[yantra3d]

First off thanks to everyone who has shared their knowledge and experiences here at the forums. Without your contribution to the cnc community I would have never embarked on this journey. :cheers:
So, let's get on with it shall we?

Here's an overview of my build:

mill: x3 from Grizzly (G0463).
spindle motor: Kollmorgen Goldline XT (MT308TB1-E1F4) brushless servo. 1.81 HP - 3000 rpm @ 225 oz/in.
spindle controller: ServoStar CD (CE06250) w/ motion link controller software.
spindle encoder: Class F LPR incremental w/ 2048 ppr
leadscrews: ABBA Precision rolled Ballscrews @ 5mm pitch (cncfusion x3 deluxe kit)
motors (x,y,z): Keling brushed nema 23 (KL23-120-36) w/ skewed rotor design. 3300 rpm @ 230 0z/in. (36VDC - 19A peak)
gear reduction (x,y,z): 3:1 hi-performance planetary gearhead w/ backlash = 6 arc-minutes.
encoders (x,y,z): US Digital optical (E4P-300-250H-PK1) w/ 300 cpr (1200 ppr @ 1:1) from Kelingcnc.net.
drives (x,y,z): Gecko 320 brushed servo drive - purchased from Kelingcnc.net.
motion controller (x,y,z): Gecko G-Rex G100 w/ 6-axis control from Geckodrive.com.
cam software: Mach 3 by ArtSoft w/ 6-axis control. (purchased from Keling).
coolant system: Fogbuster 1/2 gl sprayer (#10100) & quick mount w/ mag base (#00316)

Total cost to date:

For the above mentioned items I have invested almost $3,100. However, this doesn't include the costs for all of the miscellaneous tooling and other items that would be required if someone were starting from complete scratch like me. I will try to get a total on these things and post them here at some point.

Items still needing to be purchased:

> E-stop, limit and home switches.
> electrical power supply for x,y,z motion control and required general harware (e.g.; cables, case, fans, etc...).

Current build status:

I'm just now getting ready to begin the actual conversion process so I figured that this was a good time to start the log. The mill was stripped and cleaned in 20gl parts cleaner upon arrival and is now partly re-assembled and mounted on new table/stand (see pics).

Right now I am trying to figure out the power supply requirements so I can purchase the components for building the power supply to drive all this. I will likely follow up a post with more details on the PS in hopes of getting some feedback from other users here before I commit to buying parts.

A word on the x3 vs. the new sx3:

So, I wanted to comment on my decision to go with the standard x3 over the new sx3. After looking into it I found that I could retrofit the regular x3 with a much higher quality spindle servo system for the same difference in cost. What I ended up with is this ServoStar rig from Kollmorgen that fit perfectly within the price range (thanks to the bay) and was enough to justify my decision to pass on the sx3. Plus it didn't sound to me like the sx3 users were all that impressed with the new spindle setup from some of the comments I have read online.

At a straight 1:1 direct drive this motor has more HP and RPM's than either of the stock motors and from what I can tell it should be ideal for this application. (If someone disagrees then PLEASE post your comments). It also has some awesome software control (I plan to run this controller directly from the PC using an rs232 cable) for direct tuning and monitoring of the motor performance, etc..., and I will likely drive this w/ Mach3 via the Grex if I can get my hands on a skyko p100 board (or similar) to convert 5v digital > 10v analog signal.

I welcome any and all comments, questions, criticisms, etc...., and I would greatly appreciate any advice on this build so do me a favor and please post if you get the urge.

[Al_The_Man]

Nice spindle, I will be interested in how it performs.
There is a guy on ebay that sells Toroid Power transformers if you are looking to build your own PS, they are also easy to modify or add a low voltage aux. winding if it is needed.
Al.

[yantra3d]

Hey Al, thanks for the tip on the transformers... I'm looking into those now.

I have a smaller one of these goldline XT motors w/ another servostarCD drive that I plan to use for a small cnc gang lathe build I'm designing. The rpm goes up to 6000rpm on the smaller motor. I'm hoping that this larger one works well and if so then I'll move ahead with the other small one for the lathe build.

For those interested there are some more of these nice servo motor/drive combos on the bay. They come complete with all cables and pwr supply which is really nice. I got a good deal on mine cause I combined it w/ another item and made an offer for the two of them together. The seller is "outback equipment company" and they are great to deal with.

A word of warning though... be careful if you purchase these drives/motors w/o cables cause they are really expensive to purchase separately if you have to.

[yantra3d]

So, I wanted to build a steel stand/table for my x3 and I have never touched a welder in my life. In fact, prior to this project my tools consisted of a simple hand drill and small toolbox w/ some common wrenches, etc.... So, I am truly starting this from scratch.

The first thing I did was head to Harbor Freight and purchased the following items:

Arc-120 Welder (for welding the table/stand)
4" Angle Grinder (for general use in building steel table/stand)
4 x 6 Bandsaw (cutting steel for table construction and to be used for prepping material for milling)
8 gl 120 psi Air Compressor (for fogbuster spray coolant and for painting table/stand)
Industrial Paint Spray Gun (for painting table/stand)
1-ton foldable shop crane (a must have for lifting the mill on the table!)

