New Machine Build- wanted a 8'x4'x 6" made a 13"x13"5"

[krak]

My CNC build journal

Thanks to Make magazine, I discovered that I could build my own CNC routing machine. Which would be very handy for the prototyping I do, plus sign building and rc parts that seem to require replacing often under my control. After many months of research on sites like CNCzone.com, buildyourcnc.com, and few others, I decided to join the forum to pick a few brains. I really wanted to build a 4' x 8' x 6” routing table. I was having a hard time finding a good set of plans to be able to do so. I found a few kits I buy, but I really wanted to build it from the ground up as much as reasonably possible. No need to solder up my own stepper controls, although I was considering running the machine from an Ardunio. Thankfully the good folks on the forum persuaded me to consider plans from David Steele. I ordered up the plans and by the end of May I had them in my hands.
After reading the plans for the 25” x 25” table, and taking stock the tools I hand on hand, ( hand drills, milter saw, jigsaw, skill saw and hand tools) I decided that maybe I should start off even smaller and build the 13”x13”x5” table. Without a drill press, I knew I couldn't make some of the holes for bearings by hand. But, as many have said before, I will build my first CNC to build my second CNC. In the plans it stated that it is a good idea to put the motors on at each stage of the build and tune them. I had a nema 23 and three nema 34 motors from some industrial machines I built for customers. I figured that I would be better off just ordering a motor kit for this project. So off to cncrouterparts.com I went. I got the 4 axis kit, knowing that I will likely rip the motors off this machine when the next machine is ready to go.
6-4-2010 I head out to get the hardware I will need. Home Depot wasn't much help, so it was off to Lowes I go. I pick out the ¼ 20 rods, and ½ steel rod. A decision I will later regret. I deplete the store of all 6 of there ½ bronze bushings. Then went all over town looking for 5 more bushings, but no joy. I can be a creative guy when I need to be, so I figure I will make it work. (stupid newbie)
That Friday, I spent 6 hours with my drill setup like a lathe, sanding and filing the ½ rods. The next morning I spent a few more hours sanding and filing the rods. After that I spent a few hours cleaning up the ¼ 20 rods. Finally by the afternoon, it was time to start cutting the lumber. Measure twice, cut once, measure again. Uh oh, there's a problem. All the boards are coming out a 1/8th inch off. Time to check the saw. Up to this point the saw was cutting fencing posts. Now i'm trying to cut very precise measurements and it is isn't working. The laser guide on the saw is close but not perfect. After a few more hours trying to fix that I find that the mount for the laser is not true, and it can not be fixed. The saw was later returned and a new one is in it's place.
Ok, lets recap the build so far. ½ rods are anything but smooth, the ¼ 20 rods are all dinged up, the lumber is square but not the correct length, and I only half as many bushings as I need. Time to start building. Saturday night, I get the base frame laid out, drilled, glued and put together. The x table is assembled, sort of. After one more go around town to try to find bushings failed, I decide I will cut all but one of the group I have in half. Back to the x table, I put it all together. Mount it on the rods and try to slide it back and forth. No go, time to call it quits for the night, or morning at that point. I was tired, excited and frustrated, all at the same time. I did sleep pretty good though.
Sunday, I get back to work the machine to find that it is way out of whack. I don't know if it was from the wood drying, the humidity, or what, but it worked better as a rocking chair then it did as a base. So I took it all apart, and reassembled it. This time it was true. I reworked the x table, now slides nice and smooth, mostly. I still had to file a few spots in the rods. And I found out the hard way, that if the bushing setup hit the frame, they would got out of alignment and not want to slide anymore. So physical stoppers were added to the table. I know, limit switches and the controller software should prevent the system from crashing itself, but I also do automation for industrial machinery, I have become a good acquittance with Murphy and his laws.
Now that the x table was done, with my spare nema 23 motor on it, it was time to move onto the gantry. It did not take very long to build the gantry. A few hours at most. But getting it square was a process. I had to use washers as shame to get the frame square, thanks to the wood warping. Not a big deal, but time consuming. Buy the end of the night I had the y table on the machine, with the rods and lead nut, but no motor.
Monday, 6-7-2010, I begin work on the z axis. Without a drill press I had a hard time building the rod supports. But I seem to manage to get something ugly put together. When I try to get the assembly to slide I might as will pick the machine up by the z. It took lots of time, and trial and error to figure out that the screws in the back of the bushings were causing the bushings to deflect and pinch onto the rods. I removed all the screws and bingo, it slides like a champ. I forgo the ability to adjust the z axis, but at least it moves. Monday afternoon the motors show up a day or two before I thought they would. I have just enough time to mount one on the y axis. Then I have to pack up for a two week job.
Saturday, 6-12-2010, I have just enough time to finish mounting the motors, and replacing the x table motor with a new motor from the kit. I then make a holder for my HF dremel type tool. I wire up an estop, the motors, power supply, and driver. Turn on the power, test the estop, and nothing explodes. I happy so far. I pack up for the second week of the two week job.
Tuesday, 6-22-2010, finally back to work on the cnc project. I try to run Mach from my laptop. I can get everything to work except for the charge pump. Of course it took a lot of time to get to know Mach. There was a lot reading, trial and error, and maybe a few dirty words. I knew from reading that a laptop is not recommend for running Mach, but I just wanted to test it out. I convince my wife to be, to let me take back my old Dell tower. She had been using it for her business, but hated it. So I played mister IT, and transfered her files off the computer and onto another. I get the Dell all setup with Mach. Go to run my first test, and the charge pump still does not work. Shut the pc off double check that I had en-fact changed the port to the right config, and try again. Still would not work. I spent a good amount of time checking through the port settings in Bios, input / output setting in the software, changing the kernal speed. Nothing worked, that is until I found a small feature in the general config screen in Mach that turns on or off the charge pump use. Bingo!
Time to move onto tuning and testing. I'm running 1.8 degree motor, on 10 micro step driver, on 20 thread per inch rod. My math tells me that 40,000 steps per inch should be right. I plug it in, restart the software and give it test, with the sample gcode. Bam! The x table slams the stops and bends the ¼ 20 rod. The z axis is just slipping on the hose coupling. But motors are running as they should. I think.
The next step is to add the limit switches, and replace the bend rod. I have a few questions if anyone could help me. How do you know what Kernal speed you should be set to? Is my math correct for the motor tuning ( I have set the units up to be English). How do you Jog the motors? Can someone point me to some sample Gcode to test a 13x13 table?

