video: assembly and conversion

http://www.youtube.com/watch?v=-rkPU32INyU

Assembly video: from parts, to standard 3 axis router configuration, to wheeled-cart

RedBlueCNC: model progress

The actual model building is going well.  The majority of the welds and drilling has been made, the X axis is operational and needing minor welds to make the Y and Z axis automated as well.  Hopefully by the end of this week everything will be ready for paint.  Final renderings hopefully will be started, as well as the exhibition display table I'll be custom building specifically for the CNC.

In spite of the time crunch, I have decided to make the rotational adapter to make the cart concept fully functional.  The rotational adapter will add some needed height as well to allow more clearance of the Z axis from the surface (estimating 8"-10" total clearance from surface to the bottom of the Z axis).  Added height can be easily accomplished by various measures as well.

I'm using 1/4" aluminum for the majority of the build.  It is a little heavier than expected but still not as heavy as most production CNCs out there.  Estimated overall weight about 60lbs.  Overall dimensions about 24" wide x 36" depth (side arm supports) x 24" height.

RedBlueCNC: more concepts

Here is my ideal concept for the wiring.  A simple flush mounted plug similar to a USB located on 2 sides on each box.  There are 2 locations specifically because if the user prefer to mount the box on the side where the wire would come out from, then it would cover the plug. 

But in the prototype world (real world), I don't have time in making a new plug so will be using a DB9 serial port plug similar to many hobby CNC setups.

One day I came across another idea of making it more portable.  If the boxes all pivot onto itself, it can be neatly stacked vertically in an organized manner.  Relocate the side support arms and attach a handle and wheels, now you have a cart in which you can easily carry your CNC anywhere!

The rendering also shows all the main components of the CNC package.  In which case the user, if preferred, can easily arrange the boxes or build a custom frame to specifically suit their purpose.

This rendering shows an upgraded concept of my wall-CNC setup.  The side support arms are flipped to allow closer access to the wall.

RedBlueCNC: specs and dimension

Since Concept 3's internal design for the Y and Z axis was working fine, I decided to continue the internal design for the RedBlueCNC (concept 4).

There are 3 main pieces for the box:
1) the top (where most parts attaches to)
2) the bottom (access cover for the mechanics)
3) the tray (not pictured)

Here is the finalized design, about 8" x 6" x 22".  The Z axis will be 18" long as the slides I bought are shorter length.  Each box can technically be as long as the user desires to be easily upgraded.  The top part is proposed to be aluminum extruded.  The bottom part will not be financially feasible to be fabricated out of extruded aluminum so am proposing it to be hand welded since it "would" be a limited scale production.  Ideally a strong plastic extrusion version could be made for entry level CNC or for those not needing stiffness (3d printing, etc). 

Cutting area is about 12" x 12" x 8" depth.  I purposely chose this size as (a) most designers and model makers would be able to do most at this size, (b) keep the size down as most people don't have room for larger tools, and (c) keep costs down for my prototype as I am a student still.  But as mentioned it can technically be lengthened to larger size easily.

Prototype #3: final prototype

This is insides of the Y axis prototype, Z axis is similar as well.  The build is rough as it is only used as a proof of concept.  The final material will be out of aluminum. As you can see the mechanics is simple: motor turns screw, screw turns nut, nut moves tray.





Here are pictures of the final proof-of-concept prototype model of Concept 3.  This is where I ended my first semester of my school project.  It is a fully functional 3 axis CNC machine.  It's setup at about 120 inch per minute, and an accuracy of about 0.015"  I used a floor engraver setup configuration as supposed to a typical desktop CNC configuration.  In this setup I am capable of doing CNC work on the surface below which I demonstrated during my end of semester presentation.  Built time: 1.5 weeks

Prototype #3: Introduction

By this time, I am starting my final year in my Industrial Design degree. Since I always wanted to update my CNC with better improvements I decided to use it as my grad/thesis project. My original intent for the project was a portable CNC that is multi-functional/transformable to allow CNC technology to progress (as I believed CNC technology has had very little progress in the past decade).

I ordered faster lead screws, this time using Acme 1/2" 8 start threads. This will be 8x faster than my old setup, going from 16 inch per minute to 120 inch per minute.  I ordered the Acme coupling to attach the motor to the screw instead of using a hose as per my earlier machines; less fuss and maintenance. Also got an end clamp for the other end of the Acme screw instead of having it free spinning; this reduces potential backlash and makes the screw more aligned all the time.

Bearings and slides are now all fully supported.  X and Y axis are using 24" Thompson bearings/slides while the Z axis is by another brand (bought separately). Motors and control boards are the same Xylotex setup from my old setup.

Prototype #2: Improvements and Specs

Prototype #2 has many improvements over typical CNC setups.  First being collapsible.  Now people (like me) who can't afford a permanent space to be used for a CNC can store the machine in a closet when not in use.  It is easier to carry it from point A to point B as well, carrying lighter parts than heavier wholes.  Though being collapsible creates issues as well.  It can take longer for setup and has to be aligned every time to make sure the dual X axis tracks are parallel.

A second improvement is having an open table, though some CNC machines have this as well so it's not as a break-through.  This does allows for oversized materials to be placed through the CNC, like a tree log or long lumber.

A third improvement in prototype #3 is it allows materials/stock to be worked on from above the surface, like any other CNC machines) but also below the surface.  I can do engraving work up to 6" below the surface if I wanted to.  This means I can prop my machine on top of an oversized picnic table and engrave on the table top.  I can technically mount the machine to a living tree and do some work on it if I wanted to.

As a typical setup, I clamp an MDF wasteboard onto the CNC then mount the stock to be cut on the wasteboard (as pictured).  Cutting area is about 17" x 17" x 8" depth.  Depth can be easily adjusted by bolting the router adapter plate up or down, or by making a new adapter plate.

Parts & Resource List

Some parts I use on my CNC projects:

Xylotex: Electronics & Motors
-4 axis control board
-4x 269oz bipolar stepper motors


DumpsterCNC: Anti-Backlash parts

CNC Zone: forum for tech help

McMaster-Carr: misc parts (Acme screws, etc)

ebay for used bearings and slides