I think a .25" bit should be limited to .5" of Z at most. The motor shaft is best suited to 1/8" tools. This is not a Bridgeport! The way to approach the use of any tool is to first understand its limits, then program to that standard. I can only speak anecdotally based on my experiences with other machines. It is good that I intuit correctly often, else there wouldn't be much of interest to this thread. Still, I am often wrong, and I simply can not make claims about the performance of this spindle until I have put it through the paces.

A few things I think I can say:

Dremel Schemel!
125,000 (holy!!) RPM!
Bad-ass torquey little beast!
The spindle is separate from the XYZ robot, not tacit.
I flambe'd the first ESC.
PWM spindle control is awesome (and I'm working now on a fuzzy logic that can adapt the spindle speed based on measured local conditions, don't hold your breath).

I dunno, but the micRo is now 99% finished. Robin and I spent a long day today finishing the parts that needed drawings before he takes off for some Summertime fun (lucky bastard). Over the next few days I can put the micRo together and start running jobs to provide the parameters we require.

I haven't researched tools yet as I was waiting to see what kind of spindle you came up with. So are 1/8" inch shank tools reasonably easy to come by?

Looking forward to seeing it run some jobs!

Sure, 1/8 is very common:

http://www.wttool.com/category-exec/catego..._End_Mills_USA_

I didn't mention that I'll be testing a slightly larger syncro that may be a good candidate for 1/4" tools.

hi! i've been following this topic closely and have read through all the posts. and i really want to buy one of these kits.

bottom line question up front, expanded on below: how do i physically mount a "spindle" (e.g., dremel) to the tool holders?

a little of my background to provide a little context: i've been a computer programmer/developer for over 25 years and have the "usual" wide range of geeky interests. many of these interests are just theoretical, with no real hands on experience (e.g., CNC, robots). some interests are practical and i've had a lot of experience (e.g., gadgets, toys, legos, fixing things around the house). and some are a mix of both (e.g., electronics, woodworking). when i was a kid, my dad and i used mostly woodworking items including: drill press, lathe, radial arm saw, jig saw, manual/power hand tools, etc.

unfortunately for me, i'm a complete newbie regarding machining or milling.

and while i very much understand that the micRo is:
my current interest is in using micRo with some sort of milling/cutting head (e.g., spindle, or "dremel").

if these two 1"x1"x2.5" tool holders are final:
then it seems to me that there is virtually no room for mounting hardware!

it seems to me that no matter what, i have to drill holes into the (delrin? UHMWPE? HDPE? can't remember which you ultimately decided on) no matter whether i tap into or bolt through.

the problem: to me it doesn't look like there is enough room between the guide shafts and the screw-shaft for much of a hole. plus, it seems like there's definitely only room for one hole on each side of the screw-shaft. (maximum of 4 holes, 2 per tool holder.)

am i just ignorant of the tool holder material's tolerances?

thanks for any info!

[edit: why doesn't the quoted image show up?]

I'm headed to the LLHQ now to pick up all of the micRo pieces to bring home to assemble and test over the coming week. Tonight I'll snap a pic or two of how the spindle will mount.

Done. Just send the paypal invoice and I'll send the remainder.

Cool! Thanks for the link! It'd be a shame to have a micRo and no tools. Cutting with a Sharpie would be slow going! My options up here in AK are limited so I have to search online to find the best deals, with the best shipping options. Some companies basically refuse to ship to Alaska.

Is the larger syncro the one from the OP? Or is it a different one?

Either the faces of the bloks are drilled and tapped at the intervals you require, or are provided by me with a standard hole pattern. The tool holder simply conforms to the mount. I did not get the pictures I wanted to show tonight; give me until tomorrow.


Sure! How do I do that again?


There is no shame in micRo! For the syncRo; you'll see soon enough! Cheers.

no problem! just trying to fill in the gaps in my understanding/knowledge. thanks.

So, how would we go about building a baseplate for ourselves? What materials, dimensions, etc etc. ?

Pictures tonight, we'll discuss.

wooooooot cant wait

Great prograss so far, Brainchild. I'm back from vacation and catching up on all of your hard work -

Good morning friends!

Today my folks made a spontaneous 8hr drive to Asheville which meant K and I could "dump" the babies on them just minutes after they arrived (poor grandparents hehe, they're in Heaven). We headed to LLHQ where young milfy-mom Kellie knocked down some stacks of DIY shipments in short-shorts while I sweat it out in the "shop" trying to close up some remaining details with the Napoleon of CNC machines. Yes the mighty micRo is looking for some breath of its own, but as usual the little beast will take blood if it has to!

