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View Full Version : Yet another Joe's, questions from Nashvegas



elmosxyls
03-15-2007, 11:02 PM
Hello all,

First, a big thanks to Joe for the design. Second, this machine is about a year old, give or take. Third, I know Joe will notice from the pics, the Z carriage is upside down...I noticed it after the glue had set and had to modify it to work.

My question concerns the methods used to properly align everything. The reason is that I can get 30ipm max from both the Y and Z axes without the motors stalling out. I am quite certain that it is an alignment issue between the screw and the rails. How does one go about aligning these components?

You may notice that the first two pics have servos and the latter have steppers. I have a DeskCNC kit but it has had issues from day one...not saying that their stuff is bad (the CAM portion of the software is great), but I have had a difficult time getting the controller to function properly so I got a Xylotex kit for now...still working on the DeskCNC kit for the second machine though.

I have also since installed "wipers" to the outside of the gantry to clear chips from the rails, but I don't have pics yet...I'll be adding a much needed dust collector soon.

Any advice on the alignment issue will be appreciated.


Thanks,

Elmo

elmosxyls
03-21-2007, 02:37 PM
6 days, 81 views, and no comments or suggestions...I feel neglected.

I was hoping that with the number of machines out there based on Joe's design, and the expert advice of everyone in the zone, I could find suggestions as to the recommended procedure to properly align the screws and rails.

Joe says he gets 80 ipm and others have claimed 100. I would be OK with 50 but would prefer to able to get 60 consistently. Right now, I can get 30 ipm consistently (at higher speeds, the motors on the Y and Z axis stall, especially near the end of travel).

Also, what is the recommended lubricant for the screws?

Forgive me if this has been covered elsewhere, but I have not found answers to these specific questions in the 100+ pages of Joe's main thread or in the countless other related threads.

Thanks,

Elmo

bp092
03-21-2007, 09:55 PM
Most that I've heard use litheum grease from home depot. I've been using regular bearing lube/general purpose wet to dry spray on lube and it works well. You may pm Ger or if you want request your thread moved to joe's 06 model dedicated sub forum. You will get much more response from there.

joecnc2006
03-21-2007, 10:20 PM
Sorry, did not see this thread.

to make adjustments on the y axis you tighten and loosen the crews in pairs front two and rear two will slightly tilt the z-axis slide.

you said it is upside down, i yake it you had to make new holes in the rear of the slide to acommidate the leadscrew to be aligned to the gantry sides.

The main alignment of the leadscrews to the motors and bearings are pretty much setup automatically when the machine is put together, if you slide the gantry to the front you the antibacklash leadscrew hole should be lined up to the bearing, and the same at the rear, and also the same goes for the y-axis.

Like i mentioned the only very slight adjustment on the machine ate the 5/16" bolts which press on the bearing blocks.

some things others have done to help are:
1. add a 1/2"-10 2 start leadscrew on the x-axis and y-axis.
2. makesure the anti-backlash nuts are just barely snug, using the two 1/4" bolts
3. makesure it is well lubed.
4. a good power supply, if using xylotex use 30v and i would go with more than 5amps.
5. add some rubber garmets between the motors and motor mounts.

there may be more but i am limited on time and brain power right now.

Hope that helps some what for now.

Joe

elmosxyls
03-21-2007, 10:57 PM
bp092,

Thanks for the advice, I have been using some old lithium based grease, just didn't know if it was recommended. I have a set of ballscrews (too short for the existing Joe's design, I was thinking of making a second Joe's, just smaller to accomodate the ballscrews) and I had read that engine oil would work for those...never tried it though.

As to moving the thread...I had not noticed that the "Joe's" were in their own sub-forum...sorry about that. I'll PM Ger about moving the thread.

Joe,

Thanks to you as well. About that Z carriage...yep, it's upside down. I did have to make new holes in back. I should probably just make a new carriage.

As to the alignment...it all "looks" good, but when it runs, I "think" I see a misalignment on the Y axis as the screw spins and I definitely have motor stalling issues on both Y and Z. I am running a Xylotex board. It seems to perform well. I can run the X axis up to 60 ipm with no problem but I am limiting all speeds to 30 ipm until I fix the problem in the other axes. What is the real difference between the Xylotex and others?

Also, about adding rubber spacers...I have the motors mounted to 4x4 aluminum extrusions (borrowed the idea from Bob Campbell). The motors have relatively short output shafts and to add the spacers may mean making new motor mounts. Do you have any twisting issues with your motor mount design?

Thanks again.

Elmo

gacrwell
03-22-2007, 12:47 PM
I can't offer any suggestions on alignment, since I haven't built mine yet, but I'd sure be interested to see pics of your 'wipers'; when you get a chance.

Gary

elmosxyls
03-23-2007, 10:03 PM
Well, with the help of another cnc addicted friend, I think I may have found a few areas of mis-alignment. It's very difficult to see these things by yourself and another set of eyes can watch while you push the jog buttons.

In the pics, Yalign and Zalign show the problem areas with the screws positioned at the points of greatest misalignment. I will be shimming these areas to try and fix the problems.

JOE - I included a pic showing the "fix" to the Z carriage (I had inadvertently flipped the top and bottom plates after glueing and had to re-drill the screw and mounting holes)

gacrwell - I am including three pics showing the quick and dirty wipers...they are stiff foam "scrubby pads" rough cut and screwed to the X carriage and Gantry panels (opposite side). Most of my dust problem will be solved when I install the dust collector...but these work for a quick fix...I also thought about covering the area directly over the bearings since cutting small parts renders the wipers almost useless...but they worked well for larger cuts.

Most of what I am cutting these days is high density foam and it generates a ton of dust..."most" of it falls all around the machine...still, I really need a dust collector.

I am making a small cyclonic collector and plan to use my shop vac (4 HP) or the two old vacuum cleaner blowers that I have running parallell to increase flow rate ...my only question is how best to route the vac hose to the dust skirt. I thought about suspending it way overhead (like I now have the router power cable). Any other ideas?


Elmo

joecnc2006
03-23-2007, 11:51 PM
Your motor misalignment looks like an easy fix by shiming up one side of the motor mounts.

elmosxyls
03-27-2007, 04:14 PM
Well, I shimmed the motor mounts and it helped quite a bit on the Z axis and maybe a little on the Y axis...I still think there is a mis-alignment issue between the Y axis screw and rails.

I have started the process of making a new Z carriage and have also begun the CAD work to build a smaller version of the router to make use of the ballscrews that I have...they are too short for a full scale Joe's 2006 model (X 40.875" w/ 36.75" travel, Y 40.375" w/ 36.25" travel, Z 13.625" w/ 9.5" travel...although, travel does not count the ballnut length which is approximately 2"). The screws were for my first ever router...long sad story.

Question, and I know it has been asked elsewhere...but what vendors would anyone recommend for 0.125" and 0.25" ball end mills? I would prefer US manufactured.

Thanks,

Elmo