I ended up building a very small welding table w/ a decent top (24x24x3/8") so that I could have something flat to work on. This got me off the ground and gave me something to clamp onto. (see pics)

For materials I purchased all scrap metal from my local supply store and ended up with this 2x2 (16 ga) steel tubing and 13 ga sheet metal for under $.60/lb for a total cost of $55. The leg leveling mounts were approximately $7 each. Primer and paint for build was under $10. So my total material cost for this stand was less than $100.


Here are some pics of my x3 stand/table build in progress:

Main table frame construction:

pic #1: making first 45' cut for tabletop frame w/ 4x6 HF bandsaw.
pic #2: prepping for first tack weld on tabletop frame.
pic #3: clamping for more tacking of tabletop frame.
pic #4: clamped and prepped for tabletop cross-bracing. (this is where the mill base mounts will bolt through).
pic #5: clamping arrangement for a leg and cross brace.
pic #6: tacked tabletop resting on tacked legs - preparing to tack the tabletop to the legs.
pic #7: bottom plates w/threaded nuts welded to bottom of legs for mounting leg level mounts.
pic #8: finished product after grinding welds off btm plates.

Tabletop pan/tray construction:

pic #9: rigged up the cheap 4" HF grinder to cut a strait groove in the tabletop to help with bending the edges up to create a pan.
pic #10: groove cut completed - finished product.
pic #11: corners notched to accommodate angle after bending edges up.
pic #12: I decided to drill and countersink holes in the top plate so I could spot weld it to the main table frame underneath. This was because the steel tubing has a rolled edge on the corners making it impossible to weld it to the top sheet metal since there is no way to get my 1/16" rod within proximity for welding the two together where they make surface contact.
pic #13: spot-welding completed - finished product.
pic #14: my make-shift bending solution. A temporary welded frame with matching dimensions to the tabletop so I could bend both short and long sides up.
pic #15: close-up of bending frame in action.
pic #16: first-bend completed.
pic #17: final product after bending was completed.
pic #18: final welded edges.
pic #19: final corners after edge welds were removed w/ grinder.

Final construction, surface prep & finish:

pic #20,21: lining up and cutting mounting holes for mill base.
pic #22: couldn't resist - a little bondo body filler action.
pic #23: first coat of primer started (mill base riser platform)
pic #24: first coat of paint applied.
pic #25: second coat applied.

Mounting mill onto table/stand:

pic #26: rubber sheeting applied to help w/ absorbing vibration.
pic #27: prepping crane to lift mill onto table/stand.
pic #28: mounting mill onto table.

About half way through building the table I had the idea of modifying it for a full enclosure design to accommodate a flood coolant system. But, after many hours of R&D I realized that it was nothing short of a nightmare to design and build and in the end I really couldn't swallow the whole concept of drenching my costly components in water. It just seemed like a real bad idea to me. Besides the cost and design involved in fabricating a full enclosure is something that should not be overlooked. Just calculating the angles for the drain pan and dealing with vibrations and seals, etc..., is a royal PITA from my point of view.

I ended up moving forward with my original design (the one you see here in the pics) with the intention of building a small splashguard-like tray that mounts to a tooling plate that can be directly mounted to the milling table itself. Here's a sample of what I'm referring to here on the cnccookbook.com site:

cool splashguard design

This design paired with a fogbuster spray coolant system should be a great alternative to flood cooling for my x3 setup. People say the fogbuster is an expensive solution but if you add up all of the time and cost (not to mention the hassle) involved in designing and fabricating a full enclosure on top of building or buying a decent flood system - it's actually cheaper! Not to mention all the maintenance issues of dealing with a flood system and also the damage caused by soaking your quality parts in water all the time!

Anyway, hope this little table build inspires those of you who are starting from absolute scratch like I am. It was a lot of fun and a great learning experience so it was well worth the hassle. Also, I am really happy with how stable the mill feels on the stand - it's very sturdy from what I can tell so far.

[alexccmeister]

Wow, putting your machinist talent to great use with custom tools. Interesting idea on using the grinder to cut a slit and bending the steel plate. Gave me an interesting idea with the grinder trick.

I wonder, can you angle the grinder at 60 degrees to cut a dovetail on a steel flat bar? How smooth will the surface be? Thanks.

Alex

[yantra3d]

I'm sure you could make it work for you if you designed and built a jig that could allow you to raise and lower it while maintaining the correct angle. That way you could take a couple of passes at it to achieve the desired depth. I think if you followed that method and went slow then you might be able to get an accurate cut.

I fab'd that little jig up after having the grinder jerk out of my hands while trying to manually maintain a straight line. It ended up working pretty well actually and it was a breeze to make the cut. Nice and smooth.