My goal for the evening was to begin the run-in for the Z (100s of cycles). I made a list and checked it twice, but when I put everything together at home I realized my only DB25 cable is.....you guessed it! Always the one little irritating deal-killer! Still, the micRo is home on my dining-room table (if a table can be a whore, this is it). Even more ironic is that a shipment of 50 DB25 cables is still at large (I decided to stock them...Staples wants $42??? It is a $10 piece...).

Imagine your joy receiving some kit like this:

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I left a little blood on the Z, just so you'd know....(notice the rounded corners, the CNC'd corners are making me bleed too much; I recommend you take some sandpaper and round the corners yourselves, or at least wear gloves). Handling the fresh pieces is errr painful.

Click to view attachment

I've tested so many couplers...but what is really needed is a coupler that has zero backlash and is also convenient to use for the end-user. I love Dumpster's couplings, but they will add about $100 to the final cost. Costs like these make the micRo price rise to >$1000, so some rethinking is needed. A major problem with the screws is the end-machining needed to adapt the screw to the coupler, but the thread itself is already accurately machined. By making a very simple press-on coupling we can eliminate several parts and a lot of hassle; and guess what? (testing 123) These simple couplings are adhered to the screw and press-fit on the motor shaft. The machined fit is tighter than the shear of the torque for the motors. Being a "rigid" coupling, no same-axis backlash efforts need to be made on the other end of the screw which saves a couple part$. The key to proper performance is the sequence of assembly which allows the screw to be rotated while the adhesive sets..

Click to view attachment

Click to view attachment

When it is all put together you can see the high tolerance in the Z. This is the "baseline" assurance, there is still wear compensation that can be added, increasing tolerance to .0001 or so..

Click to view attachment

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It should now be running the Z paces to verify the coupler and allow for the run-in. I'm not anxious to make the drive at 2:30am though...tomorrow!

Just sorting out the essential information from all the dribble above...


Man, I'm getting sold on the MicRo, too! But with my 70 sqm (753 sqf) garage nearing completion, it would be a shame not to go for the full monty (RoBLOKS, that is). Hell, the cars have survived outside this long...

Your wisdom is near infinite and worthy of emulation by others.

I feel like a Democrat starring at a blue dress...

Makes a great gift for her, and about the size of a sewing machine.

as a Democrat i laughed at this.

Is that 1/2" x 5 TPI 2 start lead screw?

Fantastic pics & video, but is this a cnc dog?

Click to view attachment

Hey guys,

Let me start by saying, holy crap this is some nice work. I should preface everything by pointing out that I am a computer engineer, with worlds of experience and know-how in embedded systems, programming, and analog/digital electronics. I'm fairly new to the world of mechanical madness ;-). It is a reality of life, however, that many projects that I would undertake require some level of mechanical fabrication to be done correctly. I'm looking at the micRo as a way to make that happen, and also for a few pet interests (pick and place, laying solder mask/paste, and perhaps even hot-air reflow--i'll leave hte actual routing to printers which are perhaps better suited).

With that in mind, I have a few questions if you would oblige. I've tried to read all 13 pages of the blog so as not to repeat information, but if I do--forgive me

1. As a first tool, and first run, I think a router is a fairly simple--if minor function--way to go. Being that the micRo is, well, small...it seems that a custom electric motor would be the way to go--as opposed to these people you see using sears hand routers duct-taped to the side :-D. I'm interested in the little beast you posted videos about. Do you have any specs on that/is it within a reasonable price-range? (I view reasonable price range for a tool as being very minor compared to the overall cost of gantry--ie less than $100 as a starting point).

2. I'm positive someone has asked, but I would like to ask as well--any pics/details about mounting holes on the z-axis?

3. My wife thinks I'm silly for undertaking this (don't worry, baring nuclear winter i'll be placing an order for the kits in the next month)...any suggestions?

4. Any chance of you offering (in the near-term) a separate kit that contains an introductory router-type tool (ie mount, motor, everything a non-advanced user might need)? --Please? ;-)

5. What kind of lifetime are you thinking the micRo will have? It seems to me that the plan of screws going through the Delrin (that is hte material right?) as the stepper mechanism would tend to wear out. Delrin, if I remember correctly from college, is fairly rigid compared to many plastics, but would tend to grind down more than metal--introducing slop. Forgive me if this is stupid--remember Computer Engineer (yea I wear glasses and have carpel tunnel -- hehe!).

