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boblon
03-17-2007, 02:00 PM
Well I've finally started building. I know I've asked a lot of dumb questions here already, but I don't see that stopping anytime soon now that I've begun to build :)

I'm following the Rockcliff plans, albeit not too closely as I'm adjusting to suit the parts as I go. I've finally got most of the parts I'm going to use in hand but still am waiting on AB Nuts from Dumpster CNC.

It's an MDF first time build by a real noob so we'll just have to see how it comes out.

I'm using 1/2" X 10 TPI Acme lead screws. I've got Nema 23, 282 oz motors from Keling and thier KL-5042 drivers to go with them. I also got thier KL- 3815 PS (500 W, 38VDC/15A) and a BOB. Oh yeah, got a Mach3 license from them too.

John from Keling is a great guy to deal with.

I know those drivers and PS are probably more than I need right now, but I figure this first machine is just to get my feet wet. I'd really like one that will cut close to 24" X 48" so hopfully I'll only have to replace the motors if need be.

Anyhow, it's good to finally be building, hopefully it will do SOMETHING and I won't have to start all over before I can make any sawdust with it :)

I'm sure I will have more questions and I appreciate all the help you guys have already given me.

For now, back to the garage, breaks over.

BobL.

boblon
03-17-2007, 04:46 PM
Still going strong.

I had ordered my Acme lead screws from EBay and it wasn't untill after I purchased them that I realized that they were only 30 minutes from me. So I went and picked them up. When I was down there I asked them about thier aluminum motor mounts. They said they didn't have any and only worked on them when they had time between other jobs.

Well I called them this morning to see if they had any per chance. Not only did they have some, the guy said I was lucky to find them there as they don't usually work on Saturdays. So, bottom line is I've got the motor mounts too.

When I got back I checked my mail box and lol-and-behold, the AB nuts were here. After 1 false start and 2 orders that shipped with incorrect parts maybe things are finally going my way (unless of course I just jinxed it) :).

I had already built the torsion box base while waiting for parts to arrive and I'd really like to get the Y-Axis done today, although it's starting to get late on me.

I will try to post some pics of my progress later this evening.

BobL.

boblon
03-17-2007, 06:52 PM
Well, I didn't get as far as I would have liked, but then, I never seem to.

The table is not yet mounted and the Y rails are only tacked down so I can make final adjustments and verify the table moves from one end to the other without binding.

But so far I'm fairly pleased with how it's coming along. Pictures aren't that great, I'm not much of a photographer, but then again it could be those 3 pots of coffee I've had today :)

3367633677

BobL.

dz1
03-17-2007, 07:20 PM
build is looking great, you have chosen a nice collection of upgrades. I am about ready to start my second machine and the linear rails/bearings and upgraded screw were on the definate list of things to add. The motors mounts are slick too nice to be able to adjust the coupling without dismounting the motor. Cant wait to hear how it cuts :)

boblon
03-18-2007, 10:10 AM
Ok, lesson learned. LOL

When dealing with TKO style linear bearings DO NOT just slide the carriage off of the rail....DAMHIKT !!

What a PITA.

Luckily I found all but a couple of bearings. I hope it will be alright...geeez.

BobL.

boblon
03-18-2007, 06:26 PM
Gotta quit for today. Got quite a few things figured out as far as how I'm going to do the Z-axis. Up until today I wasn't really sure how I was going to do it.

Several trips to the hardware store really drove home how a project like this can nickel-and-dime you to death. Amazing what small metric cap screws cost. I'm sure I could have got them cheaper on line but I wanted them now and I don't mind feeding the Mom-n-Pop H/W store down the street, keeps 'em in buisness (and handy for me).

Nothing I've done today is bolted in it's final positon, just clamped up to do trial fits and measurments. I am very happy the Z-axis is coming together, I was a little worried about that.

Anyhow here's a few more pics.

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Thanks for looking,
BobL.

boblon
03-21-2007, 08:03 AM
Haven't had a lot of time the last couple of days to work on my machine, but some.

I've been working on tyring to get the table rails firmy secured and aligned. Having problems getting all of the binding out. I may remove them and try a different method of installing/aligning them. I really want to get going but this is gonna hold me up until I fix it.

I have also been doing a little more work towards getting the Z-Axis going. Still more work needed there.

I expected a few problems so I can't say I'm surprised.

BobL.

boblon
03-21-2007, 07:08 PM
I spent some time at work thinking about what to do about the table rails.

