My CNC Setup.

What to Buy, Cost, etc; Don't forget to read my Starting Out In Machining/CNC; >> Click Here <<

IT BEGINS! 04-25-00



It all started off with a manual Sherline Milling Machine. All Sherline products I have bought have been very well built, delivered on time with excellent customer service! 
Sherline Tabletop Machines

STEPPER MOTOR MOUNTS

I bought the Sherline stepper motor mounts and while a little more expensive then others, they are WELL worth it! They are for frame size NEMA 23 motors. They come with a wonderful coupler making the "perfect" setup a little easier. Spend the extra money and go for a better setup now. It will save you in headaches and disappointments later. 1-01-02

From what I understand, bipolar steppers are a better choice due to lower heat output and power/speed ratio. If possible, servo motors are even a better choice.

PARTS



I bought NEMA 23 Sanyo Denki 180 oz/in BIPOLAR double-shaft STEPPERS. I attached the hand wheels on the opposite side and find this to be a huge advantage. I suggest buying bipolar double shaft motors so you can adjust the axis or perform mild milling manually as needed (plus the wheels look cool spinning around :). The number is 232-180-DB from the link below. The motors came on time and were packed with great care, thanks! They are PERFECT  for the Sherline. Don't forget to balance the handles if you do plan to mount them. Note: A combination of motors, 180 oz/in on the Z axis and around 100-180 oz/in on the XY would also work. Here is the link:  CNC Retro Links 
Note: You can get much cheaper rex step 260 oz steppers for $40!! HomeShopCNC 
I bought the rest of the stuff from MPJA Supply. Good service and good prices! Also, you can pick up cheaper surplus motors, just do a search. Here are some places, American Supply and Surplus, Ebay, All Electronics, My Links...etc

Updated 12-18-06

STEPPER MOTORS?
Want to learn more, Click HERE

SERVO MOTORS?
As I learn more, servo motors are even a better choice with their drivers, they are however more expensive. Gecko 201 drivers seem very nice, check them out. SERVO motors usually have a "closed feedback system" so if the motor stalls or "loses steps" it feeds back to the computer to let it know. The software then compensates for the lost steps in hopes that the part will still be made correctly. ** This, however, is not a reality in our hobby cnc yet that I know of.** Servo motor cannot be stalled or they will burn out quickly, Basically a servo motor is a DC motor with an encoder. Very neat.

A STEPPER motor system (mine) which is "open-loop," my software has no idea where my motor is at any given time. If one stalls the steps to the motor keep going as the computer thinks nothing is wrong (no feedback). You can add a feedback to steppers if you like but then, you might as well get the better setup- servos. HOWEVER, I can say a 180 oz motors geared down with the leadscrew on my Sherline makes for a VERY strong system. It will snap a 1/8" endmill and larger in a blink! It will also crush a finger (don't ask me how I know this :) Personally I don't think I have had problems with losing steps but again if you can afford 

Psst: I have servos now :) Click here

Overall impression? Steppers are a but louder, run a bit hotter, but can be stalled all day and do the job just as good as a servo motor. I don't see much of an advantage in getting servos over steppers. They both run, they both work.

-CHECK AXIS AND LEADSCREW
FOR "PARALLEL-NESS"-

While tightening down your stepper motor mounts, check to see if the TIP of the leadscrew deflects. If so, your mount is not parallel to the axis and you will find binding in the system. First try to reposition the motor or the mount to minimize this deflection. If that does not work, file, add shim, do what you need to make the movement minimal. Check to make sure you have smooth movement throughout the axis.

I had to file my Y axis base vertically to make the mount fit parallel. I also added a shim (broken piece of single edge razor blade) under the motor mount on the Z axis to make the leadscrew runs parallel to the axis. Check this now.

-GRIND FLATS-

File or grind some flats on the stepper motor shafts where the set screws will tighten. DON'T omit this very important step or you may not be able to get your motor off without excessive force and damaging your motor or mill.

NEW Y-AXIS MOUNT

My Y-Axis, stepper mount holes stripped and I tried a few things to fix it. It finally dawned on me to make a  plate with fresh tapped holes for the stepper motor mount (sometimes I forget I have these machines:). It added 6.5mm of travel to the Y axis.

