Motivation

• Robot making

  I have been making a humanoid robot. Contoroller and Controller software have made, robot needs its own body. Body making needs special skill and equipments(e.g. machine tools...). We can pick-up machine tools as lathe, miling-machine, drill press and so on. In the machine tools, miling machine has lot of capability, therefore, I dicided to get miling machine. Machine tools handling as same as playing music instruments, we have to know how it works, dayly training are needed and understanding characteristics of itself.

• At least, stepping motor driving...

  I want to make robot body. Body making needs a lot of skills of machine tools handling. However, I can not wait to get handling skill of machine tools. I have gotten to know miling machine CNClization in the net. Basically, CNClization is very simple, add stepping motor X, Y, Z axises with G-Code parser. Unfortunately, they are still useing obsolted technic as direct touch of parallel port. I think more sophisticated technics for realizing my own CNC.

Architecture

　
1. Overview

   CNC needs miling machine(of course) and PC, stepping motors, controller. This project has not been restrainted from compatibility. Therefore, we can use our components freely. The first priority is performance, second is cost.

   　
2. Miling machine

   Model number is XJ9512. This miling machine is distributed from OEM sytle. Made in R.O.C.

   　
3. Mechanics
   1. Stepping motors

      Driving axises, add to each axis.

   2. Stepping motor mounting bracket

      Special parts. We have to customize them for target miling machine.

      1. X-Axis

         Customize for X-Axis.

      2. Y-Axis

         Customize for Y-Axis.

      3. Parts
         1. Alminium sheet

            200mm x 100mm x 5mm. Get from here.

         2. Screw (5mm x 80mm)

            Fixing for stepping motor to X-Axis with collar.

         3. Screw (5mm x 90mm)

            Fixing for stepping motor to Y-Axis with collar.

         4. collar

            We have to consider mounting margin. Mounting bracket uses 5mm sheet and stepping motor has mounting space as 5mm, total 10mm.

         5. Couppler

            
            To connect Axis and shaft of stepping motor.

   　
4. Hardware
   1. Controller circuit

      Using USB experimental PCB as miniFX-2.

   2. Stepping motor drive circuit

      My design. Driving stepping motor from controller circuit.

   　
5. Software
   1. Firmware

      Firmware generates stepping pulse from command of host software. The firmware has additional feature as USB control.

      1. USB engine

         FX2 frame work.

      2. Stepping signal generation timer

         Implemented stepping signal generation timer on above frame work.

      3. Download

         Contact here.

   2. Host software

      We need software for handling CNC system. Hostsoftware has several features for user handling.

      1. How to use

         We have been considering features. Several state are existing hostsoftware. Interlock mechanism will be waked up, if moving state for fool-proof.
         

         　
         1. AutoFeed

            Basic feature of CNC as position setting for moving. Abs/Inc mode available.
            

            　
         2. Jog 　

            Useful feature not only direct numeric input, but also jog mode. This system also avilable joystick input.
            

            1. Joystick available

               We confirm that following joystick and game controller can controll with hostsoftware

               1. CyborgEvo

                  
                  Full single hand operation. Big foot print, Space eater :-<

               2. Playstation2 controller (Sammy products)

                  
                  Full operation

               3. (GameCube controller)

                  
                  X, Y, Z button already equiped :-)

            2. JOG

            　
         3. CNC Now implementation

            Now implementation. File mode and One liner mode.
            

      2. Configuration

         
         

         1. Concentrate One dialog

         2. Considering UI

            Joystick direction and table moving...

         3. Color with direction

            Positive direction is Cyan. Negative one is Green. Error condition is Red.

         　
      3. Download

         Contact here.

Build

We focus for building up CNC system

　
1. Cost

   In case of Japan, the 1st generation of electronics hobby is (broad casting) radio making. Next is amature radio (with license), micro computer making (before IBM-PC/AT comaptible), PC peripheral system. I guess those motivation is cost. In today, hobby/hand made is the worst cost-effective choise. I'd like to do revival of cost-effecitve.