I had pretty much decided to remove them when I got home and try a different way to mount them. However, when I got home I went out to the garage to mull over the situation a little and move the table back and forth.

It seemed to move a lot better than I remember leaving it last night. Of course I had spent a couple of hours fussing with it and was getting a little frustrated when I left it.

Anyhow, did a little more fussing with them and I think I will leave them alone for now. They are not perfect, but they might just work. I may have to tweak them a little later, but for now I've decided to proceed with the build and when I'm done banging things around and get the rest assembled I will take another look at them then.

Bottom line is I might just be back on track (so to speak). I did a little more work on the Z-Axis assembly, stopped as I am now waiting for some glue to dry.

I will try to post a couple of more pics tomorrow evening, but it may not look a lot different from the last one, even though there are a few more hours in it.

I took Friday off, hopefully now that I'm building again I can make some good progress.

I got some motor connectors from EBay in the mail today. I'm not sure but I think the only major thing I don't have is a box/case to hold the electronics. Not sure what I'm going to do there yet. The first power on test is liable to find electronic assemblies and wires strewn everywhere.

BobL.

boblon
03-22-2007, 07:56 PM
Spent the few hours I had tonight doing some work on the Z-Axis assembly.

I'm really hoping to put some power to it this weekend. Have a lot of work to do to get to that stage though.

I never really noticed it until now, but I now realize it seems one of the big difference between the Rockcliff plans and the others I looked at is the orientation of the motor on the Z-Axis assembly. With this design the motor takes itself for a ride, while on others the motor is stationary and the carriage that holds the router is the only piece that moves.

The Z-Axis seems to be getting heavier the more I build it and I hope these motors I got will move it.

Anyhow, here's a couple of pics of tonights progress on the Z assembly.

BobL.

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boblon
03-23-2007, 06:50 PM
Got the Z-Axis assembly done for now. I made a temporary clamp to fit a RotoZip. I don't plan on that being permanent but plan on using it to make a proper one for the tool I end up putting there, which is undecided at this point.

Screwed up one of the gantry sides and had to make another one. Glad I didn't pick a critical piece to mess up.

It is clamped up in a semi-aligned state. Have to figure out how I'm going to attach the Y crossbar assembly to the gantry sides.

Being as it's made out of MDF I'm wondering if I should try to build in some sort of fine adjustment for potential movement of the Y-crossbeam? The gantry sides are going to be bolted (not glued) to the sides, so I imagine that would provide the necessary adjustments.

I'm also wondering how much those with MDF machines find tuning the alignment over time necessary?

Also wondering if I should hook up the electronics before performing final adjustments?

But that's it for today.

BobL.

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boblon
03-24-2007, 06:24 PM
Well, I will be ready for the initial power up and testing tomorrow.

All I have to do is finish the preliminary alignment and lock her down.

As you can see in the pic my Y-axis lead screw could be a little longer. Got it before the linear slide. Oh well. I haven't secured the bearing block on the Y-Axis yet either (need some material).

It sure has been a learning experience up to this point. I can sure see why everybody seems to build the first one just to turn around and build a second one. Not only because of what you've learned as far as what your trying to accomplish, but so many things that you wish you would have done different.

But, be that as it may, what's done is ALMOST DONE !!

Now, if I can hook up the drivers withoug blowing them up I will (hopefully) see some motion out of this beast. Can't wait.

BobL.

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glenfraser
03-24-2007, 07:00 PM
HI Bob.
A couple of questions...

1) Were do the metal stepper coupler boxes come from ( the bit between the mdf and the stepper)

2) Were do the anti backlash nuts come from....


Thanks


Glen (UK)

boblon
03-24-2007, 07:11 PM
Hey Glen,
I got the motor mounts from the same place I got my lead screws. I was actually just about to buy some lead screws I saw on EBay until I noticed the seller was only 30 minutes from me, so I just called them. Anyhow, noticed that they also had some of the mounts listed at the time. When I went to pick up the lead screws they were out of the mounts. He said they just make them between other jobs. Luckily they had some when I needed them.

Just found them on EBay here:

http://cgi.ebay.com/NEMA-23-Motor-Mounts-for-CNC-Stepper-Motors_W0QQitemZ230108639705QQcategoryZ57122QQcmdZViewItem

He charged me 20 US dollars for mine. I don't know if that's good or not, but just didn't want to spend time cobbling up something.

I know I saw some for sale somewhere else, but for the life of me I don't remember where now.

