My ideal idea was to go out and buy a CNC router and make a small business out of it. Then reality hit - these things are VERY expensive. They start at $5000US! Kind of steep for a hobby. I also know very little about them, so I could see me making yet another bad investment!! The solution seemed easy...build it myself. I would learn a lot along the way, and end up with (hopefully) a usable machine at a reasonable cost.
I started to search the web for design ideas and quickly decided NOT to reinvent the wheel. There was just too much to learn to manufacture a machine before my interest would fade.
John C. Kleinbauer seems to have reasonably priced plans and from the looks of it good designs for the hobbiest. Check out John's excellent web site for additional information. John is a wonderful resource. He regularly contributes to the news groups and is very helpful with email questions.
John's PipeDream!
I decided to go with John's "PipeDream" CNC machine, being driven by his "Piker4X Stepper Driver" and an old 486 I had in the garage. John's Piker 4X Board was as difficult to assemble as he had indicated. The board has traces very close together that requires extremely good soldering and troubleshooting skills. My Piker4X notes give you some idea of what it looks like, and the troubles I had building it.
Once built the Piker4X board runs exactly as I had hoped. The steppers, limit switches and relay outputs work well and are very easy to control through the parallel port. John has designed the board to be very compatible with CNC Pro.
The gathering of all the bits and pieces started the first of March in 2002.
Some Parts Found/Made
The steppers in the photo are about the size of floppy drive stepper motors. They were great to test the Piker4X as they are 12V motors and did not need any current limit resistors. They however are too small to drive the load required. The NEMA 23 motors are much larger, and work great!
Lead Screws Cut With Floating Nuts Made!
Using 1/4-20 All-Thread for lead screws saves a lot of money, but the unit does not have much speed (its the Tim Allen in me). I may retrofit to a larger diameter with fewer threads in the future. I have found that the machine is capable of 8-10 inches/minute jog rate, with cutting rate depending on the material and the cut depth/cutter.
The floating nuts work wonderfully. There is very little backlash, and they eliminate any deflections caused by the hardware store quality leadscrews. I have been asked by many people how to build these. Your best bet is to buy (yes BUY) John's plans. He has worked very hard, and produced very good plans for very little money. The floating nuts are his design and I will not supply info on how to build them without his permission. You will not be sorry you bought the plans.
Constructing the gantry unit (the X-Axis) was fairly involved and took me a considerable amount of time. I was not familiar with terms like NEMA 23, so a lot of the measurements did not mean much to me.
The Jig To Drill Angle Bracket
I completed the X Axis in about a month of part time "puttering".
Now the callenges come in. The Y and Z axis require parts that I can not find locally. I have given up on John's design and went for a more standard approach.
The Y-Axis will be designed with two 15" THK linear slides that I purchased off eBay (thanks Tom!). These slides ended up costing me about $75 Canadian after the conversion and shipping was taken into account.
The Z-Axis will be designed with old dot matrix printer hardware. I have managed to salvage several high quality Thompson linear slides that were salvaged and built into the vertical axis.
For the cutter, I have decided on using the RotoZip Rebel. It is a 5.0Amp rotery tool that has two speeds and has collets for 1/8 and 1/4" collets. I was very impressed with this machine, so I bought 2, one for a dedicated CNC cutter, the other for home repair/woodworking. I did have trouble with one of the RotoZips speed controllers dieing...I opened it up and found that the triac had died. The triac that is used in these tools is a MAC12M 12A, 400V. A search on DIGIKEY gave a Q4015L5-ND for $2.96
For a "quieter" engraving cutter, I picked up a surplus motor that I have retrofitted. I have a couple left if anyone is interested. Check the for sale page.
For the software, I am planning on trying out Yeager's CNC Pro (see the suppliers page).
Here are a couple of pictures of the completed machine:
My CNC Front View
Closeup Of Cutter Assy
Left Side Of Machine
May 28, 2002 - SUCCESS!!!! I powered up the steppers, fired up the PC and ran CNC PRO (shareware right now) and milled the first sample file (a square). It worked great! Now its off to GCODE School :-)
My first GCode file can be downloaded at CNC by Steven which surprisingly, prints out "CNC by STEVEN" the hard way!
Here is a photo of the finished product cut in walnut:
Project Made From GCODE
It was difficult to get a good photo of the small sign, but it turned out really nice. I used a 1/8" spiral up cut router bit in the 1/4" collet of the RotoZip. It had no trouble machining through knots or variations of grain.
Well, it is now the 1st of June, and I finally have something is is working! It has taken me three months to find parts, assemble and test the unit. It is now working, and is a lot of fun to watch run!
June 5th and all the limit swiches are installed and the machine is working great! I have started using several of the shareware programs available on the net with great success. I have found CNC Pro, KCAM, DeskEngrave, GCODE2000, TTFtoDXF all to be fabulous programs, and well worth trying out.
I started milling some plexiglass with a 1/16" cutter, using a feedrate of 4 ipm, and all was well, except I had the depth of cut too deep and I should have protected the top of the plexiglass. I have found that milling plexiglass can cause the shavings to melt to the cutter and then spin, causing "swirl" marks on the plexiglass. The feed rate was ideal, and the cuts were good...just the finished product was not as expected due to swirls :-(
Here is a photo of the PipeDream engraving a sign in plexiglass:
Machining Plastic
Notice the plastic (which is used) has been covered with packing tape to protect the finish (no more swirls). Also notice the custom clamps that are used to hold the thin plexiglass. Clamps for larger material can be seen in the back of the plexiglass.
I have found that a 1/8" spiral up cut bit with the Roto-Zip on low speed to work best in plexiglass. This gives really nice results using 1" high letters. For 1/2", I use a two flute fine bit, again with the Roto-Zip on low.
June 12, 2002 and things are getting more interesting. I have been able to mill stencils, cut signs and scan in logo's and mill them! This CNC stuff is very COOL! I wish I had done this way before this. If you are new to this I would really recommend buying John's plans to start off with. Once you get the machine running you will know way more than if you just bought one. Also the machine will do as he indicates and it may be all you really need (we really do need more tools right?).
Here is a photo of the new CNC Controller I am building. The electronics is built around the CAMTRONICS 2A Chopper board. I have encorporated an AC Speed controller, 12VDC Supply, 18VDC 8A Supply, switches to allow the CNC Computer to turn on the aux AC outlet, switches to allow full/adj speed, 4 axis out (3 enabled currently), as well as limit switch connections (stepper and limit connector is a 5 pin DIN socket).
New CNC Controller
The aluminium was designed in Corel Draw, and milled on the PipeDream. There were a few challenges during the cutting (my daughter bent the panel before I got to it, I had two cutters break, and there was some cuttings under the spoilboard). All in all the project turned out very nicely. Started in July...should be done in July - thats WAY TOO COOL!
Some "could'a, should'a, and still might..." can be found in my next time list for some of my comments on the process.
As usual, most of my web pages are under construction. Check back often and you may see more info or photo's.
If you want to email me I would like to hear from you! Go back to my main page for some other totally irrevalent information!