CNC Mill Drill

**andrew_mx83** · 31st August 2013, 12:23 AM

Hi

This was my first CNC project. The forumla is fairly simple:
Start with the most solid drill press you can find (the Parken has a 70mm SOLID column!)
Fit Hafco compound table with ballscrews and stepper motors
Fit 2hp motor to drive spindle. I rebearing'd the head and played with the pulleys for approx 1100, 2200 and 3300 rpm
Make Z axis happen
Wire it all up with a Gecko G540 controller

The result is outstanding. I can slot through 5mm alloy plate with a 5 or 6mm cutter no dramas. It also cuts steel, although this is a fairly noisy affair. The finish ranges from average to excellent depending on feedrate, DOC, etc

Here is an early vid of it in action:
https://www.youtube.com/watch?v=-lSF...e_gdata_player

I dont really have a lot of photos, but here we go
*note: all parts are made on a lathe and/or drill press. I did not own a mill at this point

Ballscrews, motors and bearings mounted. The screws are supported by 2 deep groove ball bearings and 2 thrust bearings. Hidden inside are the ballnut mounts, the X axis is quite tricky. I might get photos if people want.
The motor mounts are solid alloy, and are bored at each end to concentricly locate the motor to the bearing mount. I can't see how you would do it any other way and expect good results, i cringe when i see 90% of the DIY motor mounts out there.

Limit switches mounted, with adjustable ramps.

FIRST CHIPS!!! This was exactly 3 weeks after conception of the idea on sunday evening (no Z axis yet)

Z axis bearing block, motor mount and ballscrew mount. A tricky bit of gear to design and make. It needs to hold the ballscrew dead parallel to the quill, so had to mount up on a true, square, machined surface. I removed the pinion which drives the quill and found a nice 40mm bored hole perpendicular to the axis. Great! Now to just machine something up to hold everything together, aligned, using only a lathe. It started as a piece of 80mm barstock.
Behold:

A view of the bearing recess. Again we have 2 deep groove, but only 1 thrust bearing. Some seriously tricky offsets for this to all sit in the right spot on the machine, hold the bearings properly, and mount the motor, all while keeping the screw parallel to the quill. This was the first time i really made friends with my 4 jaw chuck.

Mounted. The long spigot is a big interference fit into the aforementioned pinion bore. Perfect alignment! Woo hoo!

The end result. 4 weeks from concept. You can just see the electronics enclosure in the background.

**andrew_mx83** · 31st August 2013, 12:47 AM

So far it has been a fairly reliable machine, and it has done a hell of a lot of work. It is a light production machine and definitely earns its keep. Its happy to make chips 12 hours a day for a week straight.

Here is s rundown of the fixes, mods and upgrades i can remember doing, in no particular order.
Upgrade from grub screw to clamping motor couplers
Upgrade Y axis ballnut mount
Electrically isolate table from spindle. Best mod ever. Every tool is now a touch probe. Center over a hole or set tool height in G code

)
Upgrade to ER32 collet
Replace start cap on spindle motor
Stop swarf getting in the electronics box, but still get the heat out
Replaced a power supply

I also added lube, but i hate water based lube systems. Drown my machine tools in rust causing water? No thanks. Ill use a lube that protects instead.
So i dreamed up what i later found out is referred to a an MQL system. Id been using a neat cutting oil in the shop for a while, and it is highly effective in very small, low mess amounts, so i wanted to squirt a bit at the tool every few seconds.
Again activated in Gcode, flood coolant gives a squirt every 3 seconds and mist every 7.
20lt of oil lasts for months and months, in a total loss arrangement.

It uses a car EFI fuel pump and adjustable pressure reg inside a 20lt drum, and a fuel injector powered by a PMW driver. I recently added a large oil cooler to the circuit to help keep the pump cool as i killed the first one due to overheating

https://www.youtube.com/watch?v=Nxco...e_gdata_player

**Ueee** · 31st August 2013, 01:33 AM

Hi Andrew,
Your one clever cookie!

The noise in the vid is pretty bad though, have you thought of trying to bush the top of the spline to try to get rid of some of the knock? Anyone with a HM50 knows what i mean

. Dave J did a thread on it i think.

How is the chuck held on? Without positive holding power i would not think that the taper alone would be enough.

On a side note what sort of cleaning bath is that you are running in one of your vids?

Cheers,
Ew

**andrew_mx83** · 31st August 2013, 02:07 AM

Well it is working pretty hard there! I have since learnt to keep the table up high and quill as far retracted as possible, just enough for a tool change. Also to keep little tool past the holder. Simple stuff, but i hadnt really done any milling before

It is a fair bit quieter in operation now but i am interested in this spline bushing. Not that i'm inclinded to pull it apart again... i have a new toy now, will start another thread at some point.

The chuck is long gone, as it had a tendency to fly off its R8 arbor while cutting. I bashed the ER32 holder in pretty hard, it's on an MT2 taper with no drawbar and has not yet come loose. i wouldnt want to try and get it off though!!

The hot tank (version 2) is a traffic light cabinet (ssshhhh!) with about 300lt of volume, a 3kw heating element, a thermostat, a drain cock and some nasty chemicals. The pump died, and i got a bigger replacement but havent had time to fit it yet (maybe 2 years ago? haha)
version 1 was the same deal, in a 60lt drum. couldnt fit cylinder heads though and had no lid. the new one can fit an entire I6 engine with change and holds heat quite well

**jhovel** · 31st August 2013, 08:28 PM

Very inspirational!
The second video when clicked tells me it's private - sorry....
Is there a reason or could you share it?
What size motors did you use and what voltage, please?
Also interested in the ballscrew pitch.

**kamusur** · 31st August 2013, 11:56 PM

You must have good taste the Parken is a pretty hot machine for starters.

Steve

**andrew_mx83** · 1st September 2013, 12:16 AM

Video fixed. Reason is i dont know how to work the youtube!

The motors are 387(?)oz units running at 48v. Whatever the biggest you can run on a gecko is (3.5a from memory)
I bought the package from Homann designs with the gecko and power supply, the kit was great value and Peter is fantastic to deal with. When the power supply died he was very quick to get it sorted.

The ballscrews are 5mm pitch, Chinese ebay jobies. They are 'ok'
I end up with around 0.11mm backlash on the x and the y which is dialled out crudely in mach3.
Statically, i can place the machine to within roughly 0.05mm across the travel repeatedly, better in a smaller range.

The Parken is a really nice bit of gear. I would buy another in a heartbeat if i saw one. It took 3 of us to load/unload!
I bought this one for $60 with no motor or chuck. When i saw it up close, that sealed the deal and gave the project a kick start.

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