardware as possible.
Not only i can reuse robo springs, but screws that held the motor will also work.

Slight changes with the pivoting screw to allow just that, as well as more inset for other screws so that old screws that held the motor could be used.

I am thinking about reusing screws and nuts on the current extruder spring mechanism, but i would have to create a nut insert in the piece that locks the nozzle in place instead.
Right now you have those inserts in the base of the assembly and its fine. I personally think that it'd be easier to not only have it my way, but it will also make those screws accessible from the right which would make it allot easier for most right handed people like me.

Here is what i have so far. I was not able to test it because the MK8 pulley did not come with a screw, so i gotta wait again before i try.

 

Ok, i think i entered the "TESTING" phase.
I still need the locking screw for the MK8 drive gear that will come Monday or Tuesday, i will then be able to tell 100% if it worked or failed.

Picture reflects all printed parts and screws required.

 

Reason why i started to look for another extruder is to reduce whiplash effect caused by center of weight of the extruder was sitting to far away from the belt.
Your setup does help allot by dropping the motor down and moving it closer toward the belt.
How ever its not exactly what i had in mind when i saw it.
I thought that motor would be behind and i would see the mecnahism in front of me.

Personally i dont understand why old extruder was setup in such as way that feeder is in the back. Gotta go around every time to change.
So i came up with what i already have but in reverse.

This print will REQUIRE to shave off some plastic from BLACK carriage to allow nozzle to fit thru, but it should be eazy and no accuracy is required.
Also Base and Base Extruder clamp need to be printed. Everything else is unchanged.

This way there is very little weight at the front which helps to fight the whiplash effect.
Benefits are simple:
1. Faster speed
2. More accurate
3. Easy acces

I dont have a fan in mind yet, but i saw plenty of bigger fans on thingiverse that would have no problems attaching at the front or even in front of the assembly as there is plenty of room to do just that.

 

Since you're retaining the stock x carriage my low profile fan duct design will fit front or back. The brackets clip to the carriage for easy attachment and removal. I've noticed my bracket design has been used by a few others which is good to see.
http://www.thingiverse.com/thing:431160

 

Exactly what i had in mind.

My next challenge all those wires i have left hanging.

 

With a direct drive extruder setup isn't the extrusion length accuracy reduced?

Will the stock extruder nema motor handle the extra torque requirements for direct drive extrusion?

 

From what i found it will get hotter.
How much hotter and IF its dangerous i dont know.
There is room at the front that i can perhaps modify to fit the stock 40x40x10 fan. Should be enough.

 

I have some 40x40 heatsink I'm yet to attach to my nema motors. I want to design a clip on bracket to hold them in place. But that's after I finish your bed upgrade.