Overview

Mechanics

• Maximum travel distance: x300 y100 z120 mm
• Mechanical axis: ball screw, lead 4 mm/r
• Maximum mechanical resolution (full-step mode): 0.02 mm (~0.00079 inch)
• Weight: > 100kg

Electromechanics

• Stepper motors: Phytron ZSH 100-200-10 (10 A,0.3 Ohm, 200Steps/R)
• Incremental encoders: Heidenhein ROD 426.014 (not in use)
• Switches: e-stop, combined limit+reference for x,y,z axis
• Router: Metabo FME 727 (Many thanks to my good friend Mathes for that gift!)

Electronics

• Machine controller: x86-PC with LinuxCNC
• A 19" housing contains the power supply, stepper drivers and the parallel port interface.

Pictures

Publish date: 2011-08-15
Last update: 2014-01-12

Machine-Controller interface

This is my DIY opto isolated parallel port interface.

The component interfaces the PC with the stepper motor drivers, limit-switches, probe-switch, emergency switch, ...

I use two parallel ports to interface the machine. One configured for output, the other configured for input. This results in 16 input and 18 output ports for the machine.

Features

• 16 inputs (PC parallel port > machine)
• 18 outputs (Machine > PC parallel port)
• Opto isolation
• Maximum input frequency >100kHz
• Maximum output frequency ~1kHz (to be optimised)
• 2x 5V power supply (PC and machine)
• Maximum idle current @20°C: 24mA (each card)
• Maximum current @20°C: ~264mA (each card)

The reasons why I made two separate cards are:

• I had/have a bunch of single sided PCBs.
• I was not able to fit the complete input/output circuit on one single sided board with keeping my design constraints for isolation routing.
• No experience with isolation routing of two sided PCBs.
• Enough room in the 19" case for two cards.
• I was not able to route a 96pin header on a single sided pcb.

Pictures

Download

• Limit-Probe-E-Stop wiring (.jpg)
• Schematics input card (.pdf)
• Schematics output card (.pdf)

Publish date: 2012-04-07
Last update: 2013-04-18

Power supply

Do not rebuild this circuit if you are not familiar working with mains voltages. Risk of electrical shock!

Features

• 500VA Toroid transformer. Primary 230VAC. Secondary 30VAC
• 42VDC for the stepper motors.
• 25VDC for the stepper driver logic.
• 5VDC for the interface card.
• Inrush current limiting.
• Plug-in card.
• Step down converters for the 25V and 5V rails.

Pictures

Download

• Schematic power supply (.pdf)
• Schematic inrush current limiter (.pdf)
  A defective relay may lead to massive overheating of the resistors! Secure self de-soldering of the resistors might be a solution.

Publish date: 2011-12-16

Stepper motor driver

3x Phytron SMD101

• Maximum motor voltage: 120VDC (supplied with 42VDC)
• Maximum motor current: 10A/Phase (set to 2A/Phase)
• Logic level: 24VDC (supplied with 24VDC)
• Fullstep or halfstep selectable
• Boost input
• Home and error output
• Open collector inputs
• DIN41612 connector

Publish date: 2011-12-16

Machine controller

Hardware

• x86-PC
• Motherboard: Asus AT3GC-I (Mini-ITX)
• CPU: Intel Atom 330
• Memory: 1GB
• Parallel port 1 : onboard
• Parallel port 2 : PCI card (Delock 89015)
• 15" TFT
• Keyboard+Touchpad: KEYSONIC ACK-540U+
  (This was a bad idea: Resistive touchpad!)

Pictures

Software

• LinuxCNC

Publish date: 2011-12-16

Simple tool length sensor (a work in progress)

This is going to be my first (very) simple tool length sensor. I was not the brainchild of the working principle and found it on the net.

Requirements

• Easy to manufacture.
• Only use available parts.
• Better precision/repeatability than manual "measurement".
• Little height.
• At least 2mm headroom to end stop.

Materials

• Aluminium bar 20x5xX mm.
• FR3 pcb
• 4x screws 3mm
• Cable + Connector

The sensor

This is the actual sensor. Not very beautiful but working well so far.
At the contact area of the two pcb I used some solder to protect the surface from oxidation.

Repeat accuracy

For a quick test, I initiated 5 manual G38.2's with "touch off" of the z-axis after the first G38.2.
Surprisingly there was no deviation on the next 4 cycles. Axis always reported 0.000mm for the z-axis.
For me that is good enough for now.

Redirection of the M6 command

To be done.

Simple custom panel for Axis

Under work.

Publish date: 2013-01-03

Machine tool lightening

My cellar compartment is quite dark and since I am an apprentice concerning cnc milling, I need and want to see, how the cutter and the workpiece go along with each other ;-). The acrylic glass cover will protect the circuit from minimal splash water and metallic chips. Unfortunately the pictures do not show the actual brightness.

Dimensions: L70, W16 (w/o connector), H6.3 [mm]
Circuit: LED LCWE6SG-V2BA-4J8K (Osram) with 56 Ohm series resistor and 5V voltage supply.

Publish date: 2012-02-26

Dust collection (Dust shoe)

The dust collection works together with a standard vacuum and a rough dirt separator.

Pictures

The pictures show the version 1 + 2.

Videoclip

"The making of version 2". Click on vimeo to watch full scale.

Publish date: 2012-11-11
Last update: 2014-02-09

Rough dirt separator

This is my simple (but working) rough dirt separator version 2. Unfortunately the first version did not last long since the bucket broke (imploded) due to the high vacuum when the suction hose is blocked.
The 2nd version is made of one 10l (1€) plastic bucket, plywood, a 90° plastic pipe and adhesive seal tape.

Publish date: 2012-04-17

PCB milling with KiCAD, PCB2GCODE and LinuxCNC (EMC2)

The following article briefly describes my way of making a single sided pcb with free tools and my cnc machine.

Used software versions:
KiCad (2013-mar-04)-testing,
pcb2gcode 1.1.4,
pcb2gcode_gui 0.6.0,
LinuxCNC 2.5.2.

Description and Picture gallery

Click on the pictures to read the descriptions.

Video clip

This clip shows the milling procedure of the light source pcb for my optical bench. A bit blurry though.

Publish date: 2012-04-06
Last update: 2014-05-24

Video clips

Here you can find some video clips of my machine in action. Since they are taken with my mobile phone they are a bit blurry though.

Milling test in MDF

2014-02-05

A test for a new hardware project and the output of my simple g-code generator.

Publish date: 2014-02-04

Links

LinuxCNC - Software for realtime control (formerly: EMC2 - Enhanced machine controller)

PCB2CODE - Gerber to g-code converter for isolation routing

F-Engrave - Text and image engraving and V-Carving

Gewinde Normen - Screw thread norms

Last update: 2013-10-31