Favorite Build, CNC

Home Made CNC Build

 This is my absolute favorite project I have ever worked on!  After 3d printing and customizing the CYCLONE PCB CNC,  I decided it was time to go onto a project I have dreamed about starting for several years.  A full size CNC with a coolant pump that is capable of cutting Aluminum! 

  This is the first axis (Y axis) installed on the 1"x1" square tube (1/8" thick)  steel frame.  The current stats are 30" Y-axis (length),  a 20" X-axis (width)  and the Z-axis (height)  will be adjustable by a changeable carriage.  My current goal is going to be a 6" cutting height.  

  The frame sides are welded.  The 3/8" case hardened rods are anchored at the ends in aluminum blocks with the steel tube ends mounted to the aluminum blocks.  The bed is attached to the steel tube ends.  This allows the bed and rail to be locked at a specific distance and will be true throughout the entire Y-axis! 

  The result is the Y-axis rods are locked into the bed,  even if the frame was off.  Even though the sides of the frame are spot welded,  almost every other part is being attached with black oxide hex nuts and tapped/threaded holes.  The bed is standard 20mm x 60mm openbeam t-slot aluminum. 

  My design is made to lock one part into the next,  before being screwed together.  BUT,  if any part were off and needed adjusting,  they can easily be shimmed.  That is another design goal with this project.  I want everything to be replaceable/upgradable.  For example,  I am starting with NEMA 17 motors (because I already have them.),  but think I will be upgrading almost immediately to NEMA 23 for aluminum.  The Z-carriage will be able to swap out for different heights and cutters. 

  Next will be building the X-axis.  Hope it goes as well.  Check back for updates. 

Cyclone PCB cnc

I've been a little sidetracked with a cnc build lately.  This is a wonderful first cnc project using a standard Arduino Mega 2560 with Ramps 1.4, running Marlin as the gcode controller.   I printed the parts in a combination of black PLA and red ABS. Printed on a modified Prinrbot simple maker's edition. 

  This is the cyclone v2.1 pcb cnc which is located at https://github.com/carlosgs/Cyclone-PCB-Factory/tree/v2.1

 I managed to build it before there were a detailed instruction file.  But they have recently added it to:  http://reprap.org/wiki/Cyclone_PCB_Factory/build

 There is also a support group located at: https://groups.google.com/forum/m/#!forum/cyclone-pcb-factory

   I'll try and post a video of it cutting some shapes in to plexiglass on the next few days.  Be sure to print the gears out of ABS since PLA will not last more than a few runs. 

Lawnbot's off road test drive video!

 Here is an updated video of the actual lawnbot running on the lawn.  (water rationing in southern Calif.  So not much actual lawn!)
 Initially it kept stalling out a couple times a minute.  Pause for just a second.  I thought it was pulling to many amps and the code was shutting the circuit down for safety.  This was not the case.  It was actually reading the radio to soon and was dropping packets.  This result in a no connection result that put the code into a loop till it received valid data from the transmitter.
  I did find that the current readings were topping out at 10amps (each motor)  with a quick change of directions.  So I installed the - 30 to +30amp current sensors and have them safety checking at about 15-17amps. I'll check after the added weight of the propane motor and it's electric starter motor,  to adjust it any further.  Right now the pwm is limited to 90 out of a possible 255, so there is still a lot of performance possible in this build!
  In the video,  you will notice that it manages to drive up and over the border bricks.  This was a surprise since I didn't think it had that kind of torque/power.  Still quite a bit of fun left in all these recycled scraps!
  Motor mounts for the propane motor and it's custom starter motor are next on the list (after weight/amp tests).  So be sure to check back.  Any questions,  please let me know!

Lawnbot finally moves!

06/03/2015
  It's been a while since I have been able to work on this project,  but it is now sitting in the middle of my living room for some major upgrades and testing!  (and my wife is still talking to me?!?)
  I had a 30amp circuit breaker attached.  The first time I tested it, It blew the circuit breaker under load.  So I installed 2 ACS711EX Current Sensor Carrier -15.5A to +15.5A.  The PWM is set to max out at 60 (out of a possible 255) and with the current sensors shutting down the current draw at 13amps per motor,  it seems to run quite well.  Higher Current supply or different motors will be a future upgrade after I get everything running correctly.
  A couple other upgrades you may notice from the video: it has a separate wireless control that will be able to take control during autonomous activities or in an emergency.  The remote is made with an analog thumbstick/joystick,  an arduino nano clone,  4x16 lcd display and an nrf24l01 2.4ghz radio (2nd one on the lawnbot).
  I also added a mosfet and relay switch to allow the lawnbot's mega2560 to turn the high voltage/current to the motor controller.  The mega does a simple voltage check to ensure there is enough of a charge. If so will turn on the motor controller's,  motor current feed.  It does this with a simple voltage divide reading on analog pin 0.
  With the upgrades of the current sensors,  relay,  nrf24 radio,  new main power switch,  circuit breaker and various leds,  it has been rewired a couple dozen times and has some new 3d printed parts.  I think the controller will outgrow the enclosure soon,  so I may have to design another mount.  I'll try to get some newer pictures in the next few days.  (already much different than what is shown in the video above!)
  The next steps are to test the failsafe controller by driving it around the lawn for a bit. The living room is only big enough to do some parallel parking tests.
  If that works out well,  then I will start building a custom mount for the propane motor and it's starter motor as well.  These will always be manually controlled for safety reasons!

Wireless controller before 3d printed housing.  Uses external 5v USB batter

A view of the control assembly from a few weeks ago.  When the wires were still manageable! 

3D Printer Linear Motion without Linear Bearings!

 I currently use several modified Printrbot Simple Maker's Editions. They are very solid machines and make some impressive and fast prints. My largest print size is 200mm x 320mm. Roughly 8” x 14".

  The one thing that is a constant battle for higher speed prints is slop or flexing parts during the movements. I started experimenting with different materials to use in place of linear bearings for use in 3d printing. Although 8mm linear bearings and case hardened rods are the go-to solution, they still have play that is evident in the prints (especially when changing direction)..

  One quick, possible solution for my existing printers are the small round parts in the pictures. They are 8mm I.d. x 10mm x 10mm linear bushings. The are self lubricating bronze linear bushings with a hardened carbon steel outer casing and a PTFE (Teflon) inner liner. Extremely nice fit with no play, but they will require some new mounts to be fabricated to fit my existing bearing mounts.

The white part on rails is a test for my custom designed printer. The plastic is also self lubricating, but is HDPE. 

  I am very excited about this test as it is smoother than the bearings could ever hope to be and will easily be fabricated so there will be no play when mounted correctly.

  It's 5/8” thick HDPE and has had all 4 sides routed top and bottom, leaving a 3mm tab that fits snugly into the 3mm screw rail of  15x15 mm extruded aluminum (openbeam v2.1).

   This is an idea that I hope to develop in my custom printer and maybe even for the CNC machine I have been planning for the future.

  The last item is a roll of PTFE tape. I had considered using it to line the edges of an aluminum plate that could also run in the extrusions rail with HDPE wheels to provide side pressure, removing all play. That is something I will be trying and sharing the results here as well.
  It may be necessary to use aluminum/Teflon combo over the HDPE glide depending on how well my ideas work out to prevent heat creep on the heated bed and extruder mount. HDPE is my material choice for these projects. Wonderfully smoother linear movements without bearings.