novamill atc retrofit

[jonnydeen]

Love having a novamill but frankly changing tools manually is a massive PITA. Even with the clearance stealing easy change holder.
Was wondering if anyone had any success retrofitting an atc? Maby someone has atc parts or a power drawbar that are surplus to requirements even in need of refurbishment.

Any info on the subject would be awesome

[angel-tech]

have you seen this pdf

[jonnydeen]

Cheers. Angel-tech
Nice of them to include details such as air cylinder size. And from that drawing mocking up a release mechanism would be handy.
Now, if only there was a detailed drawing of the drawbar itself... And a spec on those bellevilles.

This is looking promising

[Steve]

All the parts would be still available from Denford if all you wanted to do was add a spring stack and an air cylinder at the back. If you then wanted to manually load the tool and just apply air to release the old tool and then fit another. The problem would be if you wanted a auto toolchange arm and carousal as that requires castings that we no longer have the patterns for.
I attach a drawing of the Drawbar and Air cylinder mounting plate.
The following parts are still available under different numbers:
TR20/109 is now VMC/0106
TR3/110 is now VMC/0111
RM6/103 is now VMC/0703
Belville springs still BI00196E
Piston Rod Clevis still BI01127F

[jonnydeen]

Wow Steve, that's pretty awesome. I'll have to get prices and go from there.
The drawbar is really the crux of the system. The carousel could be simpler and utilise the same control aspects as the original. I personally like the simplicity of the sliding carousel like you would see on most Haas vmcs, sure they aren't perfect and sometimes even fall off but you cant get much more straight forward.

[Steve]

Will post the carousel drawings but there are lots of parts and will make the interface complicated.

Not something Denford would be prepared to do.

Will share the drawings though.

[jonnydeen]

Will post the carousel drawings but there are lots of parts and will make the interface complicated.

Not something Denford would be prepared to do.

Will share the drawings though.

You, my good sir are a gentleman and a scholar.
The carousel disc and the Geneva gear are my main points of interest. The belt drive does seem to complicate matters but I would do away with it anyway and go direct drive.

Thanks again.

[angel-tech]

when you design a carousel tool changer be aware of the need for swarf clearance and coolant issues, as swarf will end up in the mechanism at some point.

PS. great info guys.

[Steve]

Only these parts are still available as they are still used today.
TR20/109 is now VMC/0106
TR3/110 is now VMC/0111
RM6/103 is now VMC/0703
Belville springs still BI00196E
Piston Rod Clevis still BI01127F

The Tool change arm and Carousel are all obsolete

Attached are the schematics for air and tool change arm assembly.

[Steve]

This post also shows the spindle assembly. There are 27 Belleville Springs


download/file.php?id=3456

[jonnydeen]

Preload nut is £45
Drawbar collet is £90
Bellevilles are £0.75 each with 27no required
And the drawbar is not available
never enquired about the other components
And that is +£10 delivery + vat

never enquired about the other components

Prices aren't bad but considering I work as a cnc machinist, its hard to justify when I can make my own parts. Will have to buy the bellevilles though.

Would like to see if the wee novamill has the guts to machine en24. Only ever used aluminium, brass and copper. Not holding my breath but would be nice to see it machine its own parts

[moray]

Excellent topic.
I never realised the actual spindle was the same between non-atc and atc machines, so this should be a reasonably easy upgrade.

Jonny, am I correct in assuming by Drawbar collet, you mean the part (TR20/109 or VMC/0106) the balls go in and grips the holder?
Out of all the parts needed, that is probably the hardest part to make considering it's meant to be case hardened, so £90 doesn't seem too bad.

Also, anybody know what style of retention knobs would be needed?
A quick google suggests there are at least two different versions for BT holders.

[DavidJ]

... And a spec on those bellevilles.

Information previously supplied in another thread
Disc Spring 28.0 O/D x 14.2 x 1.25 - I bought a bag full on-line from Associated Spring - they are a standard DIN size.

The extra drawings here should be helpful when I get round to doing some more work...

[DavidJ]

The problem would be if you wanted a auto toolchange arm and carousal as that requires castings that we no longer have the patterns for.