Z-AXIS BACKLASH


I had to figure out a way to get the backlash
out of the Z axis. For details on this setup
Click HERE

SWITCH/LIGHT LAYOUT

I lightened my mill by cutting off the larger
pulley and removing the control box. Not only is it LIGHTER the work is MUCH easier to see.

I added a red 110 volt light to tell me when the mill is on and another to tell me when the spindle is on (bright yellow LED). Click HERE for my 110 volt modification. 

The control box is now mounted to the back of the Sherline. I also made a larger motor pulley and made my mill's pulley smaller to increase rpm. A lot of work but well worth it!

Make sure your comfortable working with wires and soldering before you attempt this modification! Don't go ruining your perfectly working mill.

FULL VIEW

I added some springs to aid in pulling the Z-axis up (bought from the local hardware store). I made simple mounts which are mounted to the stepper motors existing holes and put the springs on them. At the bottom I just drilled and tapped for some 10-32 screws.  Even when the Z axes moves down there is some "backlash" amount that it may get pulled further down by the endmill (think about it). My design is to try to keep this from happening and to aid the stepper. Others say this is not a good way to do things and to have the springs pulling the Z axis down into the work which aids in trying to get that backlash out in the first place.

I bought a cheap 12V 20 watt halogen light from Target. I used some of the parts and made a new light  which is attached to the mill. The power for the light is a small track lighting unit bought from the local hardware store and is also mounted on the back. Its 12V 35 watts, It gets a little hot but the light is bright, white, and sharp.

-MOVEMENT OVERVIEW-
The endmill should move TO THE PART.

Sadly, these boards are no longer available

I bought Drivers from Camtronics, 3 Axis 2 Amp bipolar choppers and they work great. These are step/direction drivers made for bipolar motors. You can connect a 4, 6, or 8 wire motor to these drivers. Odd number wires motors are unipolar (you can connect a 6 or 8 wire motor to unipolar too-I think?). Camtronics

Dan suggests you check out the Xylotex boards.

For other ways to run a stepper or servo also check out Gecko 201 (if you know of others please write me so I can add them here)

Sadly, these boards are no longer available

Later I bought a single axis 2 amp driver for my 4th axis. You will need to make larger heat sinks and add a cooling fan if  you plan to run the boards on 24v as I am.

Note: I would buy a 4th axis driver after you find a reason for its use and know how to use it.
Making the rotary table CNC ready is an excellent idea still! You can plug it into the Y axis and get a lot accomplished (everything I have done to now). Again, Dan suggests you check out the Xylotex boards.

-POWER TO BOARD-

Here is the schematic for powering your boards and stepper motors. The parts here are listed in the previous window.

I used 12 volt computer fans for cooling but they kept burning out as the transformer put out approximately 13.7v on that section. Finally I bought a 110 volt fan from radio shack ($20) and have not looked back. Lots of air out of this thing.

I made LARGER  heat sinks for my drivers since I am running them on 24 volts. I used 1/8" aluminum and 1/8" 90° angle putting many cuts and holes to increase the cooling surface area.

I blew out all of my L298 chips!
I was connecting an "all windings off" switch to the jumper on the Camtronics board. I figured I would connect the single axis and the 3 axis ones (in series) with one switch. ZAP!  You can see how one of the L298 actually cracked! Ouch. Don't do this in series. I ordered them from Mouser electronics. Thanks Dan for the help

-DRIVER BOX ENCLOSURE-
4-21-01

I designed my box and had a sheet metal shop bend it using 1/8" aluminum. Overall they did an ok job (pic of box is after a lot of cleaning up). The price for the box $65. I used a Dremel with a router bit and the smaller router attachment to cut the box. Use the 35,000 rpm setting and get ready for a lot of mess!

Here is my new enclosure!  3 days of work, 50+ hours, and it came out great! This side shows where my steppers plug into and the spindle over ride switch. I predrilled a hole for a sixth connection incase it was needed in the future. The box is painted with spray paints and holding up well.
4-21-01

Here is the other side of the enclosure. These are the 2 exit holes for the fan. I have the fan blowing air into the box right at the heat sinks.

 

Here is the back. The fan, computer parallel port and fuses can be seen. It Works GREAT.

Currently, I have moved the spindle over-ride switch to the front and have added an AWO (all windings off) switch too.
5-01-01

I wired the steppers using a radio shack 5 pin DIN connector. Using my lathe,  I made a tapered backing out of 3/8" round aluminum stock so they would look nicer! I glued it to hold the plastic wire wrapping in place and it's done!

