CNC Router

02/06/09 Updates

12/05/09 Updates

07/19/10 Updates

11/26/10 Updates

11/18/14 Updates


After making several printed circuit boards and drilling all of those holes, I decided it was time to build a simple CNC router/PCB drilling machine. I figured I would also be able to use it for making bezels, cut outs in panels, and other enclosures. I selected a set of plans from John Kleinbauer’s CNC Router site. John calls this machine the 7th Sojourn and plans were quite inexpensive. John specializes in machines for beginners who are getting started in the hobby and want to build a machine at a low cost and with easily obtainable materials. He uses materials such as MDF, black iron pipe, skate wheel bearings, and threaded rod.

Here are several pictures of my machine at various stages of construction:

frame (30K) This is the beginning of the base frame. The material is ” MDF which is available from most home improvement stores. MDF is very stable, flat, and hard. It also machines easily with sharp, carbide cutters and saw blades. Most people drill and tap the MDF and assemble it with machine screws. I found that I had a tendency to strip the holes so used another method that I have had luck with in the past. I drilled ” diameter holes in the piece that would normally be threaded at right angles to the attaching hole. I then glued a short length of ” oak dowel into the hole. Then I used 2” - #8 square drive wood screws to attach the pieces. Although a little time consuming, I am very pleased with the results. The frame is very strong.


y axis front (32K) Here’s the router with the completed Y axis. John’s plans call for using ” black iron gas pipe for the rails with 90 elbows, nipples, and flanges. Although the pipe was fine, I could not get flanges that were flat enough to give me consistent rail height when I tightened them down. I switched to ” drill rod instead and the results appear to be quite good. I stacked the two end pieces that support the drill rod in order to drill the ” holes in them and alignment seems to be fine.


z axis (36K) This is the completed Z axis with stepper motor mounted and ready to go.


x axis (37K) Here’s the completed machine without any of the wiring done.


front complete (40K) Finally here’s the machine with the wiring to the motors completed and the tool holder completed and mounted.


tool holder (36K) Here’s the tool holder. I’m using a Dremel MultiPro but instead of mounting the whole unit, I mounted the flexible shaft spindle. This gives me less weight hanging off the X axis and also mounts the weight closer in to the axis. So far it seems to work fine.


computer (40K) Here’s the finished machine with the computer hooked up and ready to go. So far I’m using TurboCNC and it seems to work quite well. The computer is one I had put out of service. It has a Pentium II 233 and is just running DOS 6.22. I’ll probably look for an old laptop since it takes up a lot less room but this works for now.


I made some simple cuts on some cedar I had laying around and everything seemed to work fine. I need to get some carbide bits yet in order to really put it through its paces. So far with a 24 Volt power supply for the motors and a Xylotex controller I have been able to get about 18 IPM. That’s in 1/8th microstepping mode and I haven’t spent any time trying to optimize it yet. I still have several things to do yet:

In the end I made very few changes from John’s plans:

Well that’s it – I guess now it’s about time to start thinking about another machine. I would like to build one with a larger surface – maybe 24” X 36” and with the capability to take a larger router like a Porter Cable 690. But that’s another story.

Updated - 02/06/09


It's been a while since I put together this page and, while I haven't gotten around to building a bigger router, I have made a number of changes and this seems like a good time to update this page.

slidesThe most significant change was replacing the X and Z axes.  The original design utilized aluminum window channel and I could never really completely eliminate the play in either axis.  While doing some research, I found the Rockcliff Machine site.  I liked what I saw, ordered a set of their plans, and ended up using their skate wheel bearing guided design for both the X and Z axis.  I like the results.  Both axes move quite easily and exhibit no noticeable play.

I also used the opportunity to replace the vacuum hose couplers with some very nice machined couplers from DumpsterCNC.  I also purchase one of their anti-backlash nuts for the Y axis and will probably eventually replace the nuts on the other two axes as well.  Their parts are very high quality, reasonably priced, and work well.




RotozipI was using a Dremel with a flexible shaft attachment for the tool but decided I wanted a little more power as well as the capability to use 1/4" shank bits.  Since I already had one, my solution was a Roto zip REV01 tool.  It has adjustable speeds, an LED light to illuminate the work surface and  interchangeable collets for either 1/8" or 1/4" shank bits.  I just built a simple holder that bolts right to the front of the Z axis.  I actually have several sets of holes in the holder so I can move the tool up or down to allow for thicker material.









StandI found I was constantly moving the machine around my shop to make room for some project or another so I decided to build a rolling stand.  The stand is really simple 2 X 4 construction with some nice locking casters.  I also added a drawer to store bits and other pieces and finally a pullout shelf for the laptop I use to run the router.












Here's another picture of the stand with the shelf and laptop all tucked away.















