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Author Topic: Success! Mini Machining Center under Mach3 control - Video link  (Read 331565 times)

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Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #230 on: March 19, 2012, 05:46:20 AM »
Finally, the last piece of the puzzle; a comprehensive motor controller specifically designed to take advantage of the 4ths axis Indexing and Turning capabilities.

Check out the YouTube video - link here: http://www.youtube.com/watch?v=vBLuF_F2_qs

This new motor control took 200 hours to develop and is a complete system consisting of the control box seen in the photo below, 15 or so 'control' macros, another 20 or so embedded macros ('M' macros to embed in G-Code) a Mach brain program, and a set of custom Mach screens.

The controller has its own PLC and generates its own step and direction signals independent of Mach, but it is also tied into Mach to retrieve and deliver data for two separate speed modes and also retains all normal indexing 'A' axis functionality.

My favorite feature (other than being able to control the 4th axis with screen clicks instead of manually entering macros into the MDI) is what I call 'AutoSpeed'. This mode monitors the distance from center of the cutting tool on either the Z or Y axis and automatically calculates the 4th axis spindle RPM to maintain a specified SFM. A significant portion of the 200 hours of development time went into creating this mode.

Over 2,000 lines of C code run on the internal PLC and the controller is connected to Mach thru ModBus. The PLC can also communicate using Modbus Ethernet, but that version of ModBus lacks some features that I need for certain operations, so I had to stay with the slower interface.






Offline Vogavt

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #231 on: June 19, 2012, 02:12:00 PM »

It is a Honeywell model HOA 1887-012

I now have these on all of my machine axis and also on the 4th axis and they will be used on the commercial verison of the 4th axis as well. You simply need a 100 to 150 ohm resistor on the 5V that feeds the LED (red wire) You can use 5V or up to 30V for the trigger side.


@ simpson36 (or others)
Can you be a little more descriptive of your wiring scheme? There are more wires attached than what you describe. And with me being eletronics challenged and I frequently blow things up when I don't know what I'm doing.

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #232 on: June 21, 2012, 10:31:38 PM »
I *think* you are talking about the sensor?

If so, then I think a description of how it works is better than a simple 'hook wire A to terminal B' type of answer.

These type of sensors are quite simple. They work by shining a light at a photosensitive 'receiver', which is just a switch that turns on when you shine a light on it.  Note that the light is in a range not visible to humans.

The light source is on one side and the 'switch' on the other side. Between those goes your shutter wheel, a tab on your mill table. etc. This breaks the bean and turns off the switch. When you remove the obstruction, be it a tab attached to your table or a hole or slot in a shutter wheel, then the light reaches the switch and it turns on. That's all there is to it.

So you have a power and ground on the light source side (sometimes, but not always red and black). You have to obey the rules on this as you would with any other LED. You MUST restrict the current to a level that is tollerated by the LED or you will burn it out. In the case of the referenced sensor, if you feed it with 5V, then you need between 100 and 150 ohms resistor in the wire to 'slow down' the juice to a level that keeps the LED healthy. This resistor can be anywhere  in either the positive or negative wire and the value is not super critical.

The receiver side has sometimes (but not always) a green and a white wire. Since the device burried in the sensor and attached to these wires is just a switch, you don't need to be so careful. If you are only feedijg a pin on a BOB, just do not exceed the sensor's volatge spec and you are pretty much golden. The switch does have polarity, meaning that the power will only flow in one direction, so if you get it hooked up backwards, it won't work. Good news is it probably won't be damaged so just reverse the wires.

TIP: with the light side powered up and no obstruction, the switch should be ON. You can check this with an ohmmeter, continuty tester, etc. Put the probes on each way and you will get continuity  in one direction and not the other so you will be able to see which way to hook it up. A catalog cut (spec sheet, data sheet, etc) also will define which wires are for what purpose.

Hope this helps.

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #233 on: June 23, 2012, 05:12:29 AM »
HARD TAPPING!!    Finally, I got some time together and added the last few parts to convert the mill spindle to full servo power. this opens up a lot of possibilities, but for now, I am basking in the hard tapping capability. I despise tapping. I have TapMatic heads, and Custom made floating tap holders and a reversing manual speed control on the mill spindle . .  which makes thing go faster and with a lot less effort, but it still requires an operator full time to . . operate.

No more . . .    This video is a 'by request' to overview the concept of parametrics, but the new servo driven spindle is the perfect vehicle to demonstrate some basic functions:

http://www.youtube.com/watch?v=Cu61oBY5-rw

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #234 on: July 13, 2012, 10:06:46 AM »
The 4th axis is getting a new custom designed and built spindle. The motivation for launching into this prokect was three fold;

1) need for strong, safe, standard chuck mounting for large chucks.

