X Axis Works!

I managed to mount the stepper motor for the X axis and connect it to the lead screw with the flex couplings I got off eBay.

After running the X axis back and forth and running through the EMC2 default G-code, I realized that I am going to need bearings to keep the nylon sheet from lifting off the rails. So, I built two bearings.

Two bearings on the underside, catercorner to each other.

Same design as the other bearings.

I also started working on the Y-axis and once again, the nylon sheet is not flat so I have to add tubing to flatten the sheet.

Close up of Y-axis bearings

Cronstruction Continued

I am slowly making progress in the construction of my CNC machine. I got two 12" x 12" x 1/4" thick nylon sheets from McMaster to use as the material to slide on the aluminum rails. It seems to slide fairly well. Unfortunately, The sheets I got were not flat. So I bolted steel tubing to flatten the sheets out. Luckily they were fairly square so I could use the edges to make sure the x and y rails are perfectly square.

Bearing Mounts
 I used a plastic cutting board to make mountsd for the bearings that support the lead screw. It seems to work well. I double nutted the screw to keep the nuts from loosening themselves.

 
Anti-Backlash Nut
I used cutting board material to make the nut. The nut is threaded in two sections which can then be tightened together once the lead screw is threaded through both sides. This allows me to adjust the nut. The tighter the screws, the less backlash however the friction increases. Finding the perfect balance will be a challenge.

Rail Bearings
The bearings are made from skateboard bearings with one side fixed (bolted into the nylon) while the other side is tightened into place. The bearings only ride on one rail because I can not guarantee that the two rails will be perfectly parallel.

Base Construction

I recently started construction of the base frame. I am using various aluminum extrusions which can be purchased from Lowes, including:

• Square tubing: 3/4" x 3/4", 1/16" thick wall
• U channel 5/8" wide x 1/2" tall, 1/16" thick wall
• 90 angle 1/2" x 1/2", 1/16" thick wall

Machine Base

Structure mad out of the square tubing, diagonal made out of the 90 angle, and the two X-axis rails made out of the U-Channel.

Ebay Goodies, Concept

I recently won several goodies off Ebay to construct my DIY CNC machine including:

• 80 ABEC-5 Skateboard Bearings - $26.00
• 3 1/4" flexible shaft couplings - $26.50

ABEC-5 Skateboard Bearings

1/4" Flex Shaft Couplings

 Now comes the theory. I want to build a cheap yet accurate machine. I have decided to build the machine out of metal, predominately aluminum, in order to produce a rigid machine. However, I don't want to sink my teeth into a 8020 based machine with Finelineautomation hardware.

So after scouring the internet for the last couple months I have decided to base my machine on this instructable. Except I have some ideas to make it bigger, smoother, and more precise. Now lets just see if I can do it! Maybe I will try to draw up a CAD rendering.

2D Conceptual Design

Concept Mock-up

Electronics, Software, Why?

I decided to start building a CNC machine. The primary reason is that a CNC machine is the ultimate tool when it comes to making one-off parts and prototypes. Sure I have a Dremel, but what if I had a Dremel controlled by a computer to make precise cuts all by itself? So after researching DIY CNC machines for the past year, I decided to start buying parts to play with. So I got a stepper motor controller off Ebay!

Ebay Special: 4axis CNC Stepper motor controller with TB6560 chips.

I got an old computer from my parents to install Ubuntu and EMC2. After playing with the settings in EMC2 I got it to work, no thanks to the Chinese manual. I also got 3 steppers off ebay.

Ubuntu, EMC2, 3 steppers, stepper controller and power supply.

Everything works great! Specs are:

• Software: EMC2
• Stepper controller: 4 Axis, TB6560, 2 amp per channel, ebay special
• Steppers: NEMA 23, 120 to 128 oz/in, 2A, 2.2V, 1.8 deg/step, FH6-1809 01
• Wires: ORG A, BRN A-, GRN B-, BLU B, BLK Common, WTH Common
• Power Supply: 36V, 9.7A