[yantra3d]

Took some measurements for sizing a gas strut to the z-axis. I had a tough time finding info on the weight of the x3 head assembly so I did what I had to do and broke out the bathroom scale.

pic #1: I wasn't about to pull the head off the column just to weigh it so I just lowered the head onto the scale by removing the side plates from the z-axis support and then loosened the gib screw until the head started to slide down the column onto the scale.

pic #2: milling head total weight = 65.6 lbs (minus the motor assembly & top cover/cap).

pic #3: motor assy & top cover/cap total weight = 24.5 lbs.

pic #4: top cover/cap total weight = 9 lbs.

pic #5: stock x3 motor assembly total weight = 13 lbs.

It looks like the total weight for the stock x3 head assembly is approximately 90 lbs!

With the weight out of the way the next thing required for sizing the strut is to figure out the stroke length and/or the min (compressed) and max (extended) length.

One thing that I plan to do is to mount the strut so that it helps offset the cantilevered effect due to the weight of the head's overhang. To accomplish this I will likely use the existing mounting hole located in the side of the head. (see pic #6) This is a pretty good position to mount the strut to help offset the cantilevered effect.

Since I plan to keep the quill locked in it's fully retracted state I had to base my measurements on that configuration. To calculate the shortest length (compressed) I lowered the head down to the table and the raised it back up to compensate for the quick-change collet holder that I'll be using (H2689).

Based on this reading it looks like I will need a compressed length of 12" or less. (see pic #6) I raised the head to the max position and it looks like 22" would be the absolute max that I would need for the strut's extended length.

According to the Mcmaster.com chart I can get a 90lb strut with a min and max length of 12" and 20". This is slightly shorter than I needed, however, I didn't exactly account for the added length of the milling bits and I also plan to mount a somewhat permanent tooling plate on top of the table which will decrease the overall length of travel even more. With all things considered; I'm satisfied enough to place an order for a gas strut.

[acondit]

Your conversion is looking real good. I would love to see it in person someday.

Alan

[yantra3d]

Hey thanks Alan! At the rate I'm going I'll probably still be working on this conversion by the time we get the chance to hook up.

I got some more parts in for the build this week:

1) 12x20 gas strut from mcmaster
3) 1/2" bore lovejoy couplings (for planetary gearheads)
6) limit switches - short roller type from Enco
1) 12x10x5 electronics enclosure for G-rex and G320's
3) Lambda 48v/10A regulated power supplies (one for each axis)
*extruded aluminum heatsink material (for mounting to drives)

I still need to purchase a few more micellaneous items like fuses, cables, connectors, etc...

power supply:

I ended up buying some nice Lambda power supplies off the bay and am going to give those a try. I got three - one for each axis. They are each 48v/10A rated though they are set to output 42V. I am still kinda clueless as to my power supply requirements at this point but based on all the number-crunching I've done to this point I feel pretty confident about rolling with these so I bit the bullet and grabbed them at $25 ea.

planetary gearheads:

The gearheads I bought are size nema17 so they will require some slight modification to get them to work w/ my nema23 motors. According to the specs these gearheads can easily handle the motor's output so the smaller size shouldn't be any problem other than figuring out how to mount them into my setup w/o losing the integrity of it's design.

Basically, I will have to bore the drive/coupling shaft to accomodate the larger nema23 sized .25 rotary motor shaft. I will also need to fabricate some adapter plates to connect the gearheads to the mounting plates for both the motors and the cncfusion kit.

If I can get enough torque out of temporarily mounting the servos directly to the leadscrews then I'll try making these mounting adapter plates via CNC. Otherwise I'll be forced to make them in good ol' manual mode.

If I have to go manual then I'll have to invest in either a boring head setup for the x3 or I could spend the cash on a 4-jaw chuck for my little 7x12 lathe. I have been holding off on buying a boring head cause I could likely get by w/o one once I get the x3 under CNC. However, I know that the holes made from boring head are more precise than ones cut from an endmill so I will have to consider it more before I commit.

scraping or lapping:

The next item on the agenda is to check the accuracy of the ways, gib strips and ballnut mounts for all 3 axis. Based on what I've read I don't think I'll have to touch the ways but I expect to run into some trouble with the nut mounts and chances are that the gib stips could be improved. Will know after I check them.

I was initially planning on lapping the gib strips using my surface plate but after reading about the advantages of scraping over lapping I am now considering scraping the gib strips. I already planned on scraping the ballnut mounts anyway so I'll start there and see how that goes.

Does anyone else have experience with lapping their gib strips and can comment on the results? Anyone have any advice or comments regarding scraping vs lapping?

[coolman]

yantra3d,

Nice stand. What is the thickness of the sheet metal for the stand where grooves were cut and ends were flipped upwards? Also, what is the size and thickness of the frame of the stand? I plan on making my own someday and need to know how strong I need to build my version.

Thanks,

[Oldmanandhistoy]

Does anyone else have experience with lapping their gib strips and can comment on the results? Anyone have any advice or comments regarding scraping vs lapping?

http://www.cnczone.com/forums/showthread.php?t=11874

John

[skmetal7]

Wow this is goin to be a nice conversion!

Im thinking about using the same servo motors and encoders for my x2 conversion, instead of steppers. Im just starting to redesign my mounts for these. And I need to find a power supply.