2) larger size to allow the frame to be lengthened and eliminate the cantilevered main drive pulley mount.

3) consistency and precision.

When I have more time, I will try to do a blog on the build but for now here are just a few photos of the finished spindle. I am currently building a new prototype 4th axis to house this new spindle. The spindle nose is 'universal in that it can mount standard D1-4 and also A or B style chucks.

Photo 1 compares the new spindle to the previous. The nose and front bearing surfaces are ground, hoever, both the Chuck mount and 5C tapers as well as the face of the flange will all be ground in-place after the machine is assembled and under its own power. This will provide for the runout that equale the bearing spec. The new spindle also can accomodate ABEC7 angular contact pairs for a high precision option.



Photo 2 shows the 'universal' mount. Note the cam loc parts and also the threaded inserts. More on this later.



Photo 3 shows the new spindle on the balancer . .  which needed some modifications to hold the new spindle.

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #235 on: July 21, 2012, 08:28:07 AM »
Drive parts are completed. Some more pics:

First photo shows the monster main drive pulley. Big pile of aluminum after making this guy.



Motor extension is needed to hold dual pulleys. In this case, the small pulley and the shaft are made from a single piece of steel. I am using a clamp collar in this design and there are still set screws just for redundancy. While very robust, I think it will be difficult to balance this arrangement, so it may not make it past prototype. The ratty looking larger aluminum pulley is carried over from the current prototype.



The new counter shaft is heavier and is also made from a single pice of steel for the shaft and small pulley. The bearing case is a stock item from the previous design, just put in here to show the components. A new casing with built in belt tracking adjustment will be used on the new 4th axis.

Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #236 on: July 23, 2012, 08:38:43 PM »
Thank you very much for taking the time to share.  You have built quite a 4th axis!  How does your balancer work?  I will have a few projects coming up soon that I will need to balance electric motor shafts.

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #237 on: July 24, 2012, 01:57:31 AM »
The balancer duplicates the functions of a commercial balancer. The end support are free to swing on ball bearing fulcrums and an accelerometer measures the movements imparted by imbalance. On one end is an absolute encoder which provides azimuth data so that the exact position of the imbalance is known.

A little PLC collects the data in real time and then sends the data to the computer via USB where it is analyzed by a separate Windows program.  The data is checked for validity and then reduced to a specific relative imbalance 'severity' number and the azimuth of the imabalance. Dynamic balancers are potentially dangerous machines and you may notice the nylon wire ties which are just for safety in case the part being balanced decides to try to become 'free to move about the cabin'. For liability reasons, I do not sell balancers nor share any technical information about them. I was quoted between US$150 and 200 per spindle to do the balance, and the cheapest used (and working) industrial balancer I could find was about US$35,000 so it was worth my while to build one for my own use.

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #238 on: July 24, 2012, 02:30:28 AM »
Couple more photos:

The meet spec for precision bearings, a new method for machining the 4th axis frames is shown here.  

The frame uprights are bolted to the fixture (here a 6" chuck and later will be a 12" face plate), indicated and the top and bottom faces trimmed parallel to the centerline. The frame is then assembled and torqued in-place on the fixture. A heavy steel (.875" thick) top plate is installed to stabilize the frame uprights and provide a good balance for the spinning frame. The top plate is later removed and replaced with the permanent .160" 7075 aluminum top cover.

With the assembled frame in the fixture, the base is faced to be perfectly parallel to the centerline.



The pre-roughed bearing pockets are then line bored first the rear bearing:



And lastly the front bearing pocket is brought to size. The image is captured from a video so the quality is not great. When I have time, I will do a blog and/or video on the entire new machine including the new spindle and the new frame.


« Last Edit: July 24, 2012, 02:45:24 AM by simpson36 »

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #239 on: August 04, 2012, 07:32:55 PM »
Project is just about completed. This new machine will be operational in a day or two and the current 4th axis prototype is now for sale if anyone is interested. It is the machine making the parts for this new prototype and in the latest videos. PM me for details.

A couple of interesting componenets are the belt tracking adjuster built into the counter shaft housing. The housing is mounted via a ball socket and can be angled a couple of degrees by alternate tightening of the flange bolts to effect belt tracking.



Looks like this assembled:



Balanced main drive pulley and hub. Note the drilled holes in the hub for balancing. In this close up, you can see the super straight teeth afforded by the spindle lock.



Some 'undressed' shots of the finished new 4th axis are next. The new 'Mega' 4th axis has pretty covers with the name imprinted on them, but I do not have photos of that yet.