David Orlo Centered-Axis Mod for Cartesian 3D Printers

I've developed a modification for Cartesian 3D printers that significantly improves tramming/leveling and reduces or completely eliminates Z wobble/banding with Rev.2 or Rev.3.

This mod not only enhances resolution but also increases Z axis speed, making your printer more reliable and efficient. It's straightforward to implement and reversible if needed.

TL;DR

Rev.1

• A great way to get started with minimal parts needed (printed parts, nuts, and bolts).
• It should resolve any Z Wobble/Banding issues unless your Z Lead is severely bent.
• Z Speeds can at least double, especially beneficial for Z-Hop enthusiasts.
• Only squared up my printer once since the mod and have moved it three times without the need to re-mesh the bed, except for temperature profile adjustments.

Rev.2

• Relocates the Z Stepper to the top of the printer, removing weight from the gantry and altering the dynamics of the force used to move it, contributing to auto-leveling/balancing.
• Features a Non-Captive Z Stepper—meaning the LEAD SCREW DOES NOT SPIN. (Refer to the videos)
• Uses an affordable Nema 17 stepper motor; also a good time to switch your Z Lead to a 1 or 2 start if you're using a 4 start.
• Faster with a 2 start lead than a normal setup with a 4 start.
• Standard aluminum gantry plates can be used for stepper and lead screw mounting, or you can print your own.

Rev.3

• This is what was originally planned as the end result with direct drive conversion in mind
• Fully centered / Fully balanced Design with a beautifully minimalistic approach
• Linear rails are required on the X and Y axis due to the location of the drive belts, steppers and Lead Screw Mount
• Utilizing off the shelf components once again, no machining or custom pieces required

Centered-Z Mod: Rev.1

• Reduce / Eliminate Z-wobble
• Consistently Reliable Tram & Level
• Z Speed up to 3x Faster

Benefits of the Mod

• Resolves common tramming/leveling issues.
• Reduces Z Wobble / Z Banding.
• Increases resolution without speed loss. (w/ Lead screw change)
• Achieves much faster Z speeds.
• Reduces the likelihood of issues.
• Simple to perform and easy to reverse if not suitable.

Parts and Resources /Links Below

• Main Components:

  1. Right Hand Extruder Mount
  2. Upper Lead Screw Mount
  3. Lower Stepper Motor Mount

• Additional Hardware Needed:

  1. T-Nuts and Screws for mounting.
  2. Lead Screw Coupler (Oldham Coupler recommended).
  3. Stepper Motor Extension wires.

• 3D File Design Iterations: 3D Parts marked "Rev.X" are for iteration tracking (not in reference to a specific mod). "Final" indicates no further improvements planned. These are designed to fit on 2020/2040 Aluminum and should clear most roller and belt setups on the X gantry.

• 3D Files Availability:

  • Tinkercad (Login Required)
  • Thingiverse Designs
  • Printables Profile

Firmware or Hardware Changes

1. Change Stepper Rotation Direction (Choose one):

   • Marlin: Toggle True/False for Z Stepper in Config File.
   • Klipper: Add/remove '!' on the Z Stepper DIR line in Config File.
   • Hardware: Flip Stepper Wires (Guide).

2. Suggested Firmware Change:

   • Increase Z Park Height (especially for 8mm Lead Screw).
   • Marlin: #define Z_AFTER_HOMING 35
   • Klipper: z_hop: 35 (Please verify this setting).

Visual Resources

Get a closer look at the Rev.2 modifications with this picture gallery:

• Centered-Z Photo Gallery
• Short Video Clip
• David Orlo's YouTube Channel

Centered-Z Mod: Rev.2

• Great for Bowden Setups

• 100% Eliminate Z-wobble (The Lead Screw Doesn't Spin)

• Consistent Tram & Level

• Increased Z resolution

• Further Increases to possible Z Speed up to 5x

• This is the second revision of the Centered-Z mod.

• The first version served as a proof of concept, offering an easy solution with minimal modifications required.

Parts and Resources / Links

Main Components:

1. Right Hand Extruder Mount (3D File below)
2. Lower Lead Screw Mount
3. Upper Stepper Motor Mount
4. Non-Captive Nema 17 Stepper Motor (Also known as Linear Stepper Motor)
5. Lead Bushing (e.g., Oldham)
6. Lead Nut POM
7. 10mm ID Collar/Clamp to prevent rod spinning

Suggested Parts:

• 4mm Lead screw (not required but recommended)
• Oldham bushing for Lead Screw mount (useful if screw and motor aren't perfectly aligned)

Part Examples:

(Note: I don't benefit from these links; they are for reference and purchase if needed)

• Stepper | Nema 17 | Lead Screw
• Top Stepper Motor Mount
• Bottom Lead Screw Mount
• Z-Lead Stay Collar
• POM Lead Nut
• Oldham Bushing for Lead Screw

3D File Design Iterations:

3D Parts marked "Rev.X" are for iteration tracking (not in reference to a specific mod). "Final" indicates no further improvements planned. These are designed to fit on 2020/2040 Aluminum and should clear most roller and belt setups on the X gantry.

3D Files Availability:

• Tinkercad (Login Required)
• Thingiverse Designs
• Printables Profile

Visual Resources

Get a closer look at the Rev.2 modifications with this picture gallery:

• Centered-Z Mod Revision 2 Picture Gallery
• Short Video Clip

Centered-Z Mod: Rev.3

• Ideal for Direct Drive Setup
• Beautifully Minimalistic Design Approach

This is the version that was envisioned originally by its creator David Orlo Absolute centered-design, this time taking things a step further and centering the X stepper and Y Stepper motors in addition to the Z stepper Why the Y Steper you ask? See what I did there? Noise and space saving, most of the time the Y stepper hangs off the printer and causes the printer to have a larger footprint than necessary. In addition to this, I've found that relocating the Y Stepper to a more centralized position reduced noise levels generated by that stepper significantly. On my Anycubic printer this was the noisiest stepper by a fair margin. The aluminum extrusion would resonated it certain frequencies and it was unbearable enough that I would alter my print speeds to avoid specific resonances.