Build Thread- 3-axis machine build

[Kroko]

Hello

My name is Andrej. I'm computer programmer and my hobbies include building rc model aircrafts, geocaching, electronics,...

I love flying wings and three years ago I created my first CNC foam cutting machine. At that time I was learning how to program microprocessors. I created controller for my machine which was using RS232 to communicate with computer. Controller accepted dxf for wing root and another for wing tip and send step/dir pulses to stepper drivers.

I used that machine for some time. Main disadvantige was, that creating those dxf files took quite some time and a small change meant that everything has to be done again.

Some months ago, I needed to cut some wings. I found out, that Profili2 supports 4-axis GCode generation. Time to create new controller has come.

GCode parsers, linear, circular and helical interpolators were programmed, USB support was added and CNC USB motion controller was born. Cutting wings with my foam cutter was now easy thanks to great Profili2 / CNC USB motion controller compatibility. Check out video on my foam cutter page.

But why stop here. I had everything ready for true 3+1 axis machine. Except machine itself. A friend of mine Ultralajt created his machine and I decided I'll create mine.

Main design goals were, that everything must be build with simple tools becouse I don't have any special equipment. Machine must be cheap but parts must be upgredable to better quality ones.

I don't have any plans and all my sketches are not publishable. I doubt anybody but me understands them. I'll try to photograph everthing. Feel free to ask any questions.

I can't wait no see full power of my CNC USB motion controller

[Kroko]

While I'm waiting for some materials I ordered to arive, I build box with all electronics.

Here are contents of box:
30V power supply for steppers with delay relay
5V power supply for logic
12V power supply for relays.
4 PICStep drivers
CNC USB motion controller

On the back I need:
-main power connector
-three connectors for connected devices
-4 connectors for steppers
-connector for limit switches
-connector for jog keyboard
-connector for development

On the front I need:
-main power switch
-power suplly LED indicators
-reset button
-USB connector
-jog keys and speed dial
-emergency stop button

Here are images of what I did today.

[Ultralajt]

Hi!
Nice to see you here at CNCZone! Best wishes for your new CNC machine.
I will follow this building thread as I am very curious what steps will you take and basic layout, regarding the mechanical part. I am sure (on the basis of our PM exchanges some days ago) that it will be very interesting.
I like your way of thinking.... as cheap as possible build..... very close to mine!

Cross fingers!

See you!

[Kroko]

I created quick electrical sketch. All main electrical componets are drawn.

Computer is connected to CNC USB motion controller with USB cable. PICStep drivers (or any other Step/Dir drivers) connected to this controller drive stepper motors.

[harryn]

Hi, it will be very interesting to watch this build progress, esp. with your controller.

Good luck,

Harry

[Kroko]

I finished 5V power supply board with 3x16A relays which will be driven by controller and one relay for motor power. This relay has 1sec delay (I used 555 timer) and it ensures, that all logic is powered on when 30V for motors is applied to motor drivers. At shutdown it prevents discharging main capacitor through motor drivers.

[Kroko]

Today I got power transformer. It is 24V AC, 400VA. This gives me 32V DC.
Power supply and relay board is now wired and finished. 1 second delay works great.
PICStep boards and CNC USB motion controller are next.

[Kroko]

Electronic part is finished. Everything works as expected.
CNC USB motion controller controls 4 PICStep drivers and 3 output relays.

On front panel are on/off switch, reset button, main power LED, motor power LED, controller status blinking LED, USB connector, 3 LED for output relay status, 8 buttons for manual movement, knob for speed of manual movement.

I also got some aluminium parts and next week I'll start mechanical build.

Machine will be 800mm x 600mm x 100-200mm (not decided yet) and made from aluminium.

[Kroko]

I received DryLinW linear system from IGUS so that I can continue my build.

[Ultralajt]

Originally Posted by Kroko I received DryLinW linear system from IGUS so that I can continue my build.

Tell us how it slides. Any freeplay to feel by hand? Fricrion? I was interested in those rails, but a friend of mine convionced me not to use....

Mitja

[Kroko]

This build is so sloooow.
I'm waiting for some more parts before I continue.

Slides have very low friction. There is some freeplay on floating side. I think that freeplay can be adjusted. I'll report more when parts will come and I can continue my build.

In the mean time I'm working of software for CNC USB Controller . I have implemented bootloader so that firmware updates are possible.
Software has folowing new features:
- MDI input which excepts gcode commands (type gcode in textbox and machine will execute it)
- better dxf support - import dxf and use it as toolpath for 2.5D routing (LINE, ARC, CIRCLE, POLYLINE, LWPOLYLINE)
- export tollpath to gcode
- export toolpath to dxf (will finish in a few days)
(it is possible to use it as gcode to dxf converter and dxf to gcode converter)
- import .jpg, .bmp or .png image and create relief toolpath.

I'll put this updated version on web site in a few days.

I accept feature request but without any promises.

Andrej

[harryn]

Hi Kroko, the area to be careful with when using sliding type bearings is the ratio of length to width. If this falls below 2:1, then there is a tendency for this type of bearing to stick - slip. I am convinced that most end users with problems did not understand this design constraint.

Pacific bearings has this info in their catalog, but it is buried very deep.