First Build 5 x 12 Steel Frame CNC router

[Scott Damman]

Have you Earthed the Frame.? Common cause of troubles like this.

No I hadnt, I added a separate ground for the frame and grounded each part of the machine, i.e. Gantry and Z. Thanks for the suggestion.

I learned some hard lessons last night while continuing to tune the servos.

1st, make 400% sure that the ballscrew mid-supports can not get hung up on a sudden change of direction.


This bent back pretty easily but I will need to make some modifications to make sure it cant happen again. Basically the machine stopped before the support flipped and on change of direction it caught on the ballnut mount. No other damage observed which is good.

2nd, and this is the big one, when butting linear rail together remove the lead in on each rail. I had known this was the case but being that I got the rails for cheap and not having a way to accurately grind the rails I chose to try it.... bad choice.



What the pictures show (or what I assume happened), as the block went past the joint a ball dropped into the joint, caused alot of extra force and blew the end of the block off. At lower speeds it seems to be fine, but I was running past it at ~1000 ipm. I think the block counldnt handle it I was able to stop it before the other 2 blocks hit the joint. I have 4 extra blocks that came with the used rails so I can put it back together for now but I need to make a plan for future.

I think my options are
1 - remove rails and have them ground and put back together - this is a no go as the cost would be more than just buying Hiwin rails
2 - buy Hiwin rails and blocks - definitely the best option but costly
3 - try to fill the groove/lead in
- Im thinking of trying this method, couple options, epoxy, babbitt, other options?
- I think I just need to keep the balls from dropping in there, I think there shouldnt be too much stress on the fill otherwise.
4 - just use the 8ft of full length rail for now???

Any thoughts are appreciated...

[JAZZCNC]

Ouch.!! . . . Bad luck. That's difference between Servo and steppers. They take no prisoners! . . . Stepper would have stalled before bending that bracket or possibly ripping the bearing end cap apart.!

1st Choice is no brainer new Hi-win rails.

2nd Choice new Hi-win Rails

3nd Short term Choice fill with Metal Epoxy. Think it's called JB Weld in states.

No other choices IMO.!

[Scott Damman]

Ouch.!! . . . Bad luck. That's difference between Servo and steppers. They take no prisoners! . . . Stepper would have stalled before bending that bracket or possibly ripping the bearing end cap apart.!

1st Choice is no brainer new Hi-win rails.

2nd Choice new Hi-win Rails

3nd Short term Choice fill with Metal Epoxy. Think it's called JB Weld in states.

No other choices IMO.!

Short term I have moved the entire machine to the other side of the joint and moved my X home switch. Gives me 6.5 feet in the x and 5.5 feet in on the Y and gets me going with making parts. I have ordered machinable epoxy to do a pour to try to fill the joint. Long term after a few paying jobs, probably going to order some new full length rails. This will unfortunately require some modifications to the machine as the rail height will be different.

Im still waiting on my spindle cooling fan adapter so I cant cut anything yet. So I put a sharpie in the spindle and made a drawing. Pretty geeked that it actually made something, even just a drawing.

[Scott Damman]

While still waiting on the fan adapter so I can cut with the machine, I decided to draw up a dust collection adapter mold to lay up fiberglass in. Video shows the machine running this code.





I put the X and Y to 1000ipm as 2000ipm scared me and while I am learning about this machine I wanted to be a little safer.

I also have a question about what a ballscrew/ballnut should sound like. I have never been up close to a ballscrew before so I wonder if these sounds are normal. The sound I am referring to sound like bearings circulating through the ballnut but just doesnt sound real smooth... Sorry pretty hard to tell on the video I guess but if anyone has insight please let me know.

[Boyan Silyavski]

I have seen dust collection but your blasted me from my chair If thats not OTT, i dont know what is. May be what once i have seen the whole spindle in the dust tract.

[Scott Damman]

I have seen dust collection but your blasted me from my chair If thats not OTT, i dont know what is. May be what once i have seen the whole spindle in the dust tract.

