[MrBean_pm]

Hello Guys,
Ok, firstly a bit about myself: I am a systems-specialist for Metso Automation, a QCS and DCS supplier to Paper, Pulp, Power and energy, as well as Marine and a few other Industries.

Our systems are for example controlling the Cruise-vessel, the Queen Mary II, military vessels, many paper-machines across the world, Power stations, et al....

With that said, I am an expert with process-controls, and have access to some of our own hardware and applications to make for a killer automated setup - 16-bit analog control anyone :rofl:

With that said though, I am pretty much a noob when it comes to milling-machines. Six years ago, when I left South Africa for Australia, I sold my Chinese round column-based Mill, and have wanted/needed to replace it ever since,

Getting tired having to outsource my multitude of small jobs, so decided it's time to get a new machine.

I had 2 options, either the MachTech Vh1000, which I could have had for AUD 5,200, and that would have included 3-axis DRO, cooling system, limit switches, et al, and it would have been a much better buy than the BF46 - but, it weighs in at 1080kg vs the 630kg (Mill and base) of the BF46.

The VH1000 would be difficult to maneuver into my garage, plus, it is to big for my intended application. Thus, I decided on the very nice, and arguably the best Bench Mill available on the market - the Opti BF46 Vario. Paid AUD 4,450 (incl 10% GST and delivery) for this machine, with a good quality collet set, as well as a 150mm/6" vice. Not to bad I would reckon. The Mill excl. GST was a bargain at $3,700 at Applied Machinery in Dandenong/Melbourne. A very nice sales-engineer, by the name of Kris assisted me - ask for him next time you need help/advice, luv'ed dealing with him. Ok, it was on the floor for $4,200, but as I said, Kris wanted to do business, so....


Ok, now a few questions to those that have done a CNC conversion on this Mill before:

I know the manufacturer sells a CNC kit for this - I will get the ballscrews of them.

What I need though is the mounting brackets/plates for the motors - just them, not the motors etc. I will still make my mind if I'm going steppers, or servos (leaning in this direction for now, due to my automation background)

So, anyone pointing me to a source for the mounting hardware, will make my day.

The machine will be delivered tomorrow, paid for it this morning, and I will uncrate and take a few pics on the weekend - not sure you guys want to see a virgin BF46 though, but would be nice to document y build from the start.

Look forward to input/advice/feedback.

Kind regards,
Phillip aka mrbean

[photomankc]

I'd be real interested in seeing one. I have to say though, at the cost for these machines I'd be far more inclined to go to an RF-45 type mill. However Optimum makes a really nice machine so perhaps the refinements are worth the money.

I have a few ideas for a bigger mill and a side business floating around in my head and this is one of them, along with a Tormach 1100.

[jerbro]

I know I'm interested in seeing all the pics you can muster on the BF46 from start to finish - there are so very few of them available.

I've been reading up for a few months now, and have decided on the same path - though I'm in the US, so I'll import from MTW and as such, I'll be getting the TopTech BF46. The pictures on MTW show a slightly-uncrated BF46 with a one-shot oiler installed?! I don't see that anywhere in the specs, so I'm interested to know if you get that.



Are you going with the 2HP 3-phase or the 3HP single phase motor?

Looking forward to pictures!
Jeremy

[MrBean_pm]

Heya Guys,
Thanx for the feedback

In hindsight, and considering the fact that the HV1000 came with cooling system, 3-axis DRO, limit switches et al, and only AUD 800 more, it would have been a much better deal.

Thing is, I have no real way to unload and move it around at my place, unfortunately, it simply is to heavy at 1080kg - sad, I know.

With that said, the BF46 would be much better suited (at this point in time) for my application - who knows, if I need a bigger machine in 5 years, I will buy one, and relegate this to bench-mill duties then.

2 Jerbro: Mine did not have the one-shot oiling system, so I guess that is non-standard, so don't bargain on it - see it as a bonus should you get it pre-fitted.

These machines are pretty big for a bench-mill - I am 1.90M tall (or should I say my height is 1.90M rather, otherwise I am suffering massive e-peen) and with this machine sitting on it's stand, must be around 2.1-2-2m high.

The pictures are deceiving, it is a pretty big machine.