I also made a few electrical changes.  I added an E-Stop switch, new motors, and, since I am approaching max current on the Xylotex drives, a fan for cooling.  For the most part this has all worked well.  However I still have an issue with the new motors.  I went from 80 oz.in. motors to 282 oz.in. motors from Keling Inc. and, while the new motors have a great deal of torque, I haven't yet figured out how to get as much speed as I expected out of them.  I'm still working on this problem and expect I may need coarser drive screws.  I'm also planning to add a relay board that I purchased from Probotix to automatically control the Rotozip switch as well as the drive enables.







Here's a picture of my latest project.  I decided to make some ornaments for Christmas presents for friends and family and got a little carried away.  I ended up making 8 sets of 8 ornaments.  Each ornament in a set is a different species of wood.  I used cherry, walnut, mahogany, alder, maple, birch, oak, and poplar.  The ornaments are approximately .080" (2 mm) thick and I used a 1/16" diameter solid carbide bit for the machining.  Some of the woods (cherry and mahogany) machined very nicely and others ( birch and maple) were a little more problematic.  All in all I learned quite a bit about machining different woods.  Below are some pictures of individual ornaments and details of the software process.







I used several software packages in the process.  Most of the ornaments were published in a November, 2007 issue of Wood Magazine as scroll saw plans.  I scanned them into bitmap files and then imported them into the freeware version of WinTopo which I used to convert the bmp images to vector images, scale them to the appropriate size, and save them as dxf files.  I used DeltaCad to verify the files and the finished image sizes.  DeltaCad also now has the capability to move individual points to make it easier to clean up drawings.  Another option that I will try next time is to import bmp files into DeltaCad and then draw over these files on a new layer and export that image as a dxf file.  I then imported the dxf files into Sheetcam TNG where I specified the tool sizes, material size and toolpath offsets.  Sheetcam then produced the G-Code files to run on my router.  I also used CNC Simulator to test the files and verify that they would cut correctly.  Finally the files were loaded into Turbo CNC to do the actual cutting on the router.  It was quite a process and it took me numerous trials to get everything correct.  In the end I was quite happy with the results.

Here's another sample ornament.
















And one more.

















Here are some more new ornaments.
























This has certainly been an interesting learning experience.  I'm still getting my head around some of the things you can do even with a small machine.  My last project was cutting the openings in the face and back of my Internet Clock.  This was much easier than previous attempts.  The final packaging has always been my least favorite part of electronic projects but this machine is quickly changing that.

My next step is to figure out these new motors and what I have to do to get more speed.  More to follow.....

Updated 12/05/09


Well, after doing quite a bit of research, it seems I need dampers on the axes to eliminate or reduce resonance and get more speed.  There are several sources for commercial dampers but they all seemed to be quite expensive.  There are also several hobbyist web sites with examples of homemade dampers.  One excellent source of information is the Solsylva web site.  There's also lots of information on this thread on CNCZone.  And here's some commercial dampers.

The concept didn't seem too difficult so I set out to make my own and this is what I ended up with:

damper

damper


The first picture is the X axis and the second picture is the Y axis.  You'll notice that the Y axis damper isn't installed on the motor shaft, it's actually installed on the opposite end of the lead screw.  I had to do this because I didn't have enough room at the end of the Y axis motor shaft and, as it turned out, this was just as effective as the damper mounted directly on the motor shaft.  The parts were very simple.  Each damper was composed of 2 #9961K15 clamp collars purchased from McMaster Carr @ $2.67/ea.  One 3/8" ID part #3388 T-Track roller purchased from Peach Tree Woodworking @ $6.99 for two. One compression spring from ACE Hardware @ $0.69/ea. One 2-1/4" piece of aluminum tubing 0.375" X 0.065" X 0.245" purchased from Online Metals @ $3.59/12".  The total cost for each damper was about $10.19.  In reality I spent more for shipping than the cost of the parts although the spring was local and I purchased the rollers at a woodworking show.

The only thing I had to do was open up the ID of one of the pieces of tubing slightly since the ID was 0.245" and the motor shaft was 0.250".  I did this with a 1/4" drill bit on my drill press.  My lead screw was already 0.244" OD so I didn't need to do anything for that one.

So, how did it work?  Until now, the fastest I had been able to run these two axes reliably was between 15 and 20 ipm.  I am currently able to run them both at 75 ipm and, in fact, I really haven't tried to go any faster.  That's plenty of speed for my little router.  Needless to say I am extremely pleased.  In case you're wondering, I didn't add a damper to the Z axis since I really didn't see much need for it.

Well that's where I am for now.  Not sure what my next improvement will be - but it will probably be improved dust pickup and control.