Boyan, thanks I think it might be a little much and also Im not real sure how it will work but I run 6inch to all my machines and have a 10hp cyclone dust collection system so I thought it would be better to have 2 4 inch tubes down to the bit rather than just one 6 inch. I will make an update on how it works once its all hooked up and the dust shoe is made/installed.

Thanks for the comments on the ballscrew/nut the sound just didnt sound great but like I said I havent ever been close up to a machine. Of course once it is cutting those sounds cant be heard.

So I decided to make a temporary spindle cooling fan adapter and get this thing cutting. So the first thing I wanted/needed to make is the dust collection adapter mold.


Heres the machine cutting for the first time.



Turned out pretty good for the first cuts, here is a final picture and the first 1/2 of the dust collection adapter laid up in fiberglass.



I learned a few things on my machine, first one was not to difficult, I needed a better tune on the Z axis. I think you can see in the movie that the Z actually moved up and down slightly through its pass, for this part it didnt really matter so I let it run and played with the tuning a bunch more and I think I get it pretty good.

The other thing is I was making ellipses instead of circles. Again this part didnt matter that much so I let it run to look into it after. So after confirming gantry to X squareness I started looking into what else it could be.

Heres what I found and looking for a little help on this, I also want to say that I really appreciate all the help the experts on this forum give and I hope this build helps others with theirs..

I put the machine on a 10 inch X movement back and forth at a moderate speed, while watching the gantry I could see a noticeable racking of the gantry. Upon stopping, the gantry comes back to square. It looks like to me that X axis slave motor/ballscrew is noticeably slower at starting. I tried to use the motor delay setting in Mach, I moved the milliseconds up (delaying the master motor since the slave seemed slower) but I could not see a noticeable change. So for all of the experts out there, is the motor delay something I should be adjusting? Or is there something else I should look into? I have confirmed all the settings in Mach on both motors are the same. I also confirmed the settings in the servo drives are the same. Any thoughts are appreciated.

Thanks
Scott

EDIT
I just looked closer at the delay, I had assumed that it was a signal delay, but as the manual says (which I should have looked at first) the motor delay is for delaying the enable signal for that output. So now I really dont know what to do.

The reason I say the slave axis seems delayed is the gantry racks as if the master motor is the only one driving it. I thought maybe the slave motor was/is not running but the fact that the gantry gets to square when it stops I think tells me the slave servo is running (resolver is bringing the system back to correct position). The servo drives output for speed match when running as well. Hope there is a good way to adjust for this delay?

[Boyan Silyavski]

Make sure both servos have exactly the same settings in the servo drives themselves. I do that by copy-paste-upload from one servo to the other in the servo tuning program. So i am 100% sure they work the same. Do so in mach 3 in motor tuning tab and make sure to hit "apply". Close. go out of mach 3, then do check again the result. Then make sure the direction of motors is set right before you rip your gantry.

Then test.Now all must work normal





About the dust, i see. You are right that dust extraction better not be choked down. I assume you will fit a kind of shoe there. Or you will extract only the fine dust not to float around in the air? I use sometimes my dust shoe only like that, without the brush attachment. Chips stay on table but no fine dust in the air.

[Chaz]

While still waiting on the fan adapter so I can cut with the machine, I decided to draw up a dust collection adapter mold to lay up fiberglass in. Video shows the machine running this code.





I put the X and Y to 1000ipm as 2000ipm scared me and while I am learning about this machine I wanted to be a little safer.

I also have a question about what a ballscrew/ballnut should sound like. I have never been up close to a ballscrew before so I wonder if these sounds are normal. The sound I am referring to sound like bearings circulating through the ballnut but just doesnt sound real smooth... Sorry pretty hard to tell on the video I guess but if anyone has insight please let me know.

I helped someone with a kneemill yesterday. Not a new machine but still in good condition. I could also hear balls recirculating when we were moving the Y Axis. I *think* its normal but wouldnt mind the guidance from those more experienced on the forum.

[Davek0974]

My 1605 screws make a Shhhhhh noise when doing rapids, they get a bit quieter after a grease.

[JAZZCNC]

Looking good Scott coming along nicely.

The bearing noise is quite normal for that class of bearing at those high speeds. It won't be just the ballnut your hearing either, the linear bearings will make noise also.