If I win the Laser cutting machine. I will use it to produce more robots. After all even robots need skin. Not to mention all the projects I can make with such an awsome too. I use a larger one like it before and it was amazing the speed and quality of the finished parts.
So to begin with any robotic project no mater how complex you must plan, plan, plan, and then finally figure out or layout how you will go about it.. or "PLAN"...
Use your head when building anything. Use safety glasses when running mills drills or any power tool Your eye's are just little water balloons and can pop like a grape so protect them. I don't have time to create an instructable on how to replace your eye.
You're fingers hands and other appendages will lose any battle you engage in with a cnc, lathe or most power tools. Don't take them for granted. I have 30 years experience with machine tools and the building of robots I will try to make this easy. If you have a good design you can send out the drawings to have the major part fabricated fairly cheaply. If you don't know how to use a tool then learn, take a class, ask me or learn the trade. These types of machines have a mind of their own and must be respected, Safety first.
Now That the safety brief is out of the way lets get on with the show.
This picture is my last concept before i began. I created this layout with solidworks. that way i could test for any interference from moving parts in order to make sure they would all fit together just right. I also wanted to test for load bearing and lateral forces, as well as motor torque and loads. This information though not needed right away is a must for later on.
The mechanical layout is just a small piece of the design you must also consider all the programing that will be part of any robot you build especially a 6 axis robotic arm with inverse kenimetrics. More on that later. Once i had the basic layout I needed to make sure i cold afford the parts necessary to build this monster. I had to source the motors and find a supplier, as well as the gear/ drive train for each axis.
The motors i settled on were found on Ebay for 30.00 each. I bought 10 because i want to build more that one robot arm.
Step 1: Motor and Gear Choice
I chose to use a 10 to one reduction encapsulated in a planetary arrangement. this gives me great space savings as well as an efficient power out with good torque characteristics. These pictured were found on the internet and brand new cost me 150.00 apiece. Choose wisely when selecting your gear reduction or drive system. I made a mistake when i chose these units they should have been 30 to 1 not 10 to 1 as a result I will need to add a bellows system to help counteract the extra weight to avoid wearing out the motors and burning up the power supply. I will show you how I was able to fix this issue with very little effort though, sometimes you have to roll with the punches to get the job done. My solution was simple yet elegant and effective. I will install the Bellow system once I receive the parts i ordered should be here next week or so.
The last item you need to be aware of when picking a drive system is not only the motor and the transmission but the feedback system needs to be addressed. All robotic mobile systems need feedback otherwise they will not know where they are in relation to a known point, this is key to control of each axis. I have a 5000 count quadrature encoder on each axis this give me with the 10 to one gear reduction over 400000 counts per axis revolution, and as you may know the more resolution you have in your feedback loop the more accurate the robot is going to be. You can see the encoders mounted here in this pic they are located on the end of each motor with the grey cap. Renco makes these encoders.