That needn't be a huge problem these days - reproducing a pattern via 3D printing is fairly straightforward. There is always fabrication as an option too.

I would be interested in the drawings, if/when time allows posting.

I can't see any unused mounting holes for the carousel mechanism on my (non-ATC) Novamill - were these only drilled when the ATC was fitted? If so, is there a hole location drawing?

[jonnydeen]

Moray,
That's correct, and yes its not bad value but I have no problem machining and hardening one myself so its a tad redundant. I made one from en24, just need to get a few minutes peace to drill the 5 holes on the circumference, then harden.

As for pullstuds, Well spotted my good sir. I thought there was only one spec for bt30 but it looks like there is 60degree and 45degree variants, some clarification from someone in the know would go down a treat

Davidj,
There is two tapped m10 holes on either side of the top of the column, I am planning on utilising these to mount the atc.

There is a YouTube vid featuring a novamill ATC performing a tool change and interestingly I noted the tool enters the carousel vertically rather than horizontally. This makes for some interesting points.
Slower tool changes
Simpler carousel design
Inability to use tooling of a certain diameter. (no er32 holders or 50mm facemill)
Possibility of mixing BT with CAT holders as the flange is redundant

Frankly I would rather have a much more sophisticated carousel with retention forks, loading from the side than be stuck with er 17 or god forbid DA200. I'm already missing my 30int 80mm facemill and I haven't even made the switch to bt yet

[jonnydeen]

As a side note.
En24 vs 10mm 6 flute carbide end mill @ s5000, f300, 1mm doc, 5mm woc =
Any harder and resonance was an issue. Although my vise doesn't help the matter.
Extremely chuffed with that performance.

[moray]

Moray,
That's correct, and yes its not bad value but I have no problem machining and hardening one myself so its a tad redundant. I made one from en24, just need to get a few minutes peace to drill the 5 holes on the circumference, then harden.

As for pullstuds, Well spotted my good sir. I thought there was only one spec for bt30 but it looks like there is 60degree and 45degree variants, some clarification from someone in the know would go down a treat

Thanks for clarifying that, and it's very true that if you have the suitable tools, parts are easy.
I knew different pull studs were available, but I also thought they were specific to the holder style, with some oddball manufacturer specific ones thrown in, it was only when I googled to see what was available I discovered there are two type for BT. Hopefully somebody will be able to confirm the correct angle (in fact, I'll go email somebody just now who might know)

Davidj,
There is two tapped m10 holes on either side of the top of the column, I am planning on utilising these to mount the atc.

There is a YouTube vid featuring a novamill ATC performing a tool change and interestingly I noted the tool enters the carousel vertically rather than horizontally. This makes for some interesting points.
Slower tool changes
Simpler carousel design
Inability to use tooling of a certain diameter. (no er32 holders or 50mm facemill)
Possibility of mixing BT with CAT holders as the flange is redundant

Frankly I would rather have a much more sophisticated carousel with retention forks, loading from the side than be stuck with er 17 or god forbid DA200. I'm already missing my 30int 80mm facemill and I haven't even made the switch to bt yet

As long as you've already done a retrofit that will let you customise the tool change, side loading would be a far better option. Personally I'd be opting for the standard Denford setup as my Novamill runs quite nicely on VR Milling 5 via USB, so I'd have to do a retrofit to use any other method, plus I only use small cutters on my Novamill so ER16 suits me fine.

[Steve]

The spec of the pull stud is below so its 30 degrees

PULL STUD 1 14.00 50.00 7.00 MAS-BT-30.30°.M12

[moray]

Thanks Steve.

Just compared that to the dimensions that google images is throwing up, and it seems that's more commonly called a 60 degree, as the diagrams show that angle being measured from parallel with the stud body, instead of at 90deg to the stud like that diagram (got to love non-standard standards!).

Just need to work out carousel details now...

[jonnydeen]

Wow this thread is progressing nicely with some brilliant info.

Cheers for the clarification Steve

Moray, my machine is running sweet on vr2.31 and I'm reluctant to change to mach or emc for that reason.
Makes me wonder if it is possible to change the tool change instructions without treading on denfords legal toes. If not then mach or linuxcnc it is

Or use a plc, but that is probably just an extra dose of un-necessary ball ache.