The AB nuts are from DumpsterCNC:

http://www.dumpstercnc.com

I kept reading about them on this forum so I ordered some. You can specify the type/size of flanges you want on them. They are delrin, how they will hold up I will just have to find out.

Good luck,
BobL.

kiwichris
03-24-2007, 08:36 PM
The Z-Axis seems to be getting heavier the more I build it and I hope these motors I got will move it.


Never fear, I used smaller steppers on my mdf router, with the same configuration in terms of the motor going up and down with the spindle, and there was more than enough torque to get things moving, even though I used a very simple stepper driver.

As per: My build thread (http://www.cnczone.com/forums/showthread.php?t=33153)

You've got a great looking machine there, I think you'll be more than happy with the results!

Cheers, Me.

boblon
03-24-2007, 08:59 PM
Thanks for that KiwiChris.

I was just sitting here hoping it works. It's kind of funny, there's not much I can do now except give it a shot.

I've seen some cool stuff posted here and elsewhere, can't wait to see if I can do some of that myself.

Gonna be a fun day tomorrow....I hope :)

BobL.

boblon
03-26-2007, 05:10 AM
Ok, I got it jogging last night. Feel good about that.

Now I need to tune her up and see what she can do.

Gonna spend some time getting to know Mach3 today.

BobL.

snoyce
03-26-2007, 05:44 AM
Good looking build there. I'm jealous of the fully supported rails!

I had the same reservations as you with the z axis configuration. In the end the bearing blocks i used made my mind up for me and i flipped the z-axis round so the tool mount is attached to a smaller moving plate. (this was done at the expense of some z travel.

boblon
03-27-2007, 08:01 AM
Ok, I did get the motors to turn but that's when the problems began.

Looks like I am going to have to deal with the drag on the X-axis table after all.

I've spent a frustrating couple of days trying to get Mach set up, limit switches intstalled, playing with motor tuning and whatnot.

Limit switches: Got em working I think, except for the automatic overide setting in Mach 3 (R2) is giving me problems. When I hit a limit switch I can't back it off the switch before it goes back into e-stop. I suppose it could be some sort of switch bounce but at this point I just don't know.

Motors: Running Keling 282 oz-in steppers wired up in bipolar parallel, 4.2a, 38v. Spec sheet sez max temp is 80C (176F) but so far the hottest motor has gotten up to 185F. The real problem is I can even DRAW the road runner unless I keep the X-axis down to around 15IPM. This is where the work on the X slides comes in.

I can put the Y motors up to 30IPM and it will draw fine, haven't found out exactly how far I can push em at this point. I was hoping for more than that though.

Assuming I have to operate in the 30IPM range would it be better to go bipolar series on the motors?

Anyhow, it looks like the 'fun' is just beginning.

BobL.

snoyce
03-27-2007, 09:00 AM
I haven't installed the limit switches yet so can't comment there but after adjustment and tuning, the best i can reliably achieve (assuming my mm to inches is accurate about 635mm) is around the 25ipm mark. Also im using emc not mach3 just because of cost (after dropping the initial cash on building the router, i might change to mach3 later for convenience of running under windows).

Above that i get lost steps at the extremes of each axis probably due to the alignment of the rails. While not ideal (for hobby use) i've resided myself to that being the useable limit although i was thinking the supported rails would improve that figure.

Due to the flex in the rails, on a job i cut profiling some thin aluminium the rail flex does effect the accuracy of the initial plunge.

Also my steppers are wired in series.

Cheers

Steve

boblon
03-27-2007, 09:14 AM
Thanks for the info Steve.

I'm afraid I will be in the same boat as you having to accept what I get, probably in the same range as yours.

Let me ask you though, did you set your motors up in series initially or change them from parallel after you found out the speed range you were going to have to operate in?

I'm trying to decide if I should rewire to series.

BobL.

snoyce
03-27-2007, 09:34 AM
I set them up as series from the off as that was what was recommended with the (stepmasterNC) drivers. I have/am considering trying parallel but for now although it's not as fast as i would like it's cutting and thats rewarding enough.

I wasnt expecting the rockcliff design to be amazing and if the trade off is some speed i can live with it (for now!).

As far as i understand parallel will add some torque at higher speeds at the expense of lower speed torque and with rapid directional changes i think i'de rather have the torque at lower end to increase accuracy (with the limitations of the machine). Could be way off bat here!

Cheers

Steve

boblon
03-27-2007, 03:22 PM
Yeah, I knew that parallel gave you better torque at higher speeds, I'm just not sure where that change over point is.

I didn't know that parallel gave you faster directional changes though.

BobL.