Updated 7/19/10


Well I still haven't done anything about dust control but I have attempted to do an inlay and it came out really well.  This is a small oak box with walnut accents and the inlay is also oak and walnut.  My first attempt was with material about .040" thick but that proved to be a little too fragile.  This inlay was about .080" and it was just right.  The cutter I used was a .0625" diameter solid carbide spiral bit and worked well.

small box

Updated 11/26/10


It seems like things are always changing.  After the last box I decided that, if I wanted to make finer inlays, I would need a more accurate spindle.  The RotoZip worked fine for the ornaments but, when I worked on inlays, I was constantly modifying the tool size slightly to get the correct final part dimensions.  With accuracy and reasonable cost in mind, I decided on a spindle from CNC on a Budget.  This little spindle takes bits with 1/8" shafts and can run on either AC or DC (I am currently running on AC but may change in the future).  The spindle has a three step pulley and Paul states in the FAQ that they run at 7500, 15000, and 30000 RPM.  In practice I found that they run a little slower but certainly fast enough for what I do.  Here's a picture of the spindle installed on my router.

spindle

I also changed my software.  I had been using TurboCNC on a laptop but, since it runs in DOS, I had trouble getting it on my network and I finally got tired of running a floppy disk back and forth from the PC I was using for drawing and creating G-Code to the laptop.  My new software is EMC2 which as an open source machine control program which runs under Linux - specifically Ubuntu.  I installed EMC2 and Ubuntu on a 2.6 Ghz Asus PC that I picked up for $50 and which I also set up to dual boot Windows XP.  The learning curve for both Ubuntu and EMC2 was a little steep but not too bad.  I'm quite happy with the result and am glad I made the switch.  Here's the new setup.

emc2

So I decided to make another box with an inlay to test out the new setup.  This box is cherry and maple and only about 3-1/2" X 5" X 2-1/2" high.  The actual circle that contains the inlay is 2" in diameter.  I also decided that, in order to make finer inlays, I needed a smaller bit.  The inlay was cut from .050" stock with a 1/32" diameter bit.  I was a little worried about using a bit that small but it worked great.  The bit came from Stewart-MacDonald and ran about $18.00.  I have also recently purchased some 3-flute, solid carbide, 1/16" diameter cutters from Atlas Billiard Supplies and have been very impressed with their performance.  So here's the latest box.

memraid inlay

box open

Finally I recently cut a set of ornaments for a cancer survivorship workshop that I help to facilitate.  I used Inkscape to design the ornament and can see that I will be using this software a lot more in the future.  Inkscape is a scalable vector graphics drawing program and, although open source, is incredibly powerful and has a vast array of features.  Besides creating easily scalable images from scratch, it's easy to import bitmaps and then create an outline in vector graphic form to import into Sheetcam for final G-Code creation.  Here are the new ornaments in oak.

hope ornaments


And here's a set for another class but in cherry this time.



And another set in walnut.

walnut

I recently completed a blanket chest for my daughter and she convinced me that I needed some way to sign some of my projects.  After some thought I decided on a small engraved wooden medallion that I could glue to a project.  I actually learned quite a bit making this.  I decided to make sort of a sandwhich of maple over walnut and then engrave through the maple to expose the walnut.  I started by glueing a thin piece of .020" thck maple to a piece of .100" walnut.  When I unclamped the pieces, they were bowed badly.  I had heard about veneering both sides of a board to prevent bowing but hadn't really thought of this as veneering.  When I made a new piece that I veneered on both side, it worked fine.  I started by using a 30 degree engraving bit to engrave the text and saw image but it just didn't look good.  For the final result, the text and image are engraved with a 1/32" diameter cutter and the medallion came out great.

medallion


Updated 11/18/14


I realized I haven't made any updates to this page in a long time and I have added several changes to my CNC Router.  The two significant changes are to add a new spindle and finally add dust collection.  The new spindle, like the prvious one, came from Paul Jones and CNC on a Budget.  The new spindle has a bigger motor and uses ER-11 collets instead of fixed 1/8" shank tools.  Collets are available from 1/16" up to 1/4" and work very well.  The previous spindle, although it also worked very well, caused some problems with the allen wrench slipping in the very tiny set screw and sometimes the tool sticking in the spindle.  No problems like that with the new spindle.  Here's a picture.

spindle

You can also see the new dust skirt in this picture.  It's made out of a couple of pieces of plastic with magnets embedded in the corners and some strips of flexible clear plastic.  It ended up being so simple that I don't know why it took me so long to implement.  I'm using a Sears 2.5 gallon, 2 HP vacuum that I picked up for $25. and the combination works great - virtually no dust problems.  Here's a picture of the dust skirt and the new collet.

skirt

And here's the vacuum.

vacuum


That's all for now.

Thanks for visiting.


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