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As the title implies I have started building a very small and inexpensive CNC plasma gantry. I started on it earlier this week and plan to document the progress here as I make it. I have some goals for this project and they are as follows.
1 Small footprint-I have limited shop space because of all the other crap I have collected and therefore I am making this table as compact as possible so as to save on precious floor space. It will also be on wheels so I can roll it around when not in use.
2 Low cost- I am trying to build this thing as cheaply as I possibly can. I am using surplus/scrap/found/previously purchased materials whenever possible and buying as little new stuff as possible. Fortunately my cause is helped by the fact that I cant see good stuff go in the trash and I have been collecting useful stuff for years.
3 Quality-Cheap doesn't have to mean crappy! I may not be spending a lot of money but I am going to try to make this little thing as nice as possible. Most of the parts I have made so far are milled and many of them have pockets and curves even when a simple chunk of straight bar would do--it just looks better and gives me something to do with the milling machine that hasn't seen much use lately.( I forgot just what a mess flood coolant can make)
4 Other stuff- of course I would also like it to be fast, accurate, pretty and not smoky but that may be too much to ask for.
I do not have a plan, or a drawing, or too much of an idea in my head I am just working on one part at a time and hopefully it will fall together. It is kinda fun to design and make something when there really are no rules or anyone else to please besides myself. I will include pictures since they are the only thing that anyone else, including myself wants to see
Here are some additional pictures of the limited progress so far. The rollers are a set of interesting cam followers of sorts that I acquired years ago from a machine that was being scrapped. (cant beat 10 bucks for about 40 of them) They helped track some high speed belts and had a crown to them so I made a mandrel to mount them on in the lathe and turned them down to a straight profile so that they would ride better on the 2" square tubing that I am using as guide rails.
A few more photos..also in the previous group things were just mocked together and i just noticed that the seam of the tubing is on the "side" of the rail in those photos. As you can see in these pics the seam was installed in the down position so that the rollers only run on the three smooth sides of the tubing.
Here is a link to short video taken during the milling of a bracket that I may or may not use. It shows the pockets getting finished up around the edges. I will also attach a pic of the bracket. I ground down the face of it which is completely unecessary but made it look nice I think.
Video:
http://www.youtube.com/watch?v=MsptmgZNjmI&feature=youtube_gdata]CNC bracket milling - YouTube
Merry Christmas everyone. I had a chance to do some more work in the garage today and took a short video of one of the roller guides getting trued up on the lathe. It is below.
http://www.youtube.com/watch?v=lF0GP_SnxEc&feature=youtube_gdata]Mach # lathe truing up Followers - YouTube
Here are some more pictures. I was able to get the X axis carriage cut out and put together. I expected it to roll pretty well but I am really pleased with the way that it rolls along the tube. It is so smooth and effortless to move and yet seems very solid and seems at least to be plenty accurate for plasma cutting. I guess only time will tell if I am correct or not.
More pictures of the carriage assy
The photos with the stepper just show it sitting in place as I play around with which way I want to mount it.
I got one of the motors mounted on the carriage today. I also made a couple of brackets to attach the timing belt to and mounted them on the gantry rail. The timing belt is just held on with a couple of clamps for now soon to be replaced by a more permanent mounting block. I am very pleased with how the carriage slides along and how smoothly the belt seems to feed through the tensioning rollers on either side of the timing pulley.
I was able to spend a few hours working on the machine yesterday and I was able to get it moving for the first time. I will post a video of its first movements after motor tuning below. In the video it is moving at 600 IPM as it cuts an 18" diameter spiral working from the middle outward. I am considering fitting smaller timing pulleys to the motors because I am willing to sacrifice some speed for some better acceleration. When set to 20 in the acc box I would sometimes get a little bit of stuttering so I backed it down to 17 and it seems quite happy. I really don't need 600 ipm on what is basically a 24"X" table as far as I can tell since I am pretty sure I cant cut anything that fast and the time it takes to rapid from one place to another is not a very big issue with such a small table. I am also wondering if I just ran the steppers at a higher voltage if I could get better acceleration? I am currently running them at 12 volts with LiniSteppers for Drives. Does anyone know if that would be a good idea? I was actually able to move the x axis carriage at up to 1200 ipm since it is so light but it was scary fast especially with no limit switches installed. I also wanted both axis to run at the same speed so I the Y axis which is moving around lots more metal is the limiting factor. Let me know what you think as you can see the belts are just attached temporarily with clamps and several other things need refined and finished including a z axis but it is exciting to see it move!
http://www.youtube.com/watch?v=mnmy8x7jbL0]Cnc Plasma Gantry First Test - YouTube
Last edited by trevorhinze; 12-31-2011 at 10:23 AM. Reason: spelling
Gantry on the table saw... great idea! Looks "portable" so to speak.
It is just sitting on the saw until it gets its own legs and wheels later on. You know how it is any flat clean surface is fair game!
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