Voron CNC Kits

[ChicagoKeri]

I couldn't find a thread for CNC Frame Parts for Voron, so here goes...

On the latest iteration of my Voron 2.4 I decided that Earthing everything possible might be a good idea.  My initial plan involved many Earthing wires or graphite spray paint but I came across something I like better.... Replace many of the plastic Voron 2.4 frame parts with CNC metal ones!

In addition to providing electric continuity to parts of the Voron that were previously isolated by plastic parts, the metal parts should increase strength and rigidity at the cost of some additional weight in addition to being far more tolerant of elevated internal temperatures.  And if the parts are of decent manufacture, perhaps better tolerances than plastic parts.

As I print mostly in ABS with the chamber as hot as I can get it and have had bolts loosen in plastic parts, this seemed like a great idea!  But which CNC kit to choose?  There are many out there right now but I felt it wise to stick with parts designed similar as possible to the original plastic parts, as opposed to radical redesigns that take advantage of aluminum's greater strength.

Fortunately for me, the CNC kits that most closely follow the plastic originals are "last years models" and are often discounted heavily.  So I settled on a no name kit that looks very much like FYSETC's "Voron 2.4 R2 CNC".    (picture is of my kit, not a genuine FYSETC)

This kit contains all of the important structural parts in aluminum and very few trim pieces.  It also contains just the bolts that are different than those used in a standard build.  It includes aluminum parts for the older Afterburner extruder, including an X Carriage. As the  X/Y joint pieces are thinner at the Y carriage mounts, two spacers are included for the X/Y endstop pod.  What the kit does not include is any kind of instructions or packing list but that's OK!

Assembling the kit went well, considering the Voron had to be disassembled quite far to install it.  A total of 4 tapped holes out of dozens needed to have their threads chased with a 3mm tap.  Otherwise, the parts all fit precisely, better than the plastic originals had with one curious characteristic: Neither the Z belt adjusters or the X/Y Belt adjusters lock when tightened down... it seems the makers wanted the belts to be more easily adjusted. I remedied the Z tensioners with a piece of felt tape on the side so that they lock when the mounts are tightened, and the X/Y seems OK the way it is.

Here is one way to Earth the entire "Y" Gantry with just one Earthing wire.... a shielded CNC cable leading to the "B" Stepper.

 

Here is an all-metal Z Drive. The Z drive and Z Stepper mount are now much more sturdy than the extrusions they attach to. The shaft, bearings and pulleys all fit as they should.  As the 6 bolts do not need to extend all the way through the mount, they are a lot shorter and are included.  Excess weight is no problem at all, here. 

The pulleys all seem to rotate better than before, especially at the X/Y joints. This is apparently because of some subtle machining at the area of the pulley... it would take a tiny, thin washer to replicate this.  This feature is advertised as thus: "The 2.4 R2 CNC parts kit adds a screw isolation layer on the idler of the XY connector to avoid wear and jamming."  Sorry, I didn't get a picture.

 

And here it is, ready for a test print...  The Gantry assembly was very nearly perfectly square on the first attempt with only one small adjustment needed.

 

An Ohmmeter indicates that my Earthing exercise (in futility, perhaps?) has succeeded!   I had previously installed a Mellow CNC TAP and Earthed the Hotend.

Time for some test prints. Fortunately I had printed an Orca Cube before disassembly... Before is White, After is Red, in ABS, a 0.6mm Revo nozzle with the same file and before any tuning... printer.cfg completely untouched.

I already like it! It seemed to actually print a bit better, an unexpected bonus. The threaded bottom plug now turns more easily by hand and goes in a bit further.

   

 

So, if you intend to print at high temperatures or just like the ability to get proper bolt stretch and part clamping resulting in higher rigidity or maybe if you want really, really solid feet / Z drives that will withstand any foreseeable impact ... perhaps a CNC frame kit is for you!  

But it's better to get it before building the printer unless you liked building it so much the first time you can't wait to do it again... 

 

 

[geekandi]

Thanks for sharing!

Wanna give us an update after a couple hundred hours?

[ChicagoKeri]

Update on CNC - Modified Voron 2.4:

After some running-in and belt adjustments, the next Orca Cube came out even better.  So, time for a SHAPER_CALIBRATE command!

Here are the resulting X and Y resonances charts:

First, the X axis:

 

 

Then the Y Axis:

 

I feel that these might be pretty good results, especially considering the improvement in print quality.

 

One thing I think might need a bit more work - when the steppers shut down, I get a bit of droop on Z1... apparently either the bed is a bit high in this corner, the frame is no longer square or the gantry a bit twisted.  As it prints better than ever, I'm not especially concerned about this.

 

[Dirk]

On 3/24/2024 at 5:27 AM, ChicagoKeri said:

get a bit of droop on Z1

Thanks for sharing. 

Your x and y graphs really look very smooth. Just a single bump. Nothing else.

Did you consider using the ge5c mod? This should prevent such droppings. 

And if you find another cause, like the not so square frame, let us know.

 

If the gantry would be twisted, it would show up in your bed mesh. And cause you a lot of headache in doing first layers 

So I doubt thats it.

Edited March 26 by Dirk
Strange English... Autocorrect?

[geekandi]

9 hours ago, ChicagoKeri said:

One thing I think might need a bit more work - when the steppers shut down, I get a bit of droop on Z1... apparently either the bed is a bit high in this corner, the frame is no longer square or the gantry a bit twisted.  As it prints better than ever, I'm not especially concerned about this.

There is more weight on that back right corner where the wiring, Z-chain mounting etc.

This is 'normal'.

One way to help deal with it is to park the toolhead at the front left (0,0) when a print is complete. It will still drop though less as the weight has been moved away.

I still park at (center, center) in the rear and just let QGL take care of things on the next run.

[ChicagoKeri]

Latest test print, a CaliFlower, indicates Voron 2.4 CNC has Dreaded Skew Disease of 0.1º .... roughly similar to Stepan of CNC Kitchen's Bamboo Labs X1 Carbon.   

As a comparison, Voron 0.2 has only 0.06º of Dreaded Skew Disease.

Perhaps I will get around to mechanically reducing this but for now [skew_correction] is in play.....

[geekandi]

11 hours ago, ChicagoKeri said:

Perhaps I will get around to mechanically reducing this but for now [skew_correction] is in play.....

Chase that dragon!

[iiianydayiii]

If you find you don't like the anodized colors, you can easily clean it off to the base metal w/ a lye solution.  Takes a few minutes.

[Nilrods]

Great post!! I am getting parts for my build and decided to use some CNC parts myself.

Glad it sounds like the metal CNC parts are working for you.

Where did you purchase the kit you used?

 

[chrisalbertson]

About grounding or "Earthing" the frame.   Watch out, the aluminum is anodized.

 

If you have seen those special green grounding screws, they have what is called a "disrupted thread", that is a thread that is wavey and with some sharp parts.   This is so that the screw digs into the metal as you tighten it.  The digging in scrapes off any oxide coating.   Aluminum oxide is not conductive.

It is common to either use these special screws or to use a special kind of lock washer that scapes into the metal to both make electrical contact and to keep the screw from vibrating loose.

Using a normal M3 screw to hold a flat terminal to an anodized extrusion is not going to be very effective.  The metal needs to be roughed up

I suspect this might matter.  The DC outputs of Meanwell power supplies "float" and ABS filement sliding through a plastic tube might create static electriity.  There probibly should be a path to Earth-grouund

 

I am also wondering if it woiuld be best to tied the DC negative bus to Earth.  Some options are (1) do nothing, (2) bond them together or (30 connect them with a high value resistor, like about 1M or 100K