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

Inspiration: CNC related links

Some links I have bookmarked that may help some people:
http://makerbot.com/ DIY 3d printer
http://reprap.org/ DIY 3d printer (makerbot is based off of)
http://www.iaacblog.com Institute for Advanced Architecture of Catalonia blog, lots of CNC projects
http://replicatorinc.com/blog/ 3d printer blog
http://blubee.com/theblog/?cat=50 Art-based robot blog
http://www.nilsvoelker.com/content/_pages/robotic.html tech-based artist's page
http://www.adafruit.com/blog/2009/04/27/peter-sands-plant-fasting/ plant farming CNC
http://www.contraptor.org/ open source hardware (parts to prototype CNCs, etc)
http://www.makerbeam.com/pledge.html same as above
http://candyfab.org/ sugar-based 3d printer
 http://blog.makezine.com/ Make magazine's tech-based blog

Inspiration: CNC art

And here are some experimental CNC created art.  I had these saved for awhile so can't remember any of the artists names nor links, sorry.

Inspiration: Other CNCs

Before I continue I should mention some of CNC related technology I use for inspiration. 1

1) table top engraver by an ID student project
2) wheeled CNC plasma cutter? concept
3) hexapod spider CNC
4) robot brick layer
5) parallel robot CNC

Prototype #3: The Beginnings of Concept B

From the end result of the full scale materials testing, I decide to go back and rethink some parameters.  Concept A's main idea is to have the X axis to be relocated from top of the machine to the front of the sliding tray.  This will enable the user to use it as either a standard CNC or as a floor mounted engraver to do CNC work below the surface, much like Prototype 2.  After contemplating this, I believed I was still limiting the users by setting specific arrangements. What if the user wants to rearrange it in some odd way, they would have to do permanent modifications for that to happen.  Though Concept A is still a big step from production CNC machines, it is still limiting on what arrangements it can perform.

This is when I had a breakthrough.  Why not put all the axis into its own separate boxes instead of relying on a permanent frame/body to enclose all the axis!  Essentially each axis will be 1 box.  3 boxes will give you a 3 axis CNC.  If the user wants to have some odd setup, they would just need to make a new frame.  More people are capable of making a frame than making new CNC machines, right?  Essentially a shop can have 3 CNC machines for the price of 1; all they need to do is transfer the boxes into the desired frame.

The pictures represent the X axis.  The idea is a simple frame can be built around it to complete your desired version of a CNC machine.  People will no longer need to know how CNC works; eliminate the complex robotic mechanics that scares people away with simplified boxes with trays that move back and forth.  This in essence will promote development of new machines by allowing people to concentrate on new technology (3d print head, etc).

Prototype #3: Concept A

The original idea I had was to make a sleek looking CNC, something modern that doesn't make it look like an industrial-look cold aesthetics as most CNC have.  Here are some of my early renderings and concept development.

To do a full scale testing, I made a mold and made the X axis tray in full scale out of kevlar/carbon fiber material.  The end result was mixed, it was light weight and rigid, but have designed the molds and parts inefficient for the composite techniques I was using.

This was a good thing as it made me rethink the entire project.  As this was my class project we have to consider the audience, who is this marketed for.  It got me thinking that only a small percentage would actually need/want a super light weight CNC and would be willing to pay the premium for it.  It made me rethink why was I using space-age composite materials.  This would be the first eureka moment in my project...

Prototype #3: Materials Exploration

My original concept for prototype #3 was to make it as stiff and light as possible.  So I experimented with carbon fiber and kevlar combination as the main material.  Kevlar has great vibration dampening characteristics and is more inexpensive compared to carbon fiber. 

I did multiple experiments to see how many layers of kevlar I need and ways to make it stiffer without adding added weight.  By adding ribs or using sandwiching techniques, I was able to make it rigid and light.

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: as seen on...

Prototype #2: objects made

As practice on getting myself familiar with my new tool, I made a small handful of clocks using salvaged wood.  The time lapse videos shows one of the earlier trials.

Above is an MDF mold in which was used in creating the fiberglass skins for the upper and lower skins of the lamp.

Ironically, after making this CNC I discovered that it is often easier to make certain things by other methods rather than relying on a CNC all the time.  I have many other examples that this CNC has produced in some of my projects but these 2 examples gives you the idea of what it's capable of and it's accuracy.