In that picture, you can make out the 'Optimum' branding near the top of the gear-cover - so it's just rebranded, mine was the same, rebranded to 'MachTech'

I am awaiting delivery as I write this, and will take some serious pics once I start the log. Those of you that know me from computer-modding forums will know I document the steps quite well.

Guys, look, I am very new at Milling-machines, but know what I need, and with your advice and feedback, I will get there. Appreciate you looking, and will have the first pics up on the weekend.

I am away in Singapore next week, and with my travelling-schedule, will mostly be able to do bits and pieces over weekends only, some week-nights, and I am also moving house in the next 2 weeks, so initial updates will be slow.

Once I get the orders in for the CNC hardware, and ball-screws, things will move along.

I can start posting on the PC part though, and will post pics shortly - I have a georgious Commell LS-573 5.25" industrial SBC here, with a nice core-2-duo 3.06Ghz mobile CPU - so this thing will fly.

Check back soon for more info.

[MrBean_pm]

@ Jerbro: Before I forget, mine is the 3hp/2.2kw single-phase motor (220V AC for Australia) I would have luv'ed to have 3-phase at home, I was actually pretty stupid, just finishing the build on my new house, and should have wired it with one 3-phase power-point.

Few questions wrt stepper-motors - and would highly appreciate those with similar sized machines to chime in too
Considering the size of this Machine's head, I am opting for a Nema34/1600oz motor for that, and then 2x Nema34/878oz for the X- and Y-axis.

You guys reckon the 878oz motors would be overkill for X/Y? They have the Nema 34's also in a slightly lower rating @ 740oz if that would be a better match?

Bear in mind I will be running with the standard leadscrews for now, and convert to ballscrews somewhat later.....

Edit: Basically I am considering 2 options:

1)1x Nema34 1600 oz Stepper for Z axis
2x Nema34 878 oz for X- and Y axis
3x Gecko G203V controllers
with breakout board

or

2) 3x KL34-180-90 (Nema34 package) 1195oz servo motors
3x Gecko G320X controllers
with breakout board

For a moment, forget that the servo's are so powerful - I will do decent interlocking to prevent any issues - my first choice would be option2, due to inherent better control available with servos vs steppers.

Appreciate your feedback.

[SCzEngrgGroup]

"due to inherent better control available with servos vs steppers." - Commonly accepted "wisdom", but simply not true.... And those big servos would be overkill. I am using the smaller 850 oz-in servos on my 9x49 knee mill. It will do 400 IPM, and has enough thrust to break 1/2" endmills without losing position. Bigger is not always better.

Regards,
Ray L.

[MrBean_pm]

Hello Ray,
Thank you for your feedback - yes, I am thinking the 1200+ motors would be to big, maybe for the Z-axis, as this BF46 has a very heavy head pack.

But for X, Y and later 4th axis, I am sure the 850 oz servos woul work really well, still on the high-end of desirable....

Can you elaborate on your comment about servo vs stepper motors....coming from a process-control background, I would feel that you would get better control-resolution from servos than from 1.8deg/step 200steps/revolution stepper motors.

I have pretty high-end industrial quadrature shaft-encoders I would fit to said servos, which I had in my bin for a number of years now, they are costly items, but I got 4 for free.

So I would feel with a quality driver, and a decent shaft-encoder, you would at least theoretically get much better controlability from servos - note I say theoretically, as I do not know how notiecable the difference would be in practice.

appreciate your input

[SCzEngrgGroup]

"note I say theoretically, as I do not know how notiecable the difference would be in practice" - that's the whole point. In the real world, there are so many factors completely outside the motor that affect significantly affect precision and accuracy that the difference in motors will not make any measurable difference in the end result. I have one of those 850 oz-in motors moving the 700# knee on my mill. Moving the head on yours would be a piece of cake.

Regards,
Ray L.

[MrBean_pm]

Yep, good points, thanx - 01h30 in the morning here, so my 3 braincells are more or less dead :rofl:

Thanx Ray, with that in mind, I may very well try the Steppers then - I suspect, same as you, that in theory, and in this application, there will be neglible difference - I don't believe the 35-40% higher pricing for a comparable servo setup is justified.

