Messages

401

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: February 10, 2013, 03:01:25 AM »

all I can say is wow I have read the thread backward and forward. everything is unbelievably well documented  except the balancer it looks home built as well. I am very interested in the harmonic balancer  A spindle and some deep groove bearings have followed me hone. I have a large DC servo and made some sketches. I had not thought of the challenges of the software side of the equation.

That spindle looks perfect for a 4th axis project!

I am unclear if you have asked a specific question and also unclear if the software you are referring to is for the 4th axis or the balancer, so I will address both. First the controller:

The InTurn™ 4th axis motor controller is a fairly complex device in its current form. There are approx 3,500 lines of C code running on an Atmel processor. The controller has been thru one very major upgrade wherein the signal generation was moved off the processor to a separate digital signal synthesizer with MHz capability. I am holding the signal speed to 500KHz for practical reasons. The controller is about to go thru another fairly major update. This next update will not require any new hardware.

1) 'Manual' mode is gone. The existing speed dial and switches have been re-purposed and now provide real time variable speed for both set speed and autospeed modes.

2) The modbus comm to MACH3 has been changed from Serial Modbus to the newer serial plug-in modbus.   

3) The use of brains if much more extensive and replaces the use of the 'legacy' serial modbus register commands

4) Most of the code has been streamlined and optimised now and overall response time is improved for most functions, especially for E-stop.

There is no info posted on the new upgrade, but you can read the specs and see a video of the development and operation at www.theInTurn.com

The servo drive that you chose should have enable/disable capability. None of the hobby level drives have this so far as I know. The drive I recommend for DC is the Copley Accelnet. If you are accustomed to hobby level drive prices (Gecko, Dugong and the newer versions, Viper, Leadshine, etc), the cost of the Copley might seem quite high, but it is a commercial/industrial level drive and it priced competitively and actually far below the AC drives from Mitsubishi, Yaskawa, AB and so on.

402

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 05, 2013, 02:01:01 PM »

Feel free to call or e-mail if you need any help with the KFlop.  I'd also be happy to send you all my code as a starting point/educational tool.  I"m sure there's a lot there you could use, with straight-forward modifications.

THX, Ray.   Much appreciated, really.

I have the Kflop working with MACH  . .  well . . .  on my desk anyway. Took a bit to figure out how to get it to spit out a TTL step, but it's clicking along now. I though it had differential signals for some reason, but it does not seem to. No matter, I'll just throw line drivers on the outputs. There are some odd quirks that are probably caused by operator error   but I'll send you an e-mail about that. Not really germane to this thread.

Surprisingly, it seems to get along OK with 64bit Windoze 7 Pro . . .  so far.  It is going to live on XP and Win7 32 bit, but for now it's in my office.

403

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 05, 2013, 01:40:23 PM »

I think you've made the right choice re: rotating the head.  But how are you going to drive the Z axis if you fill the column?  Where will the ballscrew go?

I am not a fan of slotted columns. As an engineer, I'm sure you know what it does to the torsional rigidity of the structure.

When you have ball slides, the overall depth of the slide is (generally speaking) the space you have between the back of the head and the front of the column. The screw is in that space.

On this IH machine I will be mutilating, until I have my hands on it in a week or so, I won't know what is doable, but I can tell you for certain, the screw will not be inside the column, so if the owner wants to fill the column with something, he will have that option. At this moment in time, it looks like it will be treated to a Mitsu 350 series drive and motor for the spindle so filling the column might be a requirement in order to keep the head in the same county as the rest of the machine  

404

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 05, 2013, 06:03:37 AM »

Nice looking machine!  Had not seen this guy before.

The Kflop is here and I *might* have some minutes to play with it today. Initially, I just want to get it running with MACH and get rid of the smoothstepper, but I had in mind to run the ATC on it, or to it, or around it or whatever. But now Arduino has just come out with a new board with a much higher end processor that is almost a direct swap out for the MEGA board that I use in the InTurn™ motor controller, so I may go with that. The new processor is also Atmel and it similar to the processors on Atmel's industrial development boards, of which I have a couple. Up from 16 bit to 32 bit and up from 16mhz to 84mhz, DMA, native USB, blah blah blah. Couple comparos I've seen show 4x to 5x improvement. Just available in the last couple months. I have one on its way and I'll probably put my balancer software on it first, then the InTurn™ controller with the ATC code. Calculating the command params for the Digital Signal Synthesizer requires floating point math which really bogs down the MEGA.