Thanks so much for all of your work. This project is very intriguing, and for someone w/out a large garage or barn/thousands of dollars for some of the other machines out there, it is a dream come true.

Good luck, and I will be following closely!

I'll make my attempt at filling in on some of this from what I have gathered. Then again, I'm a software developer myself...so we'll see. Might save the guy's some forum time and give them some more lab time =]



I believe either in this post or another one, BrainChild mentioned that the R/C motor spindle setup would be int he <$100 price range. I assume that includes the mount for the Z-axis, the tool holder and would basically have everything taken care of with the exception of you'd probably need to drill and tap the Z Blocks.


Sure it will come...Looks like from the video last night of the Z-testing that BC should have the micRo together complete for testing by the end of the week? Not trying to put words there, but I imagine he's excited about it as we are.



Eh...I'm single. I convinced myself with the amount of practicality in it. I ride/race dirt bikes a lot (along with my dad and 2 brothers). In the dirt bike world there are a lot of aluminum and UHMW guards and parts that purchase would run you a lot of coin. With the micro and a $5 block of aluminum, and some time, I can make several of these would be $50+ parts. So, in the long run, the micRo could actually pay for itself, even if I only did that one task for it.



I think he was doing the full kit, then a separate spindle kit add on. I would assume it would be a 2 kit deal, just to reiterate that it's not just a mill.



I think he's mentioned it at some point, but it's my understanding that Delrin is a self lubricating plastic and in reality it should last quite some time. An aluminum setup would have required a good deal of bearings which would have probably required extra lubrication and probably would need replacement as often or more so than the plastic blocks. There were some adjustable lash blocks in one of the threads, and I'm sure that principle could be carried over to insure greater accuracy for longer. Then again...I'm sure with the micRo functional, you'd have no problem recreating the parts to have a replacement on hand even at replacing those once a every other year you'd be talking about what? $20-30 in materials? Compared to a lot of the things I had in mind, that should be a fairly cheap and maintenance, and probably notably cheaper than replacing the bearings.

If one had the models of the parts, one of the first jobs could be to mill the replacement parts. This would mean an unlimited lifetime.

The next morning...

touchet salesman...i neglected the fact that blocks of delrin are an ideal medium for the micRo to machine (reprap!).

6. this may be a dumb question...buuuut...the name of the website is "lumenlab open source robotics", and there seems to be lots of discussion of using the micRo to build all of the parts for the macRo ...will cad schematics be made available at some point?


...i'm getting fidgity with this order button. I really should wait, but where's the fun in doing what you SHOULD do?

Hello all, first thread post for me, I've read the thread for the micRo and am very excited about building one and attaching a machining spindle to it. I have extensive experience at work with a similar device (Roland MDX-20) with a 6"x8"x2" envelope and fixed 6,000rpm spindle. I work mostly in urethane proofboards and foams since cutting high density plastics and even easily machinable aluminum (Mic 6, 2024) on my current work machine takes FOREVER. Brainchild, do you anticipate that the micRo fitted with a suitable spindle will be able to take more than .01" deep cuts with a .08" path pitch at 30IPM with a .125" 4 flute sub-micrograin carbide square end mill in Mic 6 aluminum? Sorry for the really specific question, but I would like to make some parts at home out of aluminum heatsink extrusions and other cast easy to machine aluminums and engineering plastics. This cut is extremely taxing on my machine at work and makes it pretty unusable for that application. I am hoping that variable speed spindle control, a stronger motor and a stiffer frame will improve the performance enough to make this cut and hopefully deeper ones easily in engineering plastics and easily machinable aluminums. I'm definitely going to be buying a kit when all the details for the mini-mill spindle have been worked out if it is going to be at least this capable.

There are a lot of smart guys on this board who gave good answers to your previous questions, so I'll just answer this last one. Yes CAD/CAMs for all of the parts will be provided free to anyone for non-commercial purposes. This ensures you can machine replacement parts, or make yourself another micRo.

Delrin and technical grade HDPE will outwear steel when used as a bearing material. You'll note the dark-stained oil on micRo. The steel particles cause this.


Hi Graham, The only fair answer is; I don't yet know. It sounds like a wimpy job to me, though until I have tested I'm not 'allowed' to say. With the new spindle motor which is roughly 2x the size of the syncro in the video, and the torque made by the machine ....well I think micRo might surprise a few. What is it that you do btw? Sounds interesting...

