So winter is approaching which always signals time for change. As the colder temperature and the snow begin to sink in as an unstoppable reality the planning for hibernation is inevitable. The past couple weekends have been spent putting the yard to bed. Winter fertilizer has been applied, trees and bushes have been pruned, sprinkler system has been blown out, and the gas yard equipment is set for winter servicing and storage. Now what!!!!??????
Last winter I was able to occupy my time completing my 1965 CB160 Café Racer build. It was a good project that resulted in great success. It allowed me to enjoy 2000km worth of riding this summer which included participation in the 2014 Distinguished Gentleman’s Ride.
For the winter season of 2014-2015 a new project is in order. I have many ideas stored in my database, the one that rests upon my neck, and it was just a matter of choosing something. Over the past 4 years I have explored the idea of building a CNC plasma table. I did much research many years ago which mostly involved reading manuals surrounding the CAD, CAM, and CNC operation and design. After having a few years to let the massive amount of information sink in I decided this winter season is the time to make this project happen.
The details involved in all the pre-planning are substantial. I am not going to bore you with the entire game plan but instead I will let it all unfold in the blog. So for today I will simply set out the ground work which is necessary in order to understand what direction things are headed (yes…pun).
First off, if you do not know what a CNC plasma table is then you can read about it here, or you can just Google it. Not going to cover the basics in this blog. What I will cover is the basic equipment involved in building the machine.
First piece of equipment involves an actual plasma cutter. In my case I will be using my Hypertherm Powermax 45 unit which I purchased many years ago. I settled onto the Powermax45 for a number of different reasons and 1 significant reason was the ability to interface it with CNC to allow for torch height control. This unit is spec’d to cut up to 1” thick steel and can do .500” at 20 ipm (inches per minute) I can tell you, from experience, this unit is a work horse. Creating plasma and molten metal is what it does best!
Next important piece of equipment in the CNC table build involves the tables X,Y,Z axis movement control. Basically this involves some stepper motors attached to the tables gantry’s that allow for computer controlled movement of the torch. After much research I settled on CandCNC BladeRunner Dragon-Cut set up. There are way too many details to list about this unit, you can visit the link if you want to read up on it all. The highlights involve a power supply to run four 620 oz. stepper motors to move the X, Y, and Z axis (1 will be slaved to the Y axis). The Bladerunner also allows for Digital Torch Height Control (DTHC) which assists in the precision of the cut.
Since the BladeRunner is only a power supply controlling some stepper motors it requires a commander. In my case the boss will be a dedicated computer running specific software to shout the orders to the stepper motors. I opted to build my own PC to the specs dictated by CandCNC in order to ensure the Bladerunner will approve of the commanding officer. I stopped in at my local computer supply store and picked myself up a PC case and all the guts needed to get the electrons flowing. The PC spec’d out as follows; Intel Core i3 3.60GHz processor, Asus H81M-E motherboard, Kingston HyperX Fury Black 4GB RAM, Asus 24x DVDRW, coupled with a Kingston V300 120GB solid state hard drive.
I have never actually built a computer and really have no idea what I am doing. I figured as long as I could get all the bits to fit in the box and if I could find a place to plug in all the wires how could it possibly not work? Looks like my theory was correct, I was able to keep all the smoke contained within the components, nothing leaked out, electrons flowed and pixels were produced. The computer will only be running 1 piece of software and nothing else using the Windows 7 32 bit operating system.
So with the power supply, stepper motors, and PC all dealt with the next step was software. The CNC system requires 3 different programs in order to make the magic happen. First off is a design program in order to create whatever it is that will be cut. The second is CAM software which takes the design and turns it into “G-Code”. This code is used to tell the table software where to move the stepper motors. The third piece of the puzzle involves the CNC software. This is the program that takes the G-code from the CAM software and then sends the signals to the power supply and commands the stepper motors. I was not prepared to stray too far from my comfort level so I decided to stick with a guaranteed combination that is known to work. CandCNC recommends certain software which also happens to be some of the most popular stuff used in many homebuilt CNC units. The 4 programs I am using are InkScape design software and DraftSight CAD software as the 2 design programs, SheetCam as CAM software, and Mach3 as my CNC software.
Inkscape is a free version of design software that mimics Adobe Illustrator. I will not go into detail however I will say that it gives my grey matter a major work out. It takes a lot of time to get the hang of the software and I continue to force the education upon myself. There are lots of “clipart” type designs available for CNC purposes which eliminate the need to learn Inkscape however in my case I want to be able to design very specific components. In the case of today’s blog post I am demonstrating a “Gords Garage” gear project going from initial design all the way to cutting. In the above photo I built a gear with a GG in it and vectorized it.
DraftSight is a free version of AutoCAD and works incredibly well. In the case of my GG Gear demonstration I did not use DraftSight. In the picture above I just quickly built a gear to show what is possible. I do not use DraftSight as “artsy” design software but instead use it more for component design.
The next piece of software is SheetCAM. This program takes my vector design and converts it to G-Code. In SheetCAM I can decided how I want the CNC table to cut out my design. I tell it where I want the torch to go, I program lead in and lead out cuts, I decide how fast things should happen, and in what order. Once I have made all the crucial cutting decisions I convert it all to G-code ready to be accepted by the CNC software. I should note that InkScape, DraftSight, and SheetCAM are all run on a separate computer from the CNC therefore after I am done with SheetCAM my G-code is loaded onto a memory stick and transferred to the CNC PC.
Mach3 is the CNC software loaded on the stand alone PC attached to the CNC table. The G-code from the memory stick is loaded into Mach3. I was not about to build the table and then figure out if things work so I have set everything up on the floor in a spare room to ensure I can run mock cuts. The PC, BladeRunner components, including the stepper motors, are all hooked up for testing. With the GG Gear G-Code loaded into Mach3 I can successfully run to cut pattern. In my case all I have is 4 stepper motors buzzing, and spinning, while lying on the floor however this verifies that all my software and hardware is currently functioning. Mach3 also controls my plasma torch height control which I will not be able to configure, or test, until the table is built.
I should perhaps mention that the whole reason I have chosen to build this table is because I like building things in the garage. Everything that I have listed so far does not qualify for enjoyable time spent in the garage. They are, however, necessary components, and steps, required to ensure a successfully completed, and operational, project. A well planned project is a project half done. So now that I have spent 2 months planning, learning, and collecting components I am getting closer to spending some quality garage time.
The actual table build is what this project is about. I have much of the table mentally designed. The plan is to use the tools and equipment I have available to me, in my garage, to build a unique, quality, fully functioning 4’x4’ plasma table. I want to build as much as I can by hand including the gantries, the support system and the floating head Z-axis. I am not basing my build off anyone else’s table but instead going to approach the design using my own logic and ideas. There are many companies that can sell you all the components you need in order to complete a build. In my case I have only purchased the bare essentials and plan to fabricate the remaining. The components I have collected include a ball screw and 2 linear guides for the Z-axis, a rack and pinion set up for the X and Y axis, and a 3:1 timing belt set up for the X and Y axis.
So basically this concludes my introduction to my next project. I have only included a brief overview of what I have started. The blog posts to follow will, hopefully, give you an idea of my direction, design, and completion of the build. At the very least I guarantee to show chips flying and sparks shooting.