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I had wanted a CNC Rotary 4th Axis for a long time.
I kept thinking of all the possible things that I could experiment with on the thing: Making my own timing gears, spiral grooves, engraving on all sides of an object, True 3-D Machining, etc. etc.
Only one big problem - They're Not Cheap!!! Especially one of any quality and degree of accuracy and rigidity.
While at the Metro Detroit Metal Working Club - I mentioned this to my buddy Rick Chownyk (( aka "Rick-O-Matic" ))
Rick told me about one that he had made from a rotary 5C spin indexer that he used to some degree of success!
Well, that seemed like a heck of a good project - and a way to get more familiar with Mach3's capabilities - if nothing else.
The Rick-O-Matic loaned me his set-up, so that I could take it apart and reverse engineer it.
Not only did the Rick-O-Matic loan me his set-up, but he also GAVE me two (2) sets of timing gears and 2 belts!!! Another great reason to belong to the local metalworking group!!! :)
Therefore, all of the credit for this design and idea really has to go to the Rick-O-Matic, I merely tweaked and adjusted it to work with the components that I had on hand..
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Well, the 5C fixture that I had laying around was definitely of "far east" origin.
After taking the device apart - the face of the 5C fixture was not machined, but was "As-Cast" and painted.
This called for fly cutting the cast and painted surface smooth and square to the axis of the fixture. This is necessary to attach the mounting place to this surface, and it needs a bolt circle drilled and tapped, etc...
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There are several surfacing routines within Mach3 (( Wizards -> Pick Wizard -> ...)
I chose the "Surfacing with Tool Down in X" routine.
I used an old-fashioned fly-cutter with an insertable carbide tip lathe tool as the cutting tool.
Ahhh! That looks so much better!
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Next, I needed to find the center of the 5C Fixture's Spindle hole - to accurately machine a bolt circle to secure the mounting plate onto the 5C Fixture.
In Mach3- if you go under the Wizards -> "Pick Wizard" sub-menu option, you will find a Suite of free and very, very useful routines.
One of them is "Circle Center".
By picking up 3 points of the ID of the hole - Mach3 can compute the center of the hole! Just like the big boys in the real world do - but with much more expensive systems, software, and probes.
I didn't have a probe made up - YET (...and yet, another future project...)- and didn't want to stop and take the time to make one just now.
So - instead - I improvised....
Mach3 allows you to find the points by jogging the probe -or- entering them manually. I didn't have a probe - but I did have a digital voltmeter with an audible continuity function.
All I needed to do was to come up with a probe that was insulated from the machine, and touch off the 5C base with the probe...
...
After thinking about this for a bit, I wrapped a piece of electrical tape around the end of a piece of 3/16 " diameter drill rod, to electrically insulate it from the milling machine. Any circular piece of steel (or other conductive material) would work as well.
I secured one end of my digital voltmeter to that "probe", and the other end to the 5C spin Fixture.
By carefully manually jogging the machine - I could pick up the three (3) points of the ID - AND - Mach3 would compute the center !!!
I repeated the procedure after the wizard computed the center of the 5C spindle hole - and was shocked to see the displays barely move by 0.001 inch !
A quick check with the indicator - proved - the machine was dead-on center with the 5C Fixture's spindle hole!!!
This is extremely useful - and another great example of why Mach3 can't be beat !!!
...
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A few quick measurements with a set of digital calipers - gave me the information I needed to create the bolt circle..
Next, I created a simple 2D-DXF file in IntelliCAD - of the bolt circle.
Note: There is a Mach3 Bolt Circle Wizard - and I wished I would have tried this. Next time!
Next I loaded the .dxf file into V-carve, created the G-code file for drilling the bolt circle.
Then, I loaded the G-code into Mach3, set the Z-zero (X-Zero and Y-Zero had already been determined by Mach3) - and proceeded to center drill and drill the #10-24 pilot holes (The plate will be mounted to the 5C Spin Fixtures face via several #10-24 screws. The purpose behind drilling the bolt circle is to be able to rotate the drive mechanism out of the way - if needed.)
My buddy Gerry has a Mach3 screen set that once you have the probe hooked up to the BOB (Break Out Board) as an input - it will jog the machine automatically for you. Gerry's Mach3 screen set has a lot of improved wizards, too. More on Gerry's Mach3 2010 Screen Set later, but for now here's a Link to Gerry's Web Site.
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After center-drilling and pilot drilling the #10-24 tpi bolt circle holes, it was time to tap the holes.
I used my tapping stand to make sure that the holes were tapped true and not off on an angle.
Nothing special here - just a little elbow grease.
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After machining the 5C Spin Fixture's body - it was time to start work on the mounting plate.
I had some 0.375 inch thick 6061 aluminum stock laying around - so that's how I selected the base material. Clearly 0.25 inch thick material would have been sufficient - but I didn't have any...so........
I created the base drawing in IntelliCAD, and imported that into Vectrix's V-Carve software, and tool pathed it there for Annie (my SuperMax YCM-30 milling machine).
I aligned the vise up with the milling machine using an indicator, then used the mill to square off the end of the aluminum plate. This is a critical step - as this surface is the registration/datum surface from which all x measurements are taken, edges found, etc etc
I used a wiggler to locate the X-zero and Y-zero of the plate (( I really need to finish up my X-zero/Y-zero edge finder)).
After finding the edges with a wiggler - I reset the edges to account for one-half of the wiggler diameter (0.10 inches in this case).
After this -its a matter of loading the G-code for the mounting plate, setting the Z-Zero (((see my Z-Zero finder here))) and getting some metal chips flying!
It's a real joy to see Annie machining the aluminum, leaving a nice surface finish, and machining something useful to use, like the Rotary 4th axis.
It's times like this - that I'm really glad that Meko and I had spent the time on Annie and getting her upgraded. (more on her upgrade over here).
Ango Technology Corp.
25 Ewing Avenue
North Arlington, NJ 07031
Phone: 201-991-3300
Geckodrive, Inc.
14662 Franklin Ave.
Suite E
Tustin, CA 92780
Phone: 714-832-8874
Automation Technology Inc
2112 Stonington Ave
Hoffman Estates, IL 60169