Later that night...



Yawn~

Can I stop yet?



Getting major bored, but if the coupling breaks, you guys will gripe at me.

Torque is such a hard thing to intuit...try to crush a piece of ice straight from the freezer with your fingers.




It's alive! mwuhahahahaha I dunno, I think it's talking to me....(crank your volume).

Do you have limit switches on that, or are you just counting steps? If you drove the Z-carriage into the end block, which component do you think would die first?

-Brian

It's saying "more ice, more ice, more ice, more ice, more ice" in some twisted iambic pentameter.

So, add yet another use for the micRo - ICE CRUSHER.

How widespread is the notion that chewing ice means one is randy?

Whoops . . . gotta go . . . time for me to eat some lead paint chips.

Brain,

Is that shielding on the motor leads? Does it do any good? I know the frequencies can be high there and the leading edge of the square waves may need to be sharp, but is the shielding helping the performance?

Oh,...As much as I am interested in getting my MicRo, maybe you should get a little more sleep. I really had to laugh at the island theme.

Perhaps unrelated, but still exciting:

While on my way to pitch my 5-year-old emachines lappy that repetedly overheats last night, I happened to notice that it does, in fact, have a parallel port. This led to a brain surge, and the laptop is now in about 37 pieces. I'll mount the lcd to the basement wall, with the mobo mounted in an area of high air-flow. Usb keyboard and mouse, and I've got a dedicated controller for the micRo! I will probably modify the quicklaunch panel to electrically control something on the micRo as well--perhaps something to do with calibration. I love it when i find a use for something that was just collecting dust before.

Btw, nice vids Brain! I'm salivating

Just counting steps. Crash? Ha! It'd be dead 100x over if that's all it took to kill it. While I do hurry to hit stop when it plows into an end, the structure is much stronger than the motor. The screw coupler would be the weak link, but it has continuously survived..


Never met the guy.


I wanted to test the signal integrity over the length of the machine as it would be convenient to locate the amps close to the motor. I would randomly get a dir error which resolved on application of some foil. This means keep the amps and parport together, and bus instead the biphase power leads to the motors.


Try a bib?

Still running on the dining room table. You guys satisfied the coupling will last? I'm ready to move on to the Y.

It starts with iambic pentameter, but before you expect it, THE COMFY CHAIR!!!

o noooooes the comfy chair

My two year old son, Ixa Von is determined to make his CNC dog...

What a nearly finished micRo looks like:

Testing...

Which grade of Delrin are you using?

-Brian

Looking mighty fine Brain. So are you going with the same type of coupling for the the other axis?
Also cant wait to see more spindle motor tests

Definitely getting excited. It looks like it's all coming together...and dare I say it looks like things might start shipping soon.

Base wise. I was thinking about going with MDF to start off. Still need to check that out, never bought the stuff and not quite sure what sizing options for it are. Anyway, I was thinking of just doing some 24"x24"x3/4" pieces laminated for a nice thick 1.5" and then throwing a piece of sheet metal (thin gauge aluminum most likely) on top of it as a more solid layer that I can engrave with grid lines and drill for alignment pins.

For a bench top model, how imperative is the leveling of it? I'm sure it wouldn't take too much to put a bolt in each corner to level it but wondering how necessary that would really be. Seems if the piece is held down...then the rest would remain orthogonal to the base no matter if it was leveled out or not.

Straight up Delrin homopolymer.


Yes, a duplicate of the Z. Time will tell...


With a rigid base like 1/4 alum or mdf you needn't level it. Big machines weigh so much that the frame distorts, requiring careful leveling. You could hang micRo on the wall, wouldn't change anything.

Brain, it's looking awesome! I can't wait to get the kit. Christmas is coming early this year!

Probably a dumb question, but I haven't seen it addressed yet: Are the threaded drive rods going to be included in one of the kits, or do we need to pick those up separately?

Plays music too!!

Rock on the righteous tool path brother

What CAD and CAM software are most of you using out there? I use Solidworks 2007 for CAD because my boss is cool with me taking the license key home after work to do whatever I want with it. We don't have a CAM package at work yet, we are just using the STL file converter/machine print spooler that comes with the Roland MDX-20. Soon we'll be getting a Tormach PCNC at work and a real CAM package so I'll be using that at home as well to generate g-code for the micRo. I'd like to hear people's thoughts on various commercial packages if you have any experience with them since I'll have a decent budget for a nice 3D/4D CAM package.

Very important questions: When do you administer the Turing test?