This is part 8 of our 3D Printer build. In this part of our printer assembly, we:

  • Completed assembly of the Z stage
  • Mounted the build platform
  • Levelled the print bed
  • Time for this step: 2 hours
  • Total build time: 17 hours 50 minutes

This is the eighth and final stage of our 3D printer kit build. For the background to the project and details of the kit we are using, take a look at the introductory page here, or click here to see all our posts about this project.

Last time we were part way through mounting the Z stage, the mechanism which moves the build platform up and down. We had mounted bearings onto the Z rods, attached bearing clamps to them, and in turn attached the build platform support arms to the interior side of the bearing clamps.

We now turned to the outer part of the Z stage. The first step was to install the threaded follower nut (the beige piece in the photograph) onto the main Z stage piece and secure it with nuts and bolts. We also installed a small adjusting screw (not visible in this picture) which will trigger the Z endstop so the printer knows when the build platform is at the top of its travel. The screw allows fine adjustment of this position to cater for varying thicknesses of build platform.

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We then secured the main Z stage piece to the bearing clamps, ensuring everything was aligned and there were no gaps at any point.

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The threaded Z rod can now be screwed into the follower nut.

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As with the X-Y and carriage rods, gloves need to be worn when handling the rods to prevent corrosion.

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The Z rod connects to the stepper motor which will move the Z stage by means of a flexible coupler. The Z rod screws into the wider end of the coupler and is secured with two set screws.

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The other end of the coupler should slide smoothly over the Z axis motor shaft, where it can be tightened in place using two more set screws.


With the Z stage completed, we could now turn our attention to the final part of the build, assembling the build platform itself. The first step was to insert three countersunk screws into the platform support and secure them with M4 locking nuts.

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A flat thumbwheel attaches next to each nut to allow adjustment of the platform support height, then a second thumbwheel secures the whole thing in place. This allows fine adjustment of the build platform height at three points. We also installed the small metal clips which secure the glass build surface to the platform support.

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Finally, we mounted the BuildTak sheet onto the glass plate and then clipped the glass plate into the build platform. BuildTak is a thick plastic sheet which is designed to improve adhesion of prints to the build platform. It is installed in a similar way to a screen protector sheet for a phone or tablet, by peeling off the backing and slowly smoothing it into place. Alternatives to BuildTak include PVA glue, kapton tape or painter’s tape.

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We got there! The finished printer, ready for firmware installation and build platform levelling.

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As suggested in the printer manual, we unplugged the extruder cable harness when first switching on the printer to prevent the print heads heating up in the event of problems. We hit a slight issue at this point as the LCD screen lit up but did not display any text. We connected the printer to a computer using a USB cable and started the printer software (Repetier Host) and verified that the software could recognise the printer and read its status, which suggested the problem was the LCD rather than our wiring.

As the next step in fault finding we removed the LCD to check for loose connections or faulty soldering, and at this point discovered that when not mounted into the printer the LCD worked. After a bit of investigation we tracked down the problem to the reset switch mounted on the side of the LCD panel, it was not perfectly aligned with the hole in the side panel causing it to be permanently pressed. We carefully enlarged the hole with a drill (drill very slowly to avoid melting the plastic) and reinstalled the LCD which now lit up, showing us our printer was alive and well.


With the LCD now functioning, we reconnected the extruder harness. On the top line of the LCD display you can see the current temperature of each of the two print heads, showing that the temperature sensor thermistors are functioning correctly.

The assembly is now complete, and in the next post we’ll cover installing/upgrading the printer firmware, levelling the print bed, and look at some of the results of our first attempts at printing.

Keep an eye on the 3D Printing section for all the posts about our build, post questions in the comments or tweet us at @dannynic or @sarah_nic.