   　
2. Parts availability

   Components/Parts should be concious avialiablity from Akihabara(Electric town) and mail-order.

3. Re producability

   I have been wating your report.

　
1. Mechanics

   Consider lossless customization.

   　　
   1. Stepping motors

      Stepping motor is key component of CNC system. Usually, 6,000JPY out of the box. We use junk shop to get cheap price. Finally, I got 1000JPY/Unit in Japanese Junk shop. Next time, motorh price had been increased (Double 2,000JPY !! Why ??). However, junk means declease parts availabilty. Threrefore, we need understand principal of steppming motor mechanism both hardware/software side.

      1. Which motor should we use ?

         How to read specficaiton sheet ?

         1. Stepping resoultion
         2. Torque
         3. Frequency

         Above 1 and 2 are important. CNC needs 1 and 2.

         • MINEBEA 23LM-C004

         I could not data sheet 23LM-C004 with goodle search...

         • 6.0V/Phase
         • 1.2A/Phase
         • 1.8deg/Step

      2. How to remove spline pulley

         
         The biggest problem is using this stepmotor, which has spline pully is fixed by cotter pin. Insert precious screw driver, small impact with metal hammer.

      3. How to check wiring

         Measure resistance each wire. The stepping motor has two coils. Closed infinity resistance means that separated coils. Around 10Ohms means side point to side point. Half value means center tap of coil.

      4. Mounting position and wiring

         Rotation direction should be mounting position. Wiring should be changed, if position changed.

         Normal wiring

         1. WhiteRed
         2. Black
         3. Red
         4. WhiteGreen
         5. White
         6. Green

         Inverse wiring

         1. Green
         2. White
         3. WhiteGreen
         4. Red
         5. Black
         6. WhiteRed
         　
   2. Japan Servo K.K. (Z-Axis)

      
      To need more torque. This is not junk. Current product at moment.

      　
   3. Mounting bracket (In case of XJ-9512)

      Check table structure especially X, Y axis.

      1. X-Axis

         
         Both side of X-Axis are fixed. Direct connection with cuppler between shaft of stepping motor and X-Axis.

      2. Y-Axis

         
         One side is fixed of Y-Axis. Very loose connection. Fixed with spacer which is made from remove spline pully from above stepping motor.

         1. How to make spacer for Y-Axis

            Cut ledge of spline pully. Extend hole with 11mm - 12mm (as same as Y-Axis shaft).

      3. Common
         1. How to customize Cuppler

            
            Extend 6.5mm for stepping motor shaft.

         2. Hole stepping motor mounting bracket

            
            

         3. Hole stepping motor mounting

            Hole NEMA23 size hole position

         4. Tapping

            Tapping for stepping motor mounting.

         5. Big Hole with Hole-saw

            
            Big Hole with over 36mm. Not needed if we use CNC system...

   　
2. Hardware

   Make 3 set for X, Y, Z.
   

   　　
   1. Stepping motor drive circuit

      
      

      　
      1. Cheap darington tranjsiter array

         Designed for stepping motor driving.

         　
      2. DIN plug

         DIN plug one of example of stepping motor connector.

         　
      3. Heat Sink

         
         

         　
      4. Fat wire

         To avoid voltage dropping with big current circuit

         　
      5. Driving voltage

         Usually, stepping motor driving volatage 2-4 times of spec. voltage. Currently, 12V driving.

   2. Control circuit

      
      

      miniFX2 can be get from here.

   3. Power Supply

      12V power supply is not only stepping motor power, but also other equipment is using.

   4. Enclosure

      Size concicous design. Takachi YM-150 is suitable.

Next stage

Improve continuslly...

• Mechanics
  1. Z-Axis
• Hardware
  1. Over current detection
  2. Limit switch
• Software
  1. Improve CNC parser

Thanks to

BBS audience who gave advise, donated miniFX2 from Optimize.