I guess I will opt for 2x 640 oz steppers for X and Y, and either a 906 oz or 1200 oz for the Z. I am also then thinking the Gecko G203V's, and 1 or 2 Meanwell 48V PSU's, depending on the wattage available at JayCar's...

Again, I can always reuse those steppers and contrllers elsewhere, no biggie, if I find they are not good enough, and I would like to try servos. Somehow though, I suspect that the steppers would work pretty well for what I intend.

Anyway, appreciative you casting your eye over this!

Have a good one, talk soon.

[pete from TN]

If I had a nice EXPENSIVE machine like that I seriously doubt I would go with a Gecko setup. I would look really hard at an AC servo setup like that from DMM. Kelly is building an IH clone (MTW MD001) here and has them on both of his machines now. They will actually perform better and save you money and are essentially plug and play. When I add up what I spent for the hard parts of my system with the motors, geckos, BOB, power supply etc... it is actually more than the asking price of these systems. If I had to do it over again on my RF45 and they were available at the time I would have certainly looked very hard at these kits. The AC setups are sweet. I would also seriously consider getting the ballscrew conversion done right away. Once you get the thing working under CNC you are probably not gonna want to take it all back apart and redo it. The ballscrews are not that expensive and again for a nice machine like that I cannot imagine not going with some decent ballscrews. good luck with it either way man....peace

Pete

[jerbro]

Looking at the factory kit, the ballscrews are 25mm in all directions. The steppers are 12 nm which I figure to about 1700 oz in - for all axis. If you get their controller too, it says the max movement is about 43 ipm on the z (18mm/sec) and 47 ipm for the x/y (20mm/sec). This seems small to me, though combining the grunt of the big steppers and the slow rate should yield no skipped steps? Perhaps the Optimum guys are very conservative in their rates for some other reason?

Here's the Optimum catalog CNC hardware: BF 46 Vario New in t product he ran... [Page 136] that shows the ballscrews and New in t product he range CNC add-on kit for milli... [Page 137] that shows the cnc add-on kit.

In case anyone is interested, here is the spec sheet for the mill itself http://www.damencnc.com/files/manual...6SpecSheet.pdf

Jeremy

[pete from TN]

That is an awful lot of money for a 10x20" table travel. It sure looks like a nice machine tho... I would definitely want more speed than those from the manufacturer altho in actual machining I seldom run more than 100 IPM rapids and usually less than 50 IPM feedrates unless I am running real shallow. These larger style benchtop bedmills are certainly capable of running decent cuts at those feeds. I am interested to see what this fellow comes up with. Peace

Pete

[MrBean_pm]

Good morning Jeremy and Pete,
Thanx for the input, appreciated. This is the sort of info I'm after, and I am willing to listen and learn from those with experience.

Would save me a lot of money down the way.

I guess what Pete has said is very true, and maybe the absolute first parts to get.

1) Opti's 25mm ballscrew kit.

Once I have that, I should only consider the electronics. Jeesh, this is the problem -> so many options out there. In my case, even more than for the next guy.

I will explain in the next post, let me grab coffee first.

Br,
Phillip

[MrBean_pm]

Ok Pete, had a look-see over at DMM's website, thank you for the pointer - real nice, and ultimately what I will be using then.

So, scrap my previous rantings wrt steppers et al, I have a decent machine here, and will fit it out with DMM goodies. Let me go and check Kelley's build, and I will report back later. Will also fire an email to DMM and see what the shipping-costs will amount to.

I will give you guys a little more info and examples of what I do as a DCS/Systems-Sepcialist - you will be amazed what I could do to decent drive-controllers, directly from within our own applications-software and GUI.

I can generate whatever application controls I want, with a multidtude of interlocks, very high speed controls, 16-bit anaog resolution should I directly wish to control the drive-controller -> and this is what excites me about Pete's comment on DMM, those controllers have selectable modes for inut, one of which is analog....

Nice. But let me not bore you, I will give a few examples later. If we can control high-speed Gas-turbines, and all manner of processes, and that includes 5-9 tons of scanning platforms were we need < 2 micron accuracy on caliper control across a 7m wide paper machine....well....

