3d Printer pt 5: X axis

3d Printers:  a tool for the homestead?

3d Printer pt 2: Prusa i3 wood frame

3d Printer pt 3: Designing your parts

3d Printer pt 4: Assembling the base

Needed parts:

  • X End Idler
  • X End Motor
  • 1 x 624 ball bearing
  • 8 x LM8UU linear bearing
  • 1 x Endstop
  • 2 x M5 nut
  • 1 x M4x20mm screw
  • 1 x M4 nut
  • 2 x M3x14mm screw
  • 2 x M3 nut
  • X carriage
  • 8 x Zip-ties
  • a scrap piece of m5 threaded rod is helpful

A head’s up–I ran into some issues with building the X axis.

The first issue is with the endstop.  The second issue is with the X carriage.

Let’s start with the X carriage.

X carriage Assembly

The purpose of this assembly is to secure bearings to the carriage using zip-ties.

I ran into an issue with the zip-tie holes.  I ended up heating a needle and “adjusting” them.  I’m not upset with the printer of my parts.  I think that zip-ties are not a great design feature and I can’t wait to get rid of them.

  1.  Put the ties in the X carriage.  The heads of the zip ties do NOT go on the flat side of the X carriage.  I started the ties on the outside holes. Pull the ties taut so that the heads are touching the carriage.
  2.  Take the tails of the ties and run them to the next holes on the carriage.  This means that the zip-tie tails are now sticking out of the same side of the carriage as the heads (pic to follow in a step or two)
  3. Put the tails of the zip-ties through the heads just enough for them to catch.
  4. Load the carriage with four bearings and loosely cinch down the ties.
  5. Trim off the tails, but leave enough to cinch down tighter for a later time

Here’s what it should look like (without the rods).  While you’re looking at the pic, notice that the horizontal slots in the carriage.  The lower slot is roomier than the top slot.  Remember this when you install.  The bigger slot goes down.

20150127_083218

Besides the issue with the zip-tie holes, I believe that the carrier also doesn’t have the right dimensions for the bearings.  The bearings fit very tightly and I don’t see how they can align with each other.

X motor and Idler mods

The X idler and motor mounts both need to accept an M5 nut.  You’ll notice that the hex shaped hole for the nut is too small.  The idea is to heat up a nut and push it into place.  I find this ridiculous, but there’s nothing I can do about it.

I took a spare piece of M5 rod and put it through the hex hole of the idler.  I put a nut on the rod.  I heated the nut and pulled down on the rod until the nut sank into the plastic.  I did the same thing for the motor mount.

It’s easy to get the nut too hot, so heat it just a bit.  I used a small propane torch.  I’m betting a candle would be enough, though it would take longer.

It’s also easy to leave the nut cocked at an angle.  I hope I did a good enough job.  I need to get the printer to work so I can print a better designed idler and motor mount.

 X Idler Assembly

1.  Take two linear bearings and push them into the X Idler.  Make sure they don’t stick out.

2.  Install the endstop. using two M3x14mm screws and nuts.  I had an known issue with my endstops.  The cable adapter is in the way of the holes.  I bent it up to make room.  Do this at your own risk.

3.  Take the 624 bearing and put it in the idler.  Slide an M4x20mm screw through it and put a nut on it.  Make sure the bearing spins freely.

4.  Some people add the M5 nut to the idler at this point.  I’m going to wait.

5.  I connected the wires to the endstop.  You can do this now or later.

 

X motor Assembly

  1. Take two linear bearings and push them into the X Idler.  Make sure they don’t stick out.
  2. Some people add the M5 nut to the idler at this point.  I’m going to wait.

 

X-axis Assembly

  1. Push two smooth 8x370mm rods into the X idler.
  2. Slide the carriage onto the rods.
  3. Push the X motor onto the rods.

Here’s what you should have…

20150127_091341

I can tell that this is going to need some work.  The carrier is binding.  I’ve tried cutting the zip-ties and securing the bearings more loosely.  They still bind.  It looks like there are two issues.  First, the bearings are awful.  I suggest you buy twice the amount you need so that you can pick and choose.  Secondly, the carrier’s dimensions are off.

I think I’m going to have to order another batch of printed parts.

I’ll continue with assembly.