I just got my X2 conversion up and running and it is binding a little. I got the kit from CNC fusion and it seems pretty nice. It installed w/o too much difficulty. It would have gone easier if I could have watched the videos at work to install it, but my work has them blocked. I tried adjusting the gibs but not much luck I also tried to allign the end blocks again. Any one else had some binding and loosing steps problems?

Try loosening the screws that hold the ball nut to the table. Run the y axis towards the stepper motor and tighten the nut down. Then for the x axis you want to go away from the stepper so in the full positive direction the follow the steps above. You shouldnt have to move the end blocks that much if at all. Try and make it flush with the top of the table. Goodluck.

These cheap chinese machines are not exactly quality built, so the main reason you are experiencing binding is because the dovetails are not exactly parallel. You will find some high spots on them, and so the axis will bind in some places. The remedy for this is either lapping or scraping to remove the high spots then tighten down the gibs so that you have no slop anywhere and no binding. This is if you have the time to do so. The other way is to just loosen up the gibs until it doesn't bind any more... you will end up with a lot of slop though, which will show up in the parts you are making.

Might be another problem, but this is the most likely one. Doesn't hurt to touch up the dovetails either.

I took the machine back apart and cleaned all of the grease out that i missed. I really hate that crap. Then i sanded the marks off of the dovetails and the base, then cleaned and sanded it again. I got most of the marks off and it is pretty smooth. I put the machine back together and it runs a little smoother. I adjusted the motor settings and messed with the jibs some too. Hopefully it will produce some decent results. I still have to put limit switches on it. I forgot to make a place for the connectors I am going to use for the switches on my controller box so I guess I'll rig something up.

Could my power supply cause any of the problems? i switched from my 24v 8a supply that i bought at mpja.com to another one that has a voltage variable upto 50v at 14a and it seemed to go smoother. I can not press alt and a direction arrow in jog mode (turbocnc) or it will just freeze on me, but other than that it runs smoother.

24v? Thats not most likely enough, so yeah that will help a lot.

I have 3 500oz-in motors on my X2 and I get 80IPM rapids (limited by turbocnc) on all axis , and it accelerates up to this speed over a distance of less then a mm.

The gibs should not be too tight. You should be able to move the table back and forth with your hands (you will have to put some force on it though). Check if it has any tight spots, and if you can't get rid of those, just loosen up the gibs a bit more.

What screws are you using? What pitch? and what motors? What settings are you using in TCNC?

the ballscrews are 5/8" Thomson ballscrews with a .200 pitch. The motors are probotix 400 oz in green monsters. The drivers came from probotix too. The conversion kit came from cncfusion.com and is kit number 4 for the x2 mill. I loosened up my jibs some too.

I have a home made cnc machine at my house that i made using square steel tubing and allthread and it is binding too. I am using 495 oz in motors on that but the same power supply. That is why i thought it might be the power supply.

If you want a stepping motor to go fast, you will need higher voltage. 50V should do just fine if your drivers can hold up to it. I'm actually using 36 at the moment, but I'm looking for a new transformer.

Where do I go to set up my screw settings in turbocnc?

My drivers are rated at 35v unfortuinately.

You go to the configuration menu and choose an axis to configure. There you can set up steps/in and how fast you want it to move.. etc.

That should be enough. I have never really had any problems with my 36V supply.

I took the table off and grinded the crap out of the bottom of it to add some room. I think it helped some. At least i'd like to think so. It still sticks some. Now the z axis is just going down and not up. I switched it to a different card and it is doing the same thing. So now I have yet another problem to troubleshoot.

I got the z axis motor fixed. One of the wires inside of the cable came loose. I guess I had a cold solder joint and missed it.

When I switch back to the old power supply and run it it binds a bit. But if i do 'alt' and a direction key it goes just fine. Is this normal? Should it bind a little going slow and nothing when going fast, or not bind at all no matter what?

It should not bind at all.

How tight are your gibs? Can you actually move the table by pushing and pulling (not with your whole weight)? How have you connected the motors to the screws? You might want to check if the screws are missaligned.