Seeing that we use AutoCAD/BricsCAD to do our application programming....guess you can see where this is leading. Might be to much work to reinvent the wheel though, but at the minium, I culd very easily roll a nice and pretty DRO....

I will check out Kelley's thread first, and shoot an email of to DMM.

Cheers Guys, later.

Phillip

[pete from TN]

Yeah I wish those were available when I did my machine. They are ALMOST a plug and play option and it is a COMPLETE system built to work together. It also comes out actually cheaper than my Servo setup using Keling Motors and Gecko G320's. That is actually with me buying all three of my motors from a fellow for under $500.00. From the looks of Kelly's parts he made on his other machine, an RF31 style round column mill and his new IH clone talking to him about it he seems to be very happy with the system and has had no issues related to the system. I WISH I could say that about my setup but my wiring skills leave something to be desired. This setup the only thing I would be concerned about is actually sealing up the setup to protect it from chips and coolant. There are always ways to enclose things if you are clever tho. The power and speed available would also be nice let alone the generally maintenance free traits of the AC brushless servos. They actually have a bunch of folks here on the zone now using them so Kelly is not the only one. Peace

Pete

[MrBean_pm]

Shot Pete, appreciated

I am looking at motor-sizing, and am torn between:

60EM-DHT-36
400W AC servo motor
Max 3000rpm, Rated torque: 1.27Nm, Peak torque: 3.6 Nm
$155.00

and

92GM-DHT-72
900W AC servo motor
Max 1080rpm, Rated torque: 2.9 Nm, Peak torque: 7.2Nm
$203.00

From what I've seen, the smaller motors would do very well in a 1:3 ratio wrt torque, and be more than ample - my problem is I might be forced to go direct drive, and using couplers, so the larger motors would work out pretty well then.

I won't have access to a lathe in the near future, so pulleys are an added complexity I can do without.

So I guess for the small difference in price, and the lesser effort required with the direct coupling, it might be a better choice.

Anyway, thanx for your time, I will await further input from you guys, and go from there

[asuratman]

Mr Bean,
How long column height and what table size this BF 46?

[pete from TN]

I am not familiar with that machine at all and have only a very rough idea of the weight of that head and the table movement forces so I cannot recommend either to you. What I can do is highly recommend you contact DMM directly. I had called them awhile back and they gave me some specific recommendations for my personal machine. I am a bigger is better kinda guy but they actually found that the smaller motors they sell would be more than adequate both in power and speed based on the belt drive ratios and the ballscrew setup I was using. Just because you do not have a lathe does not mean you cannot do a belt drive setup. With servos generally you are trying to setup the power and speed to work with the motors to arrive at the best rapids to axis power you can get. Servo motors USUALLY like to spin much faster than steppers so the belt drive is a simple way to put the power in the right RPM range for any particular motor. In my personal view it can ALSO become a fusible link so that WHEN you crash the hell out of it you can hopefully watch the belt strip or break and not your expensive ballnuts, screws, etc. etc. Ask me how I know this. This is of course unless you overbuild your belt drive and use a very wide thick belt that may not fail under a crash. The nice thing about the DMM setup is that the power and torque number they show are gonna be real close to the actual power you get out of the system because the rest of the system is optimized to the motors. USUALLY with Geckos you cannot attain that with a lot of motors like my system.

I do not know if you can run these AC servos direct drive or not on your machine but I would most certainly talk it over with DMM directly to see what they recommend and follow their recommendations. They seemed to know a LOT about it at least the fellow I spoke with did. Do not get too concerned with ultimate rapid speeds either as it seems a lot of folks including myself did at first. The reality is even 100 IPM rapids on a machine of this size is probably adequate even if you are a real impatient kinda guy. Right now I can get over 200 IPM in X and Y and 150 in Z but it is NEVER set that high I usually have my rapids at around 120 and 80 respectively most of the time. Getting the right resolution and acceleration settings is a lot more useful in actual practice. Keep in mind your actual resolution and final steps per inch DOES make a difference in the ultimate accuracy of the machine. You have a real nice machine there, take some time, figure out what you intend to do with it, purchase GOOD quality parts, and build yourself a real gem and you will have it and enjoy it for a long time. Good luck man...peace

Pete

[MrBean_pm]

Hello Asuratman,
Where in Indonesia are you - I travel there for business sometimes

Here is info from the manual - see attachment: column-height is approximately 1,100mm, and here some info on the Z-axis:

Swivelling + / - 90°
Gearbox stages 3
Z-axis travel [mm] 541



- my machine is still in it's crate at my office, as I will only move into my new house in 2 weeks from today, and will move it then.

