DIY CNC Router

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Hive13 CNC Projects
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Hive13 Project
DIY CNC Router

Hive13.CNC.photo.000.jpg

Status: InActive
Start Date: 09/03/2009


Overview

Make something similar to MakerBot but leaning more toward the 2D / routing / cutting aspect. Something that could concievably be distributed as a "kit" with open-source design, off-the-shelf or lasercuttable/makerbottable parts.

Project Members

Project Plan

Phase 1 - "Get something working"

  • Lubic Frame ( contributed by cjdavis )
  • CNC cut corain frame pieces ( designed and cut by Jim )
  • sliding beearing ( corian tab in aluminum slot )
  • 4 NEMA 17 stepper motors
  • Sparkfun Easydriver
  • toolhead 1 = sharpie
  • toolhead 2 = cheap dremel

Phase 2 - Redesign for simplicity, replicability

  • Reduce number of unique parts.
  • Reduce number of custom made parts.
  • Integrate open-source electronics, software packages (RepRap).
  • Refine toolhead interchangeability.
  • Document and publish design, instructions online.

Phase 3 - ...

  • Produce a product that can be purchased either as a kit you can put together over a weekend, or as a fully pre-assembled machine. A shameless copycatting of the Makerbot Cupcake idea is what we are after here.

Phase 1

Status

We have general sketches, but need to nail down some details, and prototype the CNC.

Links of progress:

Features

  • Lubic Frame ( contributed by cjdavis )
  • CNC cut corain frame pieces ( designed and cut by Jim )
  • sliding beearing ( corian tab in aluminum slot )
  • 4 NEMA 17 stepper motors
  • Sparkfun Easydriver
  • toolhead 1 = sharpie
  • toolhead 2 = cheap dremel

TODO List

Parts List

Part Source Status Description
Frame COTS (Lubic) We have cjdavis' Lubic kit. Frame construction can begin. Hopefully we have enough pieces. T-Slot. Various lengths. Lubic is ~16mm square extruded t-slot aluminum. We should list exactly how many of each length we are going to use.
Motors COTS (eBay) Dave bought a set of 4 NEMA17 motors on eBay. They are untested. This is what we bought. Supposed to be 24v, so we may need to drive them with a non-ATX power source. http://dl.getdropbox.com/u/1966661/Hive13_Public/StepperMotorSpec.pdf
Sparkfun Easydriver (x4) COTS (sparkfun.com) purchased http://www.sparkfun.com/commerce/product_info.php?products_id=9402
Threaded rods COTS (hardware store) Needs to be purchased. mcmaster: 98861A080 / 330mm Metric Thread Size: M8 (How many? What lengths?)
Nuts, bolts, washers COTS (hardware store) Needs to be purchased. Sizes: fitted to the threaded rods (M8), fitted to Lubic frame, fitted to NEMA 17, fitted to electronics.
Plastic skid plates COTS (??) Needs to be purchased. Number? Sizes?
Sharpie Toolhead Custom built. Not yet designed. Spring loaded Sharpie Marker. Detachable from frame.
ATX Power Supply COTS Several on hand already at Hive13.
Motor Mount Plate Custom built designed by jim. Jim will cut some from corian with his home CNC machine.
Captive Nut Mount Plate Custom built. Not yet designed. Something like this: http://www.garagefab.cc/user/albanetcsr/photos/captive-nut-angle
Electronics Mounting Plates Custom built. Not yet designed.
Endstop flags Custom built. Not yet designed.

Images

Hive13.CNC.photo.000.jpg

The design work starts in 2-D CAD. The goal is to work out the top level design. Make the front, top, and right-side views adding detail as you go to see how the parts begin to fit together. Then start to detail individual parts.

Hive13.CNC.photo.001.jpg

Starting from the individual 2-D part geometries, you can then build the 3-D parts and make the 3-D assembly. At this stage you can pan and tilt, rotate and zoom to get the full effect in the 3-D CAD software.

Hive13.CNC.photo.002.jpg

This is a zoomed view of the 3-D model. You can see the aluminum extrusion rails used to build the frame. The individual parts shown here are detailed in the following pictures..

Hive13.CNC.photo.003.jpg

This is one of the four corner brackets. There are actually two left brackets and two mirror image right brackets. The full part is actually made from three cut plates that are assembled together See following slides.

Hive13.CNC.photo.004.jpg

This is the left and right side versions of one of the three parts in the corner bracket. The two parts are cut out simultaneously from one piece of stock. The parts are 'tabbed' in the stock by the CNC machining operation. The method is also called 'picture-framing'.

Hive13.CNC.photo.005.jpg

This is a second piece of stock that has the left and right side versions of the other two parts in the corner bracket.

Hive13.CNC.photo.006.jpg

This view shows another left and right pair of slider parts. Go back to the earlier 3-D view to recognize where they fit into the assembly. Note the critical alignment features are all cut on one side at one depth assuring the best possible accuracy. If you had to cut the parts in two setups (top and bottom) or in different orientations, it is harder to make them consistent.

