First machine build, mini mill

[jbluetooth]

Hey guys, I'm relatively new around here, but been lurking and reading a lot, putting together information and parts for my first build. First off, I want to thank everyone for the vault of knowledge around this place, and all those people who have taken the time to document everything, it has enabled me to create a pretty sweet, working machine in very little time. I finally finished cutting my last few parts and assembled the machine today for some movement tests. I decided to do a mill instead of a router. First, some machine info:

Machinable area of 13.5" in X, 7" in Y, and 10" in Z

Xylotex 3 axis kit w/ 425 motors (I bought this first and now I realize its downfalls, might have to add a G540 and better power supply soon)

5mm pitch precision ground ballscrews on all axis

THK SR15 rails on X and Y, HSR15 rails on Z

My spindle is a Porter cable 1 3/4hp variable speed (10k-27k) router w/ precision nut and collets

Pretty much got the motors tuned today, seems to rapid smoothly up to 200 IPM on all axes, so that's cool, better than I hoped with the Xylotex kit, the resonance is pretty apparent.

I built the entire machine out of scrap 3/4" cast acrylic from my work. First I faced it on both sides down to .600 so it was flat and consistent, then cut all my parts on our Komo VR510s. There are a few mistakes, couple extra holes here and there, hehe, but it came out pretty nice.

I still have a lot of work getting Mach 3 all setup and dialed in, as well as adding my limit/home switches, E-stop, and I'm considering closing the entire thing in and adding flood coolant. But now I dunno, it's too pretty, I don't want to use it hehe. Anyways, until I'm back with tons of Mach setup, post processor, and home switch questions, here's a bunch of pics, enjoy, question, comment, whatever:

Jesse

[TOTALLYRC]

Looking good. I would definitely consider something to keep those nice rails clear of chips. If it works well but is too flexible, you could always duplicate it in alum or steel.

Since you are uisng a router and will be using flood coolant, you might get away with shallow high speed passes on alum.

Nice job.

Mike

[Herbertkabi]

Nice job, yes,
I would like more then X-axis is verted upside down - cars of x and y on the middle-plate (now w.table) - then rails of x gives rigidity for w.table (now middle-plate) and rails are keeped clear of chips at the same time.
Nice spindle - try to convert it to brushless DC
cheers,
herbert


And bottom!
XY table and y-beam - there is no rigidity at all ???

[LeeWay]

Looks great. Nice design. I think the X table is fine the way it is. This will mean the entire table is fully supported all the time. It also allows a smaller footprint for your enclosure.

Way covers for sure.

I would be very carefull with your choice of coolant. I use Koolmist 77. For some reason, it likes to eat polycarbonate. It makes it very brittle and removes it's impact resistance over time. Not sure what is going on with it. It was more apparent where there were holes drilled. Acrylic, I think, has some of the same properties and it may act the same way on it. Not very good if your mill would just fall apart one day.

Another thing is that router is not sealed. It will be very hard to keep all the chips and coolant out of the windings especially if machining high speed. It will also like to get very hot. It might be beneficial to mount a very high CFM fan on the top blowing around and through the router. It would not get so hot with coolant on the end mill, but just a few things for you to consider.


I have run a small Ridgid trim router on my mill. I just have to be very aware of the coolant placement and I turn the pressure down some to keep it from squirting up into the router.
The router does blow air down through it when running, but it not when I have to take care the most. It's when I am clearing chips and coolant with compressed air for a new part.

[jbluetooth]

Thanks, the machine is pretty ridgid, especially the lower table section, but I should have designed more meat connecting the beam, that's definitly it's weak spot. I purposely made the beam very large to keep it from flexing, but overlooked the connection point a little, guess I was just moving too fast to get it done since I'm changing jobs and won't have access to the routers anymore. As for coolant, good thinking to watch out for the router, wasn't considering that, maybe I won't bother, I'm not sure I'll even use this machine, maybe I'll just use it to make some more parts out acrylic and learn the mach 3 interface for the next build.

[jalessi]

jbluetooth,

Your cast acrylic machine is extremely nice and very well built.

I am sure it will do a great job machining whatever you need.

Adding simple way covers and using water as a coolant cant be to difficult.

All machines have issues if you push them to there limits however it would be a shame not use such a magnificent mill.

Using scrap cast acrylic is a great idea, if you have extra scraps I would be happy to take them off your hands in a heart beat.

Material costs for constructing a mill frame are very expensive, Ill bet you saved between three and four hundred dollars using the acrylic.

Please post some of your finished parts that you make off your new mill.

Awesome job,
Bravo!

Jeff...

[Herbertkabi]

When X-axis will be verted upside down then your w.table will be much longer - you can use 4-th axis as well, or just fix something longer parts you will need ... it is 100% sure you will need it ;-)
"Entire table" will be fully supported all the time as well as when cars (wagons) bottom,
threre is no slacks in THK.
Milling acts always on the centre of machine, does not matter working table goes left or right - milling happens always between wagons (cars).
And as told before - then X-rails will be in hiding - no needs for x-ways covers.
cheers,
herbert

[Hirudin]

There's something you don't see every day: a transparent mill! Very cool!

Would it be possible to fill the column and base with something (like epoxy granite or maybe cement)?

[BobF]

If you use an Onsrud Super-O-flute bit, you can cut aluminum with no coolant. Just take small bites.
The mill is really cool looking being clear acrylic. Get some more acylic before you go and build a dust pickup.

[LeeWay]

I think this one might actually do pretty well with high speed shallow cuts. Several guys do this without coolant. Use a shop vac instead of compressed air to collect chips between part changes and I think the router might be safe.
I have used my router to cut aluminum on my router table and got away with just sprying WD40 every so often. I wasn't making real shallow cuts though. .063" thick sheets in one pass sometimes.
I needed the lube to keep the aluminum from welding to the end mill.

One other area of concern is the X axis itself.
That will be a lot of extension for it. It will try to act as a lever when cutting.
Typical mills have the spindle exended out over the table rather than the columns slide point being so high. I'm pretty sure you will see too much wiggle with any kind of heavy cut.

[jbluetooth]

"One other area of concern is the X axis itself.
That will be a lot of extension for it. It will try to act as a lever when cutting.
Typical mills have the spindle exended out over the table rather than the columns slide point being so high. I'm pretty sure you will see too much wiggle with any kind of heavy cut. "

I don't understand what you are saying here...are you talking about the mounting point on the Z axis? What do you mean the X axis itself? I'm assuming you meant the Z axis itself, and yeah, I wish I had beefed up the joint between the beam and the table, cause I can flex it a little, so light cuts will definitly be key.

[LeeWay]

Mistake on my part.
I did mean the Z.