Also from the manual, the table-size is:

Table length [mm] 850
Table width [mm] 240
Y-axis travel [mm] 260
X-axis travel [mm] 520

Thanx for looking.

Br,
Phillip

[MrBean_pm]

Math- and Theory time:
Having decided upon the DMM Servo/Drive setup, there are the question of running the smaller motors ratio'd, or the larger servos direct-coupled
(as an alternative, running the 900w motors through 1:1 pulleys=direct coupled).

Let's look at some numbers:

400W AC brushless servo motor (60EM-DHT-36)
Max 3000rpm
Rated torque: 1.27Nm(179 oz-in)
Peak torque: 3.6 Nm(507.6 oz-in)
Rotor Inertia: 0.7Kg-cm^2

Assuming a 5mm leadscrew (0.196")
For X and Y: 2:1 belt reduction will give 358 oz-in Rated and 1015 oz-in Peak at 1500 RPM, and 1500 RPM x .20" = 300ipm (to high in my opinion)

For Z: 2.667:1 belt reduction will give 477 oz-in Rated and 1354 oz-in Peak torque at
1125 RPM, and 1125 RPM x .196" = 220ipm (pretty much the theoretical max I would want anyway)

Multiply above oz-in values with 0.92 to get more realistic (read practical) oz-in numbers!

Let's see what this means in terms of load-mass these 400W servos can drive, assuming a 220ipm (and thus using the 2.667:1 pulleys):

220ipm/1125 RPM=0.196" per revolution, which equates to 0.4978cm per revolution.

Je (Equivalent Inertia) = M (Load Mass) * (L (Travel) / 2pi )^2

The 3.6Nm Motors have a Jr (Rotor Inertia) of 0.7 Kg-cm^2 and under normal CNC loads, Je/Jr<5. So Je<3.4

Thus: 3.4 = M*(0.4978 / (2*3.14) )^2

M = 541kg Load Mass /axis

Plenty much enough, what do you guys reckon?

There are standard 15t pulleys vs 40t that will give the desired ratios (2.667:1) on the 400W motors, which will take 1/2" shafts, and 3/8" belts - I will probably opt to run all 3 axis on 2.667:1 reduction, which will give ample (or still to much) torque, and max theoretical ipm I'm after.

See example from DMM in their email reply to me, which indicates the 900w motors wil be wayyyy overkill for this application, and why the experienced ones on here advise against using 'to' big motors - enough to move pretty heavy loads - much more than I would need.

If no better advice, I will order the 400w kit from DMM

Before do though, I will rerun calculations with the 300W motors too, just to see if I can bring the ipm to acceptable theoretical max limits for these benchtop-style machines, as well as dropping the max available torque down to safer levels too....keep you posted.

As always, Gents, appreciate your feedback.

Email from DMM -> The motor sizing sounds perfect with the direct drive 900W motors or 3:1 reduced 400W motors. All our motors are attributed with an extremely smooth S-curve so they can deliver full power/torque throughout the entire speed range. In fact, I think even the 400W motors reduced 2:1 will be powerful enough and you can also take advantage of the extra speed. As a sizing estimate, for example, our 900W AC Servo Motors have a peak speed of ~1000rpm

Assuming you want your machine to run rapids at ~300IPM

300IPM/1000RPM= 0.3 inches per revolution = 0.76 cm per revolution

Je (Equivalent Inertia) = M (Load Mass) * (L (Travel) / 2pi )^2

Our 7.2Nm Motors have a Jr (Rotor Inertia) of 2.05 Kg-cm^2 and under normal CNC loads, Je/Jr<5. So Je<10

10 = M*(0.76/ (2*3.14) )^2

M = 682kg

So our 900W servo motors can drive up to 682kg of load mass per axis according to these estimates. Between our 900W and 400W motors, it comes down to whether you need more speed or more power.