Introduction: Makerbot Replicator 2 Aluminum Z-Axis Stage Upgrade

By
About: It's not about me.

I came up with this design after being somewhat frustrated with the flex in the stock z-stage. I even had the aftermarket aluminum arms made by Bottleworks, but there is still much plastic in the z-stage that the stage still flexes, vibrates and needed constant leveling. These issues are exaggerated when using a heated build plate as the print bed is supported by plastic plates which get really warm.

In my quest to upgrade my printer, this is the first part I wanted to replace that is not readily available for the right price. There are few options out there. The aluminum arms and arm stiffeners have the flaw of still having plastic in the critical areas. The options that do this correctly, are fairly expensive. At the end of the day, this is just an aluminum plate, with linear bearings.

To minimize cost, the plate is made by waterjetting it from 1/4" 6061-T651 aluminum cast plate. I went thru several design iterations and 3 prototypes to get a good balance of part fit, weight, stiffness and cost. The goal here is the best part you can get at the lowest cost. And I've got a couple of hundred print hours on this design and it's been working great. No further design iterations are foreseen at this point.

To save cost, you print the one printed part, you source all the bearings and hardware, and you order the aluminum plate cut to my design. You then complete the post-processing of the part to your preference, by deburring, sanding and finish (anodizing, powdercoating, etc). Or use it as-is. It will come ready to use.

In the end, you will have an all-metal z-axis stage that is rigid, stiff and won't vibrate while printing.

Step 1: Gather Up the Parts

Below is the parts list of everything you need for the project.

  1. Qty 2 - square flange linear bearings, 10mm ID x 55mm length
    1. UXCELL Square Flange Linear Bearing LM10.
  2. Qty 2 - steel linear rods 10mm OD x 300mm length (optional, to replace the aluminum rods)
    1. 10mm Linear Rail Rod x 300mm
      1. select the 10mm diameter, 251-498.5 mm length option, and customize it with a 300mm final cut length
  3. Qty 1 - 1/4" thick 6061-T6 aluminum plate, waterjet to DXF, see attached.
    1. Order from DDFLA.com or your local metal fabrication shop.
  4. Hardware
    1. Qty 8 - M4 Socket Head Cap Screws x 16mm length
    2. Qty 8 - M4 flat washers 9mm OD max
    3. Qty 8 - M4 Nylon Lock Nuts
    4. Qty 7 - M3 x 0.5 mm Thread Socket Head Cap Screws 12 mm Length
  5. 3D print one of these from Thingiverse 2765335
    1. If you will be using a heated build plate, make sure to use a high temperature material to print it like ABS or PETG.

This list assumes a stock Makerbot Replicator 2

Attachments

Step 2: List of Tools and Supplies Needed

Tools
  1. Orbital sander or sanding pad
  2. Deburring tools (file, scraper, and/or countersink)
  3. Hex wrench set, 2mm, 2.5mm, 3mm, 4mm & 5mm
  4. 7mm wrench - one of the following
    • 7mm Open end wrench
    • 7mm Socket wrench with handle, 10mm maximum outside diameter

Supplies

  1. Zip Tie
  2. Linear bearing lubricant (low viscoity lithium grease or TRI-FLOW® Superior Lubricant)
  3. Lead Screw and Nut Grease (lithium grease or TRI-FLOW Synthetic Grease)
  4. Abrasive media (80 grit, 120 grit, 220 grit sandpaper and scotchbright pad)
  5. Cleaning agents (soap, acetone and/or isopropyl alcohol)

Step 3: Deburr the Plate (mostly Optional)

Once you receive the plate, it will have sharp edges from the waterjetting process.

Although, not necessary, you can deburr and finish it as you wish.

Here is my finishing routine, all is optional except step 2:

  1. By hand, break all edges using a metal file or 120 grit sandpaper
  2. Deburr all round holes using a countersink tool, deburring tool or larger diameter drill bit
    1. Deburr both sides of the plate
    2. If you plan on using a heated build plate, you MUST deburr the hole in the middle that the heater element wires will pass thru.
  3. Flat sand with an orbital sander with a sequence of 80 grit, 120 grit and 220 grit
  4. Continue with finer grits or use a Scotchbrite pad to get final surface finish
  5. Wash plate with hot water and soap to remove any dirt and dust
  6. Wipe down with acetone or isopropyl alcohol to remove any oils (optional)
  7. Anodize the plate if you want at this point for the ultimate in professional looks

Step 4: Lubricate Linear Bearings

Using your lubrication of choice, apply lube to the linear bearings.