What did you grind on the table? Just the curved underside?

The gibs go from tight to loose. I tighten them or loosen them from time to time to see if it helps any. So ya, I can move the table. The motors are connected to the screws with lovejoy couplers. It is possible that they could be off a little. I noticed that when i had the screw and the table off that the end that was turned down for the coupler seemed a little off from center.

I flipped the table over and ground underneath where the ballnut sits in the little cove. I ground the sharp corners (not the ones w/ the dovetails, but the ones just above the where the middle gets flat) off of the inside and smoothed the underneath off and made a little grove for the highest pont of the ball nut to sit into b/c it kind of hit the table. So i worked on the curve part of it basicaly.

You might consider lapping the ways. This removed the "tight spots" in the table movement and improved the smoothness on my X2. Also, you might want to check out:
http://www.cnczone.com/forums/showthread.php?t=51611&highlight=plunge, there is a discussion of adjusting the bearing carrier and ballscrews to eliminate binding problems.

Bill

I thought he did so already? Was the first thing I suggested here, and he said he had sanded down the high spots. You will also have to lap the gibs on a plane surface.

Sounds kind of odd.. How much power are you sending to the motors? How much power can your power supply deliver?

I sanded the dovetales and all. I will try the gibs tomorrow. One power supply is 24v @ 8a and the other is 0-50v @ upto 14a (its big too!)

bilinghm
I read your post. the thing at the end about using a depth micrometer seemed pretty interesting, but how could i do it on the x axis?

I'm still blowing black buggers from grinding all that crap today w/ the dremil.

maybe i am doing the lapping wrong? I simply sanded the dovetails and the flat surfaces w/ 600 grit then 2000 grit.

Adjusting the X requires a different strategy. Because of the way it is supported, it seemed to be easier to tune up without critical measurements. I didn't have binding in my X. However, the Y was difficult.

Lapping is somewhat different from sanding. The Industrial Hobbies site has a good description.

One problem that I discovered on my machine was poor contact between the gibb and the way. The gibb was canted and not making complete contact over its' full surface. I reground the little pockets where the adjustment screws fit, and fiddled until I achieved full contact. This helped a lot.

Bill


bilinghm

I read your post. the thing at the end about using a depth micrometer seemed pretty interesting, but how could i do it on the x axis?

I'm still blowing black buggers from grinding all that crap today w/ the dremil.

maybe i am doing the lapping wrong? I simply sanded the dovetails and the flat surfaces w/ 600 grit then 2000 grit.

I sanded the crap out of the table today and the carriage the table mounts too. I started w/ 60 grit, then 120, then 600. It is a ton better. I spent prob 3 or 4 hours sanding. I still have the underside of the carriage to do and then the mill base. Hopefully that should help alot. I had to stop today and go on an interview on base. It took almost 2 1/2 hours. It went pretty good so hopefully I will get it.

after sanding all of the marks off of the table and base and carriage I got it back together and it is doing the same thing. It runs smooth for a few seconds then it jumps foreward a notch or too if that makes any sense. I have been trying to adjust it several ways, but still nothing. It does it a little on the Y axis but it is not too bad, the X on the other hand is pretty bad. Anyone out there got any ideas?

I exactly have same problem.. but my X2 has more binding at Y. This is what i did, I took the column out. Laid it on the flat surface (i used the floor). Using the head (took off all attachments) as the lapping medium, I "sandwiched" a 180 grit in between the the dovetails and ways and move the head back and forth with more pressure at the top end where i feel most of the bindings. I think using this way, I will be assured that the lapping will not create a "bow", or slightly depressed regions in the dovetails and ways... i felt some bit of bindings at X too usually at near ends. Using the table or the head as the lapping medium (adjusting the gibs little by little) is the way to go.. I will take some time and several changes of the used grit. It took me 3 hours last night, i noticed some significant reduction, almost smooth but not yet perfect (at least on gut feel). I ran out of 180 grit, i will finish this off using 600.

you can use some dykem die or a magic marker on the ways to see where the high spots are. where ever it rubs off, that's where you sand.