An IH bench mill is being shipped to me today. It gets a conversion with ground ball screws and the new head along with ball slides on the Z.  Seems like a pretty nice machine. Owners like them. Very difficult to actually get one though, especially a manual version.

I wanted to mention that the new head will NOT rotate. Feedback I got here and elsewhere was all the same; nobody uses the rotating head and several people said it was actually a problem occasionally. Most likely the mount will be 12" x 12" x 1.25" surface ground plate with the slide bearings bolted to the back and the head to the front.

Finally, I have some data on a filled column vs cast iron, so I may be able to compare the two and satisfy myself that a steel tube full of epoxy or concrete is equal to (or better by some accounts) than grey cast iron.   'Course, now I have to start all over and build another head . . .

405

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 03:18:16 PM »

Ray,

Are you going to spill the beans about your new milling machine voluntarily, or do I have to send Carmine over to see you? 

406

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 12:40:46 PM »

 My new machine is a bed mill. 

OK, I can't take it any more!

WHAT machine are you getting?    Tell me or kill me . . .  either way . . stop the pain,  . . . please.

407

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 12:36:29 PM »

I also plan to have a macro that will automatically touch off all loaded tools (I can tell which slots are occupied, and which are not), and load the tool table automatically.  I think that will be a nice convenience, and time-saver.

This was my conclusion also, but it does not seem so easy to do, at least on BT30 where there are holders with very long 'noses' that could then have very long cutters in them. Conceivably the delta could be 6 or 8 inches from a short holder+short tool to an extended holder+long tool.  Seems like moving a touch-off pad (or laser) with a LOT of travel would be the only way to do it.

I spend much more time thinking about designs, and much less time actually building them. And, in most cases, they work almost perfectly on the first try. 

Well, my observation is that you built an entire ATC over quite a long period of time with prototype components that were later replaced with final design parts. Now you have designed an altogether different one which, as described, should be quite an improvement on the first. That process seems pretty normal to me . . . . . Just sayin' 

The more common approach I've seen far too often is to rush into construction, then spend months putting on "Band-Aids" for all the things that were not well thought out up-front, and you end up with something more complex, and expensive, than it needed to be. 

Seems you have discovered my secret method. Except that after about three band-aids, I scrap the whole idea and start over . .   

Favorite saying;

"Trip of thousand miles begin with one step"
 - Asian probably - don't know who  - circa:  long time ago

"Evrybody is incopetent, just at differnent things"
- Will Rogers maybe?  cira: some time before he died

"I cut it off three times and it is STILL too short"
- my mentor . . . .  explains a lot, huh 

408

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 11:52:53 AM »

Steve not all CNC bridgeports are rigid head. 

(;-)TP

I'm aware. But it seems to me that the machines with fixed heads were designed from the git-go to be CNC and the others are in the same population as the masses of other 'converted' manual knee mills.

In my view, a typical manual knee mill is just fundamentally the wrong arrangement for CNC. The fact that you can buy lots of differnet ones in CNC trim doesn't mean it is a good idea. So the question remains, for those mils that HAVE  rotatable, nodable, or otherwise adjustable heads, how much are these features actually used on a CNC mill . . if at all. 

409

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 07:08:10 AM »

On My ATC the carousel is the C axis. I jog the axis and load the tools by hand and then do  MDI sending the C to 0 which is tool 1. I started doing it this way until I could do a custom screen set but found it was easy to do so I'll probably continue to use this method.

I don't have a tool setter on the mill. I have one on the router and it's quite accurate. On the mill it's no big deal for me to touch off manually in one way or another so I'll probably stick with that. The BT30 seems to have good repeatability so I don't envision me ever touching off after every tool change.

Just finished a run of 380 pieces. More than 400 tool changes over a 6 day period without a single miss. Without a doubt the ATC has been some of the best time and money I've spent on the mill since the original conversion. The newness has worn off and I don't even pay any attention to it anymore. It just chugs along making me money!

Derek

Good info. Thanks, Derek!

410

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: February 04, 2013, 07:04:28 AM »

Question on rotating mill head::

I have noted that Bridgeport's CNC mill has a non rotating head as does the Smithy CNC bench mill and others. Years ago when I had a shop with manual mills it was not uncommon to have the heads turned this way and that, but I have yet to ever rotate the head on any of my CNC mills.

Unless the rotation is actually an axis under CNC control, I have some difficulty seeing a justification for it.  While I think it would be beneficial to build in some kind of tramming 'assist', I am leaning toward having the head NOT rotate, per se. 

Thoughts on this?


Thanks in advance,