4030587093.jpg 4132986028.jpg

Design of a CNC

I have an idea to turn this into a few separate pages. DaveMenninger 20:21, 17 December 2009 (UTC)

Hive13 CNC Projects

Frame

I think it would be smart to try to design a frame that can be created using the CNC itself, so that it is self-replicating. DaveMenninger 15:32, 3 September 2009 (UTC)
Just like the RepRap, I think this should be a primary design goal, but I'll consider the first one a success if it can carve balsa wood :) --Cjdavis 21:27, 7 September 2009 (UTC)
What size cutting area are we looking to have? TP
I think I would shoot for 8.5x11 as a minimum. Hopefully more like 10x14 or 11x17 would be doable. The bigger, the better, IMO. DaveMenninger 18:35, 6 September 2009 (UTC)
We should base the design on t-slot aluminum extrusions.
  • There are a number of suppliers of them, many of which are compatible with each other.
  • If we handle the design correctly, simple steel box tubing could easily be used in place of the extrusions, which is available pretty cheaply anywhere in the world.
  • There are even linear motion parts for use with them that could remove a lot of design effort to start with - see ( http://8020.net/Application-106.htm ) from this page ( http://8020.net/Solution-8.asp ). However, I think this is probably too specialized a part to use in a long term design. We should at least have an alternative for people using box tubing for example.

Parts that need to connect to the frame somehow

Electronics

Hive13 Driver Board Current Status:

Moved to Hive13 Stepper Motor Driver Board

Motors

  • We need at least 3 stepper motors.
    • X-Axis
    • Y-Axis
    • Z-Axis

Drivers

Possible Arduino compatible solutions:

Controller

Something Arduino-based seems like it would be a good idea.

Also, we could do a breakout board for a parallel port for everything. This is supported by EMC2 for sure, and perhaps the other software packages.

Proximity Switches

Control software will need to know where each axis is located at the beginning of each part run. One way this could be done is to run each axis down against a prox switch to 'find' the min position, and then move to center. Not sure if a max switch is absolutely required or not. Prox switches can also be used to protect machine from CNC programming errors, which if used in this way a max sensor would be good.

  • TP: I have four (4) magnetic hall-effect sensors on order that may be usable for this purpose. I suddenly wish I had ordered six (6).

Software

We should discuss what sort of software will control the CNC machine, as that may drive pin selection on the parallel port, if we go that route.

  • Mach 3 - Jim is pretty familiar with this one (Windows only)
  • EMC2 - Free software (Linux only) - There is a LiveCD of this somewhere at the Hive.

After some research, the EMC2 can configure to interface with the pins on the parallel port in any configuration. We will have to discuss what pins we wish to support, such as EStop, limits, etc. -James

Toolheads

Should be swapable as quickly as possible. The Makerbot is pretty cool in that you can just disconnect a single cable and pull the entire extruder platform out (is that possible, or do you have to unscrew the extruder head first?) Wait, is that true? Can we just mount a tool holder where the extruder goes in the Makerbot?

Possible toolheads:

  • Ink pen
  • Rotary cutter (Dremel or router motor)
  • RepRap extruder
  • Laser cutter
  • Vinyl / paper cutter
  • Paint air gun

Parts

  • Step Motors:
    • The controller interface for the RepRap stepper driver board ( http://www.reprap.org/bin/view/Main/Stepper_Motor_Driver_2_3 ) has the signals Min, Max, Dir, Enable, and Step - with Min/Max just routed straight through to the opto boards. So it sounds like we could probably wire [the funky] motors straight to the motherboard, OR get the RepRap stepper drivers with more standard steppers - with little to no redesign needed. --Cjdavis 19:26, 7 September 2009 (UTC)
    • These motors might be appropriate for this project, esp given the target cutting area: http://www.automationdirect.com/adc/Shopping/Catalog/Motion_Control/Stepper_Systems/Motors_-z-_Cables/STP-MTR-17048 ($19 each, minus shipping). Depending on the tool, the Z-axis motor might need to be a little beefier than this. Nice bonus - they come cabled with reasonable connectors. Being basic 4-wire steppers, they should work with any driver system chosen. TP
    • I would suggest a trip up to Mendelsons, they literally have 2 Aisles of just assorted stepper motors. They are very assorted, and finding 3 matching ones could be a challenge, but it would save us shipping and we might find a good deal. Paul
  • Frame: I have an Aerocool Lubic 4480 computer case kit, which was basically a set of slightly smaller t-slot aluminum extrusions. I think they are 5/8" square if I remember correctly, and there are 12 of the longest pieces, which are ~18" long. There should be plenty of pieces for a full design. We can at least mockup the design with them, but they should be just fine for a fully functional CNC. The design should be directly transferable to use with any standard t-slot extrusion available.

Brainstorming Links

Best Links

Misc