[krak]

i tried to put some photos but something went wrong with a token. i will try again later

[ger21]

40,000 steps/inch is correct.

At 25Khz, you get 25,000 steps per second. 1,500,000 steps min. Divide by 40,000, and you can get 37.5in/min at 25Khz. If you want to go faster, increase the Kernel speed.

Jog with the arrow keys, and page up/page down for Z axis.

[krak]

great thank you. jogging will be a big help to set up the limit switches.

[louieatienza]

krak good to hear you're up and running! Would like to see some pics if possible... Might have some g-code if you need shoot me a pm....

[krak]

Just when I thought i would have some time to finish up the CNC, a water heater blows a hole in it, flooding the basement. So i haven't able put the time into to get it cutting. Which is funny, since i started the project because I had the time to work on the project. No matter, now I will have to get myself to learn Mach to really get going from here. I will be putting up some photos soon. Thank you for the support.

[krak]

So I have run into 3 problems:
1 I can't for the life of me get any photos up on this forum. I just keep getting a security token error.
2 I used the tubing and hose clamp method to hook the lead screw to the steppers and now I can't tighten the hose enough to prevent slipping. Ordered up some proper shaft couplings and a few other parts. Should be here in a day or so.
3 And this is a big one, Mach3 has now caused 2 towers to crash. Mind you, neither are spring chickens, but both were stable prior to today. The first was running xp pro, and was going to get a fresh install. The other was running 2000.

I'll be working on the pcs in the am. Well later in the am since it is already that late. I think the dell will be getting xp and linux this time. Anyone have the xp sp3 iso for download? Can anyone point me to the proper linux iso? I was told it needed to be a real time kernal, and i haven't figured out if 10.02lt will work. Nevermind, it will not work with 10.* but comes with 8.04 which can not be upgraded.

I might need rehab, i'm staying awake at night thinking the cnc machine.

[krak]

First thing this afternoon, this morning I was a plumber again, I loaded up ubuntu 8.04 with EMC2 on it. Fresh hard drive, should have been nice and clean. I very excitedly tried out EMC2, and it crashes the OS. Hard reboot, and try it again, crash. So I take the Tower upstairs to the office, plug it into the interwebs and update 8.04. EMC2 still crashes it. I try to update the EMC2 from 2.3.5 to 2.4.1. That should clear it up right? HA I went through every option on the wiki. nothing would update the software. I have never used GIT before, but I had to figure it tonight. I run Ubuntu 9.** and 10.** on some of my coputers. I like it, I'm not a big fan of terminal but I can get around. It was a little bit of a battle to get GIT in on and up and running. The wiki's did a good job explaining most of the steps. So great, I try to run EMC2-2.4.1 from the office, and what do know, it didn't crash the os ( should say freeze). Now after some good time sufing the net waiting for downloads, I can pull the tower back to the basement. I plug it to the drive, configure the pins and run it. Well, I can say that the tower came very close to logging time with the FAA. Yea, it crashed the OS.

So here I am, waiting for XP to load on to the computer, nice fresh copy. NO nothing running on it. 18 processes total. Time to add the MACH3 and see what happens.

I won't discount emc2 just yet. but if mach3 works this time around, it will be the worth the money to get it. If not, well, this tower might still log some flying time in tonight.

fly the tower is a dell dimension 4400 with a p4 1.6 ghz and about 750 mb of ram.

[krak]

well a nice clean xp install seems to be doing the trick. I have Mach3 up and running. I have most of the settings I need memorized by now, so setting up the new install only took a few minutes. Now it is back to reading manuals and playing with the machine a little more. I have so serious work to do with understanding the homing sequence and coordinate system. I should have my new parts in the am, and maybe a little free time to do some more reading.

[louieatienza]

Originally Posted by krak well a nice clean xp install seems to be doing the trick. I have Mach3 up and running. I have most of the settings I need memorized by now, so setting up the new install only took a few minutes. Now it is back to reading manuals and playing with the machine a little more. I have so serious work to do with understanding the homing sequence and coordinate system. I should have my new parts in the am, and maybe a little free time to do some more reading.

Good to hear... Did you figure out the pic uploading problem?

[krak]

I still can't upload photos. So i'm going to try an album and see if that works.

// ok so after resizing the photos for the photo album, 600 x 600. I try to upload the a photo to it.
at the bottom of the upload page it says this

"Pictures Remaining 60
Space Remaining 1.0 KB
Maximum File Size per Picture 97.7 KB
Maximum Picture Dimensions 600 by 600 Pixels"
I have 0 photos in the album. I try to load the smallest photo I have, about 26k. i get a message saying my photo is too large by 25k. WTF

So i try the resized photo here in the thread, and it seems to work.
Album not so useful, thread might be better. ARG!! I don't have a camera that will take a photo as small as 600x600. The smallest I can go is vga. So that better work.
next post will have all resized photos. after that it will be vga.

[krak]

finally got the photos issue resolved. Here are the photos from the beginning. I'll be taking some more later to show the machine in the completed state.