I prefer to use TriFlow Superior Lubricant from a drip bottle and drip it inside the linear bearings directly on the recirculating ball bearings and put a coat on the linear rods. This lubricant tends to dry and not attract dirt.

But, you can use grease if you prefer, like TriFlow Synthetic Grease.

Step 5: Install Linear Bearings

Tools required:

  • 3mm allen key
  • 7mm open end wrench, 7mm nutdriver, or 7mm socket wrench (thin wall). OD of nutdriver or socket should be less than 10mm
  1. Install the linear bearings on to the plate as shown
  2. Using the M4 hardware, install the screw from underneath with the flat washer and nylon lock nut from the top.
  3. The plate is slotted to allow for adjustment for center to center of linear bearings to match the linear rod spacing. As such, don't tighten down the nuts just yet, leave them a little loose for now

Note: Plate shown is prototype # 2 and is slightly different than the current production version.

Step 6: Remove Makerbot Replicator 2 Z-Axis

Now you can start to disassemble the Replicator 2. You basically need to remove the z-axis entirely, and the dissassembly will be covered here.

For reference, you can review here:

  1. Turn off Replicator 2, disconnect power and allow to cool down
  2. Remove the print bed by removing the 3 screws. Be sure to keep the screws, thumbnuts and springs
  3. Remove the plastic back cover
    1. Snip zip ties for cable harness and pull away cable harness from back panel
    2. Remove 6 screws holding back panel with 5mm hex wrench
    3. Remove 1 button screw holding cable clamp with 4mm hex wrench
  4. Remove the rear metal plate
    1. Remove 12 screws in back plate using 2mm hex wrench
  5. Free up the upper z-axis bracket
    1. Disconnect the z-axis limit switch cable from the board
  6. Free up the lower z-axis
    1. Remove the lower electronics cover
    2. Unplug stepper motor
    3. Remove the 2 screws from the top of the lower z-axis bracket (from inside print chamber)
  7. Lower the upper z-axis bracket down on the metal rods about 1/2" or 12mm
  8. Remove the entire z-axis assembly from the Replicator 2

Step 7: Separate the Z-axis Stage From the Rods and Stepper Motor Lead Screw

  1. Remove the upper z-axis bracket from the linear rods
  2. Turn the stepper motor lead screw so that the z-axis stage comes off the rods

Step 8: Remove the Leadscrew Nut From the Replicator 2 Z-axis Stage and Install Lead Screw Nut Into Aluminum Plate

  1. The brass leadscrew is attached to the z-axis stage with 4 screws. Remove the 4 screws to set it free.
  2. Take this opportunity to clean the old grease out of the nut.
  3. Install the lead screw from the bottom of the plate with the M3 screws from the top of the plate

Step 9: Install New Z-Axis Stage Onto Liner Rods and Lead Screw

  1. Temporarily remove the stepper motor from the lower z-axis bracket
  2. Take the assembled plate and install it on the linear rails
  3. Temporarily install the upper z-axis plate onto the rods, to give the linear rods an upper constraint
  4. Now move the stage up and down while you start to snug up the M4 screws into the linear bearings
  5. Continue to snug the screws while checking the movement of the stage until the screws are torqued down

Step 10: Install Limit Switch Height Bracket Into Aluminum Plate

Step 11: Reassemble Everything by Reversing the Disassembly Process

  • Reinstall the stepper motor into the lower z-axis bracket
    1. Thread the lead screw into the leadscrew nut
    2. Reinstall the 4 stepper motor screws
  • Install the z-axis stage back into the Replicator 2
  • Install the 2 screws from the top of the lower z-axis bracket into the bottom plate of the Replicator 2
  • Connect the stepper motor cable
  • Reconnect the z-axis limit switch connector
  • Reconnect the cable into the z-axis stepper motor
  • Install the electronics cover plate
  • Install the rear metal plate with the 12 screws into the upper and lower z-axis brackets
  • Install the rear plastic cover
  • Reseat the cable and filament feeder tube
  • Install the print bed with the springs and thumbscrews
  • Complete a bed level and confirm the bed is where it should be