Here is everything inside! Clockwise- 4th axis board, then you can see the 25 amp/400 v bridge, then 10amp 12-0-12 transformer, 15,000 uF capacitor, fuses, radio shack 110v fan, motor outputs, 3 axis board and above that, the board my brother made to turn the spindle on/off. All the standoffs for the PC boards and power supply where made out of aluminum and on the lathe.

I blew up my KBIC board, on/off and 4th axis!

Somehow I blew up my spindle ESC and single axis while turning on the power! Power surge?  I found a new KBIC board on Ebay.
For more information on the Sherline speed control click KB Electronics.

-DRIVER BOX ENCLOSURE-
UPDATE 1-5-04

I have rewired my entire setup. Everything is now in the driver box as I once wanted it. Here is a pic of the outside.

UPDATE: 

Since I moved to the servo setup on my CNC router I am using the gecko drives on the Sherline mill for the steppers. The box almost looks empty now :)

Step 1: Drawing the Picture (toolpath)

I have used Draffix and TurboCAD with good results. You will need to find a CAD program that works with you.  Also, do a search for "free" CAD to find others.

CURRENTLY: Finally! A GREAT Program, Rhino3D. It's my primary CAD program and I don't plan to part with it anytime soon:) It will do all 2D and 3D.  If you can get it at a student price, it's a steal. Also download a free rendering program for Rhino called Rhinoman! Very Nice!  Thank you Brian!! Rhino3D RhinoMan

Step 2: Convert Toolpath to G-code

I've used a free program called Ace Converter with good results. You can cut different depths via layers.  
  Yeager Automation

I've also used Flashcut for 2.5D drawings. It gives the option of putting in a DIFFERENT feedrates for the XY and Z axis.  This is an advantage as you can cut at a faster speed yet still plunge down at a safe speed.
 Flashcut CNC.

I have also used/use/tried all of the programs in my CAM Program Search Page.

Step 3: Check the G-Code

 I've used the demo version of  Cutviewer and have absolutely loved it. It has to be the best one I have tried. Download the  trial.
Cutviewer

Another simulator that looks Very Nice! 
CNCez Proz

Another simulator. Download it, give it a try, heck it is free. Thanks Dave for pointing it out). 
CNC Simulator

CURRENTLY: Using what comes with the current programs I am using.

 
Step 4: Run the G-code

If your starting out, I would get TurboCNC, a  DOS based program and only $20! I downloaded the trial just to try it out and it works very well TurboCNC. Another DOS based program is CNCzeus and it's $100, looks very nice too!. I used CNCPro, also DOS based. Overall its worked VERY well. Support for it seems almost gone over the years. Yeager Automation.

Some  windows based programs are Mach 3, Flashcut, DeskNC, and KellyWare

Last Step:

Watch, Enjoy and Get those Chips
 out of the Way :):)

Final Step:

Clean up your mess, the step I always fail at :)

Plexi-Glass

I bought 4 sheets of 18x24" "Plexi-Glass" sheets at Home Depot for about $5 each. I also picked up 90 degree aluminum angle 
for brackets. The back sheet is the full 18x24", the others are cut as shown in the pictures.

I finally found an adjustable air hose locally. This is actually a "snake" type screwdriver extension for a cordless drill which I found at a wood working store. I removed the flexible metal rod that ran through it and mounted the plastic adjustable housing on the mill. Connected to the air pump and WOW, it's great! LOTS OF AIR! (Note: my belt is an "O" ring).

Future Changes? Others Options?
My personal opinions on the CAM program I have tried. The search continues. Click Here

 Rhino3D BOUGHT IT from United Artworks, great price and great service.
 Simply the best! Try it out, download the trial! I can't say enough nice things about this program!
Also download a free rendering program for it, Very Nice! RhinoMan, Thank you! Thank you!!

Mach 3 / LazyCam I can't say enought postivie things about this program its makers. Thank you guys for such an awesome product, support, and price. 
Other people should really get pointers from you on how to make a program, keep it update, training, etc. 

° Change my G-Code interpreter to a windows based one with real-time plotting. For now, DOS is just fine :)

° Someday maybe change my stepper motors to servo motors with feedback.

° Change my leadscrews to ballscrews to a system like THK  or BSA , etc. Or cast new nuts out of Moglice as some others have done.